半干旱雨养区秸秆带状覆盖马铃薯土壤水热效应及抗旱增产机理研究

Bundled straw mulching is a technique developed by Gansu Agricultural University, which uses corn straw to make bundled mulching to resist drought and conserve soil moisture. As the technique can resolve the conflict between soil moisture conservation and decreasing soil temperature, it can significantly increase potato yield in arid area, achieving similar effect in increasing potato yield with plastic mulching. Taking bare land and the land with plastic mulch as control groups, the field experiments will be designed with, different bandwidth including double-60 and double-90, and different mulching stages (mulching in spring and in winter) on potato fields. By continuously measuring the soil temperatures and moistures at different growth stages and soil layers, and annual temperature and moisture, and by determining growth indexes, physiological indexes, yield components and so on, the study aims at systematically exploring the law governing the temporal and spatial moisture variation, the sectional features of the soil layer in potato field, the law governing water consumption and movement, the features of soil temperature and micro-climate variation in potato field. This study also intends, in terms of plant growth characteristics, photosynthetic feature and osmotic adjustment, to investigate the evidence for bundled straw mulching to adjust potato physiology, reveal the regulation mechanism of bundled straw mulching in resisting drought and increasing yield, establish and improve the technical and theoretical system of potato bundled straw mulching. Through the study, it is expected to provide theoretical and technical support for resisting drought and increasing yield in potato production.

秸秆带状覆盖是甘肃农业大学研发的一种利用玉米整秆局部覆盖、抗旱保墒的作物种植新技术，克服了秸秆保墒与降低地温的矛盾，在旱地马铃薯种植上可大幅度提高产量，增产效果和地膜覆盖相近。本研究采用大田试验，以露地不覆盖和地膜覆盖为对照，设置不同覆盖带幅（双60，双90）和秸秆覆盖时间（春季覆盖和秋季覆盖）处理，通过连续监测土壤水热季节变化、垂直变化及年际变化，同时测定作物生长指标、生理以及作物产量等指标，系统研究不同秸秆带状覆盖处理条件下马铃薯田土壤水分时空变化规律和剖面特征、水分消耗运移规律、土壤温度及田间小气候变化特征；并从作物生长特性、光合特性、渗透调节特性探寻秸秆带状覆盖对马铃薯栽培生态生理调控的科学证据，揭示秸秆带状覆盖对马铃薯抗旱增产的机制，建立和完善马铃薯秸秆带状覆盖的技术及理论体系，从而为提高马铃薯抗旱增产能力，实现马铃薯稳产增产提供理论依据和技术支持。

经2018-2021年不同降水年型对秸秆带状覆盖、地膜覆盖和露地对比研究，明确了秸秆带状覆盖马铃薯增产、水热动态变化规律及增产机制。研究表明，秸秆带状覆盖可显著改善土壤水分状况，与露地相比，秸秆带状覆盖明显提高了全生育期0-2m土壤贮水量；秸秆带状覆盖具有明显的降温效应，但随着生育期和土层不同，秸秆带状覆盖存在增温和降温“双重效应”，且降温效应大于增温效应；地温随气温的变化存在“滞后效应”，秸秆覆盖降低了全生育期土壤有效积温和日变化幅度；降温效应可显著改善植株水分状况，块茎形成期地温高低对结薯数影响不明显，块茎膨大期土壤温度显著影响单薯重，马铃薯单薯重对前期结薯数不足具有强烈补偿效应；秸秆带状覆盖显著提高了生育期耗水量，降低了前阶段耗水量，增加了中期耗水量及其占总耗水量的比例，延长块茎膨大后植株光合作用，提高马铃薯叶片抗氧化能力，延缓植株衰老，提高有机物的积累量。同时，秸秆带状覆盖能促进作物氮的吸收，减少肥料氮的残留，促进马铃薯对氮素吸收利用和器官中氮素的分配。因此，水热互调耦合实现作物前控后促是秸秆带状覆盖高产形成的主要机制。通过不同覆盖模式的比较，确定出高产秸秆带状覆盖模式为：覆盖带60cm、种植带60cm，每带种2行，秋季覆盖。