Development of a soil-plant phosphorus simulation model for calcareous and weathered tropical soils uri icon

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. (C) 2003 Elsevier Science Ltd. All rights reserved.

publication date

  • 2003
  • 2003