Yield responses of crops to changes in environment and management practices: Model sensitivity analysis. II. Rice,wheat, and potato

This paper is a continuation of our prior examination of yield responses of maize (Terjung et al., 1984b). The analysis of the response of the model YIELD to changes in a variety of basic environmental and decision-making inputs was continued for paddy rice, winter wheat, and early potato. As before, temperature, solar radiation, and relative humidity regimes were analyzed during a growing season along with different water application strategies, irrigation frequencies, soil types, and wind regimes. Among the results, yield decreased on the average by 4.9% (rice) and 6.0% (wheat) per 1 (C) increase in air temperature. A 1% change in solar radiation resulted in an average of 1% (wheat) and 0.4% (rice) change in yield. Analogous changes in relative humidity caused yield changes of about 0.8% and nothing for wheat and rice, respectively. For all crops, the relationship between irrigation frequency and yield increase was near-linear for large irrigation intervals. This linearity vanished under high frequency waterings. With respect to irrigation amounts, 1 mm/ha of applied water was related, on the average, to 75 (potato), 19 (grain corn), 8 (rice), and 6 kg/ha (wheat) of harvestable yield.