耕作与施肥对甘蔗地土壤微生物量碳、氮的影响

通过野外调查与室内分析，研究了云南蒲缥甘蔗地赤红壤不同耕作与施肥土壤剖面微生物量碳、氮特征。结果表明:不同耕作与施肥对土壤微生物量碳、氮均有一定影响，其中耕作对土壤微生物量碳、氮的影响较为一致，表现为免耕 > 翻耕。施肥对0—20 cm土层中微生物量碳的影响表现为翻耕施肥 > 翻耕，对20—40 cm，40—60 cm土层中微生物量碳的效应呈现为翻耕 > 翻耕施肥，而施肥对土壤微生物量氮影响则与其对微生物量碳的效应相反。耕作和施肥对各个土层土壤微生物商具有显著的影响（p<0.05），表现为免耕 > 翻耕，翻耕施肥条件下0—20 cm土层的微生物商稍高于翻耕，而其他土层均为翻耕 > 翻耕施肥；土壤微生物量氮与全氮的比值与微生物量氮的变化趋势相近。在不同的耕作和施肥条件下，免耕有利于提高土壤微生物量，施肥在一定程度上也利于提高土壤微生物量。

Effects of Tillage and Fertilization on Soil Microbial Biomass Carbon and Nitrogen in Sugarcane Field

The soil microbial biomass carbon (SMBC) and soil microbial biomass nitrogen (SMBN) in latosolic red soil at Yunnan Pupiao were investigated to determine how they were affected by tillage and fertilization. The results showed that different tillage and fertilization on soil microbial biomass carbon and nitrogen were affected. The effects of tillage on soil microbial biomass carbon and nitrogen were consistent, and showed no tillage > tillage. The influence of fertilization on soil microbial biomass carbon in 0—20 cm was tillage fertilization > tillage, 20—40 cm and 40—60 cm were tillage > tillage fertilization, while effect of fertilization on soil microbial biomass nitrogen contrasted with the effect of microbial biomass carbon. The quotients of soil microorganism were significantly different (p<0.05) in different tillage and fertilization and soil depth, and showed no tillage > tillage. Effect of tillage fertilization on soil microbial quotient of the 0—20 cm was slightly higher than tillage, and the other soil layers were tillage > tillage fertilization. The ratio of soil microbial biomass nitrogen to total nitrogen was similar to the trend of soil microbial biomass nitrogen. In different tillage and fertilization, no tillage would improve the soil microbial biomass helpfully, also fertilization could improve the soil microbial biomass in a certain extent.