包膜控释肥料氮素释放动力学研究

The kinetics of nitrogen released from the coated controlled-release fertilizers

采用7d静置法和土壤培养试验,对聚合物包膜控释肥料养分释放动态进行了研究。结果表明,供试的7种包膜肥料初期溶出率均小于12%,微分溶出率为0.26%～2.49%;培养期间,7种肥料配比的养分释放曲线斜率均随时间的延长而逐渐下降;养分释放曲线根据其斜率可分为3组:2种控释肥单施或配合施用的最低,单施尿素的最高,尿素与控释肥配合施用的居中;各处理的氮释放动力学方程均达到显著或极显著水平,可用一级动力学方程描述其养分释放特性;速率常数k既可反映控释肥料氮素释放速率的快慢,又可描述肥料的配比效应。与控释肥单施或其配合施用相比,尿素与控释肥配比施用,氮素释放速率增加了65.4%～164.5%,释放期缩短了11～44d。

Seven day no shaking method and soil incubation experiment were used to study the nutrient release dynamics of polymer coated released fertilizers.The result shows that the N released from seven kinds of coated fertilizers were increasing as the prolonging of incubation time and reached a remarkable or much remarkable level,with a preliminary solubility less than 12.0% and a differential solubility between 0.26% and 2.49%.The gradients of nutrient release curves of seven combinations of controlled release fertilizers (CRF) and urea all decreased with time increasing during soil incubation period.It can be divided into three groups:the lowest gradients were the two kinds of CRF and their combinations;the highest was urea treatment;and urea combined with CRF was in between of the two groups.The first order kinetics equation could be used to fit the nutrient release characteristics of different treatments.Both the nitrogen release rate and their combining effective can be reflected by velocity coefficient.In comparison with applying two kinds of CRF separately or their combinations,applying urea combinded with CRF significantly increased the rate of nitrogen released,with the increase of 65.4% to 164.5%,and decreased the nitrogen release period by 11 to 44 days.