Nitrogen and Yield as Related to Water Use of Spring Barley
1984
Kallsen, C. E. | Sammis, T. W. | Gregory, E. J.
The water-production function is the relationship between marketable crop yield and seasonal evapotranspiration. Variability in the parameters of the function for different growing seasons result in error in estimating the effect of a water management strategy on yield. The present study was conducted to determine if the parameters describing the functional relationship between transpiration and yield for field-grown spring barley (Hordeum vulgare L.), was stable for different levels of nitrogen fertility and seasonal differences in the atmospheric evaporative demand. A sprinkler-line-source was used to impose different irrigation treatments and seasonal evapotranspiration resulting from these treatments was calculated by a water budget technique. Soil-water evaporation was estimated using equations taken from the literature and transpiration was calculated by subtracting the estimated evaporation from evapotranspiration. The experiment was done on a sandy loam soil, Typic Calciorthid (coarse, loamy, mixed, calcareous, mesic family), which resulted in frequent light irrigations being applied to maintain the barley at the sprinkler line under non-moisture stress conditions. The water-production function was found to vary significantly among N-fertility levels, and between seasons. However, a constant linear relationship existed between grain yield and transpiration, independent of seasonal differences in evaporative demand, or the level of nitrogenfertility in the field.
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