干旱区滴灌农田土壤盐分变化分析

Analysis of Soil Salt Change in Drip Irrigation Farmland in Arid Area

摘要: 为了解强烈干旱农业区非或弱咸性灌溉水质条件下滴灌土壤盐分变化问题，基于12种滴灌作物，土壤层0~30 cm深度，2016至2018年三年定位采集150个样品检测土壤总盐分和土壤八项离子，形成1446个系列数据，经数理统计方法分析结果显示，从滴灌土壤盐分总体变化状态来看，滴灌土壤总盐分含量均有增加且变化差异较大，土壤硫酸根、重碳酸根和钙离子含量居多，是监测灌区土壤酸碱度高土壤呈碱性的主要成因；从滴灌土壤盐分年际变化来看，12种滴灌作物平均土壤总盐分含量随着年份增加呈现明显增加趋势，土壤总盐分由2016年的1.23 g/kg，增加到2018年的2.01 g/kg，土壤硫酸根离子(SO₄^2-)含量最高，由2016年的0.6782 g/kg，增加到2018年的0.6830 g/kg，其次是重碳酸根(HCO₃^-)由2016年的0.2631 g/kg，增加到2018年的0.3389 g/kg；从土壤盐分构成和盐分增加量来看，主要是重碳酸根、硫酸根离子、氯离子、钾离子和钠离子，表明本区土壤盐分主要是硫酸(碳酸)氯化物类型；从滴灌土壤盐分积累贮量来看，滴灌多种作物综合平均土壤盐分增量和年递增率分别为0.78 g/kg和17.70%，土壤盐分平均积累贮量和年增加量分别为3.57 kg/hm2和1.19 kg/hm2，滴灌土壤盐分积累贮量与滴灌作物用水量大小有关，灌溉用水定额较高，作物土壤盐分相对积累贮量减缓，反之，土壤盐分积累和贮量有所增加。分析结果表明，非或弱咸性灌溉水质长期进行滴灌，在干旱地区存在土壤盐分积累贮量增加的情形。

Abstract: In order to understand the change of soil salinity in drip irrigation under non- or weak-saline ir-rigation water quality in arid agricultural areas, 150 samples were collected in three years from 2016 to 2018 to detect total soil salinity and eight ions forming 1446 series of data. The results of mathematical statistics analysis showed that the total soil salinity of drip irrigation was the same as that of non- or weak-saline irrigation. From the point of view of change, the total salt content of drip irrigation soil increased and showed great difference. Soil sulfate, bicarbonate and calcium ion content were the main reasons for monitoring the alkalinity of soil with high soil acidity and alkalinity in the irrigation area. From the interannual change of soil salinity in drip irrigation, the average total salt content of 12 kinds of drip irrigation crops showed a significant increase trend with the increase of years. Soil total salinity increased from 1.23 g/kg in 2016 to 2.01 g/kg in 2018. Soil sulfate ion (SO₄^2-) content was the highest, from 0.6782 g/kg in 2016 to 0.6830 g/kg in 2018, followed by bicarbonate (HCO₃^-) from 0.2631 g/kg in 2016 to 0.3389 g/kg in 2018. Root ions, chloride ions, potassium ions and sodium ions indicated that the main types of soil salt in this area were sulfuric acid (carbonate) chloride. From the point of view of soil salt accumulation and storage in drip irrigation, the comprehensive average soil salt increment and annual increment rates of various crops under drip irrigation were 0.78 g/kg and 17.70%, respectively. The average soil salt accumulation and annual increment were 3.57 kg/hm2 and 1.19 kg/hm2, respectively. The relative accumulation of soil salt in crops with higher irrigation water quota slowed down, whereas the accumulation and storage of soil salt increased. The results show that drip irrigation has been used for a long time in non- or weak-saline irrigation water quality, and there is an increase in soil salt accumulation and storage in arid areas.