西安地区日光温室土壤养分与盐分累积状况研究

Nutrient accumulation in the soils under sun-light greenhouses of Xi'an area

选择西安市灞桥区新合镇的三个村的24个日光温室，对0～100cm剖面土壤及相邻的农田土壤养分、pH和电导率进行了分析研究。结果表明：日光温室土壤有机质含量明显增加，表层（0～20cm）平均为22．5g／kg，比农田高出9．0g／kg；有效磷、速效钾含量出现明显的累积，表层平均分别为261mg／kg和412mg／kg，比露地增加569％和194％；0～40cm剖面土壤pH与露地比较有变酸趋势，平均降低0．17个pH单位。24个日光温室0～100cm土壤剖面硝态氮含量虽有差异，但其平均值均较露地显著增加，增加量为23．1～89．7mg／kg；铵态氮与露地差异很小，说明施肥对目光温室土壤中铵态氮影响较小。目光温室土壤表层积盐明显，其电导率平均值高出露地1倍。但大部分尚未达到阻碍作物生长的指标。

The contents of different nutrients in 0-100 cm soil profiles of 24 sun-light greenhouses at the suburbs of Xian were determined to evaluate the accumulation of nutrients and salts in the soils under sun-light greenhouses. The results showed that the average content of organic matter in 0 - 20 em soil layer of greenhouse was 22.5 g/kg, which was significantly higher than that in the open fields. The contents of available phosphorus and available potassium in the layer of 0 - 20 cm of tively, which were about 569 % and 194 % higher than greenhouses were 261 mg/kg and 412 mg/kg, respecthat in the open fields, respectively. The pH in 0-40 cm soil layer of the greenhouses was 0.17 pH unit lower than that in the open fields, indicating the acidity of the soils under sun-light greenhouse. There were no significant differences in the content of NO3- - N among the 24 greenhouse soils; however, the NO3- - N in 24 greenhouse soils was significant higher than that in the open field, the increases in NO3- - N in greenhouses compared to open fields was in range of 23.1 - 89.7 mg/kg. There were no significant differences in the content of NH4 ^＋ - N in greenhouse and open fields, indicating the stable of NH4^ ＋ - N in upland soils. The electric conductivity （EC） in greenhouses was about two times as high as that in the open fields; however, the soil EC of the greenhouse was not reached the harmful level to crop in the study region.