滴灌流量对不同质地土壤水盐运移的影响研究

Research on the Effect of Drip Irrigation Flow on Moisture and Salt Transport in Different Texture Soils

为探究新疆地区和江苏围垦地区盐碱地在滴灌条件下的水盐运移规律,通过避雨土箱滴灌试验,以滴灌流量、土壤质地为控制因素,设置0.4、0.7、1.0、1.3 L/h 4种流量处理,选取新疆砂质壤土和东台粉砂质壤土两种典型土壤,研究了滴灌流量对不同质地盐碱土水盐运移规律的影响。结果表明:①随着滴头流量的增加各处理土壤平均含水率先升高后减小,砂质壤土含水率在流量1.0 L/h时达到最大,粉砂质壤土则在流量0.7 L/h时最大;②土壤距离滴头越近,盐分淋失率越高,0~25 cm土层为盐分淋洗区,25~35 cm土层为盐分积聚区。0~15 cm土层,砂质壤土淋洗效果随流量的增加而减弱,粉砂质壤土则表现出相反规律;15~25 cm土层,两种土壤的盐分变化趋势相同,均随着流量的增大先降低再升高。总盐及Na^(+)迁移表现为砂质壤土在流量1.0L/h时平均含量最低,粉砂质壤土在0.7 L/h时淋失率最高。粉砂质壤土中Cl^(-)淋洗率在流量为0.7 L/h时最高,而砂质壤土中流量与Cl^(-)迁移之间无明显规律;③综合土壤水分及盐分淋洗情况,遴选出最优滴灌流量为:新疆砂质壤土1.0 L/h,东台粉砂质壤土0.7 L/h。研究结果可为新疆地区和江苏围垦地区的滴灌系统制定更为合理的灌溉制度提供依据。

The purpose of this study is to explore the moisture and salt transport regularity of saline-alkali land in Xinjiang and Jiangsu reclamation areas under the drip irrigation.Through the drip irrigation experiment in the rain-proof soil tank,taking drip irrigation flow and soil texture as control factors,Xinjiang sandy loam and Dongtai silty loam are selected as typical soils,with four flow treatments(0.4,0.7,1.0 and 1.3 L/h)to study the effect of drip irrigation flow on the moisture and salt transport of saline alkali soil with different texture.The results show that①with the increase in drip discharge,the average moisture content of the soil in each treatment first increases and then decreases;the moisture content of sandy loam reaches the maximum at 1.0 L/h flow rate and that of silty loam at 0.7 L/h flow rate;②the closer the soil is to the emitter,the higher the salt leaching rate;the 0~25 cm soil layer is salt leaching area and the 25~35 cm soil layer is salt accumulation area.In 0~15 cm soil layer,The salt transport trends of the two soils are the same,and both decrease first and then increase with the increase in flow.The migration of total salt and Na^(+) shows that the average content of sandy loam is the lowest at a flow rate of 1.0L/h,and the leaching rate of silty loam is the highest at 0.7 L/h.The Cl^(-) leaching rate in silty loam soil is highest when the flow rate is 0.7L/h,but there is no obvious law between flow rate and Cl^(-) migration in the sandy loam soil;③The optimum drip irrigation flow rate is 1.0 L/h for sandy loam in Xinjiang and 0.7 L/h for silty loam in Dongtai according to the soil moisture and salt leaching conditions.The results can provide a basis for formulating a more reasonable irrigation system for drip irrigation system in Xinjiang and Jiangsu reclamation areas.