日光温室栽培对土壤养分累积及交换性养分含量和比例的影响

研究了日光温室栽培下陕西关中地区不同土壤养分累积及交换性养分含量及比例的变化,结果表明：日光温室栽培下土壤有机质、硝态氮、有效磷和速效钾等养分显著累积,土壤阳离子交换量明显增加,而土壤pH却出现下降趋势。日光温室土壤交换性K^＋含量显著增加;日光温室和大田土壤交换性Ca^2＋含量相比无明显差异,而日光温室土壤交换性Mg^2＋的含量及其离子饱和度有所提高。日光温室土壤钙饱和度、Ca/K和M g/K均明显低于大田土壤。认为日光温室栽培下大量施用钾肥,是土壤钙离子饱和度及Ca/K和M g/K比例降低的主要原因,建议在评价日光温室土壤养分有效性时,应综合考虑交换性养分的含量、饱和度及离子间的比例关系。

Nutrient Accumulations and Changes of Exchangeable Cation Ions in Soils under Sunlight Greenhouse Vegetable Cultivation

Nutrient accumulations and the changes of exchangeable cation ions and their ratios in the soils under sunlight greenhouses in Guanzhong Plain of Shaanxi province were analyzed.The results showed that the contents of organic matter,nitrate,and available phosphorus and potassium in the greenhouse soils were significantly accumulated.The cation exchangeable capacity(CEC) in the greenhouse soils was also higher than that in the open fields;on the contrary,the soil pH of the greenhouse was declined.The content of exchangeable K ,or Mg2 ions and the ratio of the ion to the total exchangeable ions in greenhouse soils were increased,especially for K ion.There was no significant difference in the content of exchangeable Ca2 ion between the greenhouse soil and open fields.The ratio of the exchangeable Ca2 ion to the total exchangeable ions,and the ratios of Ca/K and Mg/K in greenhouse soils were lower than that of open fields,due to the excessive application of potassium fertilizer in the greenhouses.It is suggested that to evaluate the supply of available nutrients in the greenhouse soils,not only the contents of exchangeable ions but also the ratios of these ions in soils is needed to be included.