鄱阳湖区赣北棉田地表径流氮磷流失特征研究

Research on Characteristics of Nitrogen and Phosphorus Loss from Surface Runoff of Cotton Field in Northern Jiangxi Province of Poyang Lake Region

为明确鄱阳湖生态区赣北棉田地表径流氮磷流失特征,探究氮肥减施和部分有机肥替代化肥对氮磷流失的影响,采用田间径流池法,在自然降雨条件下,连续4年进行定位监测。结果表明,试验区域暴雨主要出现在5~7月,该时期为径流发生的高风险期;棉田总氮和总磷年度累积流失量分别为7.59~22.49 kg·hm^(-2)和0.43~1.61 kg·hm^(-2),地表径流以颗粒态氮和可溶性磷为主,硝态氮是无机氮流失的主要成分。地表径流、养分流失时间、流失量与降雨量之间具有显著的相关性;在常规施肥处理下,径流量和氮、磷流失量呈极显著的幂函数相关。与常规施肥相比,减氮20%基础上配施部分(10%)有机肥的施肥措施有利于减少地表径流、降低径流系数、减少氮流失,且对磷的流失和棉花产量无显著影响。

In order to clarify the characteristics of nitrogen and phosphorus loss from surface runoff of cotton fields in northern Jiangxi of Poyang Lake ecological region,and explore the effects of nitrogen fertilizer reduction and partial organic substitution on nitrogen and phosphorus loss,the field runoff pool method was used to monitor the loss for 4consecutive years under natural rainfall conditions.The results showed that the rainstorm in the test area mainly occurred from May to July,which was high risk period of runoff occurrence.The annual cumulative loss of total nitrogen and total phosphorus in cotton field were 7.59~22.49 and 0.43~1.61 kg·hm^(-2),respectively.Particulate nitrogen and soluble phosphorus were the main component of inorganic nitrogen loss.There was a very significant correlation between surface runoff,nutrient loss time,loss amount and rainfall,and there was a very significant power function correlation between runoff and the loss amounts of nitrogen and phosphorus under the conventional fertilization treatment.Compared with conventional fertilization,the fertilization measure of reducing nitrogen by 20% and applying 10% organic fertilization could reduce surface runoff,total nitrogen loss and runoff coefficient,which had no significant effects on phosphorus loss and yield of cotton.