氮素形态对甘薯土壤微生物及酶活性的影响

Effect of Nitrogen Forms on Soil Microbes and Soil Enzyme Activities in Sweet Potato Yield

研究氮素形态对土壤微生物特性的影响对于土壤管理具有重要意义。本试验在大田条件下,采用随机区组设计研究了硝态氮、铵态氮和酰胺态氮对甘薯地土壤微生物生物量碳、活跃微生物生物量、土壤呼吸及土壤酶活性的影响。结果表明,土壤微生物生物量碳、活跃微生物量、呼吸速率和土壤酶活性对不同氮素形态的响应不同。土壤微生物生物量碳在块根膨大前中期以铵态氮处理最大,而在收获期以硝态氮处理最大。土壤活跃微生物量以铵态氮处理最大。土壤呼吸速率、呼吸熵、脲酶和蔗糖酶活性均以酰胺态氮处理最大。甘薯施用铵态氮肥有利于提高土壤活跃微生物量和微生物生物量碳,适当增施铵态氮是保证土壤生物健康的较好施氮模式。

Nitrogen fertilizer can play an important role in minimizing soil erosion and improving soil quality, so, it is necessary to reveal the effects of nitrogen forms on soil quality. A field experiment with randomized design was conducted to study the effects of different forms, in- eluding N03- -N, NH4＋ -N and amide-N, on soil microbial biomass carbon, active soil microbial biomass, soil respiration rate and quotient and soil enzyme activities in the field of sweet potato. The result showed that the soil microbial biomass carbon, active soil microbial bio- mass, soil respiration rate and quotient and soil enzyme activities responded differently to nitrogen forms. Soil microbial biomass carbon was the highest in NH4＋ -N treatment at the early and middle storage root development, and the highest in NOj -N treatment at the late growth stage. Active soil microbial biomass was the highest in NH4＋ -N treatment at the whole growth period. The soil respiration rate and quotient, activity of urease and invertase were the highest in amide-N. Based on the comprehensive analysis, ammonia could improve soil microbial bio- mass carbon and active soil microbial biomass, and proper ammonia was the better fertilizer management in enhancing soil biological health.