RT Monograph SR 00 A1 Harnos, A. T1 Impact of Semi-arid Weather Conditions on Wheat and Maize Yield YR 1994 FD 1994-07 SP 18 AB In recent years the need for assessing land capability and planning production has grown. In this paper we try to describe the impact of the weather on crop yield in semi-arid regions where weather variability and uneven distributions of precipitation strongly influence the yield. We tried to describe the relationship between the variations in the yield and the weather parameters. We give an introduction to plant phenology, and the analysis of yield time series. We describe a simple soil moisture model and, using this model, we analyze the relationship between yield and soil moisture. Finally we show a more developed model for maize which starts from the relationship between relative yield decrease and relative evapotranspiration deficit. PB WP-94-017 PP IIASA, Laxenburg, Austria AV Published LK https://pure.iiasa.ac.at/id/eprint/4192/