不同水质淋洗与改良剂施用对银北灌区碱化盐土水盐运移的影响

Effects of Leaching with Different Quality Water and Soil Amendments Application on Soil Water and Salt Transport in Alkalize Solonchaks in Yinbei Irrigation District

通过土柱模拟试验,开展了不同水质淋洗下磷石膏及其与酸性材料组合施用后对宁夏碱化盐土土壤水盐运移的影响研究。以黄河水、低矿化度农田退水和高矿化度农田退水作为淋洗水源,腐植酸、糠醛渣和硫酸铝作为酸性材料。结果表明:(1)不同水质淋洗下,垂直湿润锋推进深度、累积入渗水量与入渗时间的平方根均呈线性关系,黄河水淋洗下,改良剂组合措施表现最优,而在高矿化度农田退水淋洗下,单施磷石膏措施最优。(2)黄河水和低矿化度农田退水淋洗下,施用改良剂降低了0-50 cm土层土壤电导率,黄河水淋洗下“磷石膏+硫酸铝”处理最低;高矿化度农田退水淋洗下为“磷石膏+腐植酸”和“磷石膏+硫酸铝”处理表现较优;(3)随着淋洗水矿化度的增加,土壤pH降低深度增加,施用改良剂降低了0-30 cm土层的土壤pH,黄河水淋洗下,“磷石膏+硫酸铝”处理表现最优;低矿化度农田退水淋洗下表现为“磷石膏+糠醛渣+硫酸铝”处理最低;高矿化度农田退水淋洗下表现为“磷石膏+糠醛渣”处理最低。(4)黄河水淋洗下,施用改良剂提高了不同深度土壤含水率,不同水质淋洗下,施用改良剂提高了0-70 cm土层深度土壤含水率,而各改良剂之间土壤含水率相差不大。综上所述,针对宁夏碱化盐土的改良,建议黄河水和高矿化度农田退水淋洗下,采用“磷石膏+硫酸铝”组合措施进行土壤改良;低矿化度农田退水淋洗下,采用“磷石膏+糠醛渣+硫酸铝”组合措施进行土壤改良。

Through soil column simulation test,the effect of phosphogypsum and its combined application with acidic materials on soil water and salt transport in alkalize solonchaks of Ningxia was studied under leaching with different quality water.In this study,the Yellow River water,low-salinity farmland backwater,and high-salinity farmland backwater were used as leaching water sources,and humic acid,furfural residue and aluminum sulfate were used as acidic materials.The results showed that:(1)Under the leaching with different quality water,there was a linear relationship between the depth of vertical wetting front or cumulative infiltration and the square root of infiltration time.Under the leaching of the Yellow River water,the“phosphogypsum+furfural residue+aluminum sulfate”treatment was the best,while under the leaching of high-salinity farmland backwater,the single application of phosphogypsum was the best.(2)The application of amendments reduced the electrical conductivity of 0-50 cm soil layer under the leaching of the Yellow River water and low-salinity farmland backwater.Under the leaching of the Yellow River water,the“phosphogypsum+aluminum sulfate”treatment had the lowest soil electrical conductivity.Under the leaching of high-salinity farmland backwater,the“phosphogypsum+furfural residue+aluminum sulfate”treatment had the lowest soil electrical conductivity.(3)With the increase of leaching water salinity,the pH value of soil increased.The application of amendments reduced the pH value of 0-30 cm soil layer.Under the leaching of the Yellow River water,the“phosphogypsum+aluminum sulfate”treatment was the best.Under the leaching of low-salinity farmland backwater,the“phosphogypsum+furfural residue+aluminum sulfate”treatment was the best.Under the leaching of high-salinity farmland backwater,the“phosphogypsum+furfural residue”treatment was the best.(4)Under the leaching of the Yellow River water,the application of amendments increased the soil water content at different depths.Under the leaching of different quality water,the application of amendments increased the water content of 0-70 cm soil layer,and there was not large difference among the treatments.For the improvement of alkalize solonchaks,it was suggested that under the leaching of the Yellow River water and high-salinity farmland backwater,a combination of“phosphorgypsum+aluminum sulfate”should be used to improve the soil,while under the leaching of low-salinity farmland backwater,the combined measures of“phosphogypsum+furfural residue+aluminum sulfate”should be used.