地膜覆盖结合秸秆深埋对土壤水盐动态影响的微区试验

EFFECTS OF PLASTIC MULCHING AND DEEP BURIAL OF STRAW ON DYNAMICS OF SOIL WATER AND SALT IN MICRO-PLOT FIELD CULTIVATION

为了研究地膜覆盖结合秸秆深埋（简称上膜下秸，P＋S）措施对内蒙古河套灌区盐碱障碍土壤的水盐调控机制，进行了微区试验，以翻耕（T）、地膜覆盖（P）和秸秆深埋（s）为对照，对比分析了不同耕作措施下食葵生育期内土壤水盐时空动态变化。结果表明：（1）P＋S处理能显著增强耕层（0～40cm）土壤蓄水能力并可持续保墒，播种时其耕层土壤含水率分别较T、P和s处理高5．13％、3．49％和1．99％，食葵生长前期分别高5．01％、5．87％和2．70％，生长中期也分别高7．53％、11．02％和6．16％。（2）P＋s处理对耕层土壤具有显著且长效的控盐抑盐效果，播种时其含盐量分别较T、P和s处理低18．37％、20．33％和1．90％，食葵生长前期分别低45．46％、37．63％和39．67％，生长中期分别低17．89％、29．77％和37．22％，生长后期也分别低14．46％、13．90％和19．88％。（3）P＋s处理可显著降低单位土体积盐量，淡化耕层作用尤为明显。总之，P＋s可调控、优化土壤水盐分布，为食葵生长创造良好的土壤环境，促进食葵生长发育。

In order to explore effects of tillage on dynamics of soil water and salt in saline-alkali soils in the Hetao Ir- rigation District in Inner Mongolia, a micro-plot field experiment, designed to have four treatments, i.e. Treatment T （tillage）, Treatment P （plastic mulching）, Treatment S （deep burial of straw） and Treatment P ＋ S （plastic mulching plus straw burial） , was conducted over a whole sunflower growing period. Results show that Treatment P ＋ S not only sig- nificantly enhanced water storage capacity of the 0 - 40 cm soil layer, but also continuously preserve soil moisture. Soil water content of the 0 -40 cm soil layer was 5.13% , 3.49% and 1.99% higher in Treatment P ＋ S than in Treatments T, P and S before sowing, respectively. Compared to Treatment T, P and S, Treatment P ＋ S increased water content of the soil layer by 5.01% , 5.87% and 2.70% , respectively, at the early growing period, and by 7.53% , 11.02% and 6. 16% , respectively, at the medium growing period. Moreover, Treatment P ＋ S displayed significant long-term effect of suppressing and controlling soil salt in the soil layer. Soil salt content was 18.37% , 20.33% and 1.90% lower in Treat- ment P ＋ S than Treatment T, P and S before sowing, respectively, 45.46% , 37.63% and 39.67% lower in the early growing period, 17.89%, 29.77% and 37.22% lower in the middle growing period, and 14.46%, 13.90% and 19.88% in the later growing period, respectively. In addition, Treatment P ＋ S significantly reduced salt accumulation per unit volume of soil, showing a significant effect of desalinizing the soil, particularly the plough layer. The above find- ings suggest that Treatment P ＋ S is an optimal option to regulate and optimize the distribution of soil water and salt, and create a suitable soil environment for better growing of sunflower.