不同灌水量对黄河三角洲盐碱地改良效果研究

通过室内土柱模拟试验,研究不同灌水量对盐渍土的改良效果。试验共设计3个不同灌水量,分别为S1 (200 mm)、S2 (300 mm)、S3 (400 mm)。结果表明:(1)灌溉淋洗对0—40 cm土壤盐分淋失影响较大,其中0—20 cm脱盐率最高,表现为S3S2S1,不同处理在剖面上均出现积盐,S1、S2在40—60 cm出现积盐,说明低灌水量对土壤表层盐分具有淋洗作用,但会造成底层土壤盐分累积;(2)K~+、Na~+、Ca~(2+)、Mg~(2+)、Cl~-、SO_4~(2-)、HCO_3~-含量在灌水后有较大幅度的下降,且整体溶脱率随灌溉水量的增加而增加。各离子在0—20 cm随灌水量增加表现为不同的变化规律,Ca~(2+)先溶脱后积累,HCO_3~-变化规律与Ca~(2+)相反,表现为先积累后溶脱,其他离子均随灌水量的增加而减少;(3)灌水后,S1、S2的pH在剖面上的分布与灌水前相似,0—40 cm土壤总碱度随灌水量增加呈先增后减的趋势,表现为先碱化再脱碱,与土壤pH变化一致。研究成果可为盐碱地改良和节水灌溉提供参考。

Study on Improvement Effect of Different Irrigation Volumes on Saline-alkali Land in the Yellow River Delta

Indoor soil column simulation was used to study the improvement effect of saline soil under different irrigation volumes. The three different irrigation volumes in the experimental design were S1 (200 mm), S2 (300 mm), and S3 (400 mm). The results showed that:(1) Irrigation had a great influence on the leaching of soil salinity in 0-40 cm soil layer. Soil layer in 0-20 cm had the highest desalination rate, which performance was S3 > S2 > S1. Salt accumulation occurred in the profile of different irrigation volumes, and was observed in the 40-60 cm soil layer of S1 and S2, which indicated that low amount irrigation had leaching effect on the surface soil salt, but could cause salt accumulation in the bottom soil. (2) The contents of K⁺, Na⁺, Ca²⁺, Mg²⁺, Cl^-, SO₄^2-, and HCO₃^- decreased after irrigation, and the overall dissolution rate of salt ion increased with the increase of irrigation volumes. The variation of each ion showed different changes with the increase of irrigation volumes in 0-20 cm soil layer. Ca²⁺ firstly accumulated and then dissoluted, while HCO₃^- dissoluted firstly and then accumulated, and the other ions decreased with the increase of irrigation volumes. (3) After irrigation, the distribution of S1 and S2 pH in profile was similar to that before irrigation. The total alkalinity of 0-40 cm soil layer increased firstly and then decreased with the increase of irrigation amount, which was firstly alkalized and then alkali removed, and was consistent with the change of pH. The research results can provide reference for water-salt balance and water-saving irrigation in saline-alkali soil.