Simulating the Production Potential of Dryland Spring Canola in the Central Great Plains

Abstract

Canola (Brassica napus L.) has potential to be grown as a dryland crop to diversify the winter wheat (Triticum aestivum L.)–fallow production system of the semiarid central Great Plains. Extensive regional field studies have not been conducted under rainfed conditions to provide farmers, agricultural lenders, and crop insurance providers with information about the production potential and expected yield variability of canola in this region. The purpose of this study was to use an agricultural system model to simulate canola production under rainfed conditions in the central Great Plains and to determine the economic viability of canola production. The CROPGRO‐canola model was used within the Root Zone Water Quality Model (RZWQM2) with weather data (1993–2008) to simulate canola yield for nine central Great Plains locations under four plant‐available water (PAW) contents at planting. Average yield with 75% PAW was highest (1725 kg ha−1) at Champion, NE, in the north‐central area and lowest (975 kg ha−1) at Walsh, CO, in the south‐central area. Simulated yields increased with increasing PAW at planting at an average rate of 5.31 kg ha−1 mm−1. Yield variability was simulated to be lowest at Sidney, NE, Stratton, CO, and Walsh, CO, and highest at Akron, CO, Tribune, KS, and Garden City, KS. Yield variability did not consistently change with amount of PAW across the region. Calculated average net returns indicate that profitable canola production is possible across a large portion of the central Great Plains when PAW at planting is at least 50%.