长期不同施肥处理对红壤水稻土微生物量氮周转的影响

【目的】土壤微生物生物量是土壤重要的活性养分库。研究长期不同施肥处理下土壤微生物生物量的周转特性，探究施肥对土壤养分转化与供应能力的影响。【方法】对田间长期单施或配施无机氮肥（N）、无机磷肥（P）、无机钾肥（K）、有机质循环（C）及1/2秸秆回田（S）的试验进行采样分析，研究不同施肥处理下土壤微生物生物量、微生物量氮周转及水稻产量变化。【结果】施用磷肥有利于提高土壤微生物量碳、微生物量氮、微生物量氮周转速率以及作物产量，比未施用磷肥处理平均提高了13.2%、33.1%、31.2%及173.4%。单施有机肥也有利于提高土壤微生物量碳、微生物量氮和作物产量，比对照提高了36.1%、28.1%和68.1%，但微生物量氮周转速率降低了4.3%。有机无机肥配合施用显著提高了土壤微生物量碳、微生物量氮、微生物量氮周转速率及水稻产量，NPKC和NPKS处理的土壤微生物量碳、微生物量氮、微生物生物量氮周转速率及水稻产量分别比对照高40.1%、26.3%、177.1%、204.1%和36.1%、20.9%、192.9%、203.3%。【结论】有机无机肥配施能够提高土壤活性养分库，增强土壤养分转化和供给能力，提高稻田生产力。

Soil Microbial Biomass N Turnover After Long-Term Fertilization in Paddy Field

【Objective】Soil microbial biomass plays an important role as a dynamic sink of nutrients. Soil microbial biomass turnover was evaluated after long-term fertilizer application to understand the influence of fertilization on nutrients cycling and nutrients available for plant uptake.【Method】Using soil samples taken from long-term fertilization field of N, P, K fertilizers, organic manure cycling or half amount of rice straw, soil microbial biomass, microbial biomass turnover and grain yield of rice (Oriza sativa L.) under fertilization were determined. 【Result】P fertilizer application increased soil microbial biomass N and C, microbial biomass N turnover and grain yield by 13.2%, 33.1%, 31.2% and 173.4% averagely compared to P fertilizer-omitted treatments. Organic manure application only increased soil microbial biomass N and C, and grain yield by 36.1%, 28.1% and 68.1% , and decreased soil microbial biomass N turnover by 4.3% averagely compared to CK. Incorporation of inorganic and organic fertilizer increased soil microbial biomass N and C, microbial biomass N turnover and grain yield, NPKC and NPKS treatments increased respectively by 40.1%, 26.3%, 177.1%, 204.1% and 36.1%, 20.9%, 192.9%, 203.3% compared to CK.【Conclusion】Incorporation of inorganic and organic fertilizers increased soil available nutrients sink, soil nutrients cycling and nutrients available for plant uptake to high soil productivity.