化肥减施及节水对潮土冬小麦夏玉米轮作农田氮和磷流失的影响

Effects of chemical fertilizer reduction and water saving on nitrogen and phosphorus runoff loss in winter wheat and summer maize rotation in aquic soil

农田氮和磷的流失威胁水环境质量及人体健康,化肥减施和节水是减少氮和磷流失的有效手段。在河南省北部农区,采用2014年建设的田间渗漏池和径流池,综合研究了2018年不同施肥及节水对小麦玉米轮作农田氮、磷流失及作物产量的影响。设置常规施肥(CON)、优化减肥(JF)和优化减肥加节水(JFJS)3个处理,不同处理总氮淋失量为42.0~81.9 kg·hm^(-2),硝态氮淋失量为21.5~72.4 kg·hm^(-2),总磷淋失量为0.05~0.06 kg·hm^(-2)。硝态氮淋溶量占总氮淋溶的比率为51.1%~88.4%。总氮淋失系数为7.9%~10.4%;总磷淋失系数为0.02%~0.04%。JF比CON处理降低硝态氮淋失63.8%,JFJS比JF处理可进一步降低17.9%硝态氮淋失,不同处理磷的淋溶损失没有显著性差异。玉米季是氮素淋失的关键时期,占整个小麦玉米轮作周期的91.8%~94.6%。一个小麦玉米轮作周期总氮径流损失量为0.14~0.20 kg·hm^(-2),总磷径流损失量为0.02~0.03 kg·hm^(-2),氮磷径流损失系数分别为0.02%~0.04%和0.01%~0.02%。小麦玉米的产量均表现为JFJS>JF>CON,CON处理吸氮量最高,不同处理产量和吸氮量没有显著性差异。本研究明确了潮土区小麦玉米轮作农田氮磷淋溶是氮磷流失的主要途径及其流失系数,减少常规高量施肥能够显著降低氮素淋失,在减肥的基础上节水能达到更好的效果。

The loss of nitrogen and phosphorus in farmland threatens water quality and human health.Reducing fertilizer application and saving water are effective measures to reduce the loss of nitrogen and phosphorus.In this study,the effects of different fertilization and water saving on nitrogen and phosphorus loss and crop yield in wheat and corn rotation fields in 2018 were comprehensively studied in the northern agricultural area of Henan province by using the field leakage pond and runoff pond constructed in 2014.The total nitrogen leaching loss was 42.0~81.9 kg·hm^(-2),nitrate nitrogen leaching loss was 21.5~72.4 kg·hm^(-2) and total phosphorus leaching loss was 0.05~0.06 kg·hm^(-2) under three treatments:conventional fertilization(CON),optimized weight loss(JF)and optimized weight loss plus water saving(JFJS).The proportion of nitrate nitrogen leaching to total nitrogen leaching was 51.1%~88.4%.Total nitrogen leaching coefficient was 7.9%~10.4%,total phosphorus leaching coefficient was 0.02%~0.04%.Compared with CON treatment,JF treatment reduced nitrate leaching by 63.8%,JFJS treatment further reduced nitrate leaching by 17.9%than JF treatment,and there was no significant difference in phosphorus leaching loss among different treatments.Maize season was the key period for nitrogen leaching loss,accounting for 91.8%~94.6%of the whole wheat-maize rotation cycle.In a wheat-maize rotation cycle,the total nitrogen runoff loss was 0.14~0.20 kg·hm^(-2),the total phosphorus runoff loss was 0.02~0.03 kg·hm^(-2),and the nitrogen and phosphorus runoff loss coefficients were 0.02%~0.04%and 0.01%~0.02%,respectively.The yield of wheat and corn was JFJS>JF>CON.The nitrogen uptake at CON treatment was the highest,and there was no significant difference in yield and nitrogen uptake among different treatments.In this study,it was determined that nitrogen and phosphorus leaching was the main way and coefficient of nitrogen and phosphorus loss in wheat and corn rotation farmland in fluvo-aquic soil area.Reducing conventional high amount of fertilization could significantly reduce nitrogen leaching loss,and water saving could achieve better results on the basis of reducing fertilizer.