半干旱黄土丘陵区植物休眠期覆盖对土壤水热变化的影响

通过对半干旱黄土丘陵区植物休眠期内不同地膜覆盖下土壤水分与温度的野外试验观测,研究覆膜下土壤水分运移规律与温度变化差异。于2014年10月—2015年4月在西北农林科技大学米脂试验站远志山同一水平阶地上,观测裸地(CK)与透明薄膜覆盖(TF)2种处理下0—400cm深度内土壤水分与裸地(CK)与透明薄膜覆盖(TF)、黑色薄膜覆盖(BF)3种处理下0—50cm(15,30,50cm)深度内土壤温度。结果表明:在植物休眠期,0—400cm土壤储水量TF较CK高51.9%,差异显著(p0.05);0—20cm土壤储水量变幅最大,20—60cm的土壤储水量由上层54.9%降至26.3%;在典型晴天,非冻结阶段CK、TF与BF处理最值温差区间为2.25~2.7℃,3.45~3.5℃,1.5~1.8℃,而在冻结阶段为1.65,2.1,1.2℃,土壤冻结时覆膜保温效应不显著;覆膜保温深度可达15cm,BF处理保温效果优于TF处理。总体来看,在植物休眠期覆膜可以提高0—20cm深度范围的土壤含水量和土壤温度,减少土壤水分损失并促进水分向深层入渗,BF处理较TF处理更加有利于增温与稳定温度变化。

Effects of Film Mulching on Soil Moisture and Temperature Changes during Plant Dormancy Period in Semiarid Loess Hilly Region

A field test was conducted at the Mizhi Experimental Station of Northwest A & F University from October 2014 to April 2015,to research the soil moisture movement law and temperature difference under different plastic film mulching in plant dormancy period in semiarid loess hilly region.No plastic film mulching (CK) and transparent film mulching (TF) treatments were set up at the same level of terraces at the depth of 0-400 cm to observe soil moisture movement.Three treatments,including CK,TF,and black film covering (BF) were designed at the same level at the depth of 0-50 cm (15 cm,30 cm,50 cm) to observe soil temperature.The results showed that soil water storage capacity of TF was 51.9％ higher than that of CK at the depth of 0-400 cm in the dormancy period,and the difference was significant (p ＜ 0.05).The maximum amplitude of soil water storage appeared at the depth of 0-20 cm,and soil water storage at the depth of 20-60 cm decreased from 54.9％ to 26.3％.In typical sunny days,the maximum temperature difference between the three treatments of CK,TF,and BF was 2.25-2.7 ℃C,3.45-3.5 ℃C,and 1.5-1.8 ℃C at the non-freezing stage.Whereas the difference was 1.65 ℃C,2.1 ℃C and 1.2 ℃C at the freezing stage,and the effect of film insulation was not obvious when the soil was frozen.The depth of film insulation was up to 15 cm,the warming effect of BF treatment was better than that of TF.The above evidences suggested that the plastic film mulching in plant dormancy period could increase soil moisture and soil temperature,reduce soil water loss and promote water deep infiltration in the 0-20 cm soil layer.Furthermore,BF treatment might be more favorable for warming and stabilizing temperature change than TF treatment.