摘要
探讨绿肥对减量灌水春小麦产量构成及光合产物积累分配特征的响应和机制,可为构建新型小麦节水型种植制度提供实践和理论依据.依托2017年在甘肃河西绿洲灌区开始的小麦复种绿肥田间定位试验,于2021-2022年研究了不同绿肥处理方式下减量灌水小麦的群体生长动态、光合产物累积、转运分配和产量特性.试验采用裂区设计,设420 mm(I3,地方常规灌水量)、370 mm(I2,减量50 mm)和320 mm(I1,减量100 mm)3个灌水水平,绿肥全量翻压还田(WG)、绿肥仅根茬还田(WGR)和不种绿肥(W)3种绿肥处理方式,组成9个处理.结果表明,减量灌水降低了小麦产量和收获指数,绿肥还田可补偿因减量灌水造成的产量负效应.与I3相比,I1处理小麦籽粒产量、生物产量和收获指数分别降低11.5％、3.8％和8.1％,I2籽粒产量降低了 3.4％;与W相比,WG籽粒产量、生物产量和收获指数分别提高10.9％、3.7％和8.0％,WGR籽粒产量和收获指数提高了 4.8％和3.4％;与WI3相比,WGI2籽粒产量和收获指数分别提高7.2％和5.3％,WGI1和WGRI2的籽粒产量、生物产量和收获指数差异不显著,即麦后复种绿肥并全量还田可补偿减量灌水100 mm产生的产量负效应,可超量补偿在减量灌水50 mm的负效应.绿肥还田补偿减量灌水对小麦产量负效应的主要原因是:(1)绿肥还田提高了小麦生育后期的群体生长率(CGR)和净同化率(NAR),增大了小麦穗数、穗粒数与千粒重.与WI3相比,WGI2拔节至孕穗、孕穗至开花、开花至灌浆期CGR分别提高10.4％、10.5％和7.9％,WGRI2拔节至孕穗、孕穗至灌浆期CGR分别提高6.7％和5.7％,WGI1无显著变化;WGI2较WI3孕穗至开花、开花至灌浆期NAR分别提高4.5％、4.8％,穗数和千粒重分别提高5.7％和6.9％,WGI1、WGRI2较WI3穗数、穗粒数与千粒重差异不显著.(2)绿肥还田提高了减量灌水小麦的花后干物质积累量和对籽粒的贡献率.I2、I1较I3花后干物质积累量和对籽粒的贡献率分别降低8.8％、5.3％和23.1％、13.7％;WG、WGR较W花后干物质积累量和对籽粒的贡献率分别提高19.6％、8.9％和14.0％、9.3％;与WI3相比,WGI2、WGRI2花后干物质积累量差异不显著.在干旱绿洲灌区,麦后复种绿肥是实现小麦生育期减量灌水的可行措施,绿肥可通过优化小麦光合产物的累积和分配补偿由于减量灌水造成的小麦减产,绿肥全量还田的节水潜力更高.
Abstract
The present study investigated the mechanisms governing yield composition,photosynthetic product accumulation,and distribution characteristics of spring wheat under reduced irrigation,in response to green manure.The findings can serve as a practical and theoretical foundation for the development of a new water-saving cropping system for wheat.The study was conducted in the Hexi Oasis irrigation area of Gansu Province,China,and involved a field positioning experiment on multiple cropping of wheat with green manure since 2017.In 2021-2022,we examined population growth dynamics,photosynthetic product accumulation,transpor-tation distribution,and yield characteristics of wheat subjected to reduced irrigation and different green manure management methods.The experiment followed a split-plot design,with three irrigation levels as the main plot:420 mm(I3,local conventional irrigation),370 mm(I2),and 320 mm(I1).The three green manure treatments were assigned as the split plot:planting and returning green ma-nure to the field(WG),planting green manure but not returning it to the field(WGR),and no green manure(W).This resulted in a total of nine treatments.The results indicated that reduced irrigation water alone led to a decrease in wheat yield and harvest index.However,returning green manure to the field compensated for the negative effects of reduced irrigation on yields.Compared to I3,I1 resulted in an 11.5％reduction in grain yield,a 3.8％reduction in biological yield,and an 8.1％reduction in harvest index.Grain yield in I2 decreased by 3.4％.WG increased grain yield,biological yield,and harvest index by 10.9％,3.7％,and 8.0％respectively,com-pared to W.WGR increased grain yield and harvest index by 4.8％and 3.4％respectively,compared to W.WGI2 increased grain yield and harvest index by 7.2％and 5.3％respectively,compared to WI3.There were no significant differences in grain yield,bio-logical yield,and harvest index among WGI1,WGRI2,and WI3.In other words,returning 100％of the green manure to the field not only compensated for the negative yield impact of a 100 mm reduction in irrigation water but also overcompensated for the negative effect caused by a 50 mm reduction in irrigation water.The negative effect of returning green manure to the field on wheat yield loss under reduced irrigation conditions can be attributed to two main factors.Firstly,returning green manure enhanced crop growth rate(CGR)and net assimilation rate(NAR)during the late reproductive stage of wheat,leading to an increase in the number of spikes,grains per spike,and thousand-grain weight.Secondly,returning green manure increased dry matter accumulation and the contribu-tion rate of wheat grain after anthesis,even with reduced irrigation water.In arid oasis irrigation areas,replanting green manure after wheat can be considered a viable measure to reduce irrigation water during the reproductive period of wheat.Green manure optimizes the accumulation and distribution of photosynthetic products in wheat,thereby compensating for yield penalty associated with re-duced irrigation.Returning 100％of the green manure to the field has a high potential for water saving.
基金项目
国家自然科学基金项目(U21A20218)
财政部和农业农村部国家现代农业产业技术体系建设专项(CARS-22-G-12)
甘肃省2023年研究生"创新之星"项目(2023CXZX-681)
维普
万方数据