灌溉水质对土壤水盐动态的影响

EFFECT OF IRRIGATION WATER QUALITY ONSALT-WATER DYNAMICS OF SOILS

本文研究了灌溉水质对土壤水盐动态和牧草生长的影响。灌溉水含盐量分别为１００、１５００和３０００ｍｇ／Ｌ，设有６个试验处理。在高含盐水灌溉期间，盐分在土壤剖面中累积，低含盐水灌溉和冬季降雨期间部分土壤盐分被淋洗。由于盐分累积与淋洗反复进行，以及弱透水层的存在，可溶盐在６０—９０ｃｎ１土层明显增加，土壤溶液钠吸附比（ＳＡＲ）随灌溉水含盐量增加而增高，牧草茎叶中的盐分亦随之而变化。当灌溉水含盐量达到１５００ｍｇ／Ｌ时，牧草产量不受影响，灌溉水含盐量３０００ｍｇ／Ｌ时在不同试验处理条件下仅仅减产９％至１７％，显然，灌溉管理及盐分控制措施起着一定的调节作用。

ffects of irrigation water quality on salt-water dynamics of red-brown earthand perennial pasture production were studied. Irrigation water with salinities of 100,1500 and 3000mg/L and six different irrigation treatnients were adopted in the exp-eriment. Salt was accumulated in the soil during the season of irrigation with waterof high soluble salt concentration and partly leached away during irrigation withwater of low soluble salt concentration and winter rainfall. Tbe total soluble salts, chloride and sodium ions, appeared to be higher in the 60─90cm horizons thanother horizons in the soil profile due to repeated accumulation and leaching and thelow permeability of clay horizon.The sodium adsorption ratio (SAR) of the soil and the salt concentration of thewhite clover shoots increased with the soluble salt concentration of irrigation water.Pasture yield was not significantly affected by irrigation water with a salt concentr-ation up to 1500mg/L and only reduced by about 9% to 17% at tbe salt concentra-tion of 3000mg/L under different irrigation conditions. It is evident that irrigationmanagement could play a certain role in regulating salt-water dynamics of soils.