Paper No. JAWRA-08-0059-P of the Journal of the American Water Resources Association (JAWRA). Discussions are open until October 1, 2009.
A Multilevel Model of the Impact of Farm-Level Best Management Practices on Phosphorus Runoff1
Version of Record online: 4 MAR 2009
© 2009 American Water Resources Association
JAWRA Journal of the American Water Resources Association
Volume 45, Issue 2, pages 369–377, April 2009
How to Cite
Reckhow, K.H., Qian, S.S. and Harmel, R.D. (2009), A Multilevel Model of the Impact of Farm-Level Best Management Practices on Phosphorus Runoff. JAWRA Journal of the American Water Resources Association, 45: 369–377. doi: 10.1111/j.1752-1688.2008.00298.x
- Issue online: 25 MAR 2009
- Version of Record online: 4 MAR 2009
- Received April 7, 2008; accepted August 4, 2008.
- nonpoint source pollution;
- best management practices;
- multilevel models;
- hierarchical models
Abstract: Multilevel or hierarchical models have been applied for a number of years in the social sciences but only relatively recently in the environmental sciences. These models can be developed in either a frequentist or Bayesian context and have similarities to other methods such as empirical Bayes analysis and random coefficients regression. In essence, multilevel models take advantage of the hierarchical structure that exists in many multivariate datasets; for example, water quality measurements may be taken from individual lakes, lakes are located in various climatic zones, lakes may be natural or man-made, and so on. The groups, or levels, may effectively yield different responses or behaviors (e.g., nutrient load response in lakes) that often make retaining group membership more effective when developing a predictive model than when working with either all of the data together or working separately with the individuals. Here, we develop a multilevel model of the impact of farm level best management practices (BMPs) on phosphorus runoff. The result of this research is a model with parameters which vary with key practice categories and thus may be used to evaluate the effectiveness of these practices on phosphorus runoff. For example, it was found that the effect of fertilizer application rate on farm-scale phosphorus loss is a function of the application method, the hydrologic soil group, and the land use (crop type). Further, results indicate that the most effective method for controlling fertilizer loss is through soil injection. In summary, the resultant multilevel model can be used to estimate phosphorus loss from farms and hence serve as a useful tool for BMP selection.