Temporal and spatial variation of soil organic matters in Phyllostachys praecox stands with intensive cultivation management

Key words: 
• pedology /
• Phyllostachys praecox stand /
• intensive cultivation management /
• soil organic matter /
• temporal and spatial variation /
• carbon sequestration

Abstract: Phyllostachys praecoxis a favourite bamboo specieswith highereconomic value forits bamboo shoot as a delicious vegetable. The practice of intensive managementby overfertilizingof complexfertilizer(16∶16∶16, 2.25 thm- 2)and urea(1.125 thm- 2)peryearplusheavierwintermulching(40 thm- 2 of rice strawand 55 thm- 2 of grounded bamboo leaves)every two years starting at 5 years for the higher yield of bamboo shoot and earlier marketing at the Chinese Spring Festival season to gain better price and incomes in Southeast China, especially in Zhejiang Province. The objective of this study is to analyse the temporal and spatial variation of soil organic matters(SOM)in Phyllostachys praecox stands during last 15 years with very intensive cultivation management in Lin'an.Total of 20 soil profileswere sampled in main cultivation region of Sankou Town, choosing 1, 5, 10, 15 and 0 years(paddy fields nearby as the beginning soil Phyllostachys praecox stands as a check) plantation of bamboo stands and each by 4 replications. Results indicated thatwith the increase of plantation year,SOMdropped a little in the beginning(1 year), and then rose up steadily. SOM content in surface layer of 0- 10 cmwere gradually increased from1, to 5 years, then 10 and 15 years, andwere 30.96, 25.55, 26.35, 33.07 and 79.24 gkg- 1 respectively. Very high SOM content in 10 years and 15 years soils were resulted from over fertilization and heavy wintermulching of biomass. SOM spatial distribution in soil profiles showed that it was decreased with the soil depth increase in the layers of surface(0- 10 cm) and subsurface(10- 20 cm), but not in the bottom layer(20- 40 cm), it neither dropped at1 years clearly and nor increased lateron, showed a relative steady situation.It indicated that intensive cultivationmanagementhad vigorously effectonSOMcontentin 0- 10 cm surface and 10- 20 cmsubsurface layerswhere the bamboo shootproduced, butcould notaffectthe deep layerof soil. The effect of high content of SOMin Phyllostachys praecox stands on soil quality and its sustainable use, the significance of carbon sequestration of such high SOM accumulation by this intensive management practices were also discussed.[Ch, 1 fig. 2 tab. 20 ref.]