不同秸秆埋深对苏北滩涂盐渍土水盐动态变化的影响

Effects of Straw Mulch at Different Depths on Water-Salt Dynamic Changes of Coastal Saline Soil in North Jiangsu Province

揭示土壤水盐动态变化规律是消减盐渍障碍因子的前提。本文通过田间微区试验,研究了秸秆表层覆盖(M0)、秸秆深埋40 cm(M1)、70 cm(M2)及40 cm+100 cm双层(M3)等处理对土壤水盐分布及其动态变化的影响。结果表明:各处理土壤含水量随时间动态变化的规律基本相似,且在土壤剖面分布上,表现为秸秆表层覆盖和深埋处理均能有效增加土壤水分含量。玉米生育期内M0、M1、M2和M3处理土壤剖面平均含水量分别为275.9、280.3、293.9和302.5 g/kg,较对照处理分别增加了3.7、8.1、27.1和30.3 g/kg。从阻盐方面看,M0、M1和M3能有效抑制盐分表聚,积盐率分别较对照处理降低4.86%、8.76%和6.08%,M2处理土壤盐分含量较高,但其积盐率与对照处理相比也降低2.90%。双层秸秆埋深处理(M3)对土壤保墒和抑制盐分方面的作用最为显著,对提高该区土壤水分利用效率及土壤盐渍障碍消减具有积极效果。

Indication of soil water-salt dynamic laws is the premise and basis to reduce the saline obstacle factor. Soil water and salt content and its dynamic variation during the growing period of maize were investigated under field experiments with straw buried in different depths which were： no-straw treatment （CK）, straw surface mulch （M0）, straw buried in 40 cm, straw buried in 70 cm, and straw buried both in 40 cm and 100 cm. The results showed that, both straw surface mulching （M0） and deep burying （M1, M2, M3） could increase soil water content, which were 275.9, 280.3,293.9, and 302.5g/kg respectively, increased by 3.7, 8.1, 27.1, and 30.3g/kg compared with the control in soil profiles during the growth period of maize. According to salt restraining, M0, M1, and M3 could effectively restrain the assembling of salt on top soil, with a reduction of salt accumulation rate-4.86%, 8.76% and 6.08% compared with the control; While M2 had a high salt content with soil salt accumulation rate decreased by only 2.9% compared with the control. So, straw surface mulching and deep burying could increase soil water content, restrain salt accumulation to top soil and thus have positive effect to improve soil salinization.