碎麦秸垫式膜上灌对土壤水热盐运移及食葵高产的调控机理研究

The mulch measures regulation mechanism of soil water-temperature-salt movement and crop high yield is the core of the research on farmland mulch technology. This project, aiming at the production practice problems about straw mulching ecological adaptability and film mulching residual film difficult recovery, intending to combine the two kinds of mulch, drawing lessons from national and international theories of the soil water-temperature-salt migration about farmland mulch, using the methods of field test and indoor analysis, setting two dominant factors: mulching mode and irrigation quota, will analyze soil water storage and soil moisture movement in the edible sunflower field, and study soil temperature effect and soil water-temperature movement, and investigate the temporal and spatial distribution of soil salinity and water-salt movement law, and explore the two factors influence on the growth and yield with edible sunflower, for clearing the water-saving effect and the regulation mechanism of soil water storage under irrigation on film padded with crushed wheat straw (IFCWS), in the Northwest Arid Regions of China, and ascertaining the soil water-temperature-salt movement law under IFCWS, and revealing the intrinsic mechanism of inhibiting soil salt accumulation into the surface under IFCWS, and proving the regulation ways on soil water-temperature-salt migration and edible sunflower yield under IFCWS, and forming the edible sunflower technical application mode of the IFCWS, in the Northwest Arid Regions, China. The completion of this subject would provide the scientific theory basis for the sustainable use of water and soil resources in the Northwest Arid Regions, China.

覆盖措施对土壤水热盐运移和作物高产的调控机理是农田覆盖技术研究的核心。针对西北旱区生产实践中秸秆覆盖的生态适应性和地膜覆盖的残膜难回收问题，本课题拟将两者结合起来，借鉴国内外农田覆盖方面关于土壤水热盐运移和作物产量的研究理论，采用田间试验法和室内分析法，以覆盖方式和灌水定额两因素为主导，分析食葵田间土壤储水作用和土壤水分运移规律，研究土壤热效应和水热运移规律，探讨土壤盐分时空分布和水盐运移规律，探索两因素对食葵的生理生长及产量的影响，以明确西北旱区碎麦秸垫式膜上灌的节水抑蒸保墒效应和对食葵田间土壤储水作用的调控机理，探明碎麦秸垫式膜上灌条件下土壤水热盐运移规律，揭示碎麦秸垫式膜上灌抑制土壤盐分表聚的内在机理；探明碎麦秸垫式膜上灌对土壤水热盐运移和食葵高产的调控途径，形成西北旱区食葵的碎麦秸垫式膜上灌技术应用模式。这一课题的完成以期为河西灌区实现水土资源可持续利用提供重要的科学理论依据。

本项目针对西北旱区生产实践中秸秆覆盖的生态适应性和地膜覆盖的残膜难回收问题，借鉴国内外农田覆盖方面关于土壤水热盐运移和作物产量的研究理论，以覆盖方式和灌水定额两因素为主导，研究了碎麦秸垫式膜上灌对土壤水热盐运移及食葵高产的调控机理。结果表明：（1）碎麦秸垫膜覆盖（SF）中的土壤含水量总体优于地膜覆盖的（F），是因为碎麦秸垫膜覆盖（SF）具有地膜、秸秆双重保墒作用。这说明碎麦秸垫膜覆盖（SF）可以达到和秸秆覆盖、地膜覆盖一样的保墒效果，甚至要优于S和F。（2）碎麦秸垫膜覆盖（SF）和秸秆覆盖（S）中的秸秆具有降温作用，导致其峰值滞后1h出现，温域变窄。而碎麦秸垫膜覆盖（SF）中的地膜又具有增温效应，使其峰值比秸秆覆盖（S）的高出7℃、温域比秸秆覆盖（S）宽7℃。碎麦秸垫膜覆盖（SF）与无覆盖处理（N）、地膜覆盖（F）的相比，秸秆阻隔了太阳的直接辐射，具有秸秆覆盖（S）的降温效应；与秸秆覆盖（S）相比，又具有地膜的升温作用。（3）碎麦秸垫式膜上灌可明显降低表层土壤的pH值，在食葵苗期，各覆盖方式的土壤盐分都存在不同程度的表聚现象，0~5cm处地膜覆盖（F）的土壤盐分表聚最明显。在整个生育期内，盐分的表聚现象随着生育期的推进逐渐减弱；碎麦秸垫膜覆盖（SF）较明显地抑制了0~5cm的土壤盐分积聚，地膜覆盖（F）却明显使得表层土壤的累积盐分增加。从整个剖面上看，0~120cm土壤的含盐结构变化显著，地膜覆盖（F）具有增加土壤盐分含量的作用，碎麦秸垫膜覆盖（SF）具有脱盐的作用。（4）从食葵的生理生长指标、产量及其构成因素的影响结果考虑，SFM为最佳组合，即碎麦秸垫膜覆盖与灌水定额为M的组合为最佳组合。该项目探明了碎麦秸垫式膜上灌对土壤水热盐运移和食葵高产的调控途径，形成了西北旱区食葵的碎麦秸垫式膜上灌技术应用模式。其研究成果为西北旱区实现水土资源可持续利用提供重要的科学理论依据。