Growth and biomass carbon sequestration of young Eucalyptus grandis with fertilization

Key words: 
• forest ecology /
• fertilization /
• Eucalyptus grandis /
• growth /
• biomass carbon sequestration

Abstract: Eucalyptus is one of three fast growing tree types used widely in tree plantations，and Eucalyptus grandis has the largest cultivated area of all species because of its fast growth and favorable economic opportunities. To determine the effects of fertilization on growth and biomass carbon sequestration of E. grandis，a compound fertilizer containing 15% N，15% P2O5，and 15% K2O was applied with different treatments of （in gstem－1） 0 （ck），90 （Ⅰ），180 （Ⅱ），and 270 （Ⅲ），and a correlation analysis was employed. Each treatment has three replicates and each was arranged in random blocks. The soil was a Purple soil with an average pH of 5.60，and contained soil organic matter 15.3 gkg-1，total soil N 1.23 gkg-1，available N 82.8 mgkg-1，available P 51.38 mgkg-1 and available K 61.45 mgkg-1 prior to the start of the pot experiment. Results showed that compared to the control，fertilization treatments Ⅰ，Ⅱ，and Ⅲ significantly （One-way ANOVA Duncan Multiply Test） increased the stem base （P ＜0.05，16.3% － 38.3%），crown width （P＜0.05，17.1% － 44.5%），tree height （P＜0.05，15.8% － 45.5%），biomass （P＜0.05，21.8% － 59.5%），and root-shoot （R/S） ratio （P＜0.05，2.1% － 5.8%）. For stem base and tree height，fertilized treatments Ⅲ were significant higher than Ⅰ，but no significant difference was observed between Ⅱ and Ⅲ or Ⅰ. Among fertilized treatments，crown width was significantly different （P＜0.05）. Growth of the stem base，crown width，and tree height were significantly and positively correlated with the amount of applied fertilizer （P＜0.01） and with growth faster in July and August than other months（June and September）. For R/S，Ⅲ was significantly greater than ck. Also，among different treatments，significant differences in biomass（P＜0.05） and biomass carbon sequestration（P＜0.05） were found. Thus，for scientific management and for global warming mitigation，fertilization （at the rate of 0 － 270 gstem-1） could be beneficial for promoting growth of E. grandis，and increasing biomass，biomass carbon sequestration，and root-shoot ratio（R/S）.［Ch，4 fig. 36 ref.］