地表覆盖条件下冻融土壤水热动态变化规律研究

Experimental Study of Soil Moisture Regimes During Seasonal Freezing-thawing Period under Different Surface Mulchings

基于季节性冻融期地表覆盖条件下田间土壤温度、水分的剖面监测资料,分析了土壤的温度变化及其冻融过程,进而研究了冻融期裸地(LD)、地膜覆盖(MD)、秸秆与地膜双重覆盖(JMD)地块的土壤水分动态变化规律。结果表明:三种处理地块的土壤均经历初冻、快速冻结、稳定冻结、融化四个冻融阶段;在冻融过程中,三种地块均出现土壤水分的迁移现象,且含水率高值区及低值区出现的时间、深度以及持续的时间随地表覆盖条件的不同而异;深层土壤受气象条件及地表覆盖条件影响较小,含水率保持相对稳定。

Based on the experimental data of soil moisture and temperature profiles during freezing-thawing period, temperature changes in soil and its freezing-thawing process with different mulchings were analyzed, Soil moisture regimes of bare plot（LD）, plastic mulching plot （MD）and plastic film plus straw mulching plot（JMD） were also studied. The conclusions obtained are as follows： 1） soil freezing-thawing process under different mulchings could be divided into four stages., initial freezing, quick freezing, steady freezing and thawing; 2） the phenomenon of moisture transfer in soil profiles were found without exception in three treatment plots, and the time, depth and duration for higher moisture content and lower moisture content areas was different with mulching conditions; 3） soil moisture content at deep layers was suffered to minor influence from meteorological and mulching conditions, keeping relatively steady values.