辽宁设施栽培土壤盐分累积变化规律研究

Evolution of Salt Accumulation in Greenhouse Soil in Liaoning Province

对辽宁省主要设施栽培地区土壤盐分累积变化规律的调查研究结果表明:(1)设施栽培土壤盐分含量和电导率较露地土壤有明显增加,且变化幅度较大,是露地的2.0～6.0倍.沈阳、北宁两地设施土壤的盐分含量分别为1 347.48 mg/kg(CV=59.3%),1 274.25 mg/kg(CV=40.5%).(2)设施土壤连续种植到4年左右为盐分累积的高峰期,此时土壤的平均含盐量为1 861.28 mg/kg,EC值为0.53 mS/cm,已超过所种作物的生育障碍临界点(EC>0.5 mS/cm).此后,盐分含量因设施使用率的降低及采取的相关措施而有一定程度的降低.(3)设施土壤各盐分离子的含量均较露地土壤大大增加,盐分的累积以NO 3- 、SO 42-和Ca2+的相对富集为主要特征.(4)盐分在设施土壤中的运移同时存在着向下迁移和向表层聚集两种方式,且以表聚为主.各盐分离子的含量随土层深度的增加而降低,NO 3-、Cl-、Ca2+、Na+的累积迁移量较大,在0～100 cm各土层内的含量都高于对应露地层次,其中,硝酸盐的大量累积和向下迁移势必对环境造成不利影响.

The evolution of salt accumulation in greenhouse soils in Liaoning province was studied in this paper.The results indicated： （1）The salt contents of greenhouse soils were much higher than those in the corresponding open field soils. The average of the salt contents in 0-20 cm layer of greenhouse soils was 2 685.46 mg/kg （ CV=58.0%） in Shenyang and 1274.25 mg/kg（ CV =40.5%） in Beining. （2）The highest salt content was found in greenhouse soils used for about 4 years, mean salt content and EC were 1861.28mg/kg and 0.53 mS/cm,respectively. （3）Compared with neighboring open field soils,the contents of every ion were all increased a lot in the greenhouse soils and among them, NO3^- ,SO4^2- and Ca^2＋ were accumulated much more than any others. （4）The salt moving downwards to the bottom soil（80 - 100 cm） and salt accumulating upwards to the topsoil（0-20 cm）were very obvious in greenhouse soils. The content of each ion was decreased accompanying with deepening profile. The accumulation of NO3^- and its moving to the bottom soil in the greenhouse would have some bad effect on the environment.