腐植酸增效剂对尿素在土壤中转化及损失的调控

Regulation of Humic Acid Synergist on Conversion and Loss of Urea in Soil

通过研究腐植酸增效剂对尿素在土壤中的转化特征及其氨挥发特性的影响,探明腐植酸增效剂对氮肥增效的作用机理,为开发腐植酸肥料、提高氮肥利用率、减少土壤氮损失提供理论依据。本试验采用室内培养法,分别在北方典型潮土和南方典型红壤上,以不施肥为对照,设普通尿素、尿素+氮素1%活化腐植酸、尿素+氮素2%活化腐植酸和尿素+氮素4%活化腐植酸共5个处理,探究不同浓度腐植酸增效剂对不同类型土壤的氮素转化规律。结果表明,尿素施入初期腐植酸可抑制红壤和潮土中铵态氮向硝态氮的转化,减少硝态氮的转化量,促进中后期铵态氮向硝态氮的转化,并降低氨挥发累积量。本试验条件下潮土和红壤施用尿素的最佳腐植酸增效剂添加量分别为2%和1%。

In the research,the nitrogen transformation characteristics and ammonia emissions in soil were tested after adding exogenous urea and humic acid synergist to explore the mechanism of humic acid synergist on nitrogen fertilizer synergism and provide theoretical bases for developing humic acid fertilizer,increasing nitrogen use efficiency and reducing nitrogen loss in soil.The fluvo-aquic soil(the typical north soil)and red soil(the typical south soil)were selected for the experiment in laboratory.Five treatments were set as non-fertilization(CK),common urea(CK1),urea+nitrogen 1%activated humic acid(HA1),urea+nitrogen 2%activated humic acid(HA2)and urea+nitrogen 4%activated humic acid(HA3).The results showed that humic acid could inhibit the transformation of ammonium nitrogen to nitrate nitrogen at initial stage of urea application,reduce the transformation quantity of nitrate nitrogen,promote the transformation of ammonium nitrogen to nitrate nitrogen at medium and late stages,and reduce ammonia emission in red soil and fluvo-aquic soil.In this experiment conditions,the optimal additive amount of humic acid synergist in fluvo-aquic soil and red soil was 2%and 1%,respectively.