Crop Water Supply and its Relation to Yield of Spring Wheat in the South of Russian Plain

The proposed method to estimate water supply of spring wheat crop is based on the ratio of the water amount extracted by plants under actual conditions of growth (transpiration) to cover needs for maximum (potential) yield (potential transpiration). Estimates of spatial, inter- and intra-annual water supply variability of the spring wheat crop in basic agricultural zones are given. Dependence of the spring wheat yield on water supply is presented.