Yang Rong, Su Yong-zhong
Linze Inland River Basin Comprehensive Research Station, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China.
Ying Yong Sheng Tai Xue Bao. 2009 Mar;20(3):615-23.
With the sandy farmland in the marginal oasis in middle reaches of Heihe River Basin, Northwest China as test object, this paper studied soil NO3- -N accumulation and leaching under effects of different farmland use type and winter irrigation. The results showed that the mean NO3- -N concentration in 0-300 cm soil profile in different farmlands ranged from 1.27 mg x kg(-1) to 83.60 mg x kg(-1) Soil NO3- -N concentration was higher in 0-40 cm and 135-300 cm layers, but lower in 40-135 cm layer. Greenhouse vegetable field had a significantly higher soil NO3- -N concentration than the other farmland use types. The accumulated amount of soil NO3- -N decreased in the order of greenhouse vegetable field > tomato field > cotton field > seed maize field > maize-wheat rotation field > maize-wheat stripe intercropping field > alfalfa field > jujube plantation. The NO3- -N accumulation in 0-300 cm soil profile in greenhouse vegetable filed reached 2171.45 kg x hm(-2), which would be a serious menace to groundwater quality, followed by tomato field and cotton field. Lesser accumulation of soil NO3- -N was found in seed maize field, maize-wheat intercropping field, maize-wheat rotation field, alfalfa field, and jujube plantation, but its pollution potential would not be neglected. After winter irrigation, soil NO3- -N concentration decreased in 0-80 cm layer but increased in 80-300 cm layer, indicating that winter irrigation caused NO3- -N leaching into deeper soil depth. The leached amount of soil NO3- -N to deeper layers increased with increasing amount of winter irrigation. To mitigate soil NO3- -N leaching and groundwater contamination, a comprehensive consideration should be made on the rational arrangement of farmland use type, proper decrease of planting N-accumulated crops, and reasonable winter irrigation.
以中国西北黑河流域中游边缘绿洲的沙质农田为试验对象，研究了不同农田利用类型和冬季灌溉影响下土壤硝态氮的积累与淋失。结果表明，不同农田0300 cm土层硝态氮平均浓度在1.27 mg·kg-1至83.60 mg·kg-1之间。土壤硝态氮浓度在040 cm和135300 cm土层较高，在40135 cm土层较低。温室菜地土壤硝态氮浓度显著高于其他农田利用类型。土壤硝态氮累积量大小顺序为：温室菜地＞番茄地＞棉田＞制种田＞麦玉轮作田＞麦玉带状间作田＞苜蓿地＞枣园。温室菜地0300 cm土层硝态氮累积量达2171.45 kg·hm-2，对地下水质量构成严重威胁，其次是番茄地和棉田。制种田、麦玉间作田、麦玉轮作田、苜蓿地和枣园土壤硝态氮累积量较小，但其污染潜力也不容忽视。冬季灌溉后，080 cm土层土壤硝态氮浓度降低，80~300 cm土层升高，表明冬季灌溉使硝态氮淋溶至土壤深层。土壤硝态氮向深层的淋溶量随冬季灌溉量增加而增大。为减轻土壤硝态氮淋溶和地下水污染，应综合考虑合理安排农田利用类型、适当减少种植喜氮作物以及合理进行冬季灌溉。
