灌溉水质对土壤化学特征和作物生长的影响

EFFECT OF IRRIGATION WATER QUALITY ON SOIL CHEMICAL CHARACTERISTICS AND CROP GROWTH

本文以灌溉水矿化度和钠吸附比（SAR）为两个主要指标，组合成16个灌溉水质处理，研究了不同灌溉水质对土壤化学性质和作物生长的影响，初步提出了引起盐害和碱害的灌溉水矿化度和纳吸附比的临界值。研究结果表明，灌溉水带入土壤的盐分在土壤中累积与林洗交替进行。当灌溉水矿化度小于3g／L时，土壤剖面中的盐分处于平衡状态，超过3g／L，则有不同程度积盐，甚至发生中度次生盐化。灌溉水高钠吸附比（SAR）和高碳酸钠含量，可能引起土壤溶液中钙、镁离子因生成碳酸钙镁沉淀而使其浓度降低，钠离子浓度相对增加，从而促使可溶性钠百分率（SSP），钠钙镁比（SDR）和钠吸附比（SAR）升高，最终导致土壤交换性钠百分率（ESP）增加。当灌溉水钠吸附比大于14，矿化度大于3g／L和4g／L时，大豆和小麦生长和产量受到影响，土壤出现中度或强度次生碱化。

Effect of irrigation water quality on soil chemical characterishcs and on cropgrowth was studied in this work. The salt content and sodium adsorption raho (SAR) of irrigation water were considered to be two main indexes which were combined in the 16 treatments of itrigahon water quality in the experimenL Results showed that salts of irrigahon water were accumulated and leached altemately in the soil. Whensalt content of irrigation water was below 3.0g / L, the salt was kept balanced in soil profile. When the salt content of itrigation water was more than 3.0g / L, the salt was accumulated in the soil, even resulting in the medium secondary salinizahon. High SAR and high Na2CO3 in irrigation water can cause Ca2+ and Mg2+ to form sediment of CaCO3 and MgCO3 to decrease Ca2 + and Mg2 + concentrahon and to increase Na+concentrahon in the soil soluhon. Thus SSP, SDR and SAR were risen. As a result ESP increased in the soil. When the SAR of inigahon water was more than 14, and the salt content was more than 3.0g / L or 4.0g / L, the growth and yield of soybean and wheat were influenced, a medium or strong soil secondary alkalization occurred.