Review of nitrogen fate models applicable to forest landscapes in the southern U.S.

Authors: AMATYA, DEVENDRA - Us Forest Service (FS); Rossi, Colleen; SALEH, ALI - Tarleton State University; DAI, ZHAOHUA - University Of New Hampshire; YOUSSEF, MOHAMMED - North Carolina State University; Williams, Randall; Bosch, David; CHESCHEIR, GEORGE - North Carolina State University; SUN, GE - Us Forest Service (FS); SKAGGS, RICHARD - North Carolina State University; TRETTIN, CARL - Us Forest Service (FS); VANCE, ERIC - National Council For Air & Stream Improvement (NCASI), Inc; NETTLES, JAMI - Weyerhaeuser Company; TIAN, SHYIYING - North Carolina State University

Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/1/2013
Publication Date: 10/15/2013
Publication URL: http://handle.nal.usda.gov/10113/60420
Citation: Amatya, D.M., Rossi, C.G., Saleh, A., Dai, Z., Youssef, M., Williams, R.G., Bosch, D.D., Chescheir, G.M., Sun, G., Skaggs, R.W., Trettin, C.C., Vance, E.D., Nettles, J.E., Tian, S. 2013. Review of nitrogen fate models applicable to forest landscapes in the southern U.S. Transactions of the ASABE. 56(5):1731-1757.

Interpretive Summary: Nitrogen (N) fertilizer is used to increase managed forest productivity. Various eco-hydrological models are used to track N transport and its environmental impact. Five models that are commonly used in assessing nutrient impacts in the environment and that cover a wide range of spatial scales are characterized for their strengths and weaknesses as applied to assessing N fate and transport in managed southern pine landscapes.

Technical Abstract: Assessing the environmental impacts of fertilizer nitrogen (N) used to increase productivity in managed forests is complex due to a wide range of abiotic and biotic factors affecting its forms and movement. We review the applicability of five commonly used eco-hydrologic models (APEX, MIKESHE-DNDC, DRAINMOD-FOREST, REMM, and SWAT) in assessing N fate and transport in southern forest landscapes (<50 km2) because of their comprehensiveness and multi-scale predictions. The field-scale models DRAINMOD-FOREST and REMM contain process-level components characterizing hydrology, forest growth and N dynamics. APEX can describe N fate processes, forest growth, and plant competition at the landscape and small watershed scales. The SWAT model is best suited to hydrologic simulations at watershed scale > 50 km2 although N routing below the subbasin level does not yet exist. Similarly, the distributed MIKESHE-DNDC model has been used to assess N cycles across different spatial scales, on both uplands and lowlands, but was not intended to model lateral N transport. However, MIKESHE alone is capable of describing the hydrology and N transport. The strengths of each of the models reflect their original design and scope intent. Based on this review, none of the five models that we considered is independently adequate to address the fate of N fertilizers applied to forest stands at both small and large scales. While efforts are underway to extend their capabilities and address their various limitations, the models must be validated using experimental data before using their outputs, together with uncertainty analysis, for developing fertilization guidelines.