Modeling the impacts of soil management practices on runoff, sediment yield, maize productivity, and soil organic carbon using APEX
Modeling the impacts of soil management practices on runoff, sediment yield, maize productivity, and soil organic carbon using APEX
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DOI：
10.1016/j.still.2008.07.014
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发表时间：
2008-09
影响因子：
6.5
通讯作者：
Xiuying Wang;P. Gassman;Jimmy R. Williams;S. Potter;A. Kemanian
中科院分区：
文献类型：
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作者：
Xiuying Wang;P. Gassman;Jimmy R. Williams;S. Potter;A. Kemanian
模拟模型越来越多地用于分析流域尺度农业管理的影响。在这项研究中，农业政策/环境影响（APEX）模型进行了测试，使用长期（1976-1995年）的数据，从两个流域（W2和W3）在美国农业部深黄土研究站附近的特雷诺，爱荷华州。这两个流域种植连续玉米（Zea mays L.）W2采用常规耕作（34.4hm2），W3采用垄作（43.3hm2）。1976-1987年，通过调整曲线数、曲线数指数系数、RUSLE C因子指数残差和高度系数以及草地河道侵蚀控制措施系数，对两流域的月径流量和产沙量进行了率定。1984年，通过调整微生物衰减速率系数，标定了两个流域0.15m土层的土壤有机碳值。1988年至1995年进行了模型验证。校准的模型是能够合理地复制每月和每年的地表径流量和产沙量的验证期间，与纳什-萨克利夫效率（EF）大于0.62，除了EF为0.41的每月产沙量比较在W3。径流量和产沙量的预测值与实测值的误差均在±6%以内，1994年0.15m土壤有机碳的预测值与实测值的误差均在10%以内。在20年的模拟期内，W2和W3的预测和观测平均玉米产量之间的百分比误差分别为-5.3%和-2.7%。还进行了情景分析，以评估垄作耕作优于传统耕作的效益。20年来，垄作与传统耕作相比，对地表径流减少的预测效益在W2和W3分别为36%和39%，两个流域的产沙量减少约82-86%。土壤有机碳的累积流失量减少了63- 67%。垄作与传统耕作相比的长期效益也被量化为玉米籽粒产量至少增加3.8%。本研究的结果表明，APEX有能力预测两种耕作制度之间的差异。模型方法可以扩展到其他流域，以检查不同的耕作制度的影响。
Simulation models are increasingly used to analyze the impact of agricultural management at the watershed-scale. In this study, the Agricultural Policy/Environmental eXtender (APEX) model was tested using long-term (1976–1995) data from two watersheds (W2 and W3) at the USDA Deep Loess Research Station near Treynor, Iowa. The two watersheds were cropped with continuous corn (Zea mays L.) and managed with conventional-tillage at W2 (34.4ha) and ridge-till at W3 (43.3ha). The monthly runoff and sediment yield were calibrated for the two watersheds during 1976–1987 by adjusting the curve numbers, curve number index coefficient, RUSLE C factor exponential residue and height coefficients, and erosion control practice factor for grassed waterways. Soil organic carbon values in the top 0.15m soil layer were calibrated for the two watersheds in 1984 by adjusting the microbial decay rate coefficient. Model validation was conducted from 1988 to 1995. The calibrated model was able to reasonably replicate the monthly and yearly surface runoff and sediment yield for both watersheds for the validation period, with Nash–Sutcliffe efficiencies (EF) larger than 0.62 except for the EF of 0.41 for monthly sediment yield comparison at W3. The errors between the predicted and observed means were all within ±6% for runoff and sediment yield; predicted soil organic carbon in the 0.15m soils in 1994 were within 10% of the observed values for both watersheds. The percentage error between the predicted and observed average corn grain yields was −5.3% at W2 and −2.7% at W3 during the 20-year simulation period. Scenario analyses were also conducted to assess the benefits of ridge-till over conventional-tillage. Over the 20 years, the predicted benefit of ridge-till versus conventional-tillage on surface runoff reduction was 36% in W2 and 39% in W3, and about 82–86% sediment yield reduction in both watersheds. The cumulative soil organic carbon losses from sediment were reduced about 63–67%. The long-term benefit of ridge-till over conventional-tillage was also quantified as a minimum corn grain yield increase of 3.8%. The results of this study indicate that APEX has the ability to predict differences between the two tillage systems. The modeling approach can be extended to other watersheds to examine the impacts of different tillage systems.