有机酸改良剂对盐碱土水盐运移的影响

土壤盐碱改良剂的应用研究对土壤改良及作物生长有重要意义,其中富含有机酸的改良剂因其无毒无害效果显著被广泛使用。通过室内一维土柱入渗试验,选取“禾康”盐碱清除剂作为典型有机酸改良剂(简称OA),设置4组施用含量梯度(0.140,0.145,0.150,0.155 g/cm^2),以未施加OA的处理作为对照,同时设置不同的OA施加深度(5—10,15—20,25—30 cm),以研究OA对盐碱土水盐运移的影响。结果表明:混施OA处理中,随着OA施加量的增加,土壤入渗能力减弱,稳定入渗率显著下降,通过Philip和Green-Amp入渗模型对入渗过程拟合,Philip模型较Green-Ampt与拟合参数的一致性较好,更适合于土壤中含有有机酸改良剂作用的入渗过程模拟,吸渗率S、稳渗率A相对误差分别为9.82%,2.23%,吸渗率S、稳渗率A、饱和导水率KS及土壤水吸力Sf均呈减小趋势,土壤的持水性能和土壤脱盐率显著提升。在层施OA处理下,随着层施深度的增加,累积入渗量增大,稳渗率降低,土壤的脱盐率无明显提高。研究结果为有机酸改良剂在盐碱土改良应用中提供理论依据。

Effect of Organic Acid Modifier on Water and Salt Transport in Saline-alkali Soil

The application of soil saline-alkali modifier is very important for soil improvement and crop growth, the organic acid-rich modifier is widely used because of its non-toxic and harmless effect. This paper selected the "hekang" saline-alkali scavenger as a typical organic acid modifier (hereinafter referred to as OA) through the indoor one-dimensional soil column infiltration test, and set up four groups of application content gradients (0.140, 0.145, 0.150 and 0.155 g/cm²), with the treatment without OA as the control. At the same time, different OA application depth(0-10,15-20,25-30 cm) was also set to study the influence of OA on water and salt migration in saline-alkali soil. The results showed that mixed OA treatment with the increase of the applied amount, the soil infiltration capacity was decreased, as well as the steady infiltration rate. By fitting the infiltration process by Philip and Green-Amp infiltration models, the Philip model calculation parameters and fitting parameters calculated by the model parameter extrapolation relationship were in good agreement, and the relative errors were 9.82% and 2.23% respectively, which indicated that the Philip model is more suitable for the infiltration process with the application of organic acid modifier in soil. Both the absorption rate S and the steady permeability A decreased, and the saturated water conductivity K_S and the soil water suction S_f decreased. Furthermore, the addition of OA could improve the water holding performance of soil and significantly improve the desalination rate of soil. After layer application OA treatment, with the increase of layer application depth, the cumulative infiltration increased, the steady permeability decreased, and the desalination rate of soil did not increase significantly. It is hoped that the organic acid modifier could provide theoretical basis for the application of saline-alkali soil.