Development of a Soil-plant Phosphorus Simulation Model for Calcareous and Weathered Tropical Soils
Date
2003
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Abstract
Phosphorus (P) is a limiting nutrient affecting crop yields in many regions of the world, in particular in areas with highly weathered acid soils and calcareous alkaline soils. Given the many factors associated with P behavior in a range of soil environments, there is a need to go beyond site-specific situations. The use of crop simulation models is a valuable tool to evaluate the efficacy of applying P fertilizers under different soil, management and climatic conditions. A computer model was developed to simulate P in the soil–plant system adapted to soils with high P limitations. The soil P module is operated with two comprehensive crop simulation models (CERES and CROPGRO) within the DSSAT software. The P module comprises inorganic and organic P pools estimated from measured P fractionation data and works on a daily time step. The rate constants for P movement between the pools follow first order kinetics. The P module was calibrated and tested using three data sets from Colombia, Syria, and Tanzania. The limited testing showed that the P module simulated accurately grain yield and P uptake by wheat grown under semi-arid conditions. The wheat crop responded little to fertilization although measured Olsen P was as low as 2.6 mg kg-1 . The P module overestimated P uptake for both soybean and bean crops grown in acidic soils, but predicted with a good degree of accuracy labile P in the soil and P uptake for maize grown under the same acidic conditions. Testing with more data sets is needed to improve model predictions.
Description
Keywords
Phosphorus, Cereals, Legumes
Citation
Daroub S.H., A. Gerakis, J.T. Ritchie,D.K. Friesen and J. Ryan. 2003. “Development of a Soil-Plant Phosphorus Simulation Model for Calcareous and Weathered Tropical Soils,” Agricultural Systems, 76:1157-1181.