Youssef Mohamed A, Skaggs R Wayne, Chescheir George M, Gilliam J Wendell
Department of Biological and Agricultural Engineering., North Carolina State University, Raleigh, NC 27695, USA.
J Environ Qual. 2006 Oct 27;35(6):2026-42. doi: 10.2134/jeq2005.0249. Print 2006 Nov-Dec.
The N simulation model, DRAINMOD-N II, was field-tested using a 6-yr data set from an artificially drained agricultural site located in eastern North Carolina. The test site is on a nearly flat sandy loam soil which is very poorly drained under natural conditions. Four experimental plots, planted to a corn (Zea mays)-wheat (Triticum aestivum L.)-soybean (Glycine max.) rotation and managed using conventional and controlled drainage, were used in model testing. Water table depth, subsurface drainage, and N concentration in drain flow were measured and meteorological data were recorded continuously. DRAINMOD-N II was calibrated using the data from one plot; data sets from the other three plots were used for model validation. Simulation results showed an excellent agreement between observed and predicted nitrate-nitrogen (NO(3)-N) losses in drainage water over the 6-yr period and a reasonable agreement on an annual basis. The agreement on a monthly basis was not as good. The Nash-Sutcliffe modeling efficiency (EF) for monthly predictions was 0.48 for the calibration plot and 0.19, 0.01, and -0.02 for the validation plots. The value of the EF for yearly predictions was 0.92 for the calibration plot and 0.73, 0.62, and -0.10 for the validation plots. Errors in predicting cumulative NO(3)-N losses over the 6-yr period were remarkably small; -1.3% for the calibration plot, -8.1%, -2.8%, and 4.0% for the validation plots. Results of this study showed the potential of DRAINMOD-N II for predicting N losses from drained agricultural lands. Further research is needed to test the model for different management practices and soil and climatological conditions.
利用北卡罗来纳州东部一个人工排水农业场地的6年数据集，对N模拟模型DRAINMOD-N II进行了实地测试。试验场地位于近乎平坦的砂壤土上，在自然条件下排水非常差。模型测试使用了四个试验小区，种植玉米（Zea mays）-小麦（Triticum aestivum L.）-大豆（Glycine max.）轮作，并采用常规排水和控制排水进行管理。测量了地下水位深度、地下排水以及排水流量中的氮浓度，并连续记录气象数据。使用一个小区的数据对DRAINMOD-N II进行校准；其他三个小区的数据集用于模型验证。模拟结果表明，在6年期间，排水水中观测到的和预测的硝态氮（NO(3)-N）损失之间具有极好的一致性，并且在年度基础上具有合理的一致性。月度基础上的一致性则不太好。校准小区月度预测的纳什-萨特克利夫建模效率（EF）为0.48，验证小区的分别为0.19、0.01和-0.02。年度预测的EF值，校准小区为0.92，验证小区分别为0.73、0.62和-0.10。预测6年期间累积NO(3)-N损失的误差非常小；校准小区为-1.3%，验证小区分别为-8.1%、-2.8%和4.0%。本研究结果表明DRAINMOD-N II在预测排水农田氮损失方面的潜力。需要进一步研究以测试该模型在不同管理措施以及土壤和气候条件下的表现。
