不同淋洗方式下滨海沙性盐渍土改良效果

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。

Improvement Effect on Different Leaching Modes of Coastal Sandy Saline Soil

The author made a simulated leaching soil column experiment on coastal sandy saline soil in laboratory,including continuous irrigation and intermittent irrigation,compared the improvement of sandy saline soil effect of different leaching modes.The experiment results show: Mineralization degree of effluent drops quickly until steady at low level as the volume changed,after continuous irrigate and intermittent irrigate,It has declined from 233.8,327.4 g/L to 2.5,2.2 g/L.Intermittent irrigation can elution more salinity with irrigated in unit water.The change trend of all ions and mineralization degree of effluent are same.Leaching efficiency declines as the irrigate water ammount rises.Leaching efficiency of 15,20,25,30 cm continuous irrigation are 2.87,2.40,1.98,1.67 g/ml,but intermittent irrigation leaching efficiencies are 3.10,2.48,2.00,1.68 g/ml.Leaching efficiency of intermittent irrigation is higher than continuous irrigation from beginning to end.The soil ions constitute has changed,because the leaching speed of every ion is different.It has changed from Na+-Cl-type to Ca2+-SO2-4 type.The leaching curve is fitted,which showed the relation between soil desalting and irrigate water ammount,and the fitting efficiency is very perfect.Leaching experiment shows that: Intermittent irrigation has a higher leaching efficiency,and the water saving potential is higher than continuous irrigation.Finally,the leaching curve can be used to guide the improvement of the sandy saline soil in the field.