Effects Of Biochar Application On Forest Soil Moisture And Plants In Subtropical Regions

The research about biochar as a soil amendment attracted the world’s attention, soil erosion and deforestation in Chinese subtropical forest vegetation was getting serious along with the problem of soil degradation. Biochar was porous properties, so we put it into forest soil as soil amendment in order to increase soil capacity of preserve moisture and fertility, and improve the plant growth and recovery of vegetation.This study combined the control indoor experiment with field experiment to find the influence of applying biochar on soil moisture and plants. The indoor experiment chose three forest soil of different interferential type, and set 5 biochar concentration (ck,1%,2%,4%,6%) to observe soil saturated water content and water retention capacity. Field experiment set 3 treatments in Panshan forest (ck, low biochar(10t/ha), high biochar(30t/ha)) to observe the variation of soil moisture, vegetation growth and water status. The research mainly results are follows:(1) In subtropical regions, biochar addition significantly increased soil saturated water content (SWC), but the response of various type soil is different, it was Panshan >Tiantong>Shuangfeng. The SWC was significantly increased along with the biochar concentration, and had significant in different concentration. The water holding capacity was significantly between the different concentration, and the impact of different biochar concentration on attenuation coefficient was significant in different soil type.(2) Soil moisture was significantly increased with the biochar concentration, the variation of 0-10cm continuous soil moisture was more greatly, and the variation of 10-20cm continuous soil moisture was more obvious.(3) Soil water potential was declined with the biochar concentration, the 0-10cm soil water potential was significant difference in high concentration, but was no significant difference in low concentration. The 10-20cm soil water potential was declined, but there was no significant difference.(4) In the response of biochar amendment on plants, the tree height relative growth rate (RGR) of Pseudolarix amabilis was increased in low concentration and declined in high concentration, but there was no significant difference. The basal diameter RGR of Pseudolarix amabilis was significantly greater than ck in low concentration, but there was no significant difference between high concentration and ck. The tree height RGR of Phoebe chekiangensis was significantly lesser than ck in low concentration, but there was no significant difference between high concentration and ck. The basal diameter RGR of Phoebe chekiangensis was no significant difference among the treatments.(5) The leave water potential was no significant among the treatments. The carbon isotope of leave(δ13C) was declined with the increasing of leave age in biochar amendment, and the δ13C of new leave was lesser than old leave.Our study found that when we use biochar as soil amendment, the physical properties of soil plays an important role, so we should make corresponding adjustment according to the properties of soil. If the biochar amendment can further affect plants still has to be further study.