降水和温度变化下秸秆覆盖对旱地春小麦产量及其构成因素的影响

Effects of Straw Cover on Spring Wheat Yield and Its Constituent Factors in Dryland under Precipitation and Temperature Changes

为揭示定西地区耕作措施对气候变化下旱地春小麦产量及构成因素的影响规律,根据当地1971—2017年的气象数据,以降水、日均温度、秸秆覆盖量为可变因素,运用APSIM模型模拟小麦生长过程,分析小麦产量、籽粒数及千粒质量的变化规律。研究结果显示:产量和生物量的模拟值和实测值的均方根误差和模型有效性指数分别为135.22 kg/hm^(2)和0.83,395.97 kg/hm^(2)和0.87,验证模型模拟效果较好。在试验设计范围内,温度对产量和籽粒数的影响为负效应,对千粒质量则具有正效应;温度升高1.63℃时,千粒质量达到阈值35.33 g,然后呈现报酬递减。降水和秸秆覆盖对小麦产量和籽粒数均具有正效应,对千粒质量呈负效应。降水、温度和秸秆覆盖量对小麦产量和籽粒数的影响表现为降水>温度>秸秆覆盖量,对千粒质量的影响表现为温度>降水>秸秆覆盖量。温度与降水、温度与秸秆覆盖量对小麦产量和籽粒数的影响均呈相互抑制关系;降水和秸秆覆盖量对小麦产量和籽粒数的影响则呈相互促进关系。温度与降水、温度与秸秆覆盖量、降水与秸秆覆盖量的交互作用都对千粒质量有正效应。综合分析,秸秆覆盖可以促进籽粒数的增加,提高春小麦产量。考虑当地春小麦秸秆产出量,秸秆收获后应全部还田以促进土壤的蓄水保墒,为春小麦的高产和可持续发展提供水分补给。

In order to reveal the influence of farming practices in Dingxi area on dryland spring wheat yield and its composition factors under climate change,according to the local meteorological data from 1971 to 2017,with precipitation,daily average temperature,and straw coverage as variable factors,the APSIM model was used to simulate wheat growth process,analyze the variation law of wheat yield,grain number and thousand-grain quality.The research results showed that the root mean square error and model validity index of simulated and measured values of yield and biomass were 135.22 kg/hm^(2) and 0.83,395.97 kg/hm^(2) and 0.87,respectively,which proved that the simulation effect of the model was good.Within the scope of the experimental design,the temperature had a negative effect on yield and kernel number,but had a positive effect on thousand-grain weight;when the temperature increased by 1.63 ℃,the thousand-grain weight reached a thre-shold of 35.33 g,and then showed diminishing returns.Precipitation and straw mulching had positive effects on wheat yield and grain number,but had negative effects on 1 000-grain quality.The effects of precipitation,temperature and straw co-verage on wheat yield and grain number were in the order of precipitationtemperaturestraw coverage,and the effect on thousand-grain quality was in the form of temperatureprecipitationstraw coverage.The effects of temperature and preci-pitation,temperature and straw coverage on wheat yield and grain number were mutually inhibiting;the effects of precipita-tion and straw coverage on wheat yield and grain number were mutually promoting.The interaction between temperature and precipitation,temperature and straw coverage,precipitation and straw coverage all had positive effects on thousand-grain weight.Comprehensive analysis shows that straw mulching can promote the increase of grain number and increase the yield of spring wheat.Considering the local output of spring wheat straw,all the straw should be returned to the field after harvest to promote soil water storage and moisture conservation,and provide water supply for the high yield and sustainable deve-lopment of spring wheat.