Effects of Rape Straw Biochar on Organic Carbon Mineralization and Accumulation in Purple Soil
An incubation experiment was conducted in the laboratory to investigate the effects of rape straw biochar and rape straw on soil organic carbon (SOC) mineralization of purple soil.The experimental soil and rape straw were sampled from Dianjiang county, Chongqing city.In this experiment, different amounts of rape straw (straw/soil mass ratio is 0.25％, 0.5％ and 1％) were added to soils in J1, J2 and J3 treatments, respectively.We also established 3 treatments with the addition of different amounts of biochar, which were made by the same amount of rape straw in J1, J2 and J3 treatments under 600 ℃, respectively, and marked as S1, S2, and S3 treatments in turn.All the treatments were incubated for 56 d under 25 ℃.In the whole incubation period (56 d), the temporal changes of mineralization rate of soil organic carbon followed a power function.The cumulative mineralization amount and mineralization intensity of soil organic carbon, and the ratio of degradable organic carbon content to total organic carbon content (Ca/CSOC) in soil in the biochar treatments were significantly lower than those in the corresponding rape straw treatment (P＜0.05).The results indicated that after the rape straw was made into biochar through pyrolysis, the stability of rape straw biochar in the soil was significantly higher than that of rape straw.There was no significant difference in the cumulative mineralization amount and mineralization intensity of soil organic carbon, Ca/CSOC and the ratio of difficultly decomposed organic carbon content to total organic carbon content between the biochar treatment and control treatment (no exogenous carbon added), which suggested that the addition of biochar did not affect the SOC decomposition of purple soil.In addition, the apparent retention rate of the exogenous carbon was significantly higher in the S1 treatment than in other incubation treatments, while the apparent retention rates of the exogenous carbon in the S2 and S3 treatments were significantly lower than those in the corresponding rape straw treatments (J2 and J3), respectively.The results indicated that the biochar return was more beneficial to organic carbon sequestration in purple soil than the direct rape straw return when the amount of rape straw returned to field was at a low level.
国家科技期刊平台
NSTL
万方数据
维普
