Articles in press have been peer-reviewed and accepted, which are not yet assigned to volumes /issues, but are citable by Digital Object Identifier (DOI).
Effect of water on the mechanical performance of OSB in compression tests
CHEN Chaoyi, LI Wanzhao, MEI Changtong, HUANG Helang
doi: 10.11833/j.issn.2095-0756.20210291
[Abstract](12) [HTML](2) [PDF](2)
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  Objective  Oriented strand board (OSB) is an environmental- and eco-friendly material produced with renewable, mainly fresh wood from logs with either small or large diameter logs. Composed of cross-oriented layers consisting of thin and rectangular wooden flakes or strands that are compressed and bonded together with synthetic resins, it is an important engineered wood product widely applied in load bearing situations and its mechanical performance is largely dependent on the moisture content (MC) and water sorption/desorption. Therefore, with an investigation of the compressive strength (CS) of samples at different MC and water sorption/desorption cycles, this study is aimed to research the effect of water on mechanical performances of OSB.   Method  With samples selected from two types of OSB panels with different thicknesses, conditioned to three different MCs and treated with multiple water sorption/desorption cycles, supervision was conducted of the dimensional changes, CS and strain distribution of samples were monitored. Then the CS was measured using an Instron universal testing machine with the strain distribution recorded using digital image correlation (DIC) simultaneously.   Result  (1) An increase in both MC and water sorption/desorption cycle could lead to an increase in thickness and compressive deformation; (2) The CS of the samples was significantly decreased when they were conditioned with a relative humidity of 95% and a MC of approximately 20%; (3) High MC could reduce the final thickness of OSB after compressing whereas water sorption/desorption cycles could slightly decrease the final thickness of OSB after compressing; (4) High MC and multiple water sorption/desorption cycles were able to change the relationship between CS and displacement from two domains linear to almost linear which attributed to the disappearance of the samples’ plastic deformation domain; (5) High MC can soften wood strands and enlarge internal voids, which could lead to strain increase and the change of strain distribution profile while water sorption/desorption cycles degraded the internal structure of samples and (6) Water sorption/desorption cycles might cause compression strain accumulation in surface layers.   Conclusion  Water affects the CS of OSB in various aspects including the softening of wood strands, enlargement of voids among wood strands, diminishing of trapped stress from hot-pressing with different MCs. Such findings will help with the generation of effective manufacturing strategies that aim at good mechanical performance of OSB at different water conditions as well as optimizing the application methods and extending the application fields of OSB. [Ch, 7 fig. 1 tab. 23 ref.]
Spatial distribution characteristics of soil hydrolase activities and soil fertility evaluation of Carya cathayensis forests in Lin’an District
XIE Linfeng, LING Xiaoxiao, HUANG Shengyan, GAO Haozhan, WU Jiasen, CHEN Junhui, HUANG Jianqin, QIN Hua
doi: 10.11833/j.issn.2095-0756.20210417
[Abstract](23) [HTML](2) [PDF](2)
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  Objective  This study aims to explore the spatial distribution characteristics of soil hydrolase activity and soil fertility in Caya cathayensis forests.  Method  259 sample plots were selected from the main C. cathayensis producing areas in Lin’an District of Hangzhou City, Zhejiang Province to determine the main fertility indicators and the activities of 7 hydrolases such as α-glucosidase(AG), β-glucosidase(BG), cellobiosidase(CBH), xylosidase(XYL), leucine amino peptidase(LAP), N-acetyl-glucosaminidase(NAG), and acid phosphatase(PHOS). Principal component analysis, geostatistical analysis, pearson correlation analysis, and redundancy analysis were used to analyze the soil fertility as well as the spatial variation of 7 hydrolase activities and their influencing factors.  Result  The spacial structure ratios [C0/(C+C0) ]of AG, BG, CBH, LAP, NAG, XYL, and PHOS were 55%, 42%, 56%, 49%, 66%, 47% and 78% respectively, and the global Morans’I (Ig) was greater than 0. Available N, available P, available K, and organic matter in the rich soil accounted for 64%, 56%, 23% and 45%, respectively, and the average pH was 5.76. The soil fertility of 58.7% of the sample plots was below average. Most of the C. cathayensis plots were in level Ⅲ and Ⅳ, while only 32.7% of the plots were in levelⅠand Ⅱ.   Conclusion  Among the 7 soil hydrolases, AG, BG, CBH, LAP, NAG, and XYL have moderate spatial autocorrelation, and their variation is jointly affected by human interference and topographic structure factors. PHOS has weak spatial autocorrelation, and its spatial distribution is mainly affected by human interference. The activities of 7 hydrolases have spatial correlations and similar high and low clustering. High value aggregation occurs near Daoshi town while low value clustering occurs near Qingliangfeng town and the boundary of Heqiao, Longgang and Changhua towns. Soil pH, organic matter and available N are the key factors affecting the high and low value clustering of hydrolase activity. The results of soil fertility index classification and comprehensive fertility score show that most soil nutrients are sufficient to support the normal growth of C. cathayensis forests, but the comprehensive fertility needs to be improved. [Ch, 3 fig. 5 tab. 32 ref.]
Vertical distribution pattern of vegetation on the east and west slopes of Cangshan Mountain in Dali
ZHANG Ping, ZHANG Jun, LI Jiayu, XUE Yufei, LI Yuchen
doi: 10.11833/j.issn.2095-0756.20220136
[Abstract](20) [HTML](10) [PDF](0)
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  Objective  The purpose is to analyze the change characteristics of vertical distribution pattern of vegetation on the east and west slopes of Cangshan Mountain in Dali, Yunnan Province, so as to provide reference for effective protection of ecological environment and species diversity of Cangshan Mountain.   Method  Taking Cangshan Mountain in Dali as the study area, based on GF-2 high-resolution remote sensing images, combined with the complete vertical zonal distribution law of mountain vegetation in Cangshan Mountain, and supplemented by texture features and digital elevation model (DEM) data, the object-oriented multi-level image segmentation method was adopted by constructing terrain constraint factors to participate in the classification process, accurately select samples, and extract vegetation information in the study area with high precision, and analyze the vertical distribution pattern of vegetation on the east and west slopes of Cangshan Mountain.   Result  (1) The vegetation types extracted by the object-oriented classification method with auxiliary information were continuous and effective, and the overall classification accuracy was 95.3%, and Kappa coefficient was 0.946 6. (2) The current vegetation vertical distribution pattern on the east and west slopes of Cangshan Mountain is obvious, each of which has six vertical distribution zones. With the increase of altitude, the convergence of vegetation distribution types increases, but there are some differences between the dominant vegetation types in the spectrum of the vertical bands on the east and west slopes.  Conclusion  Compared with the traditional subjective classification method, the terrain constraint factor with vertical band spectrum information can effectively improve the accuracy of mountain vegetation classification, which fully shows that the object-oriented multi-level segmentation method is suitable for the accurate extraction of vegetation information in Cangshan Mountain. [Ch, 5 fig. 3 tab. 22 ref.]
Change in the basis of ecological compensation for key public welfare forests from area to volume
HUANG Yingli, GUAN Ying, QIN Huiyan
doi: 10.11833/j.issn.2095-0756.20220148
[Abstract](20) [HTML](12) [PDF](0)
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  Objective  With an exploration of the importance, difficulties and focus of the transformation from “forest area” to “forest stock volume” as the index for the ecological compensation in key public welfare forests, this study is aimed to provide theoretical and technical references for the such transformation in China.   Method  A three-dimensional comparative analysis of the two ecological compensation bases in key public welfare forests that involve the realization of the compensation target, the incentive of the compensation subjects and the sustainability of the compensation fund.   Result  Compared with “forest area”, “forest stock volume” is a more accurate index in the actualization of the compensation goal and displays unique advantages in terms of incentives and marketization.   Conclusion  In the formulation of the ecological compensation for key public welfare forests, the the increase in forest stock volume should be the basis of the compensation and regional differences should be fully considered to ensure the execution of differentiated policies. In addition, further explores should be conducted of market-based compensation schemes based on forest stock, with full play given to the market’s efficient regulation and distribution of compensation funds. [Ch, 4 fig. 29 ref.]
Root formation and anatomical structure of Ilex × altaclerensis ‘Belgica Aurea’ stem cuttings
ZHU Xiaoyu, TONG Wanwan, ZHAO Chu, TIAN Runan
doi: 10.11833/j.issn.2095-0756.20210283
[Abstract](24) [HTML](13) [PDF](3)
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  Objective  This study, with an investigation of the effects of type and concentration of plant growth regulators, soaking time and substrate type on the rootability and adventitious root development of Ilex. × altaclerensis ‘Belgica Aurea’ cuttings, is aimed to provide a theoretical and practical basis for the softwood propagation, introduction and domestication of Ilex.   Method  With the semi-lignified stems of I. × altaclerensis ‘Belgica Aurea’, selected as the propagation materials, an orthogonal experimental design of three factors (type and concentration of plant growth regulators, soaking time, and type of substrate) of three levels was applied to research the plant softwood cutting propagation with an investigation of the survival rate, rooting rate, length of longest primary adventitious root and root effect index of the cuttings with various treatments after 80 days since cutting. In addition, NAA was used to promote the root formation of the cutting, with observations made of the external morphological changes of the cuttings. Besides, observations were made of the anatomical structure of the cuttings via the paraffin sections regularly produced with the base of the cuttings. Then, morphological and cytological observations were made of the callus with the scanning electron microscope and transmission electron microscope.   Result  (1) The cuttings soaked in 1 000 mg·L−1 IBA solution for 10 s had a best rootability with significant difference in related index from the other treatments (P<0.01) with an increase of 12.74%−48.83% in the rooting rate. (2) There was no latent root primordia in the cuttings and anatomical observations showed that the plant was considered as bark inductive root formation type with the adventitious root primordia originating from the intersection of pith ray and vascular cambium. (3) The low rooting rate attributed to the 1 or 2 layers of annular sclerenchyma between the cortex and phloem. (4) No root primordia was observed in the callus, whose formation was independent of the adventitious root development, and rooting was not the final result of callus development. (5) There were two types callus types in the rooting process of the cuttings: embryonic callus and non-embryogenic callus. The former were white and closely arranged with the surface cells clustered and distributed in a smaller size, the nuclei being large and the organelles being abundant. The latter were dark yellow with obvious vacuolation and most of the surface cells were not plump or even dead without any organelles observed.   Conclusion  In conclusion, this study has initially screened out the best factor combination for I. × altaclerensis ‘Belgica Aurea’ cuttings, revealed its cutting rooting mechanism. [Ch, 4 fig. 3 tab. 34 ref.]
Segmentation of wood cross-section pores based on improved K-means clustering and watershed
CHENG Yuzhi, ZHONG Lihui, HE Xin, WANG Yuan, LI Chaolan
doi: 10.11833/j.issn.2095-0756.20210219
[Abstract](7) [HTML](4) [PDF](0)
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  Objective  Pore is one of the important characteristics of wood identification. Aiming at the problems of poor robustness of pore segmentation due to random distribution and different sizes of pores and the impact of noise such as wood fiber, wood ray and axial parenchyma on the segmentation effect of pores, this study attempts to propose an improved K-means clustering and watershed algorithm for segmentation of wood cross-section pores.  Method  The improved K-means clustering was used to segment the pore area, which could distinguish the pore area from noise areas such as wood fiber, wood ray and axial parenchyma. Then, an improved watershed algorithm was used to segment the rough segmentation results, and the segmented pores were basically consistent with the actual pores.   Result  On average, 97.1% of the pores were segmented in each microscopic image of wood cross section. Compared with other algorithms, the improved algorithm had a significantly improved segmentation effect, high robustness and good segmentation performance in the process of pore segmentation with different sizes and random distribution.  Conclusion  This algorithm can effectively solve the problems of noise impact and randomness of initial clustering center in traditional K-means clustering algorithm in image segmentation, and lays a solid foundation for the feature extraction and quantitative analysis of hardwood pores. [Ch, 7 fig. 16 ref.]
Research progress on ecological function and construction technology of riparian vegetation buffer strips in the Yangtze River Basin
HU Haibo, DENG Wenbin, WANG Xia
doi: 10.11833/j.issn.2095-0756.20210201
[Abstract](23) [HTML](6) [PDF](1)
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The riparian vegetation buffer strip in the Yangtze River Basin is an important part of the riparian ecosystem and has an important impact on pollution prevention and ecological environment construction in the Yangtze River Basin. The paper summarized the main ecological functions of the riparian vegetation buffer strips, analyzed the environmental impact factors faced by the riparian vegetation buffer strips in the Yangtze River Basin, expounded the construction technology of the riparian vegetation buffer strips, and proposed prospects for future research. The main ecological functions of the riparian vegetation buffer strips were flood mitigation and revetment, sewage interception and purification, and biological diversity protection. At present, the main influencing factors facing the riparian vegetation buffer strips in the Yangtze River Basin were the invasion of alien species, the construction of a large number of hard engineering projects, and pollutant emission caused by agricultural and industrial development. The construction technology of the riparian vegetation buffer strips in the Yangtze River Basin should be determined according to the characteristics and functions of different riparian strips, and the management of the riparian vegetation buffer strips should be strengthened. Future research should focus on the following aspects: (1) Research on the process and mechanism of the shading effect of riparian vegetation buffer strips. Based on the research results of the shading effect, the advantages and disadvantages of shading and the relationship between shading effect and buffering extreme climate are discussed. (2) Ecological function research under extreme climatic conditions. Models are used to simulate the interception and pollution reduction effects of riparian vegetation buffer strips under extreme climatic conditions (rainstorm, drought, etc.), so as to provide a reference for the construction of vegetation buffer strips. (3) Landscape and watershed scale study. With the help of remote sensing images and data from various meteorological stations, the impact of natural and human activities on the ecological processes and ecological functions of the riparian vegetation buffer strips is studied from landscape and watershed scale in order to explore the comprehensive treatment and management model of riparian vegetation buffer strips. (4) Establishment of a comprehensive evaluation system for the vegetation buffer strips. The structure and ecological function of the riparian vegetation buffer strips are comprehensively evaluated by real-time monitoring of the riparian vegetation buffer strips with the help of digital means, combined with field observation and sample analysis. [Ch, 43 ref.]
Differences in feeding and oviposition behavior of different populations of Batocera horsfieldi
ZHENG Kaiwen, WU Shouxin, ZHANG Dongyong, WU Jiahao, DU Yongbin, FAN Jianting
doi: 10.11833/j.issn.2095-0756.20210366
[Abstract](15) [HTML](4) [PDF](1)
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  Objective  This study aims to explore the adaptability of different populations of Batocera horsfieldi to host plants.   Method  Through indoor feeding and oviposition experiments, the difference of feeding and oviposition behaviors between B. horsfieldi in Yuyao and that in Lin’an to four host plants were measured.   Result  The feeding experiment showed that Yuyao population and Lin’an population had different feeding preference for four host plants. The feeding preference of Yuyao population in descending order was Pistacia chinensis, Ligustrum lucidum, Fraxinus chinensis and Populus lasiocarpa. Yuyao population liked P. chinensis best. Under selective and non-selective conditions, the food intake was (1 520.00±34.79) and (1 815.50±42.13) mm2. The feeding preference order of Lin’an population was L. lucidum, P. chinensis, F. chinensis and P. lasiocarpa from high to low. Lin’an population liked L. lucidum best. Under selective and non-selective conditions, the food intake was (1 347.33±51.95) and (1 173.00±75.54) mm2. Yuyao population and Lin’an population showed consistent oviposition preference for four host plants, and they all liked to oviposit on P. lasiocarpa. The oviposition preference order of Yuyao population was P. lasiocarpa, L. lucidum, P. chinensis and F. chinensis from high to low. Under selective and non-selective conditions, the number of grooves on P. lasiocarpa was 72.00±5.87 and 82.00±7.64, and the number of eggs was 60.00±6.19 and 58.00±5.66, respectively. The oviposition preference order of Lin’an population was P. lasiocarpa, L. lucidum, F. chinensis and P. chinensis from high to low. Under selective and non-selective conditions, the number of grooves on P. lasiocarpa was 35.00±5.22 and 30.00±3.85, and the number of eggs was 22.00±4.51 and 25.00±3.08, respectively.   Conclusion  In order to adapt to different habitat environments, different populations of B. horsfieldi have different feeding preference hosts. Yuyao population prefers to feed on P. chinensis, while Lin’an population prefers to feed on L. lucidum. P. lasiocarpa is the oviposition preference host of both populations. [Ch, 3 fig. 23 ref.]
Dynamic simulation of landscape ecological risk in mountain towns based on PLUS Model
LI Chen, GAO Binpin, WU Yingmei, ZHENG Kejun, WU Yan
doi: 10.11833/j.issn.2095-0756.20210237
[Abstract](37) [HTML](9) [PDF](3)
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  Objective  With an exploration of the spatiotemporal evolution characteristics of landscape ecological risks in key mountainous development zones as well as the the simulation and prediction of the changing trends of landscape ecological risks, this study is aimed to provide support for the alleviation of the conflicts between ecological protection and construction, so as to promote the sustainable use of land resources, giving full play to the regional central function and furthering the high-quality regional development in small and medium-sized towns.  Method  Based on the land cover data of 2000, 2010, and 2020, a model of risk assessment on landscape ecology was constructed on the basis of the landscape index to examine the spatiotemporal variations of landscape ecological risk in Anning in Yunnan Province. Then, a prediction was made of the spatial distribution characteristics and trends of landscape ecological risks in different contexts in Anning in 2030 employing the PLUS model which was improved from the FLUS model.  Result  Results showed that a) from 2000 to 2020, the area of artificial surfaces in the study area showed an upward trend, while the area of cultivated land, grassland, shrubland and water bodies showed a downward trend, with the area of forest land staying relatively stable; b) the spatial agglomeration state of landscape ecological risk values was significant, yet with its degree on the decline and the landscape ecological risk was mainly at medium and high levels in Anning taking up 59.76%~52.95% of the total area and c) under the ecological protection scenario in 2030, the area of high ecological risk zone will be the smallest deterioration zone taking up an even smaller share while the area of low ecological risk zone will be the largest.  Conclusion  The contradiction between ecological risk control and the construction of small and medium-sized towns in mountainous areas was obvious. The spatiotemporal distribution characteristics of landscape ecological risks were closely related to the intensity of human activity intervention, and the higher ecological risk regions were mainly distributed in the fringes of the urban areas. Therefore, focus should be laid on the dynamic changes in the structure of landscape types and their ecological risks as a result of urban land expansion. It was also found that the spatial distribution characteristics and change trends of landscape ecological risk under the ecological protection scenario are closer to the optimization path of ecological security pattern and this scenario is more consistent with the high-quality development of regional economy and society in Anning. [Ch, 5 fig. 5 tab. 30 ref.]
Research on vitality characteristics of riverside landscape belt of Shangtang River in Hangzhou based on tourist behavior
WU Jingting, WU Xiaohua, WANG Tianyu, XU Bin
doi: 10.11833/j.issn.2095-0756.20210352
[Abstract](19) [HTML](12) [PDF](3)
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  Objective  With a history of thousands of years, the Shangtang River in Hangzhou is facing the challenge of insufficient vitality. The purpose of this study is to explore the vitality characteristics of the riverside landscape belt of the Shangtang River, so as to provide research support for activating the spatial vitality of the riverside landscape belt of the canal city.  Method  The landscape space of 8 sample plots [Chengbei Sports Park (A1), Dongxinmen Square (A2), Yongfeng Park (A3), Wangchen Park (A4), Shuiluyuan Site (A5), Qiantaoyuan (A6), Tiandu Park (A7), and Xiyangqiao Park (A8)] in the first-level buffer zone of the Shangtang River were taken as the research objects, and the vitality characteristics of the riverside landscape belt were investigated by behavioral annotation method. The cluster analysis and kernel density estimation (KDE) were used to analyze the survey results.  Result  (1)From the population dimension, the order of population diversity indicators from large to small were A3 A6, A1, A7, A5, A2, A8, and A4, and the behavior diversity from large to small was A6, A7, A5, A2, A1, A8, A3, and A4. The main reason lied in that the waterfront space of A3 and A6 was more diverse and complex, and historical and cultural sites and landscape facilities attracted people to carry out spontaneous activities. (2)From time dimension, the fluctuation coefficients of crowd activities from large to small were A6, A7, A2, A5, A3, A1, A8, and A4. The number of people with activity duration longer than 30 minutes was A6, A1, A8, A2, A3, A7, A5, and A4 in descending order. The main reason was that there were riverside night scenes, cultural activities and perfect supporting facilities in A6 and A1, which attracted people to extend their stay. (3)From spatial dimension, the activity intensity was A6, A1, A3, A7, A2, A5, A8, and A4 in descending order, and the crowd density per unit time period from high to low was A1, A2, A6, A3, A5, A7, A8, and A4. The main reason was that the spatial distribution of the population would be affected by internal and external factors such as spatial boundary, spatial activity area, sense of spatial enclosure, nature of surrounding land, and surrounding population density.   Conclusion  Constructing composite riverside landscape, promoting the integration of multiple spatial functions, tapping the source of landscape and cultural scenery, adding landscape installation sketches, improving infrastructure, creating a vibrant waterfront nightscape, and holding cultural interactive activities are effective measures to enhance the vitality of the riverside landscape belt of the Shangtang River. [Ch, 6 fig. 2 tab. 20 ref.]
Analysis on the distribution pattern and the environmental relationship of natural shrub-grassland communities in the lower section of Lüzhi River
GUI Weifeng, WEN Qingzhong
doi: 10.11833/j.issn.2095-0756.20210197
[Abstract](34) [HTML](7) [PDF](0)
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  Objective  With an investigation of the distribution patterns of shrub-grassland communities as well as their relationships with the environment in the same geographical unit in the lower section of Lüzhi basin, this study is aimed to explore the formation mechanism of community distribution and then to find out the important pinch point of ecosystem restoration in dry-hot valley area so as to propose methods of systematical restoration and comprehensive management.  Method  Two-way indicator species analysis (TWINSPAN) and Principle component analysis (PCA) were employed to classify shrub-grassland communities before a proper analysis was conducted of the relationship between the shrub-grassland communities and the environment on the basis of the forest resources investigation data of the shrub-grassland community in the lower section of Lüzhi River in Eshan County.  Result  The 854 patches were divided into 19 association groups and 65 associations using the TWINSPAN method. In terms of the PCA ordination, the first axis demonstrated the changes in soil depth, rainfall interception and water holding capacity, while the second axis demonstrated the changes in dry, and heat ranges. Under the vertical climate gradient, the richness of shrub-grassland communities was presented in the following pattern: subtropical plateau zone>dry-hot valley zone>south temperate middle mountain zone. Each vertical climate zone was featured with respective typical indicator types of shrub-grassland community and. In the areas with high disturbance intensity, the main distribution patterns were Osteomeles schwerinae, Symplocos sumuntia, Quercus spp., and Rhododendron simsii.   Conclusion  Habitat filtering and human disturbance are the main formation mechanisms of shrub-grassland community distribution and with an analysis of the distribution of natural shrub-grassland communities in the same geographical unit, the ecological amplitude and the optimal living areas of species populations can be found, which can provide the selections of native tree species for ecological restoration in the dry-hot valley area. Also, the main ecological stresses on the species in the ecosystem can be confirmed in accordance with the relationship between association groups and the environment, thus providing basis and support for systematical restoration and comprehensive management. [Ch, 3 fig. 4 tab. 34 ref.]
Relationships among water transport, mechanical strength and anatomical structure in branche and root xylem of Cupressaceae species
CHEN Sen, LU Shitong, LI Yan, XIE Jiangbo, YE Linfeng, WANG Zhongyuan
doi: 10.11833/j.issn.2095-0756.20210248
[Abstract](19) [HTML](7) [PDF](1)
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  Objective  This study, with Sequoia sempervirens, Taxodium distichum and T. distichum var. imbricatum in humid regions selected as subjects, is aimed at an analysis of the quantitative relationships among the water transport, anatomical structure, and mechanical strength of the xylem of the branches and roots of the Cupressaceae species and a discussion of the trade-off between the anatomy and function of the xylem at the organ and cross-species levels.  Method  Targeting the S. sempervirens, T. distichum and T. distichum var. imbricatum grown in Mount Tianmu, Zhejiang Province, with air injection method employed, efforts were made to measure the specific sapwood conductivity (Ks) and cavitation resistance (P50) before the indexes regarding the water transport such as tracheid wall thickness (Tt), pit membrane area (Apm), pit aperture area (Apa), pit membrane diameter (Pd), pit aperture diameter (Ad), hydraulic diameter (Dh)、tracheid density (Nt), aperture opening ratio (Rap) and pit density (Npm) were measured and calculated. Then, the wood density (Dw) and thickness-to-span ratio (Ttob) related to mechanical strength were calculated. Finally, an analysis was conducted of the correlation between water transport and anatomical structure.  Result  The roots demonstrated higher hydraulic conductivity yet weaker cavitation resistance than the branches and Ks in branches of S. sempervirens and T. distichum, and roots of S. sempervirens, T. distichum and T. distichum var. imbricatum was positively correlated with P50, while Ks in branches of T. distichum was slightly negatively correlated with P50 (R2=0.03, P=0.35), showing no efficient-safety trade-off at the organ level. The relationship between Ks and P50 followed a power function with an exponent of −2.23 at the cross-species level (R2=0.91, P<0.001) whereas the mechanical strength indexes (Dw, Ttob) were strongly correlated with Ks and P50 (R2=0.20, P<0.01).   Conclusion  The safety and efficiency of the xylem of the branches and roots of the three plants were all low, and given the different structural requirements for high safety and high efficiency of the three plants, there was no efficiency-safety trade-off at the organ level. [Ch, 7 fig. 1 tab. 48 ref.]
Research progress in plant somatic embryogenesis and its molecular regulation mechanism
WANG Shiyi, HUANG Yizi, LI Zhouyang, HUANG Huahong, LIN Erpei
doi: 10.11833/j.issn.2095-0756.20210141
[Abstract](63) [HTML](16) [PDF](146)
Abstract:
Each plant cell harboring all the genetic information of the species has the genetic potential to develop into a whole plant, which is termed plant cell totipotency. Somatic embryogenesis is a form of induced plant cell totipotency, by means of which embryos develop from somatic or vegetative cells in the absence of fertilization. Somatic embryogenesis, an increasingly important tool of plant biotechnology, has been widely applied in germplasm reservation, seedling propagation, molecular breeding and basic research of many plants and it has been implied in previous studies on molecular genetics that somatic embryogenesis is subject to the regulation by a complex network composed of transcription factors, hormone signaling pathways and epigenetic modifications. Therefore, this review, with a summary of the development routes of plant somatic embryogenesis, is aimed to give a comprehensice overview of the research progress achieved in the functions of key genes and epigenetic modification in the process of somatic embryogenesis along with an introduction to the applications of several key genes in genetic engineering. The development of new technologies is conducive to better and more profound insigts into the dynamic changes of of metabolic components, transcriptional regulation, phytohormone signal transduction and epigenetic modification during plant somatic embryogenesis, which will promote the understanding of the underlying molecular mechanism of somatic embryogenesis. Besides, by using those key genes of plant somatic embryogenesis, it is possible to development new methods and technologies to improve the efficiency of somatic embryogenesis induction and genetic transformation. [Ch, 81 ref.]
Impact of risk attitude and risk perception on farmers’ willingness to transfer carbon sequestration forests
CHEN Wei, GU Lei, FENG Yiyong, ZHU Aiqin, ZHU Weiqiang
doi: 10.11833/j.issn.2095-0756.20210216
[Abstract](18) [HTML](10) [PDF](187)
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  Objective  The solution based on forest carbon sequestration is an important means to achieve the goals of “carbon peak by 2030” and “carbon neutral by 2060”. The objective of this study is to investigate the impact of farmers’ risk attitude and risk perception on their willingness to transfer carbon sequestration forests, which is of great significance for sustainable development and promotion of forest carbon sequestration projects.  Method  Based on the field survey data of farmers involved in CCER (China Certified Emission Reduction) bamboo forest management carbon sequestration projects in Suichang and Jingning, Zhejiang Province, the impact of risk attitude and risk perception on their transfer intention of carbon sink forest was qualitatively analyzed, and the binary Logistics model and mediating effect model were used for empirical test.   Result  (1)In general, 84.32% of farmers were willing to transfer to more carbon sequestration forests, 10.36% were willing to transfer out of the carbon sequestration forests, and 5.33% were willing to maintain the status quo. In terms of classification, the proportion of risk preference farmers willing to transfer in was as high as 96.67%, and the proportion of risk aversion farmers willing to transfer out was 15.95%. In terms of risk perception, 88.00% of farmers with low perception of management risk, market risk, policy risk and natural risk were willing to transfer in, while 92.00% were not willing to transfer out. (2) According to the empirical results, the risk attitude had a significant positive impact on farmers’ willingness to transfer in carbon sequestration forests at the level of 5%, and had a significant negative effect on farmers’ willingness to transfer out carbon sequestration forests at the level of 5%. Management risk, market risk, and policy risk perception had a significant negative impact on farmers’ willingness to transfer carbon sequestration forests at the levels of 10%, 1%, and 5% respectively, and a significant positive impact on their willingness to transfer carbon sequestration forests at the levels of 10%, 1% and 1% respectively. (3) Market risk perception had a significant mediating effect between risk attitude and transfer intention of carbon sequestration forests.   Conclusion  Farmers’ enthusiasm to participate in forest carbon sequestration projects is high on the whole. Compared with risk averse farmers, risk preference farmers have higher willingness to transfer in and lower willingness to transfer out. Farmers with higher perception of management risk, market risk and policy risk have weaker transfer in intention and stronger transfer out intention. [Ch, 1 fig. 5 tab. 19 ref.]
Reduction of toxicity of oxytetracycline by highly efficient degrading bacterium Arthrobacter nicotianae ZAF-05
ZHU Rongrong, ZHANG Zan, SHI Yanke, LIN Hui, ZHANG Xin
doi: 10.11833/j.issn.2095-0756.20200819
[Abstract](36) [HTML](11) [PDF](204)
Abstract:
  Objective  The objective of this study is to determine the effect of a degrading bacterium which can effectively reduce the bio-toxicity of oxytetracycline (OTC) metabolites, so as to provide a preliminary theoretical basis for practical application of the strain.  Method  Taking Arthrobacter nicotianae ZAF-05, an efficient OTC-degrading bacterium obtained in the previous studies, as the object, the degradation products of OTC were analyzed by high-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry (HPLC-Q-TOF-MS). OTC sensitive Escherichia coli, Bacillus subtilis, and Scenedesmus obliquus were used as indicators to evaluate the bio-toxicity of degradation products.  Result  HPLC-Q-TOF-MS analysis showed that the content of highly toxic OTC and its natural hydrolysate epioxytetracycline(EOTC) decreased significantly after treatment with strain ZAF-05, while the content of low toxic isomeric oxytetracyline(ISO-OTC) increased slightly. The growth of tested bacteria and alga in OTC system treated by strain ZAF-05 was significantly better than that in OTC natural hydrolysis treatment and negative control without degrading bacteria, and the difference was significant (P<0.01). The results indicated that the bio-toxicity of OTC metabolites degraded by strain ZAF-05 was greatly reduced compared with the active drug and its natural hydrolysates. Besides, the degradation effect of the strain alleviated the damage of OTC to the ultrastructure of algal cells, as well as the damage to chloroplasts and cell walls.  Conclusion  Degrading bacterium ZAF-05 can reduce bio-toxicity of OTC residues, which may be related to the conversion of highly toxic substances into non-toxic or low-toxic metabolites in the system. [Ch, 7 fig. 1 tab. 26 ref.]
Temporal and spatial variation characteristics of annual water yield and its influencing factors in Hangzhou based on InVEST model
CAI Mengqing, HUANG Lu, YAN Lijiao
doi: 10.11833/j.issn.2095-0756.20210170
[Abstract](43) [HTML](13) [PDF](211)
Abstract:
  Objective   Natural factors and land use changes are important driving factors of ecosystem services change. The analysis of temporal and spatial variation characteristics in annual water yield and its main driving factors have practical significance for maintaining or improving urban soil and water conservation.   Method   This study took Hangzhou as the research object, adopted methods of landscape pattern analysis, spatial gradient analysis, and correlation analysis with the support of the InVEST model, ArcGIS, Fragstats, SPSS and other tools, identified the characteristics of land use and meteorological factors of Hangzhou, evaluated and analyzed the temporal and spatial variation of annual water yield and its correlation with meteorological factors and landscape pattern indices.   Result   The annual water yield in Hangzhou showed a first decline and then an upward trend from 2000 to 2015. The water yield is spatially high in the northeast and low in the southwest, and increased first and then decreased with distance from the city center, reaching the maximum at 10 km. Construction land had the largest water yield. The most dramatic change in land use in Hangzhou from 2000 to 2015 was the conversion between cultivated land and construction land. On the whole, the landscape showed a stronger trend of fragmentation and heterogeneity, reaching a peak at 10−20 km from the city center. The annual precipitation in Hangzhou decreased first and then increased. The annual average temperatures fluctuating increased and the annual actual evapotranspiration fluctuated. The annual precipitation does not change significantly within 50 km of the city center. The annual average temperature decreased significantly as it moved away from the urban center, while the annual actual evapotranspiration first decreased and then increased. The correlation between water yield and meteorological factors was greater than that of landscape patterns indices. Water yield had the strongest positive correlation with precipitation in meteorological factors.   Conclusion   The change of meteorological factors was the main factor causing annual water yield change in Hangzhou, but the impact of landscape pattern was still worthy of attention. The 10 km distance from the city center was the turning point of annual water yield. [Ch, 4 fig. 7 tab. 34 ref.]
Effects of different restoration communities on understory species diversity and soil physical and chemical properties in dry-hot valley
DOU Peitong, HE Siteng, GAO Chengjie, LI Kun, LIU Fangyan
doi: 10.11833/j.issn.2095-0756.20210348
[Abstract](69) [HTML](16) [PDF](137)
Abstract:
  Objective  This study aims to reveal the effects of different restoration communities on understory species diversity and soil physical and chemical properties in the dry-hot valley of the Red River.  Method  The plant communities of Schleichera oleosa, Dodonaea viscosa, Cassia siamea, Pistacia weinmannifolia and natural secondary sparse shrub and grass artificially restored for 15 years in the dry-hot valley of the Red River were taken as the objects, the species composition, diversity characteristics and soil physical and chemical properties of understory herbaceous plants were studied by using typical plots and random sampling methods.  Result  (1) A total of 60 species of vascular plants were found in different restoration communities, belonging to 20 families and 49 genera, of which the dominant families were Leguminosae, Compositae, Gramineae, and Euphorbiaceae. (2) Among the four artificial restoration communities, the Richness index, Shannon-Wiener diversity index and dominance index of P. weinmannifolia were significantly higher than those of natural secondary sparse shrub and grass (P<0.05). (3) The similarity degree of species composition between the four artificial restoration communities and the sparse shrub and grass was at a moderate dissimilarity level. (4) The soil organic matter, total nitrogen, available phosphorus and available potassium of the four artificially restored plant communities were significantly lower than those of sparse shrub and grass(P<0.05).   Conclusion  There are significant differences in understory species diversity and soil physical and chemical properties among different restoration communities in the dry-hot valley of the Red River. Compared with the natural secondary sparse shrub and grass, the artificial restoration community can increase the species diversity in a relatively short period of time, but cannot quickly restore soil nutrients. [Ch, 2 fig. 3 tab. 35 ref.]
Changes of plant community diversity and environmental interpretation in Beichuan landslide site
ZHANG Ge, WANG Qizhi, HE Yuan, ZENG Qianting, HE Jing, WANG Yong, YANG Jie, ZHENG Jiangkun
doi: 10.11833/j.issn.2095-0756.20210188
[Abstract](43) [HTML](16) [PDF](10)
Abstract:
  Objective  The objective is to study the variation of community plants diversity in the process of ecological rehabilitation of landslide slashed after earthquake and and make environmental interpretation.  Method  Taking the soil and plant communities in Mt. Fenghuang landslide slash in Beichuan County as the objects, the landslide slashes were divided into landslide area, transition area and non-landslide area. The vegetation changes in the three areas were analyzed by CCA (canonical correspondence analysis) method, and environmental interpretation was made with regard to the distribution of the plant community.  Result  (1)From 2013 to 2019, the number of plant families, genera and species in landslide area and transition area increased by 4.00%-483.00%, and that in non-landslide area decreased by 2.00%-37.50%. (2)The plant diversity in landslide area and transition area increased by 0.02%-483.33% while in non-landslide area decreased by 2.00%-52.94%, and the evenness also decreased. (3)The sum of the eigenvalues of the first two axes related to CCA ranking in arbor, shrub and grass layer accounted for 60%-80% of the total value, indicating that the first two axes contained most of the ranking imformation. (4)Soil pH and aggregate characteristics had a great impact on the vegetation distribution.  Conclusion  The diversity of plant communities in landslide slash has been improved to some extent, and the environmental factors have crucial influence on plant communities. [Ch, 2 fig. 5 tab. 33 ref.]
Preparation of two strains of lignin-degrading bacteria solid inoculum
LI Yalin, LI Suyan, SUN Xiangyang, HAO Dan, CAI Linlin, CHANG Xiaotong
doi: 10.11833/j.issn.2095-0756.20210311
[Abstract](48) [HTML](21) [PDF](8)
Abstract:
  Objective  With two different lignin-degrading bacteria, strain A(Aspergillus nidulans) and strain Q(Trametes sp.). used as materials, this study is aimed to research the production of high-efficiency solid fermentation inoculants for degradation or composting of garden greening wastes.  Method  First, a single factor experiment was employed to determine the types of carbon and nitrogen sources and additional nutrient components of the solid fermentation medium. Then, the orthogonal experiment design was adopted to optimize the amount of carbon and nitrogen sources to be added, based on which, efforts were made to figure out the inoculation amount of additional nutrient components and the best solid medium fermentation conditions of the two lignin-degrading bacteria using a uniform experiment combined with the artificial neural network algorithm.  Result  1) The optimized solid inoculum medium matrix (mass ratio) of strain Q was with 30.000 g bran as the base, 3.000 g soybean meal powder and 0.188 g corn flour added, with extra nutrients (based on the mass ratio of the matrix) being MgSO4 1.434%, KH2PO4 0.115%, FeSO4·7H2O 1.497% whereas the inoculation conditions being 6.000% of inoculation, with the ratio of material to water as 1.000∶0.992, and the protective agent as 1.000%; 2) The optimized solid inoculum medium matrix (mass ratio) of strain A was with 30.000 g bran as the base, 1.500 g soybean meal powder and 1.500 g sodium lignosulfonate were added, with extra nutrients (based on the mass ratio of the matrix) being MgSO4 0.123%, KH2PO4 0.213%, FeSO4·7H2O 1.280% whereas the inoculation conditions being 21.000% inoculation amount with the ratio of material to water as 1∶1 and the protective agent as 19.000%; 3) strain Q and strain A were fermented on the optimized medium for 7−9 days to get the largest fermentation biomass with the D(260) value of strain Q being 0.596 and the D(260) value of strain A being 0.478.   Conclusion  The solid inoculum prepared by two lignin-degrading bacteria under optimized fermentation conditions were featured with high biomass and certain potential for degrading the lignin of landscaping wastes. [ch, 6 fig. 5 tab. 22 ref.]
Effects of drip irrigation and furrow irrigation on spatial distribution of fine roots of Populus
BI Honglei, LAN Zaiping, PENG Jingjing, MA Xin
doi: 10.11833/j.issn.2095-0756.20200808
[Abstract](42) [HTML](15) [PDF](6)
Abstract:
  Objective  This study aims to investigate the effects of different irrigation methods on the growth and spatial distribution of fine roots of Populus, so as to provide theoretical and technical basis for the cultivation of plantation by drip irrigation.  Method  The 5-year old ‘107’ Populus × euramericana ‘Neva’ was selected as the research object, and standard trees were selected from the plantations cultivated by drip irrigation and furrow irrigation. Root drills were used to sample trees at 20, 50, 100 and 150 cm from tree trunks in the directions of inter plant, diagonal and inter row. The differences of fine root biomass density, fine root length density and fine root specific root length were compared.  Result  In inter plant direction, the difference of fine root biomass density between drip irrigation and furrow irrigation increased with the increase of horizontal distance, and the difference was significant (P<0.05). With the increase of horizontal distance, the differences between diagonal and inter row directions decrease. Under drip irrigation, the fine root biomass density was the highest at 50 cm away from the trunk in the direction of inter plant, and the highest at 20 cm away from the trunk in the direction of diagonal and inter row. Under drip irrigation, the difference of fine root length density with furrow irrigation increased with the increase of the horizontal distance(P<0.05), while the difference of diagonal and row direction decreased with the increase of the horizontal distance. Under drip irrigation, the root length density of fine roots was the largest at 50 cm from the trunk in the direction of inter plant, and the largest at 20 cm away from the trunk in the direction of diagonal and inter row. Under drip and furrow irrigation, the fine root biomass of 0−40 cm soil layers accounted for 81% and 73% of that in 0−60 cm soil layers, respectively, while the fine root length accounted for 85% and 80%. The specific root length under drip irrigation and furrow irrigation increased with the increase of horizontal distance, and the difference of specific root length under furrow irrigation was greater than that under drip irrigation. The difference of specific root length in different directions was the largest at 20 cm away from the trunk and the smallest at 50 cm away from the trunk.  Conclusion  Drip irrigation can promote the growth and turnover of fine roots, affect their spatial distribution, and improve forest productivity. [Ch, 4 fig. 1 tab. 28 ref.]
On the structure characteristics of culm form of Phyllostachys edulis in Zhejiang Province
YANG Fan, TANG Mengping
doi: 10.11833/j.issn.2095-0756.20200796
[Abstract](65) [HTML](21) [PDF](6)
Abstract:
  Objective  With an analysis of the relationship between stalk structure factors and the dominant factors in stalk structure factors as well as an investigation into the stalk structure factors of culm and their distribution rules dependent on relatively high with the actual high replaced by the ratio of bamboo joint height and bamboo high (i. e. relative high, value range 0−1), this study is aimed to reveal the structure characteristics of culm form so as to better evaluate the growth and development of bamboo (Phyllostachys edulis).  Method  With 10 counties and cities (districts) of Zhejiang Province selected to set up sample plots of moso bamboo forest, the sample bamboo trees were cut down to measure the number of bamboo nodes, the length of bamboo nodes and the central diameter of bamboo nodes. Then the distribution patterns of culm form factors depending on relative height were fitted by parabola and line before the relationship between culm form factors was investigated with the correlation analysis whereas the main culm structure factors were studied with the factor analysis.  Result  The number of bamboo bamboo knots was concentrated in 53−67 sections, consistent with the normal distribution, and the confidence interval of the average bamboo knots at the 95% confidence level is (58.1, 60.4). The length of nodes and the central diameter of nodes depended on the relative height distribution with parabola and straight line distribution respectively while the central diameter of bamboo nodes decreased by 10% with a 10% increase of culm height. With the increase of diameter grades, the length of longest bamboo node tended to increase gradually, but there is no significant variation in the relative height of the longest bamboo node ranging between 0.47 and 0.52, and DBH was positively correlated with the number of bamboo nodes, length of node in half height, the length of longest node and the length of node in chest height(P<0.01), while negatively correlated with the number of nodes in chest height(P<0.01).  Conclusion  The culm form of bamboo was featured with both stability and variation but there was no significant variation in the relative height of the longest bamboo nodes with different diameter class, generally at half height. Also, the bigger the bamboo was, the larger the number of nodes was, the longer the bamboo nodes were, and the longer the average length below the chest height was. The wall thickness factor, the length of nodes at half height, the number of bamboo nodes and the culm factor in the height of the chest are the main structural factors reflecting the culm structure. [Ch, 6 fig. 6 tab. 28 ref.]
Evaluation of forest community stability in Xianrendong National Nature Reserve, Liaoning
SONG Wenlu, ZHANG Hua, FU Jie, ZHANG Jun, DU Weixin, YUAN Zhiyan, ZHAO Haihan
doi: 10.11833/j.issn.2095-0756.20210330
[Abstract](45) [HTML](16) [PDF](2)
Abstract:
  Objective  The objective of this study is to evaluate the stability of 9 typical forest communities in Xianrendong National Nature Reserve, Liaoning Province, and to analyze the main influencing factors.   Method  Taking the survey data of 9 typical forest communities in the reserve as the data source, the population regenerative potential, basic community characteristics, species diversity, population niche overlap, litter characteristics and soil fertility of 9 forest communities were compared, and a stability evaluation system was constructed based on the above 6 indicators and 44 factors. The subordinate function value method in fuzzy mathematic was used to evaluate the stability of each forest community.  Result  (1)Pinus densiflora+Quercus acutissima-Parthenocissus tricuspidata+Zanthoxylum schinifolium-Amphicarpaea edgeworthii+Cardamine leucantha had the best regeneration potential, species diversity and soil fertility. The average value of basic characteristics of growth and development of P. densiflora-Rubus crataegifolius+Z. schinifolium-Carex callitrichos var. nana community was the highest. The niche overlap of the 9 communities was similar, and the litter accumulation and water holding capacity of Q. dentata+Q. acutissima-Indigofera kirilowii+Corylus heterophylla-Artemisia keiskeana+C. callitrichos var. nana community were the best. (2)The stability ranking of the 9 forest communities from high to low was P. densiflora+Q. acutissima-P. tricuspidata+Z. schinifolium-A. edgeworthii+C. leucantha, Q. dentata+Q. acutissima-I. kirilowii+C. heterophylla-A. keiskeana+C. callitrichos var. nana, Q. acutissima+Q. variabilis-Z. schinifolium+C. heterophylla-C. callitrichos var. nana, P. densiflora-Lindera obtusiloba+Rhododendron micranthum-C. callitrichos var. nana, P. densiflora-Z. schinifolium-C. callitrichos var. nana, Q. mongolica+P. densiflora-R. crataegifolius+R. micranthum-C. callitrichos var. nana, Q. mongolica-R. crataegifolius-C. callitrichos var. nana, P. densiflora-R. crataegifolius+Z. schinifolium-C. callitrichos var. nana and Q. dentata+P. densiflora-C. heterophylla-C. callitrichos var. nana. (3)Among the 6 forest community stability indicators, the load coefficient of population regenerative potential, species diversity and soil fertility was the largest in the first principal component.  Conclusion  There are significant differences in the stability of the 9 typical forest communities in Xianrendong National Nature Reserve, and the main influencing factors are regenerative potential, species diversity and soil fertility. [Ch, 10 tab. 31 ref.]
Input and output balance of cadmium (Cd) in cultivated land with moderate pollution in Songyang County
XU Huozhong, WU Dongtao, LI Guisong, WU Lintu, YE Chunfu, GUO Bin, MA Jiawei, YE Zhengqian, LIU Dan
doi: 10.11833/j.issn.2095-0756.20200728
[Abstract](69) [HTML](29) [PDF](2)
Abstract:
  Objective  This study is aimed at an accurate interpretation of the source of Cd pollution in farmland soil so as to put forward relevant suggestions for soil heavy metal remediation.  Method  An investigation was conducted of the input and output of heavy metal Cd in a typical piece of cultivated land in Songyang County of Zhejiang Province for three consecutive years by collecting local inputs and crops.   Result  During the period time from 2017 to 2019, 1) fertilizer and atmospheric deposition were the main agricultural pollution sources of Cd, accounting for 49.78% and 40.16%, 50.20% and 39.14%, 34.04% and 48.09% respectively whereas the total input of Cd accounted for 0.18%、0.17% and 0.14% of the total soil Cd, respectively; 2) the total output of Cd from rice, rape and tea were 2820.00, 2706.00 and 2629.50 mg·hm−2·a−1, respectively, with an average of 2718.50 mg·hm−2·a−1 and a relatively stable overall annual average output and 3) the annual input and output decreased year by year, but the annual output was greater than the annual input, which may attribute to the enrichment of plant species.  Conclusion  In conclusion, it is advisable to devote efforts in the continuous implementation of long-term supervision over the atmospheric deposition in the region, the avoidance of direct return of straws to the field, the effective utilization of resources, and the timely restoration of the local contaminated soil and plants. [Ch, 1 fig. 5 fig. 25 ref.]
Kinetic modeling of total phosphorus removal from farmland drainage with submerged macrophyte-type ecological purification system
GONG Miaomiao, CAI Feixiang, JIANG Peikun, CAO Yucheng
doi: 10.11833/j.issn.2095-0756.20210260
[Abstract](86) [HTML](36) [PDF](2)
Abstract:
  Objective  The objective of this study is to investigate the dynamic performance of ecological purification system with submerged macrophytes as pioneer species for treatment of phosphorus pollution in farmland drainage.  Method  A batch-mode mesocosm experiment was performed to study total phosphorus (TP) purification efficiency and kinetic parameters of two submerged macrophyte systems: Vallisneria natans and Ceratophyllum demersum. Four kinetic models including first-order kinetic, Grau second-order kinetic, Monod kinetic and modified Gompertz model were used to evaluate TP removal efficiency.  Result  At the end of the experiment (day 49), there was no significant difference in TP removal efficiency between the two mesocosm systems (P>0.05), and the TP removal rates were 82.8% for V. natan and 84.0% for C. demersum, but the difference in TP removal efficiency was uncertain in time scale. Kinetic simulation analysis showed that except Grau second-order kinetic, first-order kinetic, Monod kinetic and modified Gompertz model were proven capable of predicting TP removal process of the two submerged plant systems under experimental conditions, with R2(coefficient of determination)>0.930 and RRMSE (relative root mean square error)<0.200. Among them, Monod kinetic and modified Gompertz model showed a higher fitting degree(R2>0.970), and a better agreement between the predicted value and the observed value (RRMSE<0.110).  Conclusion  The kinetic parameters obtained by the three effective model fitting show significant differences at the plant species level (P<0.05), and V. natan has higher kinetic parameter of TP removal efficiency compared with C. demersum (P<0.05), indicating that TP removal efficiency of V. natan is better than that of C. demersum. [Ch, 5 fig. 2 tab. 35 ref.]
Resistance of four endophytic fungi to Fusarium sp. of Picea mongolica
JIANG Haiyan, DI Jialin, CONG Lin, YAN Wei, BAI Nana, ZHANG Xu, BAI Hui
doi: 10.11833/j.issn.2095-0756.20210287
[Abstract](107) [HTML](42) [PDF](3)
Abstract:
  Objective  This aim is to investigate the antagonistic effect of endophytic fungi of Picea mongolica on Fusarium sp., in order to provide the basis for the development and utilization of biocontrol fungi.   Method  Four strains of endophytic fungi of P. mongolia with strong antagonistic effect were selected as experimental materials, including Alternaria alternata (SDYS36), Fusarium tricinctum(SDYS63), Penicillium chrysogenum (SDYS95), and Aspergillus sydowii(SDYS180), with Fusarium sp. as the target. Using in vitro confrontation and pot experiment, the antagonistm of endophytic fungi against pathogens in vitro and the changes of morphology and related physiological indexes of susceptible seedlings were determined in five groups. The dominant antagonistic strains were screened by significance analysis.  Result  The four endophytic antagonists showed antagonistic activity against Fusarium sp. The antagonistic activity of SDYS180 fermentation broth was the highest, reaching 78.67%. The antagonistic activity of SDYS95 strain was the highest, up to 69.64%, and the antagonistic activity of volatile metabolites of SDYS63 was the highest, up to 16.94%. The four endophytic antagonists showed different degree of antagonistic activity against Fusarium sp. in potted P. mongolica. The plant height, ground diameter and root length of infected seedlings increased by 17.12%, 32.64% and 16.56% respectively by inoculating SDYS180. In the infected seedlings inoculated with SDYS95, MDA content decreased by 5.27%, SP content, POD activity, SOD activity, and CAT activity increased by13.41%, 224.46%, 37.05% and 9.02%, respectively.  Conclusion  Strains SDYS180 and SDYS95 are selected as the dominant antagonistic strains to control seedling blight of P. mongolica.[Ch, 8 fig. 1 tab. 23 ref.]
SSR analysis of genetic diversity of male Torreya grandis
ZHENG Liuhui, ZHAN Liyun, HOU Yu, YU Weiwu, ZENG Yanru, DAI Wensheng
doi: 10.11833/j.issn.2095-0756.20210279
[Abstract](76) [HTML](33) [PDF](11)
Abstract:
  Objective  This study aims to analyze the genetic diversity and population genetic structure of 121 individual plants from 5 wild populations of male Torreya grandis using SSR fluorescent markers, in order to provide reference for genetic background, germplasm resource evaluation and elite germplasm screening of male T. grandis.  Method  The genomic DNA of T. grandis was extracted by CTAB method, and the primers were designed. The polymorphic sites of the male T. grandis were detected by capillary electrophoresis using fluorescent primer PCR amplification.  Result  A total of 85 alleles were detected by 24 pairs of primers, ranging from 2−7, with an average of 3.542 per marker, among which the average effective alleles were 1.915. The average Nei’s genetic diversity index and Shannon’s information index in 5 populations were 0.365 and 0.608 respectively. Among the 5 populations, the percentage of polymorphic sites ranged from 75.00% to 95.83%, with an average of 82.50%. The order of genetic diversity of the 5 populations from large to small was Shengzhou, Lin’an, Fuyang, Huangshan and Chun’an. The gene flow among the populations was 4.172, the coefficient of gene differentiation was 0.096, and the degree of genetic differentiation was very low. The results of clustering analysis showed that the genetic similarity coefficient (GS) of the 5 populations varied from 0.865 to 0.978, with an average of 0.932.  Conclusion  The genetic diversity of male T. grandis populations is relatively rich. The genetic variation of the male T. grandis mostly exists within the population, but the gene exchange is also present between the populations. The 5 populations can be divided into 3 groups, which is similar to the results of phenotypic genetic diversity analysis. [Ch, 4 fig. 6 tab. 32 ref.]
Insect resistance and metabolome of four willow species
LI Wenjie, CUI Lulu, MA Yunjiao, LIANG Haiyong
doi: 10.11833/j.issn.2095-0756.20210166
[Abstract](72) [HTML](31) [PDF](1)
Abstract:
  Objective  This purpose is to explore the insect resistance of different willows(Salix spp.) to Plagiodera versicolora, and to provide reference for the breeding of willow cultivars with strong insect resistance.  Method  3 clones of S. caprea, S. matsudana, S. babylonica and S. triandra were tested in laboratory for insect feeding, and the differential secondary metabolites between insect resistant and non insect resistant groups were determined and screened.  Result  The survival rate of indoor feeding was 98% for S. matsudana, 93% for S. babylonica, 90% for S. caprea and 0 for S. triandra. There were 23 main different metabolites between the non insect resistant group and the insect resistant group, among which 15 were up-regulated, including fer-agmatine, L-ascorbic acid, gallic acid, (−)-epigallocatechin, (+)-gallocatechin, myricitrin, L-(+)-tartaric acid, D-(−)-arabinose, hydroxy-methoxycinnamate, N-feruloyl agmatine, gluconic acid, 2′-Hydroxygenistein, N-Acetyl-DL-tryptophan, eupatilin 3-glucoside, and hexadecylsphingosine, and 8 were down-regulated, including quercetin 3-O-(6″-O-malonyl)-galactoside, hesperidin, rutin, D-galactopyranuronate, 2,5-dihydroxy benzoic acid O-hexside, quercetin O-acetylhexoside, 3-hydroxy-5-methylphenol-1-Oxy-β-D-glucose, and bioquercetin.  Conclusion  S. triandra has the best insect resistance to P. versicolora. There are significant differences in the main secondary metabolites between the non insect resistant group and the insect resistant group, which indicates that the secondary metabolites of S. triandra may be toxic to the larvae of P. versicolora, or lack of nutrients necessary for larvae growth and development, resulting in the death of the larvae. [Ch, 4 fig. 1 tab. 23 ref.]
Screening and identification of a lignin degrading strain and its optimized liquid fermentation conditions
LI Yalin, LI Suyan, SUN Xiangyang, HAO Dan, CAI Linlin, CHANG Xiaotong
doi: 10.11833/j.issn.2095-0756.20200814
[Abstract](91) [HTML](30) [PDF](7)
Abstract:
  Objective  The purpose of this study is to produce a high efficient liquid inoculum with lignin-degrading bacteria as raw materials for garden waste.  Method  The target strains were screened from 22 isolated and purified strains by the aniline blue plate fading circle method and the guaiacol plate fading circle method, and were identified by Internal Transcribed Spacer (ITS) sequencing, and then the single factor test was used to optimize the culture time, inoculum amount and medium formula (carbon and nitrogen source) of the target strains. Finally, according to the results of single factor test, the optimal fermentation conditions of the target strains were found by uniform experiment combined with artificial neural network algorithm.   Result  According to the results of plate fading and color development, strain Q01 was selected as the target strain and was identified as Trametes. According to the results of single factor test and uniform test, the optimal fermentation conditions for strain Q01 were determined as the culture time of 5 days, inoculation amount 12.5%. The medium formula was composed of sodium lignosulfonate 14.00 g·L−1, peptone 12.30 g·L−1, yeast powder 5.00 g·L−1, soybean cake powder 3.00 g·L−1, copper sulfate pentahydrate 0.12 g·L−1, sodium chloride 0.53 g·L−1, and natural pH. Under the optimized conditions, the biomass, manganese peroxidase activity and lignin peroxidase activity of strain Q01 increased by 1.27 times, 31.71 times and 19.12 times respectively. Laccase activity decreased slightly, but the total enzyme activities of three kinds of lignin enzymes increased by 4.38 times.   Conclusion  The liquid inoculum prepared by strain Q01 under optimized fermentation conditions has the characteristics of high enzyme activity and high biomass, which has certain application potential in degrading lignin in garden waste. [Ch, 6 fig. 3 tab. 29 ref.]
Agrobacterium tumefaciens-mediated genetic transformation system of Torreya grandis ‘Merrillii’ immature embryos
ZHOU Jiajun, HU Hengkang, GONG Li, GAN Ange, YU Weiwu, WU Jiasheng, HUANG Jianqin, ZHANG Qixiang
doi: 10.11833/j.issn.2095-0756.20210196
[Abstract](83) [HTML](31) [PDF](6)
Abstract:
  Objective  The purpose is to explore genetic transformation mediated by Agrobacterium tumefaciens using Torreya grandis ‘Merrillii’ immature embryos as receptors, so as to reveal key factors affecting its genetic transformation and establish A. tumefaciens mediated transformation system of T. grandis ‘Merrillii’ embryos.  Method  The immature embryos of T. grandis ‘Merrillii’ seeds of 8 to 11 weeks after breaking through seed scales were used as transgenic acceptors. The effects of embryo age, A. tumefaciens concentration, infection time and antibiotic concentration on genetic transformation efficiency were compared. Hygromycin, GFP fluorescent expression and GFP gene polymerase chain reaction were used for positive screening and selection of immature embryo culture.  Result  The stress resistance increased, the contamination rate decreased and the survival rate increased with the increase of embryo age. The survival rates of 10-week and 11-week young embryos were 52.1% and 52.3%, respectively. The contamination rate, survival rate, callus induction rate and somatic embryogenesis rate of young embryos were significantly affected by the concentration of A. tumefaciens and infection time (P<0.05). When the liquid optical density [D(600)] was 0.5, the callus induction rate and somatic embryogenesis rate of young embryos were the highest, which were 17.9% and 17.3% respectively. When the infection time was 10 minutes, the callus induction rate and somatic embryogenesis rate were the highest, reaching 17.5% and 17.1% respectively. Carbenicillin had a significant effect on the removal of A. tumefaciens (P<0.05). When the concentration was 300 mg·L−1, the survival rate, callus induction rate and somatic embryogenesis rate were the highest, which were 60.5%, 15.8% and 17.5% respectively. The concentration of hygromycin in different treatments had a good effect on the positive screening of young embryo culture. The survival rate was 30.5% when the concentration of hygromycin was 100 mg·L−1.  Conlusion  Immature embryos at the 10th week after the breakthrough of scale, 0.5 [D(600)], 10 minutes duration, 300 mg·L−1 carbenicillin, and 100 mg·L−1 hygromycin were the optimum conditions for genetic transformation of T. grandis ‘Merrillii’. [Ch, 3 fig. 5 tab. 37 ref.]
Soil aggregate stability and anti-erodibility of typical forest stands in Huaying mountain area
CHEN Tao, ZHOU Lijun, QI Shi, SUN Baoping, NIE Zexu
doi: 10.11833/j.issn.2095-0756.20210142
[Abstract](131) [HTML](38) [PDF](2)
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  Objective  The objective of this study is to explore the characteristics and influencing factors of soil aggregate stability under typical forest stands in Huaying City, Sichuan Province, so as to provide theoretical basis for elucidating the composition and stability mechanism of soil aggregates in this area.  Method  Five typical stands (Cupressus funebris pure forest, Cunninghamia lanceolata pure forest, Pinus massoniana-Loropetalum chinense mixed forest, P. massoniana-C. lanceolata mixed forest, and near natural C. lanceolata pure forest) were selected as the research objects. The soil physical and chemical properties of the surface layer (0−15 cm) and subsurface layer (15−30 cm) of the stands were measured to analyze the effects on aggregate change characteristics and soil erosion resistance.  Result  (1) The contents of soil macroaggregates in five typical stands were 77%−93%, with significant differences in mean weight diameter (MWD) and soil erodibility (K) among different stands (P<0.05). The MWD value of C. funebris forest was the largest (2.33 mm, and that of P. massoniana-L. chinense mixed forest was the smallest(1.53 mm). The K values of soil erodibility from large to small followed the order of near natural C. lanceolata pure forest, C. funebris forest, C. lanceolata pure forest, P. massoniana-C. lanceolata mixed forest, and P. massoniana-L. chinense mixed forest. (2) Redundancy analysis (RDA) showed that available potassium, total porosity and organic carbon were significantly positively correlated with MWD and negatively correlated with K value, and soil bulk density was significantly negatively correlated with MWD and positively correlated with K value.  Conclusion  Among the five typical stands, C. funebris and near natural C. lanceolata pure forest have the highest stability of soil water stable aggregates and strong erosion resistance, while P. massoniana-L. chinense mixed forest displays the lowest stability of soil water stable aggregates. Under the traditional management mode, the soil aggregate of C. funebris is more stable and soil anti-erodibility is stronger. The near natural management mode is conducive to the improvement of soil aggregate stability and soil anti-erodibility. [Ch, 3 fig. 3 tab. 32 ref.]
2021, 38(5).  
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2021, 38(5).  
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2021, 38(5).  
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Simulation research on the effects of nitrogen input on carbon cycle process in a coastal wetland: review and prospects
CHEN Yawen, HAN Guangxuan, CAI Yanjiang
2021, 38(5): 883-895.   doi: 10.11833/j.issn.2095-0756.20210118
[Abstract](506) [HTML](86) [PDF](45)
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As one of the key processes controlling global carbon storage, carbon cycle in coastal wetland is a process significantly affected by nitrogen input due to the inshore water eutrophication. Given the fact that nitrogen input affects the carbon cycle of coastal wetland in a rather complex way, carbon cycle model has been selected as an effective method to clarify the process with the ultimate purpose to evaluate the carbon storage function of coastal wetland under the global climate change. With an review conducted of the migration and transformation of carbon components in coastal wetlands at different interfaces of atmosphere, vegetation, water and soil and a summary made of the regulations of the response of carbon cycle on nitrogen, it was found that carbon storage and flux is affected by multiple factors. Also, on this basis, carbon cycle models with carbon, nitrogen and water related modules were introduced along with the efforts made to promote their adaptability to wetlands and their application on wetlands, which shall provide reference for the employment of the model in the description of the carbon exchange in coastal wetland under the influence of nitrogen input. Finally, it was concluded that, to further develop the model, closer attention should be focused on the tidal process with nitrogen input and the promotion of model simulation accuracy. [Ch, 1 fig. 1 tab. 126 ref.]
Response of nitrogen transformations to moisture changing in red soil
DAN Xiaoqian, CHEN Zhaoxiong, CHENG Yi, CAI Zucong, ZHANG Jinbo
2021, 38(5): 896-905.   doi: 10.11833/j.issn.2095-0756.20200624
[Abstract](283) [HTML](70) [PDF](88)
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  Objective  Soil moisture variations can affect microbial-mediated N transformation. The purpose of this study is to determine the gross transformation rate of soil N, and explore the dynamic change of N in soil and the response mechanism of N transformation to soil water change.  Method  By using 15N paired labeling technique and a numerical optimization model, the gross conversation rates of the main N transformation processes including organic N mineralization, \begin{document}${\rm{NH}}_4^{+} $\end{document} microbial assimilation, autotrophic nitrification, heterotrophic nitrification, \begin{document}${\rm{NO}}_3^{-} $\end{document} consumption in red soil under different water conditions (20%, 60%, 80%, 100% water holding capacity) were measured and fitted.  Result  The responses of different types of soil N transformation to moisture change varied substantially. With the increase of soil moisture (from 20% to 100% water holding capacity), the gross mineralization rate of labile organic N (\begin{document}$M_{{\rm{N}}_{\rm{lab}}} $\end{document}) increased from 1.757 to 2.598 mg·kg−1·d−1, while the gross mineralization rate of recalcitrant organic N (\begin{document}$M_{{\rm{N}}_{\rm{rec}}} $\end{document}) remained stable, and the total gross rate of N mineralization (\begin{document}$M_{{\rm{N}}_{\rm{lab}}} $\end{document}+\begin{document}$M_{{\rm{N}}_{\rm{rec}}} $\end{document}) was significantly enhanced by increasing soil moisture from 20% to 100% water holding capacity. The gross rate of autotrophic nitrification (\begin{document}$O_{{\rm{NH}}_{4}} $\end{document}) increased significantly with increasing moisture, and reached the maximum value (0.266 mg·kg−1·d−1) at 100% water holding capacity. The gross rate of heterotrophic nitrification (\begin{document}$O_{{\rm{N}}_{{\rm{rec}}}} $\end{document}) firstly increased and then decreased with the increase of soil moisture, reaching the maximum value (0.115 mg·kg−1·d−1) at 60% of the maximum water holding capacity. \begin{document}$O_{{\rm{N}}_{{\rm{rec}}}} $\end{document} value (0.115 mg·kg−1·d−1) was lower than that of \begin{document}$O_{{\rm{NH}}_{4}} $\end{document} when soil moisture was 80% and 100% water holding capacity, and the total gross rate of N nitrification (\begin{document}$O_{{\rm{NH}}_{4}} $\end{document}+\begin{document}$O_{{\rm{N}}_{{\rm{rec}}}} $\end{document}) increased continuously with the increase of soil moisture. The gross rate of \begin{document}${\rm{NH}}_4^{+} $\end{document} microbial assimilation rate (\begin{document}$I_{{\rm{NH}}_{4}} $\end{document}) increased linearly with increasing moisture, and the highest rate (1.941 mg·kg−1·d−1) was observed at 100% water holding capacity. The gross rate of \begin{document}$ {\rm{NO}}_3^{-} $\end{document} consumption (\begin{document}$C_{{\rm{NO}}_{3}} $\end{document}) increased significantly at 80% and 100% water holding capacity, and the total inorganic N consumption rate (\begin{document}$I_{{\rm{NH}}_{4}} $\end{document}+\begin{document}$C_{{\rm{NO}}_{3}} $\end{document}) increased obviously, and exceeded total gross rate of N mineralization at 80% water holding capacity. In general, the net rate of N mineralization firstly increased to the maximum value at 60% water holding capacity, and then decreased rapidly to negative value(i.e. net consumption) at 80% and 100% water holding capacity.  Conclusion  Different types of inorganic nitrogen production and consumption have different responses to water change in red soil. The availability of nitrogen in red soil could be improved by increasing soil water content appropriately. [Ch, 5 fig. 1 tab. 48 ref.]
Stable isotope natural abundance techniques in the studies on nitrous oxide production and emission processes: a review
HUANG Jin, YU Longfei, LI Wenjuan, HUANG Ping
2021, 38(5): 906-915.   doi: 10.11833/j.issn.2095-0756.20210458
[Abstract](151) [HTML](35) [PDF](30)
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Nitrous oxide (N2O) is one of the potent greenhouse gases and also plays an important role in ozone layer decomposition. N2O production and emission processes in soil are complexed. Therefore, accurate source partitioning will help to constrain emission budgets. The application of stable isotope natural abundance technique have stimulated significant progress in N2O source partitioning and promoted identification in various N2O microbial production processes, which make use of various N2O isotope signatures δ15Nbulk(the average of15N), δ18O(the average of 18O) and δ15Nsp(site preference of 15N in different positions of N2O molecule). However, some factors also add uncertainties to N2O source partitioning, such as the range of isotope signatures, changes of isotope composition, and various fractionation factors associated with N2O reduction. It is also noteworthy that microbial processes and related isotopic effects are critical. In this review, the isotopic effects during N2O production and reduction and related factors are summarized; advances in approaches for N2O source-partitioning are concluded, including isotope natural abundance and isotopomer methods. The review focused on the progress of isotopic signatures δ15Nbulk, δ18O and δ15Nsp value in constraing N2O sources. In the future, the measurement of isotope fractionation, a combination of isotope signatures and advanced methodologies are advised for better studying N2O sources and pathways. [Ch, 2 fig. 80 ref.]
Effect of simulated root exudates input on soil nitrogen transformation: a review
CAI Yinmei, ZHANG Chengfu, ZHAO Qingxia, LI Xinying, HE Tengbing
2021, 38(5): 916-925.   doi: 10.11833/j.issn.2095-0756.20210293
[Abstract](156) [HTML](195) [PDF](31)
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Global climate change accelerates plant growth and biomass accumulation, and nitrogen has become one of main limiting factors for primary productivity in forest ecosystems. The microbial process mediated by root exudates in rhizosphere is of great significance in driving soil nutrient cycle and increasing nitrogen availability. This study reviewed the effects and mechanisms of simulated root exudates input on soil nitrogen mineralization, nitrification, and denitrification. It was found that organic acids, sugars, and amino acids in root exudates accelerated the decomposition of organic matter and nitrogen mineralization, which partly alleviated the demand of plants for nitrogen. Root exudates inputs with different carbon content and C/N ratio drove rhizosphere microorganisms to exercise different nutrient utilization strategies. Through biological and abiotic effects, root exudates mineralized nitrogen in organic matter and supplied it to plants for absorption and utilization. Biological nitrification inhibitors in root exudates inhibited soil nitrification and reduced nitrogen leaching. Root exudates also promoted soil denitrification by controlling the denitrifying bacterial community in the rhizosphere. In conclusion, plants can improve underground carbon distribution and affect nitrogen transformation in rhizosphere soil by increasing the input of root exudates, which is vital for maintaining nitrogen cycle and alleviating nutrient limitation. [Ch, 2 tab. 70 ref.]
Effects of biochar application on soil nitrogen transformation and N2O emissions: a review
QU Tianhua, LI Yongfu, ZHANG Shaobo, LI Linlin, LI Yongchun, LIU Juan
2021, 38(5): 926-936.   doi: 10.11833/j.issn.2095-0756.20200549
[Abstract](441) [HTML](128) [PDF](32)
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The sustainability and uncertainty of global climate warming have a profound impact on the sustainable development of human society. The continuous increase of atmospheric N2O concentration is one of the major contributions to the global climate warming. Soil is an important site of nitrogen transformation and a biochemical reaction reservoir of the nitrogen cycle, and also an important source of N2O emissions. Therefore, changes in soil N2O emission rate will significantly affect atmospheric N2O concentration. Biochar refers to the aromatic chemicals prepared by pyrolysis of biomass under the condition of complete or partial hypoxia. Biochar has the characteristics of porosity, strong adsorption, chemical stability, high pH and large cation exchange capacity. After it is applied to soils, biochar will directly or indirectly affect the transformation process of soil nitrogen and significantly affect the soil N2O emissions. This article reviewed the research progress of biochar effects on nitrogen transformation and N2O emission in the soil ecosystem, elaborated the effects of biochar input on the dynamic changes of soil inorganic nitrogen, nitrification, denitrification and N2O emission. Futher, in terms of biochar’s absorption and reduction of nitrogen leaching, effects on soil physicochemical properties, abundance and diversity of soil ammonia oxidizing bacterial, along with functional genes of denitrifying bacteria, the machamnisms influencing the processes above-mentioned are specifically elucidated in details. The future research of biochar in increasing soil sinks, reducing emissions and mitigating the greenhouse effect, as well as the related technology promotion, have been prospected. [Ch, 109 ref.]
Effects of water-retaining agent on soil nitrous oxide emission in Camellia oleifera forest under nitrogen and phosphorus addition
GAO Yu, WANG Baihui, ZOU Yu, WANG Shuli, XIANG Lang, FU Yanqiu, HU Dongnan, GUO Xiaomin, ZHANG Ling
2021, 38(5): 937-944.   doi: 10.11833/j.issn.2095-0756.20210411
[Abstract](87) [HTML](25) [PDF](34)
Abstract:
  Objective  The application of chemical fertilizer accelerates soil nitrous oxide (N2O) emission and intensifies global climate change. Soil moisture content is a key factor affecting soil N2O emission in arid and uneven rainfall distribution areas, so the application of water retaining agent (such as polyacrylamide) affects soil N2O emission. The purpose of this study is to explore the effect of polyacrylamid on soil N2O emission under the application of N and P fertilizer.  Method  Taking Camellia oleifera forest soil as the research object, different treatments were set, including different fertilizer additions (N, P, N+P, ck), different polyacrylamide dosage (C0: 0 g·kg−1, C1: 1.0 g·kg−1, C2: 2.0 g·kg−1) and their interaction. The soil N2O emission during the growth of C. oleifera seedlings was determined by static chamber gas chromatography.  Result  (1) The application of polyacrylamide significantly increased the soil moisture content of C. oleifera (P<0.05), which increased with the increase of the application amount. Compared with C0, the soil moisture content of C1 and C2 increased by 47.1% and 57.4% respectively, but the application of polyacrylamide did not promote soil N2O emission (F=2.75, P>0.05). (2) The application of P fertilizer significantly increased the cumulative soil N2O emission (P<0.05), which increased by 13.3% compared with ck. (3) Compared with the soil supplemented only with polyacrylamide, the N2O emission fluxes of soil treated with 1.0 g·kg−1 polyacrylamide and N, P, N+P fertilizer increased significantly by 56.0%, 61.7%, and 40.7%, respectively (P<0.05). The N2O emission fluxes of soil treated with 2.0 g·kg−1 polyacrylamide and P, N+P fertilizer increased significantly by 38.7% and 58.1%, respectively.  Conclusion  The application of polyacrylamide in C.oleifera soil can effectively improve soil water holding capacity, but will not promote soil N2O emission, which is conducive to the development of efficient water-saving forestry and the mitigation of global climate change. [Ch, 5 fig. 1 tab. 35 ref.]
Response of soil N mineralization to long-term N addition and season in Cunninghamia lanceolata plantation
YANG Shiming, CAI Qiankun, LIU Wenfei, WU Jianping
2021, 38(5): 945-952.   doi: 10.11833/j.issn.2095-0756.20210403
[Abstract](166) [HTML](26) [PDF](27)
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  Objective  With an experiment conducted Guanzhuang National Forestry Farm, Sha County, Sanming City of Fujian Province, this study is aimed to investigate the effects of long-term nitrogen (N) deposition and seasonal change on inorganic N and N transformation rates in the Cunninghamia lanceolata plantation.   Method  Besides a long-term (10-year-long) N addition experiment with four gradients (control: N0, low: N1, medium: N2, high: N3), the cultivation experiment in situ was conducted to determinate the N mineralization, nitrification and leaching rates in response to N addition.  Result  (1) N addition significantly increased the mass fractions of ammonium N (NH4 +-N), nitrate N (NO3 -N) and total inorganic N, showing the trend of N3, N2, N1 and N0, and the ammonium N was higher than nitrate N. (2) N transformation rates increased with the N addition gradients, while high N addition significantly promoted the N transformation rates. (3) Seasonal changes significantly affected N transformation rates, and the N mineralization, nitrification and leaching rates were higher in summer and lower in winter.   Conclusion  N addition significantly increased soil inorganic N and N transformation rates whereas soil pH, C/N ratio and temperature may be the factors of N addition driving soil inorganic N and N transformation rates in the C. lanceolata plantation. Therefore, closer attention should be paid to the response of soil nutrients and N transformation rates to exogenous N input in the management of C. lanceolata plantation. [Ch, 2 fig. 3 tab. 40 ref.]
Research progress in the impact of different mycorrhizal types on soil carbon cycling
JIN Wenhao, SHAO Shuai, CHEN Junhui, QIN Hua
2021, 38(5): 953-962.   doi: 10.11833/j.issn.2095-0756.20210531
[Abstract](249) [HTML](29) [PDF](41)
Abstract:
Mycorrhiza is a bridge between plants and soil in terrestrial ecosystems, and acts on soil carbon cycling by affecting litter decomposition, soil aggregation, and root exudates. Different types of mycorrhiza have different physiological functions, among which ectomycorrhiza (ECM) and arbuscular mycorrhiza (AM) are the most widely distributed mycorrhizal types. Previous studies showed that different mycorrhizal types affected soil organic carbon input through the distribution of host photosynthetic products. The stability of soil organic carbon was affected by the differences of metabolites and winding action, and the soil organic carbon mineralization was affected by regulating the litter decomposition characteristics and interrelationship between mycorrhizae and microbe. In order to understand how ECM and AM affect soil carbon cycling and its key regulatory factors, this study reviewed the effects of different types of mycorrhiza on soil carbon cycling from four aspects and discussed the influence mechanisms: differences in the distribution process of photosynthetic products such as providing carbon and litter quantity to mycorrhizae, carbon sink functions of different mycorrhizal types and the impacts on soil aggregation, differences in soil organic carbon mineralization such as litter decomposition, priming effect and soil respiration in different dominant mycorrhizal ecosystems, and different accumulation capacity for soil carbon and corresponding microbial communities in different dominant mycorrhizal ecosystems. Finally, the future research direction is proposed, aiming to provide theoretical basis for how to enhance the carbon sink functions of ecosystems by relying on mycorrhiza in the context of “carbon neutrality”. [Ch, 2 fig. 94 ref.]
Effects of the mole fraction of elevated atmospheric CO2 on soil organic carbon stability
HAN Mixue, YU Hongyan, LIU Panyang, RAO De’an, TENG Yue, ZOU Luyi
2021, 38(5): 963-972.   doi: 10.11833/j.issn.2095-0756.20200502
[Abstract](368) [HTML](56) [PDF](27)
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The fast development of the industry has been accompanied with a significant increase of the global atmospheric CO2, which will affect the transformation and renewal of soil organic carbon (SOC), and then its stability. Therefore, an exploration of the effects of elevated atmospheric CO2 on SOC stability is not only an important attempt to evaluate the feedback effect of terrestrial ecosystem on climate change, but also of great significance to the effective storage of element C in soil and the sustainability of soil fertility. With an overview of previous researches, this study is aimed at a summary of the effects of elevated atmospheric CO2 on SOC stability and its stability indexes (biological index, chemical index, other index, etc.), the interaction between exogenous N and elevated atmospheric CO2 on SOC stability as well as the variation trend of SOC stability over time. The results showed that elevated atmospheric CO2 resulted in an increase in the proportion of labile organic carbon (readily oxidized carbon, particulate organic carbon, dissolved organic carbon, etc.), and a decrease in SOC stability, especially in nitrogen limitation environment. It was also found, with a summary of the research findings in recent decades, that there was a gradual decrease in the SOC stability reduction rate with the increase of high CO2 treatment time, indicating that the soil itself is equipped with the capacity to adapt and recover on its own. In conclusion, given the the feedback effect of SOC stability variation on plant physiology and growth, future researches on the effects of elevated atmospheric CO2 on SOC stability should be focused on promoting the sustainability of soil fertility in farmland ecosystem and increasing crop production and productivity. [Ch, 1 fig. 74 ref.]
Research progress on soil organic carbon and microbial characteristics of Cunninghamia lanceolata plantation and their influencing factors
ZHU Danmiao, CHEN Junhui, JIANG Peikun
2021, 38(5): 973-984.   doi: 10.11833/j.issn.2095-0756.20200598
[Abstract](180) [HTML](56) [PDF](159)
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As an important part of soil carbon pool, the stability, growth or attenuation of soil organic carbon are closely related to the change of atmospheric CO2 concentration. Soil microorganisms, an indispensable part of forest ecosystem, participate in the decomposition of organic matter and the transformation of soil matter and play an important role in maintaining soil quality. The relationship between soil organic carbon and microbial characteristics is extremely close. In recent years, the research on soil in Cunninghamia lanceolata plantation in China has mainly focused on litter decomposition, soil nutrient turnover, soil microbial characteristics and so on. With the wide application of high-throughput sequencing technology, the research on soil organic carbon and microbial characteristics of C. lanceolata plantation has made a lot of important progress. In this study, the research progress on pool characteristics, activity, and stability of soil organic carbon as well as community structure and diversity of soil microorganisms and their influencing factors in C. lanceolata plantation were reviewed, and the future research direction of soil organic carbon and soil microorganism in C. lanceolata plantation was put forward. [Ch, 79 ref.]
Soil organic matter chemistry based on pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) technology: a review
MA Shuqin, Degyiyongzom, QIN Xiaojing, CHEN Youchao, HU Yang, WANG Ziwei, LU Xuyang
2021, 38(5): 985-999.   doi: 10.11833/j.issn.2095-0756.20210133
[Abstract](303) [HTML](76) [PDF](28)
Abstract:
Soil organic matter (SOM), an important component of ecosystems, plays an important role in the biogeochemical cycling of soil nutrients. However, it is difficult to analyze SOM chemistry due to its complexity and diversity resulting from microbial and physicochemical transformations of organic residues from plants, microorganisms and animals. Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) is a fast and reproducible technique to obtain qualitative and quantitative analysis of SOM chemistry, in which has been commonly used in recent years. This paper summarized the components and sources of SOM, accordingly, reviewed the literature which study on chemical composition of SOM with Py-GC/MS technology. The basic theoretical studies of SOM chemistry with Py-GC/MS technology mainly focus on: the chemical composition of SOM and precursor substances from which it is derived, the analysis of specific SOM chemical components, SOM responses to climate change and land use change, and the effects of SOM chemistry on soil processes and functions. The application of Py-GC/MS technology on SOM chemistry included: evaluating the stability of SOM, investigating the cycling of soil nutrition and the succession process of ecosystem. This study showed that: (1) There are some differences in SOM chemical composition among different ecosystems, because the accumulation of compounds from different plants and the mechanisms related to the chemical composition of initial litter can directly influenced the chemical composition of SOM; (2) The SOM chemical composition is closely related to the external environmental conditions and is the result of the comprehensive influence of several factors. For instance, climate is the most important factor that influenced the content and dynamic of SOM by affecting the distribution of vegetation, photosynthetic production and soil microbial activity. Besides, nitrogen deposition, land use change, wildfire and tillage pattern also can influence the contents and qualities of SOM. Overall, it is important to investigate the SOM-related ecological process and the mechanism of SOM response to climate change and human activities, from the perspective of the essence of SOM (chemical composition and structure) based on Py-GC/MS technology. [Ch, 1 fig. 107 ref.]
Research progress on effects of cutting on forest soil respiration
ZHU Wenjian, ZHANG Hui, WANG Yixiang
2021, 38(5): 1000-1011.   doi: 10.11833/j.issn.2095-0756.20210365
[Abstract](206) [HTML](50) [PDF](12)
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Logging, as one of the routine forest management activities, is an important human interference measure affecting forest soil respiration, an important source of atmospheric CO2. Therefore, research on the effects of logging on forest soil respiration has important scientific significance and application value for better understanding forest carbon cycle and coping with global climate change. This paper, with logging divided into two types: clear cutting and partial cutting (further classified as selective cutting, gradual cutting, thinning and regeneration cutting, etc.), is aimed to conduct a review of research advances on the effects of clear cutting and partial cutting on soil respiration, a discussion of the main mechanisms of clear cutting and partial cutting on soil respiration as well as a summary of the effects of current cutting on forest soil respiration and its components and soil temperature sensitivity (Q10) with future research prospects put forward. Results showed that the researches on soil respiration are mainly focused on the following aspects: (1) the direction and extent of the effect of clear cutting or cutting intensity on soil respiration; (2) the dynamic characteristics of soil respiration with time and environmental factors such as soil temperature after clear cutting or partial cutting; (3) effects of clear cutting or partial cutting on soil respiration components; (4) the effect of clear cutting or partial cutting on Q10 and (5) the effect mechanism of clear cutting or partial cutting on soil respiration. The main conclusions are as follows: (1) the effect of cutting varies with different cutting intensity, cutting measures, treatment of cutting residues, climate types, forest types and vegetation restoration time; (2) the results showed that the soil autotrophic respiration usually decreased and heterotrophic respiration usually increased after logging, and the total soil respiration showed that autotrophic respiration and heterotrophic respiration offset each other, and this effect would decrease with the increase of vegetation restoration. It is proposed that further efforts should be focused on the impact of different intensity of harvesting, different vegetation restoration stages, other forest management measures and rising atmospheric CO2 concentration on regional soil respiration and components, so as to better understand the impact mechanism of harvesting on forest ecosystem carbon cycle. [Ch, 2 tab. 89 ref.]
Impacts of poplar harvesting residue additions on soil nutrients and CO2 emission
LAN Ziyu, DING Sihui, FANG Shengzuo
2021, 38(5): 1012-1022.   doi: 10.11833/j.issn.2095-0756.20210186
[Abstract](105) [HTML](72) [PDF](22)
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  Objective  Impacts of the addition of poplar harvesting residues on soil nutrients and CO2 emission were investigated in controlled conditions to provide a reference for its potential utilization.  Method  The indoor incubation experiment was carried out by selecting logging residues of twigs, barks, and leaves from a poplar plantation and the rice straw as research materials. Based on the litter amount in the unit area of the poplar plantation, the fresh soil equivalent to 100 g of dry soil weight and biomass materials equivalent to 2% of dry soil weight were mixed evenly. Then the mixed soils were loaded into a homemade polyethylene plastic box, and incubated in a constant temperature incubator at 25℃ for 180 days in darkness. During the culture period, the soil moisture content was controlled to 60% of the field moisture capacity. Dynamic variations in microbial biomass carbon (MBC) and nitrogen (MBN), inorganic nitrogen (NH4 +-N and NO3 -N), available phosphorus (AP) and available potassium (AK) as well as CO2 in the soil were measured.  Result  (1) The addition of all four residue biomass significantly affected microbial biomass and nutrient availability in the soil (P<0.05). Compared with the control, the soil MBC contents treated by the residue biomass of poplar twigs, barks, leaves and straw increased by 50%, 31%, 80% and 109% respectively, while the soil MBN contents increased by 54%, 40%, 72% and 203%, respectively. The contents of NH4 +-N in the soil treated with bark and twigs residues were higher than those in the control and rice straw treatments, whereas the NO3 -N content in the soil was in the order of control>rice straw>leaf residue>bark residue>twig residue treatments. The highest AP content was observed in the soil treated with twigs, while the AK content in the soil treated with rice straw was higher than that treated with other biomass residues. (2) After adding biomass residues into the soil, the daily release rate of CO2 from the soil showed a tendency with being relatively fast in the initial period, gradually slowing down in the middle stage, and tending to be stable in the later stage of the incubation. After 180 days of indoor incubation, the cumulative CO2 emission from the soil treated with rice straw was significantly higher than that of the other treatments (P<0.05), followed by the soil treated with poplar leaves. (3) Correlation analysis showed that microbial biomass, nutrient contents and CO2 daily release rate in the soil were obviously correlated to the properties of biomass residues. Of them, a significantly positive correlation of soil microbial biomass to the contents of total nitrogen, total phosphorus and total potassium but a significantly negative correlation to the total carbon content and C/N ratio in the biomass residues were detected (P<0.05). Meanwhile, the CO2 daily emission rate was positively correlated to the contents of MBC, MBN, NH4 +-N, AP and AK in the soil (P<0.05), whereas a significantly negative correlation of the CO2 daily emission rate to the contents of NO3 -N was observed (P<0.01).  Conclusion  From the views of soil nutrients and environmental effects, application of poplar harvesting residues not only can increase the contents of soil available nutrients, but also relatively reduce carbon emissions compared with the rice straw. [Ch, 3 fig. 3 tab. 47 ref.]
Changes of soil organic carbon storage in Pinus tabulaeformis forest and its influencing factors
WANG Yue, LUAN Yaning, WANG Dan, DAI Wei
2021, 38(5): 1023-1032.   doi: 10.11833/j.issn.2095-0756.20210390
[Abstract](138) [HTML](50) [PDF](13)
Abstract:
  Objective  The objective is to explore the vertical and temporal variation characteristics of soil organic carbon(SOC) content and storage in Pinus tabulaeformis forest, so as to provide a theoretical basis for soil carbon storage prediction and carbon sink management in P. tabulaeformis forest.  Method  Based on the literature data from 1980 to 2017, the characteristics of spatial and temporal variation for SOC content and storage in P. tabulaeformis forest under brown soil and cinnamon soil types were discussed using the methods of one-way ANOVA, multiple comparison, correlation analysis and path analysis, and the driving factors were analyzed combined with China’s forest management measures and growth characteristics of P. tabulaeformis in different periods.  Result  The change of SOC content and storage in P. tabulaeformis forest decreased significantly with the increase of soil depth (P<0.05), and 0−20 cm soil layer was the main contribution layer of carbon pool, accounting for 45%−50% of SOC storage in 0−60 cm soil layer. In the past 40 years, the content and storage of SOC showed the temporal variation characteristics of first decreasing and then increasing, among which 2000−2009 was the lowest, and then increased significantly, reaching the highest storage point of 247.02 Tg in 2017.  Conclusion  Soil bulk density, soil total nitrogen and stand canopy density are the main factors affecting the change of SOC content, and the profound effects of forest management and protection measures on the three factors are the important reasons for the significant temporal changes of SOC content and storage in P. tabulaeformis forest. [Ch, 3 fig. 5 tab. 49 ref.]
Distribution characteristics of soil organic carbon storage in photovoltaic power station under different vegetation restoration modes
ZHAO Jing, HAO Mengjie, WANG Qingyu, LIU Meiying
2021, 38(5): 1033-1039.   doi: 10.11833/j.issn.2095-0756.20210500
[Abstract](77) [HTML](31) [PDF](14)
Abstract:
  Objective  This study aims to explore the change characteristics of soil organic carbon mass fraction and storage at 0−40 cm under different vegetation restoration measures in the environment of photovoltaic power station, so as to provide theoretical basis for the optimal allocation of ecological management mode of photovoltaic power station in arid area.  Method  Three artificial vegetation plots(Pinus sylvestris var. mongolica, Astragalus membranaceus var. mongholicus, Medicago sativa) in the photovoltaic power station were selected as the research objects, and the natural vegetation plots undisturbed by power station construction were used as the control.  Result  After replanting, the soil organic carbon mass fraction and storage of P. sylvestris var. mongolica, A. membranaceus var. mongholicus and M. sativa were still significantly lower than those of the control (P<0.05). However, compared with the other two plots, the soil organic carbon mass fraction of P. sylvestris var. mongolica sample plot increased significantly by 4.99 and 6.80 g·kg−1, while the organic carbon storage increased significantly by 14.52 and 19.37 t·hm−2 (P<0.05). The mass fraction and storage of soil organic carbon in the study area decreased significantly with the increase of soil depth (P<0.05). Vegetation type, soil depth and their interaction significantly affected the organic carbon mass fraction in the study area. In addition, soil pH and electrical conductivity were also important indicators affecting the mass fraction and storage of organic carbon.  Conclusion  With the advancement of environmental governance in the power station, compared with herbages, P. sylvestris var. mongolicacan can be artificially planted in the photovoltaic power station to improve soil carbon sequestration and minimize human interference in the later stage, which is of great significance to improve regional ecological benefits. [Ch, 2 fig. 3 tab. 39 ref.]
Ecological effects of microplastics contamination in soils
ZHOU Yumiao, HE Ganghui, MA Shaofeng, SHAO Fanglei, FEI Yufan, HUANG Shunyin, ZHANG Haibo
2021, 38(5): 1040-1049.   doi: 10.11833/j.issn.2095-0756.20200729
[Abstract](406) [HTML](140) [PDF](29)
Abstract:
Large amounts of microplastics have been accumulated in soils and their degradation is relatively slow. The residual time of microplastics in soils could be extended to decades or even over a hundred years. Therefore, the ecological effects of long-term residual of the microplastics in soils has been of concerned widely in recent years. Published papers related to the microplastics and their effects in soils were collected and introduced in order to make a full review in the field. The research advances were presented based on the different ecological receptors, which included change of soil physical environment due to the accumulation of microplastics, ingestion of microplastics by invertebrates from soils and their effects on the enteric microorganism, response of soil microbial community and soil enzyme to microplastics pollution, plant uptake of microplastics and their effects. The studies of effects on soil physical environment in the present of microplastics mainly focus on soil density, soil aggregate composition and water hold capacity. Such effects were supposed to have further impacts on soil enzyme activity, microbial community composition and even plant growth based on current limited studies. Many other studies at present were also concentrated on the migration of microplastics induced by soil invertebrates e.g. earthworm, springtail. Meanwhile, microplastics in the soil might be ingested by soil invertebrates and subsequently caused some negative effects and influence on the gut microorganism community of the soil invertebrates. There were also some studies focusing on the microplastics accumulation through food chain regarding the effects of microplastics on soil animals. For example, microplastics might be accumulated in chicken through the predation of earthworm by chicken. After the introduction of current studies, several research proposal were put forward based on the complication of microplastic’s properties and the shortage of current researches. These proposal contained four aspects: (1) development of standard protocols for the study of ecotoxicology of soil microplastics pollution, (2) studying the interaction mechanism between microplastics and microorganisms, plants and invertebrates, (3) revealing microbiological mechanisms that regulation of the transformation of materials and microplastics in soils, (4) exploring plastishere in soils of different ecosystems. All these researches are expected to be supportive to assessment of the ecological effects of soil microplastics pollution. [Ch, 80 ref.]
Stoichiometric characteristics of soil C, N and P in Torreya grandis stands of different ages
YUAN Ya’nan, LI Zhengcai, WANG Bin, ZHANG Yujie, HUANG Shengyi
2021, 38(5): 1050-1057.   doi: 10.11833/j.issn.2095-0756.20200761
[Abstract](163) [HTML](56) [PDF](77)
Abstract:
  Objective  This objective is to investigate the contents and stoichiometric characteristics of soil organic C, total N and total P in Torreya grandis stands of different ages, so as to provide basic data for the management and protection of T. grandis.  Method  T. grandis of four different ages (0−100, 100−300, 300−500 and >500 a) were selected from Zhuji National Forest Park of T. grandis‘Merrilli’ in Zhejiang Province. Soil samples were collected from different soil layers (0−20, 20−40, 40−60 cm) to analyze the content and stoichiometric characteristics of soil C, N, and P in T. grandis stands of different ages.  Result  (1) The contents of soil organic C and total N at four ages were 10.90−24.22 and 1.22−2.22 g·kg−1 respectively, which increased first and then decreased with forest age, but without significant differences. The contents of soil total P ranged from 0.24 to 0.80 g·kg−1, which decreased first and then increased with forest age, but the differences were not significant(P>0.05). (2) The average values of soil C∶N and N∶P at four ages were 8.59−10.89 and 3.06−6.16 respectively, which increased first and then decreased with forest age, but the differences were not significant(P>0.05). The soil C∶P ratio was 31.54−63.72 at different forest ages, which showed a trend of decreasing first and then increasing with age, and the C∶P ratio of some forest ages had significant differences(P<0.05). (3) There was a significant positive correlation between soil C, N, and P contents at different forest ages, and extremely significant positive correlation between C and N (P<0.01). There was a significant negative correlation between P and C∶P ratio, P and N∶P ratio, and an extremely significant positive correlation between C∶P ratio and N∶P ratio(P<0.01).  Conclusion  The growth of T. grandis is mainly limited by soil P. Therefore, reasonable addition of P fertilization can be considered to improve soil fertility and nutrient cycling between plant and soil. [Ch, 4 tab. 34 ref.]
Ecological stoichiometric characteristics of rhizosphere and non-rhizosphere soil of Pinus sylvestris var. mongolica plantations at different ages
CHENG Haotian, KONG Tao, LÜ Gang, WANG Dongli, ZHANG Lili
2021, 38(5): 1058-1065.   doi: 10.11833/j.issn.2095-0756.20210211
[Abstract](73) [HTML](12) [PDF](15)
Abstract:
  Objective  The purpose is to explore the relationship between C, N, and P contents in rhizosphere and non-rhizosphere soil and ecological stoichiometric characteristics of Pinus sylvestris var. mongolica plantations at different ages in sandy land of northwest Liaoning Province, so as to provide theoretical basis for cultivation and management of P. sylvestris var. mongolica plantations in this area.  Method  Using space-temporal exchange method, six P. sylvestris var. mongolica plantations (10, 20, 30, 40, 50 and 60 a) were selected in Zhanggutai area to analyze the differences and influencing factors of C, N, P contents and stoichiometric ratio between rhizosphere and non-rhizosphere soil of different stand ages.  Result  The soil of P. sylvestris var. mongolica plantation in the sandy land of northwest Liaoning was poor, and the contents of C, N, and P in rhizosphere soil were higher than those in non-rhizosphere soil. The root system had a significant effect on nutrient enrichment and balance maintenance. Stand age, rhizosphere, and their interaction had significant effects on soil C, N, P contents and their ecological stoichiometry. Soil C∶N of the P. sylvestris var. mongolica plantation was mainly affected by total N, soil C∶P was mainly affected by soil organic carbon, and soil N∶P was more affected by total N than total P. The soil C∶N ratio of P. sylvestris var. mongolica plantation at all ages was much higher than that of the national average level, which was manifested as N limitation, especially in the 60 a over mature forest. The limitation of N and P in rhizosphere soil of P. sylvestris var. mongolica plantation was synergistic to some extent.  Conclusion  The growth of P. sylvestris var. mongolica at all ages is restricted by N, and non-rhizosphere soil is more deficient in N compared with rhizosphere soil. In forest management, the difference between rhizosphere and non-rhizosphere soil should be fully considered. It is suggested that N fertilizer and N-fixing plants should be applied and introduced to P. sylvestris var. mongolica plantations in sandy land of northwest Liaoning to relieve N limitation, and P fertilizer should be added to the root system. [Ch, 1 fig. 5 tab. 28 ref.]
Soil fertility in Carya cathayensis plantation: a review
HU Yingbing, JIN Jin, TONG Zhipeng, WU Jiasen
2021, 38(5): 1066-1075.   doi: 10.11833/j.issn.2095-0756.20210501
[Abstract](102) [HTML](19) [PDF](9)
Abstract:
Chinese hickory (Carya cathayensis) is a unique woody nut and oil tree species in China. Chinese hickory industry brings high income for local farmers in its main production region. Soil fertility such as nitrogen, phosphorus and potassium in soils determines the healthy growth of Chinese hickory. Therefore, research related to soil fertility are attracting more attention in China. The soil fertility of Chinese hickory plantation was mainly influenced by elevation, parent materials and antropogenic management, among which the intensive management plays an important role in soil fertility variation. Intensive management could lead to the heavy decrease of soil fertility such as soil acidification, the decrease of soil organic carbon and available nutrient contents. The removement of understory resulted in the severe soil erosion as well as obvious nutrient loss. The composition of soil microbial community changed and its diversity declined. What’s more, due to the deterioration of soil quality, the yield and quality of hickory nut dropped. The application of organic materials and sod cultivation increased soil pH, as well as the contents of soil organic carbon and available nutrients, and further effectively improved soil fertility. Current researches mainly focus on the spatio-temporal changes of soil fertility. Reasonable fertilizer application and the effect of net harvesting of hickory nut on soil fertility need further study. The formation mechanism along with the control techniques of soil erosion in Chinese hickory plantation also need deeply explored, which can provide basic information and technique support. [Ch, 71 ref.]
Comprehensive evaluation of soil fertility in relocated land for landscaping
WU Haibing, HE Xiaoli, LIANG Jing
2021, 38(5): 1076-1081.   doi: 10.11833/j.issn.2095-0756.20200753
[Abstract](163) [HTML](79) [PDF](14)
Abstract:
  Objective  The objective is to analyze soil fertility index and soil fertility quality in typical relocation sites in Shanghai, and to explore the soil fertility quality characteristics of the relocated land in villages and industrial enterprises in the city, so as to provide basis for the use of the relocated soil in landscaping.  Method  The 20 typical relocation sites of urban villages and 16 relocation sites of industrial enterprises in Shanghai were selected, and 7 soil fertility indexes including pH, electrical conductivity(EC), organic matter, hydrolytic nitrogen, available phosphorus, available potassium and bulk density were selected as fertility evaluation indexes. The modified Nemoro method was used to comprehensively evaluate the quality of soil fertility in the relocation sites.   Result  The soil in the relocation site was alkaline, with suitable EC, relatively low contents of organic matter and hydrolytic nitrogen, rich contents of available phosphorus and available potassium, and high soil bulk density. The average comprehensive index of soil fertility in Shanghai was only 0.86. The comprehensive index of soil fertility in the relocation sites of urban villages was significantly higher than that in the relocation sites of industrial enterprises (P<0.05).   Conclusion  The soil fertility in the relocation sites of Shanghai is relatively poor, 59.3% of which belong to “poor” grade and 40.7% belong to “general” grade. The soil fertility of urban villages is better than that of industrial enterprises. Before the relocated land is used for urban landscaping, soil fertility quality should be improved by technical means to meet the requirements of planting. [Ch, 5 fig. 2 tab. 23 ref.]

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