Crop Production and Economics in Northwest Kansas as Related to Irrigation Capacity

Abstract

Crop production and economics of corn, grain sorghum, soybean, and sunflower under irrigated and dryland conditions were simulated using 34 years (1972-2005) of weather data in Northwest Kansas. Irrigation system capacities ranged from 2.5 to 8.5 mm/day. The simulated long-term annual average net irrigation requirements for corn, grain sorghum, soybean, and sunflower were 375, 272, 367, and 311 mm, respectively. Assuming a 95% application efficiency (Ea), the average long-term crop yield is approximately 12.9, 8.2, 4.4, and 3.2 Mg/ha for corn, grain sorghum, soybean, and sunflower, respectively. Although corn is currently the predominant irrigated crop in western Kansas, projections for the year 2006 indicate soybean is a more profitable alternative. Net irrigation requirements for soybean are only about 2% lower than corn, so a shift to soybean will not result in significant water conservation. If the price of corn increased just 10% relative to stable prices for the other crops, it would become the most profitable irrigated crop. This indicates that net return projections are very volatile, subject to changes in crop prices and input costs.