【摘要】 连续2年对陕西杨凌地区设施栽培菜地土壤剖面的养分含量进行了测定。结果表明,菜地土壤有机质和全氮含量较农田明显增加,但与高产优质菜地对土壤有机质含量的要求相比,仍属较低水平。菜地土壤0～100cm剖面硝态氮含量以及耕层及20～40cm土层有效磷、有效钾含量均较农田土壤显著增加,表明养分特别是硝态氮在土壤剖面发生明显的淋溶作用,由此可能引起的环境问题值得关注。土壤硝态氮、有效磷和速效钾与土壤电导率间有密切的关系,其中硝态氮含量与土壤电导率间的关系更为密切,说明过量施用肥料特别是氮肥是引起土壤盐分累积的主要原因。更多还原

【Abstract】 Nutrients in soil profiles under canopy vegetable cultivation in Yangling, Shaanxi have been determined in the past two years. It has been found that the contents of organic matter and total N in the soils significantly increased in comparison with the soils for open fields. However, the content of the organic matter in these soils was lower for cultivating the vegetable crops with high yield and quality. The contents of NO3- N in 0～ 100 cm soil profiles and available phosphorus and potassium in 0～ 40 cm soil layers were significantly increased, indicating the heavy accumulation of nutrients, especially NO3- N in the soil profiles, therefore, more attention should be paid to the problems induced by high accumulation of these nutrients in the soils studied. There were close relationships between the electric conductivities of the soils and the contents of NO3- N, available phosphorus and potassium; and the correlation coefficient between NO3- N and electric conductivities of soils was highest, which may indicate the over- application of nitrogen fertilizers was the main reason for salt accumulation in the soils under the canopy vegetable cultivation.更多还原