Co-Authors:
Amir, J., Agricultural Research Organization, Gilat Experiment Station, Mobile Post Negev 2, 85-200, Israel
Sinclair, T.R., USDA-ARS, Agronomy Physiology Lab., University of Florida, Bldg. 164, Gainesville, FL 32611, United States
Abstract:
A simple, mechanistic model describing the growth and yield of spring wheat (Triticum aestivum L.) was extended to water-limited conditions. The activities of three physiological processes were potentially retarded upon soil dehydration: leaf growth, crop gas exchange, and rate of ontogenetic development. Each of these processes was related directly to soil water content, which was calculated daily based on estimates of transpiration, soil evaporation, and water additions. For eight of the nine years experimentally studied at Gilat, Israel, the agreement between simulated and observed grain-yields differed no more than 26 g m-2. In the ninth year (1979/80), a severe drought during seed maturation decreased yields and caused the simulation to overestimate the yield. Nevertheless, the simple, mechanistic model demonstrated the importance of water availability in accounting for seasonal variations in yield. Both the amount and pattern of seasonal rainfall were found to be important in determining yield. Drought stress at anthesis was found in the simulations to have a particularly large negative effect on grain-yield, because anthesis coincides with the period in crop development requiring the maximum amounts of water. © 1991.