Replanting strategies for grain sorghum under risk

Abstract

Risk analysis of replanting strategies for grain sorghum at three Kansas locations was conducted using stochastic dominance techniques. Yield data were simulated for seven planting dates, six seeding rates or target plant populations, and three maturity classes over a 33-year period using weather data for each year at each location. The results showed that optimal planting dates, seeding rates, and maturity classes vary by location and risk preference. In northeast and southcentral Kansas, planting at later rather than earlier dates was preferred as risk aversion increased. In southwest Kansas, generally no change occurred in the preferred strategy as the level of risk aversion increased. Early- and medium-maturing hybrids and low-to-moderate seeding rates often were selected. Late-maturing hybrids never were selected by risk-averse managers. The degree of risk aversion did not significantly affect the selection of a replanting strategy for southcentral and southwest Kansas, but did for northeast Kansas. However, whether managers replanted immediately or delayed, replanting varied with the replanting decision date and degree of risk aversion. Replanting on the first replanting decision date in southwest Kansas rather than delaying 2 weeks or more was preferred by all risk-averse managers. More strongly risk-averse managers in the northeast and all risk-averse producers in southcentral Kansas preferred to delay replanting of damaged stands, in some cases by 2–4 weeks after the decision date. Results also showed that when a stand was damaged late in the season, the expected yield from the damaged stand had to be lower than that from a stand damaged early in the season in order for replanting to occur. Price changes had only minor impacts on the preferred replanting strategies. A higher crop price caused replanting to occur more often, because the yield reduction of a damaged stand required for replanting to be economically feasible grew smaller as the price increased.