秸秆覆盖秋浇后盐渍土壤冻融过程及水盐运移特征

发布时间：2018-04-05 21:19

本文选题：河套灌区　切入点：秸秆覆盖　出处：《水土保持学报》2017年05期

【摘要】：为了探讨在寒旱盐灌区覆盖秋浇后冻融土壤的冻融特性及水热盐协同调控机制,在盐渍土壤进行覆盖后秋浇田间冻融试验,设5个处理,秸秆覆盖量1.2kg/m~2(F1.2)、秸秆覆盖量0.9kg/m~2(F0.9)、秸秆覆盖量0.6kg/m~2(F0.6)、秸秆覆盖量0.3kg/m~2(F0.3)、未覆盖(CK)。结果表明:秸秆覆盖影响了土壤冻结融化推进过程,改变了土壤温度对气温变化的响应关系,影响了水分、盐分在土壤剖面(特别是土壤表层和耕作层)的重新分配,提高了翌年春季水分可利用量,抑制了表层及耕作层春季返盐,提高了秋浇的灌水效果。秸秆覆盖处理的最大冻结深度小于CK处理4~26cm,初冻时间滞后0~12d,融化时间滞后0~21d;秸秆覆盖的各处理由于覆盖层的存在,消融水蒸发受到抑制,表层积盐现象较弱;消融期结束后,在土壤表层0—10cm,F0.9的土壤含水率最高,处理F1.2较秋浇前脱盐率为81.18%,脱盐效果最好;在耕作层0—40cm,F0.9的土壤含水率最高,处理F0.6较秋浇前脱盐率为75.65%,脱盐效果最好;为保证在翌年春播时的适宜含盐量及含水率,以覆盖量0.6~0.9kg/m~2为宜。研究结果可为河套灌区秋浇制度的优化提供参考。
[Abstract]:In order to study the freeze-thaw characteristics of frozen and thawed soil after autumn pouring in cold and dry salt irrigated area and the mechanism of coordinated control of water, heat and salt, the freeze-thaw experiment was carried out in the field after mulching in saline soil, and five treatments were set up.The amount of straw mulching was 1.2 kg / m ~ (2) F ~ (1.2), the amount of straw mulching was 0.9 kg / m ~ (2) F ~ (2) F ~ (0.9), the amount of straw mulching was 0.6 kg / m ~ (2) F _ (0.6), the amount of straw mulching was 0.3 kg / m ~ (2) C ~ (2) F _ (0.3), the amount of straw was not covered with CK.The results showed that straw mulch affected the process of soil freezing and melting, changed the response of soil temperature to temperature change, affected the redistribution of salt in soil profile (especially in topsoil and tiller layer).The amount of water available in spring of the following year was increased, the return of salt to surface layer and tiller layer was restrained in spring, and the irrigation effect of autumn irrigation was improved.The maximum freezing depth of straw mulch treatment was less than that of CK treatment (4m ~ 26cm), the initial freezing time was delayed by 0 ~ 12 days, and the melting time was delayed by 0 ~ 21d.The evaporation of ablation water was restrained and the salt accumulation in the surface layer of straw mulching treatment was inhibited because of the existence of mulching layer, and the salt accumulation in the surface layer was weak after the ablation period ended.In order to ensure the suitable salt content and moisture content in spring sowing in the next year, 0.6~0.9kg/m~2 is suitable for mulching.The results can provide a reference for the optimization of autumn irrigation system in Hetao irrigation area.
【作者单位】：山西农业大学资源环境学院;内蒙古农业大学水利与土木建筑工程学院;山西农业大学农学院;
【基金】：国家自然科学基金项目(51369018) 山西农业大学科技创新基金项目(2015YJ13) 国家“十二五”科技支撑计划重点资助项目(2011BAD29B03)
【分类号】：S152

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