A simple model for chickpea growth and yield

Chickpea (Cicer arietinum L.) is a major crop in cool and cold semi-arid en vironments of Iran, where yield is limited by climatic factors, water avail ability and genotype. A robust crop model can assist in evaluation of bioph ysical limitations in crop yield. The objective of this study was, therefor e, to develop a simple mechanistic model for chickpea to be used in assessi ng production limitations. The model simulates crop phenology, development of leaves as a function of temperature, accumulation of crop biomass as a f unction of intercepted radiation, dry matter accumulation of grains as a fu nction of time and temperature, and soil water balance. Phenology, leaf gro wth and senescence and biomass production were made sensitive to soil water content. The model uses a daily time step and readily available weather an d soil information. The model was tested using independent data from a rang e of Iran's environmental conditions. In most cases, simulated grain yield were similar to observed yield and ranged from 0.4 to 3.25 t/ha. The root m ean square error was 0.24 t/ha. The agreement between simulated and observe d grain yields showed the robustness of the model in predicting chickpea gr owth and yield for both irrigated and rainfed conditions. It was concluded that the model can be used in simulation studies of potential yield and pro duction limitations. (C) 1999 Elsevier Science B.V. All rights reserved.