不同水肥组合对岗南水库周边冬小麦-夏玉米体系中氮素平衡及淋失的影响

Effect of Different Water-Fertilizer Groups on Nitrogen Balance and Leaching in Wheat-Maize Cropping System Surrounding Gangnan Reservoir

针对岗南水库水体中度富营养化的现状,在保证作物稳产的同时,最大限度减少农田养分流失是降低农田面源污染、缓解水体富营养化的必由之路。以氮平衡原理研究氮素的盈余或亏缺,开展了不同水肥组合对岗南水库周边冬小麦-夏玉米种植体系中氮素淋失的影响研究。结果表明：在岗南水库周边旱地小麦-玉米轮作体系下,施氮量、施肥类型和灌水共同影响了硝态氮向深层的淋失,且施氮效应大于灌水效应。除不施氮的对照处理以外,其他水肥组合的土壤氮素均有盈余,淋失到140 cm以下的硝态氮量在35.23~212.53 kg/（hm2·a）。推荐环境友好水肥组合为缓控释肥的精确施用处理N控W2,比农民习惯施肥量的处理N2W2氮素淋失量减少141.19 kg/（hm2·a）,减少了80%。通过合理施肥与灌溉能有效降低岗南水库周边旱地小麦-玉米农区氮素淋失,提高肥料利用率,减少硝酸盐对地下水的威胁,对于保护石家庄珍贵的水资源具有十分重要的意义。

According to the serious eutrophication status of Gangnan reservoir,reducing the N leaching in maximum when meeting the need of crop growth is the only way for minimizing the non-point pollution in cropland.In this study,balance theory of nitrogen was used to research the effect of water-fertilizer coupling on surplus or loss of nitrogen.The results showed that fertilization and irrigation both effected NO3-N leaching to deep soil layer,and fertilization was the prominent factor.N in 0-140 cm soil layer of water-fertilizer combination was surplus except CK.Leaching NO3-N under 140 cm was between 35.23-212.53 kg /（ha·a） with different water and fertilizer.The most environmental friendly combination was NconW2,and it reduced the nitrogen leaching 141.19 kg /（ha·a） than N2W2,the rate was 80%.The reasonable fertilizer and irrigation can effectively decrease the nitrogen leaching,improve the fertilizer utilization efficiency,and reduce the menace from nitrate to groundwater in Wheat-maize cropping fields surrounding Gangnan reservoir.