生物炭对土壤氨氮转化的影响研究

通过测定NH3挥发和氯仿灭菌试验,探讨了生物炭如何通过影响NH3挥发和微生物来影响土壤中NH4+-N的变化,为研究生物炭对土壤外加N素的影响机制提供一定理论依据.结果表明:生物炭加入稻田土后,土壤中KCI浸提态的NH+4-N含量减少34％,其中由于微生物作用受到影响而引起的NH4+-N减少约占总减少量的42％.生物炭加入红壤后,KCl浸提态的NH4+-N含量减少了13％,生物炭对红壤中微生物影响不大.生物炭使两种土壤的pH值升高,引起NH3的挥发,生物炭处理的稻田土和红壤外加NH3-N累计挥发量分别为未加生物炭时的7.8倍和1.7倍.

Influence of Biochar on the Transformation of Ammonia Nitrogen in Soils

Biochar addition to soils has been proposed as a method to increase soil fertility and carbon sequestration. However, the effect of biochar on nitrogen transformation and availability is poorly understood. This study was conducted to determine how the rice straw biochar affected NH+4-N transformation in two soils with contrasting properties using the NH3 volatilization and chloroform fumigation experiments. The results showed that the biochar reduced NH+4-N concentration in the KCl extract of Gleyi-Stagnic Anthrosols soil by 34%, with 42% of the reduction attributed to microbial activity. Less microbial activity was observed in the biochar-amended Argi-Udic Ferrosols soil, so NH+4-N concentration in the KCl extract was reduced by only 13%, compared to the untreated soil. Biochar elevated pH of both soils, resulting in the accumulated NH3 volatilization in Gleyi-Stagnic Anthrosols and Argi-Udic Ferrosols soils as much as 7.8 times and 1.7 times the untreated soil, respectively. The results obtained from this work are helpful for us to understand the mechanism of biochar-induced nitrogen transformation in soils.