Quoted from: Motew, Melissa, Xi Chen, Eric G. Booth, Stephen R. Carpenter, Pavel Pinkas, Samuel C. Zipper, Steven P. Loheide et al. "The influence of legacy P on lake water quality in a Midwestern agricultural watershed." Ecosystems 20, no. 8 (2017): 1468-1482. https://doi.org/10.1007/s10021-017-0125-0 

        The Agro-IBIS model is a spatially explicit land surface model that simulates the movement of water, energy, momentum, carbon, nitrogen, and now phosphorus, in both natural and managed ecosystems. The structure of Agro-IBIS has been described in detail (Foley and others 1996; Kucharik and others 2000; Kucharik 2003), and many components of the model have been validated across a range of ecosystems at various spatial and temporal scales (El Maayar and others 2001; Kucharik and Brye 2003; Kucharik and others 2006; Kucharik and Twine 2007; Soylu and others 2014; Zipper and others 2015). Recently, Agro-IBIS was integrated with the variably saturated soil water flow model HYDRUS-1D to enable simulation of groundwater–vegetation interactions (Soylu and others 2014). For this study, several additional updates have been made to Agro-IBIS. First, biogeochemical cycling of P and loss of P to runoff were added to Agro-IBIS to enable simulation of P dynamics, including interactions between surface water quality, climate, and land management. The new terrestrial P module is largely based on SurPhos, a state-of-the-art dissolved P loss model for agricultural systems receiving manure (Vadas and others 2004, 2005, 2007; Vadas and White 2010). The new P module features P application, transformation, and loss of dissolved P to runoff; in-soil cycling of organic and inorganic forms of P; and loss of particulate-bound P with erosion (Figure 2). Land cover categories have also been expanded in Agro-IBIS to include four classes of urban areas (high, medium, and low intensity as well as open space) along with alfalfa, pasture, and wetlands. Finally, changes were made within the soil physics routines to improve representation of surface hydrology and improve model stability. Details for all changes made to Agro-IBIS are provided in Appendix A in Electronic supplementary material (ESM). https://static-content.springer.com/esm/art%3A10.1007%2Fs10021-017-0125-0/MediaObjects/10021_2017_125_MOESM1_ESM.docx