典型设施栽培土壤盐分变化规律及潜在的环境效应研究

SALT IN TYPICAL GREENHOUSE SOIL PROFILES AND ITS POTENTIAL ENVIRONMENTAL EFFECTS

研究了山东寿光设施土壤盐分的变化规律。结果表明:(1)设施土壤的盐分含量高,变化幅度大。耕层盐分含量为2.69 g kg-1(CV=58%),而相应的露地仅为0.61 g kg-1(CV=14%)。(2)设施土壤连续种植到4 a左右,其耕层的盐分含量则可达到限制作物正常生长的临界点,此后盐分含量随采取的各种管理措施而有所降低。土壤次生盐渍化是造成温室可持续利用周期较短的主要原因。(3)除HCO-3外,NO3-、SO24-、Cl-、Ca2+、Mg2+、K+、Na+在剖面的累积明显高于露地,且以NO-3和Ca2+的相对富集为主要特征,两者可占耕层盐分离子总量的47.4%和19.3%。(4)与露地相比,盐分离子在设施土壤剖面存在着明显的累积和向下迁移现象,同时在剖面的分布还具有明显的表聚特征,其中NO-3的大量累积和向下层迁移已严重影响到当地地下水水质。

Salt in greenhouse soils was studied in Shouguang, Shandong Province. The results indicate that 1 ） the salt content in greenhouse soils was much higher than that in open field soils, with an average value being 2.69 g kg^-1（ CV = 58 % ） and only 0.61 g kg^-1（CV = 14% ）, respectively, in 0 - 20 cm soil layer; 2） the salt content in greenhouse soils might reach the threshold value for normal growth of crops after 4 years of cultivation, and secondary salinization of the soil is a main limiting factor for sustainable development of greenhouse cropping; 3） apart from HCO3^- , the contents of NO3^- , SO4^2- , Cl^- , Ca^2＋ , Mg^2＋ , K^＋ , Na^＋ increased significantly in greenhouse soils, and Ca^2＋ and NO3^- were the major ions in the soils, accounting for 47.4% and 19.3% of the total salt in the topsoil, respectively; and 4） compared with neighboring open field soils, greenhouse soils displayed apparent phenomena of salts leaching downwards to the bottom of the soil （80 - 100 cm） and salts accumulating in the topsoil （0 - 20 cm）, especially NO3^- that has seriously affected quality of the groundwater in the area.