Quantitative Evaluation of the Native Fertility of Tropical Soils

An implementation of the QUEFTS (Quantitative Evaluation of the Native Fertility of Tropical Soils) model. The model (1) estimates native nutrient (N, P, K) supply of soils from a few soil chemical properties; and (2) computes crop yield given that supply, crop parameters, fertilizer application, and crop attainable yield. See Janssen et al. (1990) for the technical details and Sattari et al. (2014) for a recent evaluation and improvements. There are also functions to compute optimal fertilizer application rates.