间作条件下土著AMF对滇池流域坡耕地氮素利用及损失的响应机制

Eutrophication of Dianchi water bodies is the major environmental problems for Yunnan lake management.Nitrogen (N) element is one of the major limiting factor for lake eutrophication.The study of N transport and the effect factors for agricultural non-point source pollution in Dianchi Lake Watershed was the focus of soil and environment sciences research. Among them, N fertilizer application, rainfall, slope, soil type, soil microorganism and vegetation were the major factors. Currently, no or little study or report about the reduction and control of arbuscular mycorrhizal fungi (AMF) and intercropping on N transport in Dianchi Lake Watershed was known. In this study, the effects and role mechanisms of inoculation by indigenous AMF on soil N uptake and utilization by typical intercropping plants( maize/soybean) grown in red soil and purple soil of Dianchi Lake Watershed sloping farmland will be conducted through 3 kinds of intercropping simulation pot experiments (root separations, general intercropping and two-compartment incorporating air-gap respectively). Moreover, the effects and role mechanisms of AMF inoculation on N leaching in soil through leaching simulation experiment, and on reduction and control of N loss on soil surface by runoff simulation studies will also be conducted. Furthermore, field verification experiment about N utilization and loss effect will be supplemented. The results will reveal the influence the mechanism of mycorrhizal symbiotic and intercropping system on soil N uptake and utilization by pants, N leakaging loss in soil, and runoff loss on sloping soil of Dianchi Lake Watershed, and will be a rich for non-point source pollution control theory, and will also provide a scientific basis for the theory and application support to guide eutrophication governance of domestic and international surface water bodies.

滇池水体的富营养化，是云南湖泊治理亟待解决的重大环境问题之一。滇池流域农业非点源污染中氮素迁移及影响因素研究是当今土壤与环境科学研究关注的焦点。其中，氮肥施用、降雨、坡度、土壤类型、土壤生物及植被因素的影响较大。目前，尚缺乏菌根与间作对坡耕地氮素迁移减控的协同研究或报道。本研究以滇池流域主要类型土壤（红壤、紫色土）和玉米/大豆间作体系为对象，通过根系分隔、空气隔板分室与常规间作盆栽模拟、以及淋溶、径流模拟试验研究土著AMF对坡耕地间作土壤氮的吸收利用，壤中淋失和表层流失影响及作用机理，并结合田间试验研究验证土著AMF对间作土壤氮素利用、损失的响应。研究结果将揭示菌根与间作系统互作对滇池流域坡耕地土壤氮素的吸收利用、渗漏损失及径流损失的响应机制，丰富非点源氮素污染控制理论，并为指导国内外地表水体的富营养化治理提供科学理论支持与应用基础。

滇池水体的富营养化，是高原湖泊治理亟待解决的重大环境问题之一。氮是水体富营养化的主要限制因素之一。农业非点源污染中氮素迁移及影响因素研究是当今土壤与环境科学研究关注的焦点。其中氮肥施用、降雨、坡度、土壤类型、土壤生物及植被因素的影响较大。本研究以滇池流域主要类型土壤（红壤、紫色土）和玉米/大豆间作体系为对象，通过Illumina MiSeq PE300高通量测序，明确了玉米/大豆间作根际土壤里的丛枝菌根真菌（AMF）物种组成及优势属。通过根系分隔、间作盆栽、空气隔板分室等模拟试验探明了不同分隔条件接种AMF对间作作物种间氮素利用及在土壤-植株体系迁移的影响、AMF菌丝在间作土壤氮形态转化、吸收利用中的积极作用和作用机制以及阐明了土著AMF与间作对作物吸收不同形态外源氮的影响及响应机制。通过盆栽渗漏、淋溶与径流迁移等模拟试验探讨了不同坡度、种植模式和不同形态氮施用对间作菌根作物氮吸收利用及渗漏液各形态氮的影响、明确了坡耕地红壤和紫色土间作体系土著AMF对氮素壤中和表层迁移的减控作用及关键影响因素。通过不同坡度氮迁移田间试验验证了土著AMF和间作模式在红壤坡耕地表层氮素迁移过程中的减控效应。系统研究结果表明土著AMF与间作协同通过促进植株氮累积、降低土壤氮残留及形成水稳性大团聚体等机制减少了氮的流失，揭示了AM真菌和间作模式通过吸收与形态转化利用、壤中固定与表层减控等多途径影响坡耕地土壤氮迁移的作用机制。项目相关或资助发表论文共17篇，其中在《Environmental Science and Pollution Research》、《农业工程学报》、《中国农业科学》、《土壤学报》、《植物营养与肥料学报》、《菌物学报》、《水土保持学报》、《生态环境学报》等刊物以通讯作者发表核心及以上论文16篇（其中SCI论文1篇，EI期刊论文1篇），授权专利3项，参编专著1部，作为主要参与者获云南省科技进步奖三等奖1项；项目主持人晋升教授职称，并被评为云南农业大学“百名”青年学术和技术带头人。项目直接培养已毕业硕士研究生4名和本科生13名。