Department of Soil and Water Sciences, China Agricultural University, Beijing 100193, People's Republic of China.
J Environ Qual. 2010 Feb 19;39(2):667-77. doi: 10.2134/jeq2009.0204. Print 2010 Mar-Apr.
Understanding water and N transport through the soil profile is important for efficient irrigation and nutrient management to minimize nitrate leaching to the groundwater, and to promote agricultural sustainable development in desert oases. In this study, a process-based water and nitrogen management model (WNMM) was used to simulate soil water movement, nitrate transport, and crop growth (maize [Zea mays L.]) under desert oasis conditions in northwestern China. The model was calibrated and validated with a field experiment. The model simulation results showed that about 35% of total water input and 58% of the total N input were leached to <1.8 m depth under traditional management practice. Excessive irrigation and N fertilizer application, high nitrate concentration in the irrigation water, together with the sandy soil texture, resulted in large nitrate leaching. Nitrate leaching was significantly reduced under the improved management practice suggested by farm extension personnel; however, the water and nitrate inputs still far exceeded the crop requirements. More than 1700 scenarios combining various types of irrigation and fertilizer practices were simulated. Quantitative analysis was conducted to obtain the best management practices (BMPs) with simultaneous consideration of crop yield, water use efficiency, fertilizer N use efficiency, and nitrate leaching. The results indicated that the BMPs under the specific desert oasis conditions are to irrigate the maize with 600 mm of water in eight times with a single fertilizer application at a rate of 75 kg N ha(-1).
了解水和氮在土壤剖面上的运移对于高效灌溉和养分管理至关重要，可以最大限度地减少硝酸盐淋溶到地下水，并促进沙漠绿洲的农业可持续发展。本研究采用基于过程的水氮管理模型（WNMM），模拟了中国西北地区沙漠绿洲条件下的土壤水分运移、硝酸盐运移和作物生长（玉米[Zea mays L.]）。该模型通过田间试验进行了校准和验证。模型模拟结果表明，在传统管理实践下，约 35%的总用水量和 58%的总氮输入被淋溶到<1.8 m 深度以下。过量灌溉和氮肥施用量、灌溉水中高浓度的硝酸盐以及砂质土壤质地导致了大量硝酸盐淋溶。在农场推广人员建议的改进管理实践下，硝酸盐淋溶显著减少；然而，水和硝酸盐的输入仍然远远超过作物的需求。模拟了超过 1700 种结合各种灌溉和施肥实践的情景。进行了定量分析，以获得最佳管理实践（BMPs），同时考虑作物产量、水分利用效率、氮肥利用效率和硝酸盐淋溶。结果表明，在特定的沙漠绿洲条件下，BMPs 是用 600 毫米的水灌溉玉米，分八次进行，单次施肥量为 75 公斤 N/公顷。
