A two dimensional simulation model of phosphorus uptake including crop growth and P response

Abstract

Modelling nutrient uptake by plants implies to consider the processes controlling the soil nutrient supply in the rhizosphere, the uptake by the root system and the plant growth response to the amount of nutrient absorbed. A model is presented for the simultaneous dynamic simulation of maize growth and phosphorus uptake. The plant part of the model was derived from the Monteith’s model. The potential soil P supply to the roots was calculated using the diffusion equation and assuming that roots behaved as zero sinks. The actual P uptake, and the plant growth were calculated at each time step by comparing the carbohydrate and phosphate supply-demand ratios. Model calculations for P uptake and plant growth were compared to field observations on a long term P fertilisation trial. The proposed model correctly simulated the crop development and growth under P non-limiting conditions. The crop development processes, which were affected in the low P treatment were also correctly predicted. Nevertheless the P uptake was slightly over-estimated in the low P treatment.