不同植物与夏玉米间作修复模式阻控农田氮污染研究

Recent years, groundwater and surface water are polluted by NO3-N reason for nitrogen fertilizer over-used; moreover, farmland ecosystems and environment are also greatly destroyed. Nitrogen fertilizers are heavily applied in China and nitrate pollution of ground-water has become a major challenge in agricultural areas. If crops did not utilize nitrate, its downward leaching cannot be avoided because of its high solubility in water and low retention in soil. The intensively managed arable lands characterized by over-application of nitrogen fertilizers have had negative effects on the environment (e.g. soil, surface-and ground-water pollution) and losses of nitrogen (through leaching and emission). Nitrate loss through leaching can be alleviated by optimizing soil and crop management, choice of fertilizer types, irrigation management, farming practices, and mulching. A lot measures, however, are not suitable for application because of its economical, convenient, and practical characteristics. The reduction of farmland areas and the food security are the main restricted ingredients to increase agricultural productivity; this would be one of the most important hotspots in agricultural fields that using phytoremidation on how to obtain higher food productivity and reduce nitrate leaching in farmland. The proposer and his co-workers have been done some exploratory works on using phytoremidat ion to reduce and cure area-source pollution and obtained some valuable conclusions. Therefore, they considered that bring into cover crops (peanut, soybean, alfalfa, and ryegrass) and setting up compound planting patterns in farmland would be settled out these difficult questions, and this would be an effectively, significantly and meaningful research.

近年来，由于氮肥的过量施用，造成农田地下水体以及地表水体硝酸盐含量严重超标，农田生态环境也受到了严重的破坏；国内外虽然就控制农田氮淋洗进行了较多研究，如改进施肥方式、氮肥类型、施肥次数等方面，但是有相当多的研究成果由于经济、实用、方便等因素，难以进行有效的推广和应用。当前农业又面临耕地资源缩减、粮食安全等重大问题，研究保持当前农田生产能力的前提下，利用生物途径，即利用植物修复的技术，通过构建或配置合理的作物复合种植模式，保证获得较高农田粮食产量的前提下，从源头上有效的消除农田氮污染，就成为农田研究的热点领域之一。项目申请人及研究团队就利用植物修复的途径来减少和控制面源污染等方面进行了探索性的研究，并取得了一定的研究成果。同时，申请人认为通过在大田作物群体中引入其它功能性物种(花生、大豆、苜蓿、黑麦草等)来构建适宜的复合种植模式能够解决这一问题，为农田氮污染修复提供借鉴。

通过国家自然基金青年科学基金项目“不同植物与夏玉米间作修复模式阻控农田氮污染研究”（31301284）的实施，在不降低当前粮食生产能力的前提下，较为系统的研究了适量(D)、过量(G)2种施肥水平下玉米‖苜蓿(CMX)、玉米‖黑麦草(CHM)、玉米‖花生(CGT)、玉米‖大豆(CST)和玉米单作(CK)的配置种植模式减少氮淋失的效果。在适量施肥条件下，玉米籽粒产量依次为： DCMX＜DCK＜DCST＜DCGT＜DCHM，生育期内氮淋失量大小依次为：DCMX＜DCGT＜DCST＜DCK＜DCHM；氨气挥发主要发生在喇叭口期，灌浆期、成熟期量很少，田间氨气挥发量依次为：DCHM＜DCGT＜DCK＜DCMX＜DCST。在过量施肥条件下，GCHM、GCMX、GCST、GCGT处理分别比GCK高出1269.4、823.0、591.6、588.3 kg/hm2，依次为：GCK＜GCGT＜GCST＜GCMX＜GCHM；淋失量大小依次为：GCGT＜GCMX＜GCST＜GCHM＜GCK；氨挥发主要发生在喇叭口期，成熟期少部分；喇叭口期依次为：GCST＜GCMX＜GCK＜GCHM＜GCGT，成熟期依次为：GCHM＜GCST＜GCGT＜GCMX＜GCK。表明减少氮淋洗的较好的模式为玉米‖花生（CGT）、玉米‖大豆（CST）的种植模式。在适量施肥条件下，不建议使用间套作的生物修复技术模式；在过量施肥条件下，玉米‖花生（CGT）、玉米‖大豆（CST）的种植模式对土壤氮淋失具有较好的阻控效果。在国内外期刊上发表文章6篇，其中SCI 1篇，授权国家专利2项，其中发明专利1项；较好完成了项目的预定任务。