Wang X, Saleh A, McBroom M W, Williams J R, Yin L
Texas Agricultural Experiment Stn., Blackland Research and Extension Center, 720 E. Blackland Rd., Temple, TX 76502, USA.
J Environ Qual. 2007 May 25;36(4):983-95. doi: 10.2134/jeq2006.0087. Print 2007 Jul-Aug.
Hydrologic/water quality models are increasingly used to explore management and policy alternatives for managing water quality and quantity from intensive silvicultural practices with best management practices (BMPs) in forested watersheds due to the limited number of and cost of conducting watershed monitoring. The Agricultural Policy/Environmental eXtender (APEX) model was field-tested using 6 yr of data for flow, sediment, nutrient, and herbicide losses collected from nine small (2.58 to 2.74 ha) forested watersheds located in southwest Cherokee County in East Texas. Simulated annual average stream flow for each of the nine watersheds was within +/- 7% of the corresponding observed values; simulated annual average sediment losses were within +/- 8% of measured values for eight out of nine watersheds. Nash-Sutcliffe efficiency (EF) values ranged from 0.68 to 0.94 based on annual stream flow comparison and from 0.60 to 0.99 based on annual sediment comparison. Similar to what was observed, simulated flow, sediment, organic N, and P were significantly increased on clear-cut watersheds compared with the control watersheds. APEX reasonably simulated herbicide losses, with an EF of 0.73 and R(2) of 0.74 for imazapyr, and EF of 0.65 and R(2) of 0.68 for hexazinone based on annual values. Overall, the results show that APEX was able to predict the effects of silvicultural practices with BMPs on water quantity and quality and that the model is a useful tool for simulating a variety of responses to forest conditions.
由于流域监测的数量有限且成本高昂，水文/水质模型越来越多地被用于探索管理和政策选择，以通过森林流域的最佳管理实践（BMPs）来管理集约造林实践中的水质和水量。农业政策/环境扩展（APEX）模型使用从位于东德克萨斯州切罗基县西南部的9个小型（2.58至2.74公顷）森林流域收集的6年流量、沉积物、养分和除草剂损失数据进行了实地测试。九个流域中每个流域的模拟年平均流量在相应观测值的±7%以内；九个流域中有八个流域的模拟年平均沉积物损失在测量值的±8%以内。基于年流量比较，Nash-Sutcliffe效率（EF）值范围为0.68至0.94，基于年沉积物比较，EF值范围为0.60至0.99。与观测结果类似，与对照流域相比，皆伐流域的模拟流量、沉积物、有机氮和磷显著增加。APEX合理地模拟了除草剂损失，基于年值，咪唑烟酸的EF为0.73，R²为0.74，嗪草酮的EF为0.65，R²为0.68。总体而言，结果表明APEX能够预测采用BMPs的造林实践对水量和水质的影响，并且该模型是模拟对森林状况的各种响应的有用工具。
