灌溉方式及腐植酸用量对温室内土壤Cd迁移的影响

目前,我国温室大棚栽培面积呈逐年递增趋势。与露地栽培相比,温室大棚栽培肥料用量大,土壤表层养分含量高,土壤污染严重,直接影响农产品的品质和栽培经济效益。采用温室内土柱模拟试验,研究了不同灌溉方式以及腐植酸用量下土壤Cd的迁移转化行为。结果表明,添加腐植酸促进表层土壤Cd2＋向下迁移,该迁移行为与灌溉方式、腐植酸添加量关系密切,随腐植酸用量的增大,灌溉淋出的Cd2＋量逐渐增加。与常规灌溉相比,滴灌使Cd2＋多存在于土壤的表层,通过减少Cd2＋的淋滤量而减轻对地下水安全的威胁。

Effect of Irrigation Methods and Humic Acid Supply on Soil Cd Translocation in Greenhouse

At present,the areas of greenhouse in China are increasing year by year.Compared with open field culture,greenhouse cultivation was with much higher fertilizer supply,higher nutrient content in surface soil and heavier soil pollution,which evidently affected the quality of agricultural products and economic benefits.Soil column-leaching tests were conducted in greenhouse to study the leaching and transloca-tion behaviors of soil Cd as influenced by different quantities of humic acid（HA）supply and irrigation methods.The results showed that the migration of Cd2＋ from up-soil to deep-soil in the column was promoted by HA application and was also tightly related to the quantity of HA and different irrigation methods.Cd2＋ concentration in soil leaching solution was significantly increased by the application of HA,which im-plied HA addition could promoted Cd desorption from soil.More Cd2＋ stayed in the soil surface layer with drip irrigation than that with the conventional irrigation,which indicated the environmental risk of Cd pollution with drip irrigation was less than that of conventional irrigation for underground water.