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选择对滨海沙性盐渍土进行室内土柱模拟淋洗试验,采用连续淋洗与间歇淋洗2种方式比较不同淋洗方式下沙性盐渍土的改良效果。结果表明,淋出液矿化度随着体积变化急剧下降,直至稳定于很低的水平,连续淋洗与间歇淋洗淋出液矿化度分别从233.8,327.4g/L稳定至2.5,2.2g/L。间歇淋洗单位水量淋洗的盐分要高于连续淋洗。淋出液的各离子随体积变化趋势与矿化度变化相似;淋洗结束后土壤盐分变化显示,随着用水量的增加,淋洗效率逐渐降低,15,20,25,30cm水量下连续淋洗的淋洗效率分别为2.87,2.40,1.98,1.67g/ml;间歇淋洗的淋洗效率为3.10,2.48,2.00,1.68g/ml,间歇淋洗的淋洗效率始终要高于连续淋洗;由于各离子溶脱淋洗速率不同,改变了土壤中盐分离子组成,土壤由原来以Na+-Cl-型转变为以Ca2+-SO24-型。根据淋洗过程中土壤盐分变化与用水量之间的关系拟合出的淋洗曲线效果较好,相关系数分别为0.968和0.970。淋洗试验表明,间歇淋洗具有更高的淋洗效率,节水潜力要高于连续淋洗,由此得出的淋洗曲线可用于指导大田沙性盐渍土改良应用。
In order to compare the improvement effect of sandy earthen soil with different elution methods, two consecutive elution and intermittent elution experiments were conducted to simulate the earthen soil column leachate in coastal sandy saline soil. The results showed that the salinity of leachate dropped sharply with the change of volume until stable at a very low level. The salinity of leaching solution and intermittent leaching solution stabilized from 233.8, 327.4 g / L to 2.5, 2.2 g / L. Intermittent rinse unit water rinse salt is higher than the continuous rinse. The leaching solution ions with the change trend of volume and salinity similar; leaching soil salt changes after the end of the show, with the increase of water consumption, leaching efficiency gradually decreased, 15,20,25,30 cm of water under continuous washing The leaching efficiencies were 2.87,2.40,1.98 and 1.67g / ml respectively; the leaching efficiencies of intermittent leaching were 3.10,2.48,2.00 and 1.68g / ml, the leaching efficiency of intermittent leaching was always higher than that of continuous leaching ; Because of the different leaching rate of ions, the composition of salt ions in the soil changed. The soil changed from Na + -Cl- to Ca2 + -SO24-. According to the relationship between the change of soil salinity and the water consumption during the leaching process, the leaching curve fits well, with the correlation coefficients of 0.968 and 0.970 respectively. The leaching test showed that the intermittent leaching had a higher leaching efficiency and a higher potential for water saving than continuous leaching. The leaching curve obtained from this leaching curve can be used to guide the improvement of the field sandy saline soil.