不同钠钾比微咸水对土壤入渗性能和水盐分布的影响

Effects of saline water with different sodium-to-potassium ratios on water infiltration and distribution of water and salt

为探究不同钠钾离子组成微咸水对土壤入渗性能和水盐运移的影响,开展室内一维土柱入渗试验,依据不同钠钾比设置3种微咸水处理(S1、S2、S3:1∶0、1∶1、0∶1),以去离子水作为对照组(CK)。比较不同处理下土壤湿润锋运移速率的差异,而后通过Philip、Green-Ampt和Kostiakov模型对入渗过程进行拟合,并分析淋洗液电导率、浊度变化和土壤剖面的水盐分布特征。结果表明:(1)与CK处理相比,微咸水处理降低了相同时间内湿润锋的运移距离,在入渗时间达到600 min时,S1、S2、S3处理湿润锋运移距离分别降低41.31%、28.75%、19.94%。在0~60 min内S2和S3处理湿润锋运移距离无显著差异,但在60 min后,S2处理湿润锋运移速率显著低于S3处理;Kostiakov模型拟合效果优于Philip和Green-Ampt模型。(2)S1、S2、S3处理土壤积盐率分别为76.11%、74.16%、73.25%;在淋洗开始的1000 min内,不同处理淋洗液浊度表现为S1>S2>S3>CK。(3)与CK处理相比,微咸水处理并未改变土体内的总含水量,但是增加了不同深度土壤剖面含水率分布的不均匀性,S1、S2、S3处理土壤剖面含水量的变异系数分别为CK处理的3.99、3.26、1.62倍;微咸水处理增加了土壤含盐量,其中S1处理盐分累积效应最大,土壤盐分在0~5 cm和35~40 cm土层聚集;微咸水处理降低了土壤pH值,且S1处理的降低程度最大。研究可为微咸水长期高效利用提供理论支撑。

To explore the effects of saline water with different sodium-to-potassium ratios(Na+∶K+)on soil infiltration performance and transport characteristics of water and salt,an indoor one-dimensional soil column infiltration test was carried out.Four treatments were set up with deionized water as the control(CK)and three saline water treatments with the same electrical conductivity.Different Na+∶K+ratios were 1∶0(S1),1∶1(S2)and 0∶1(S3),respectively.Soil water infiltration process was analyzed,and the infiltration results were fitted by Philip,Green-Ampt and Kostiakov infiltration models.In addition,this study analyzed the variation of electrical conductivity and turbidity of leaching solution as well as the distribution characteristics of water and salt.The results showed that(1)Compared with CK,S1,S2 and S3 all reduced the wetting front movement distance at the same time,and when the infiltration time reached 600 min,distance of S1,S2 and S3 were 41.31%,28.75%and 19.94%lower than CK,respectively.There was no significant difference between the S2 and S3 treatment within 0~60 min,however,after 60 min,the rate of wetting front movement of S2 was greater than S3.Kostiakov infiltration model had better fitting effects than Philip and Green-Ampt infiltration models.(2)The accumulation rates of S1,S2 and S3 were 76.11%,74.16%and 73.25%,respectively.The turbidity of all treatments in the 0~1000 min period of leaching time was in the order of S1>S2>S3>CK.(3)Compared with CK,all of S1,S2 and S3 did not change the total water content in soil column,however,increased the uniformity of water content distribution along soil column profile.The coefficient of variation along soil column section of S1,S2 and S3 were 3.99,3.26 and 1.62 times than CK,respectively.S1,S2 and S3 increased soil salt content compared with CK,and salt accumulated in 0~5 cm and 35~40 cm of S1,and the effect of salt accumulation of S1 was higher than S2 and S3.S1,S2 and S3 all reduced the soil pH,and the decreasing degree of S1 was greater than S2 and S3.This study provides theoretical support for long-term and efficient utilization of saline water.