不同年限日光温室土壤硝态氮和盐分累积特性研究

土壤养分与盐分累积是设施农业面临的突出问题，为了探明日光温室生产对土壤养分与盐分累积的影响，以甘肃石羊河流域不同种植年限的日光温室及其附近露地粮田为研究对象，应用野外调查与取样分析相结合的方法，分析了日光温室土壤硝态氮和电导率（EC）变化特性。结果表明，日光温室土壤表层有硝态氮累积和盐分积聚现象；在同一耕作层剖面上，日光温室内各土层平均土壤硝态氮含量和EC值分别为露地粮田的1.2-3.3倍和0.7-3.2倍；耕层以下土壤硝态氮含量和EC值随种植年限延长而增加，其峰值及其所在深度随种植年限延长而增大。日光温室传统的大水大肥种植习惯是造成温室土壤养分和盐分累积的主要原因，应适当调整温室生产中的灌水施肥水平，采取节水节肥的高效灌溉施肥制度。

Study on the Accumulation Characteristics of the Soil Nitrate Nitrogen and Salinity in Greenhouses of Different Cultivation Years

The accumulations of the soil nutrients and salinity are the main problems in the development of the protected agriculture. To find the impacts of the development of greenhouses on the accumulations of the soil nutrients and salinity, the study chose the greenhouses of different cultivation years and the near wheat-maize fields in Shiyang River basin and analyzed the soil nitrate nitrogen and soil electric conductivity in the field survey and sample analysis method. The results indicated that the nitrate nitrogen and the salinity are accumulated at the surface layer in greenhouses; the average soil nitrogen content of soil layer in greenhouse is 1.2-3.3 times than in wheat-maize fields in the same soil profile, and the average EC of soil layer in greenhouse is 0.7-3.2 times than in wheat-maize fields; the nitrate nitrogen and EC increase with the increasing of cultivation years in a depth under the root zone; with the increasing of cultivation years, the maximum value is increased, and the accumulation depth is more deepened. The accumulations of the soil nutrients and salinity are mainly caused by the over-fertilizer and illogical irrigation, so it is necessary to adjust the coupling of the water and fertilizer and to take the efficient irrigation schedule of water-saving and fertilizer-saving.