间套作强化农田生态系统服务功能的研究 进展与应用展望

间套作是我国传统农业的精髓,其存在2 000多年,必然蕴含重要的科学原理。过去的研究表明其不仅能够大幅度提高作物产量,而且能够充分利用地上部的光热资源,充分挖掘和利用地下部水分养分资源,强化农田生态系统服务功能。近年来,国内外对其资源高效利用的研究取得了显著的进步,特别是地下部资源高效利用方面。本文首先综述了相关研究的进展:间套作作为增加农田生态系统生物多样性的重要措施,具有重要的生态功能,如提高作物产量,增加作物生产力的稳定性,充分利用地上部光热资源和土壤水分、土壤和肥料中的氮素和磷素以及微量元素等。随后,对间套作提高资源利用效率的机制进行了分析,包括水分需求上的时间和空间生态位互补,豆科/禾本科间作体系中的豆科作物生物固氮和禾本科作物对土壤氮素利用上的互补和促进作用;磷活化能力强弱搭配的间作体系中,磷活化能力强的作物对活化能力弱的作物的促进作用;双子叶和单子叶植物的搭配,改善双子叶植物的Fe、Zn等微量元素的含量等。最后,对间套作进一步研究方向和应用提出了一些看法和思路。在研究方面,包括作物多样性与农业可持续发展,地下部作物种间信号的传递,地上地下部多样性的互反馈调节机制,以及作物生长模型等。在应用方面,包括豆科作物纳入农业生产体系发展生态集约化农业,利用间套作发展有机农业,利用种间相互作用提高磷肥利用率和增加作物可食部分的微量元素含量等。并认为间套作中的机械化、育种等问题的解决将有利于间套作的进一步发展。

Intercropping enhances agroecosystem services and functioning: Current knowledge and perspectives

IntercroppingisoneofthetraditionalfarmingsystemspracticedbyfarmersinChinaformorethan2000yearswith some intriguing ecological principles. Previous studies have shown that intercropping enhanced not only cropproductivity,butalsotheutilizationefficienciesofresources,includingabove-ground(e.g.,land,thermal,radiationandspace)andbelow-ground(e.g.,waterandnutrients)resources.Recenteffortshavemadesomeprogressesonintercroppingresearch.Here, we reviewed the potential of intercropping to strength ecosystem services and functions at the agroecosystem level,prospective research directions and highlight practical uses in modern agriculture. Intercropping increased biodiversity,productivity and stability of agroecosystems. At the same time, intercropping enhanced water use by isolating the time formaximum water requirements of one species from the other, and spatial complementarity by hydraulic lift of water. TheenhancementofnitrogenacquisitionwasattributedtonichedifferentiationofNresourcesinwhichcerealsacquiredmoremineralNfromthesoil,whilelegumesfixedmoreNfromairN2.ThiswasbecausethatcerealswasmorecompetitivethanlegumesandmineralNcompetitionincreasedsymbioticN2fixationoflegumes.SomePmobilizedspeciesfacilitatedtheconversionofsoilunavailablePintoavailableP,whichbenefitednotonlythespeciesbutalsotheneighboringimmobilizedotherspecies.E.g.,therootsoffababeanreleasedcarboxylatesorprotontodissolvesparinglysolublePinsoils.AlsotherootsofchickpeareleasedphytaseorphosphatasetodecomposeorganicPinthesoil,whichincreasedavailablesoilP.Therewereinterspecificfacilitationsofiron(Fe)andzinc(Zn)nutrientsinintercroppingofdicotyledonousornon-graminaceousmonocotyledonous(strategyIforFeacquisitionandnon-FeorZnmobilization)speciesandgraminaceousmonocotyledonous(strategy Ⅱ forFeacquisitionand Fe or Zn mobilization) species, which benefited micronutrient availability in intercropped non-Fe-mobilizing orZn-mobilizingspecies.Inthepaper,Ialsoidentifiedsomeimportantfuturedirectionsofintercroppingresearchandpracticaluses.Theresearchdirectionsincludecropdiversityandagriculturalsustainability,signal-controlledinterspecificinteractionsbetweenintercropped species, linkageinteractionstoabove-groundandbelow-grounddiversities,functional,structuralandempiricalmodelsforintercropping,etc.Inapplication,intercroppingcanbeusedtodevelopecologicallyintensiveagricultureand organic farming, to enhance fertilizer recovery, and to enrich the contents of microelements in edible parts of crops.Finally,itwillbeusefultofurtherdevelopsuitablemachineryandbreednewercropvarietiesforintercropping.