Impact Of Biochar Applications On Soil Nutrient, Plant Nutrient And Plant Growth In A Subtropical Forest

Biochar has been widely applied in agricultural ecosystems as the soil ameliorant, while few relevant researches have been conducted on the amelioration of forest soil-vegetation systems. Considering its desirable effect on the soil amelioration, biochar made of banboo charcoal was used in this research. It was applied in subtropical forest soil in PanShan, the gradient of which was set as CK, low biochar group (10 t·ha-1) and high biochar group (30 t·ha-1). In situ, sampling was combined in laboratory to analyze the impact on the content of forest soil carbon, nitrogen and phosphorus, topsoil (0-10 cm)’s content of stable isotope δ13C and δ15N, vegetation leave’s content of carbon and nitrogen, vegetation growth and herbage biomass. The results were as follows:(1) Biochar can increase the pH of the soil, and when it comes to the amount of 30 t·ha-1, the pH of soil can increase significantly by 3%; Soil total carbon content increases with the biochar application gradient.(2) The surface layer of soil carbon to nitrogen ratio (C:N) and carbon to phosphorus ratio (C:P) increases with the gradient of biochar application; The soil nitrogen phosphorus ratio (N:P) is not significantly changed by biochar application. The surface layer of soil shows no significant change in δ15N; while δ13C increases with the amount of biochar addition.(3) The foliar total carbon of Pseudolarix amabilis and Phoebe chekiangensis have no significant change after biochar application, the soil amendment of biochar doesn’t affect the plant foliar total nitrogen content but the content shows obvious seasonal dynamics, lower in autumn and winter, higher in spring and summer. The carbon to nitrogen ratio of plant is not influenced by biochar.(4) The relative growth rate of basal diameter (RGR) of Pseudolarix amabilis and Phoebe chekiangensis don’t change significantly after soil biochar application. The tree height relative growth rate (RGR) of Phoebe chekiangensis shows no significant difference among treatments. The tree height RGR of Pseudolarix amabilis significantly increases (low biochar group> high biochar group> CK) after the application of biochar. In addition, the biomass of herbaceous layer would be affected by the amendment of biochar.In summary, when biochar as a soil amendment, it is possible to change the subtropical forest soil characteristics, increase the dominant species tree height growth, and promote the herbaceous layer biomass. This conclusion can provide a theoretical basis and data supports for biochar used in the subtropical forest ecological restoration.