蔬菜保护地土壤硝酸盐积累及盐分变化

对天津市部分区县菜田土壤的分析结果表明，温室、大棚内０～２０ｃｍ、２０～４０ｃｍ土壤ＮＯ－３含量与全盐量的相关性分别达到极显著水平；而露地０～２０ｃｍ土壤两者的相关性达显著水平，２０～４０ｃｍ土壤的相关性极差。从定点观测的结果可以看出，春季露地表层土壤（０～３ｃｍ）的全盐量明显高于大棚土壤，其它土层差异较小。

Nitrate Accumulation and Salt Changes in Soils of Protected Areas

The protected areas for growing vegetable crops in some suburbs and counties of Tianjin is investigated,and the soil samples in the areas is also collected. The results show that the NO - 3 in the thickness of layers(0～20 and 20～40 cm) of the greenhouses and plastic covered greenhouses has very significant correlation with total salt amount, and significant one in the 0～20 cm layer and no significant one in the 20～40 cm layer of terrestrial soil.The evidences from the results of placement observation indicate that in spring, the total salt amount in the surface of the soil(0～3 cm) of terrestrial soil is obviously high in comparison with the one in plastic covered greenhouse, and the amounts in the soil layer 3～40 cm have no obvious difference between them.