秸秆覆盖条件下滨海盐渍土水盐分布及蒸发特征

Effects of Straw Mulching on Water and Salt Distribution and Evaporation Characteristics in Coastal Saline Soil

为了揭示秸秆覆盖滨海盐渍土水盐调控机理,通过室内模拟实验研究了不同秸秆覆盖量(0、0.3、0.6、0.9和1.2 kg/m^(2)分别由CK、秸秆A、秸秆B、秸秆C和秸秆D表示)对土壤水盐运移和蒸发强度的影响。结果表明,秸秆覆盖可有效提高表层及土壤剖面含水率,且增墒效果随秸秆覆盖量的增加而增加:试验期间秸秆A、秸秆B、秸秆C和秸秆D剖面平均含水率比CK依次高了41.2%、52.3%、65.7%和58.5%;秸秆覆盖可抑制表层土壤盐分积聚并有效调控土壤剖面盐分分布,秸秆覆盖量越大表层积盐量越低,土壤剖面盐分分布越趋于均衡:试验结束时,CK、秸秆A、秸秆B、秸秆C和秸秆D表层0~2 cm土壤电导率比3~5 cm电导率分别高了246.3%、242.8%、138.4%、40.5%和47.6%;土壤蒸发强度和累积蒸发量随着秸秆覆盖量的增加而降低:试验期间CK、秸秆A、秸秆B、秸秆C和秸秆D处理平均蒸发强度依次为1.79×10^(-3)、1.64×10^(-3)、0.93×10^(-3)、1.35×10^(-3)和0.76×10^(-3)mm/min,累积蒸发量分别为17.79、20.30、14.20、14.57和10.27 mm,且蒸发初期秸秆覆盖对蒸发强度和累积蒸发量的抑制作用更明显。

In order to reveal the mechanism of straw cover on the water and salt regulation of coastal saline soil,the effects of different straw coverage(0,0.3,0.6,0.9 and 1.2 kg/m^(2),denoted by CK,straw A,straw B,straw C and straw D,respectively)on soil water and salt transport and evaporation rate are studied through indoor simulation experiments.The results show that straw mulching increases the moisture content of the surface layer and soil profile,and the effect of increasing soil moisture increases with the increase in straw coverage.The average moisture content of straw A,straw B,straw C and straw D profiles are higher than CK by 41.2%,52.3%,65.7%and 58.5%during the experiment;straw mulching can suppress the accumulation of surface soil salt and effectively regulate the soil profile salt distribution.The lower the salt content,the more balanced the salt distribution in the soil profile:the electrical conductivity of 0~2 cm soil on the surface of CK,straw A,straw B,straw C and straw D is 246.3%,242.8%,138.4%,40.5%and 47.6%higher than the 3~5 cm conductivity,respectively.At the end of the experiment;the soil evaporation rate and cumulative evaporation decrease with the increase in straw coverage.During the experiment,the average evaporation rate of CK,straw A,straw B,straw C and straw D treatments are 1.79×10^(-3),1.64×10^(-3),0.93×10^(-3),1.35×10^(-3) and 0.76×10^(-3) mm/min,the cumulative evaporation is 17.79,20.30,14.20,14.57 and 10.27 mm,and the effect of straw coverage on the evaporation rate and cumulative evaporation is more obvious in the early stage of evaporation.