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研究了不同农田利用方式和冬灌对黑河中游边缘绿洲沙地农田土壤硝态氮(NO3-N)积累的影响.结果表明:不同农田利用方式0～300cm土层NO3-N含量平均值介于1.27～83.60mg·kg-1;受土壤结构、施肥及灌溉的影响,NO3-N含量在0～40cm和135～300cm土层含量较高,40～135cm土层含量较低;不同农田利用方式下的土壤剖面NO3-N含量差异极为明显,大棚蔬菜地各土层NO3-N含量均显著高于其他农田利用类型,土壤NO3-N累积量表现为大棚蔬菜地>番茄地>棉花地>制种玉米连作田>小麦-玉米轮作田>小麦/玉米间作田>苜蓿地>枣树园;大棚蔬菜地0～300cm土层土壤剖面NO3-N累积量高达2171.45kg·hm-2,对地下水污染的威胁较为严重,番茄地和棉花地土壤剖面NO3-N累积量次之,粮田、苜蓿地和枣树园土壤剖面NO3-N累积量较小,但其污染潜力仍不容忽视.冬灌前后NO3-N含量随土壤层次表现出不同的变化规律,0～80cm土层冬灌后NO3-N含量低于冬灌前,并且随灌溉量的增加NO3-N含量呈明显降低趋势;80～300cm土层基本表现为冬灌后NO3-N含量高于冬灌前,且随灌溉量的增加NO3-N含量呈增加趋势;冬灌前后0～80cm土层土壤剖面NO3-N的损失量基本为正值,80～300cm土层基本为负值,并且随灌水量的增加表层土壤NO3-N损失量增大,表明冬灌是造成土壤累积的NO3-N向深层淋溶的主要原因.从减少淋溶和地下水污染的角度考虑,需要合理地调整土地利用方式,适当减少高NO3-N积累作物的种植,并确定合理的冬灌方式和灌水量.
The effects of different farmland use patterns and winter irrigation on soil nitrate nitrogen (NO3-N) accumulation in farmland in the marginal oasis of middle reaches of Heihe River were studied. The results showed that the average NO3-N content of 0 ~ 300cm soil layer in different farmland utilization was between 1.27 ~ 83.60mg · kg-1. Under the influence of soil structure, fertilization and irrigation, the contents of NO3-N were higher in 0 ~ 40cm and 135 ~ 300cm soil layers and lower in 40 ~ 135cm soil layer. The content of NO3-N in the soil profiles of greenhouse vegetable was significantly higher than that of other farmland types. The accumulation of NO3-N in soil showed the characteristics of greenhouse vegetable land> tomato land> cotton land> seed production Corn-cropping field> wheat-corn rotation field> wheat / corn field> field> alfalfa field> jujube tree garden; the accumulation of NO3-N in soil profile of 0 ~ 300cm soil layer in greenhouse vegetable was as high as 2171.45kg · hm-2, And the NO3-N accumulation in the soil profiles of tomato and cotton was second, while that of grain fields, alfalfa and jujube fields was small, but its pollution potential still could not be ignored.N3- N content showed different variation with the soil layer, 0 ~ 80cm soil layer winter The content of NO3-N after irrigation was lower than that before winter irrigation, and the content of NO3-N decreased obviously with the increase of irrigation amount. The content of NO3-N in 80 ~ 300cm soil layer was higher than that before winter irrigation, The content of NO3-N increased with the increase of irrigation amount; the loss of NO3-N in the soil profile of 0 ~ 80cm soil layer before and after winter irrigation was basically positive, while the soil layer of 80 ~ 300cm was almost negative. The loss increases, indicating that winter irrigation is the main reason for the accumulation of soil NO3-N to deep leaching.From reducing the leaching and groundwater pollution point of view, it is necessary to adjust the land use patterns reasonably and properly reduce the accumulation of high NO3-N crops Of the planting, and to determine a reasonable winter irrigation methods and irrigation volume.