Risk Efficient Choice of Bean-Winter Wheat Rotation, Cover Crop, and Tillage System on Light Textured Soils

Abstract

The variability of net returns associated with alternative cropping systems available to farmers is important for crops grown on light textured soils. Crop productivity, and possibly profitability, can be increased and the risk of either may be reduced through the use of cover crops and conservation tillage in rotation systems. Using a stochastic dominance approach this study determined the risk efficient cropping system for three bean-winter wheat (Triticum aestivum L.) rotation systems in southern Ontario on Fox sand soils composed of 85% sand. The three beans in this study were soybean [Glycine max (L.) Merr.], white bean (Phaseolus vulgaris L.) and kidney bean (P. vulgaris L.). Within each rotation five treatments were examined. One was a conventional tillage treatment and the other four were no-till systems differentiated by the choice of cover crop. Among the three bean-wheat rotations, kidney bean-wheat systems ranked first followed by white bean-wheat rotations, while soybean-wheat rotation systems were the least preferred by risk averters. Within each bean-wheat rotation, no-till treatments generally dominated the conventional tillage alternative. Under risk averse conditions kidney bean-winter wheat with no-till corn (Zea mays L.) cover was the most profitable by approximately $4/acre and the preferred choice across all 15 crop rotation systems. Research Question Farmers on sandy soils in southwestern Ontario have been forced to evalaute alternative crops in their rotations due to the significant decrease in the demand for their traditional crop, tobacco. The productivity of these alternative crops may be increased and income risk reduced through the use of cover crops and conservation tillage. The primary objective of this study was to determine the risk efficient cropping system on light textured soils. Fifteen cropping systems, combining alternative bean and winter wheat rotations, cover crops, and tillage systems were evaluated. Literature Summary Several studies have evaluated the feasibility of growing individual alternative crops on sandy soils in southwestern Ontario. These studies have found that these crops are technically feasible but yields are highly variable. The impact of crop rotation, cover crops, and tillage systems, which may increase the productive capacity of sandy soils, addresses the need to find profitable, environmentally-sound substitute crops in light of the decreased demand for tobacco. Study Description Yield data for the cropping systems were generated through field experiments conducted at the Agriculture Canada research station at Delhi, Ontario, from 1988 to 1991. The soil in this location was a Fox sand with a pH of 6.2 and 1% organic matter content. There were five treatments within each of three bean-winter wheat rotations for a total of 15 cropping systems. One of the treatments was a conventional tillage system and the other four were no-till systems differentiated by the choice of cover crop: (i) rye; (ii) volunteer wheat encouraged through disking of wheat stubble after harvest; (iii) wheat stubble with no cultivation and; (iv) bin-dry corn. The three beans considered were soybean, white bean, and kidney bean. Applied Questions Which bean crop was preferred in rotation with winter wheat? Total net returns were highest on average for the kidney bean-wheat rotation ($182/acre) among the three rotations considered. It also displayed the least variability in net returns and so was the dominant choice across most risk preferences. White beans were the preferred crop of risk takers due to the high potential returns. Soybean-wheat rotations were generally least preferred due to the low average net returns and relatively high degree of variability. Which tillage system was preferred across rotations? The four no-till treatments were generally ranked higher than the conventional tillage treatment for both risk averse and risk preferring individuals across all three bean-wheat rotations. Conventional tillage was preferred, however, for highly risk averse conditions in the white bean-wheat rotation because of the low variability in its turns. Which cover crop was preferred in the no-till system? The corn cover crop was the preferred treatment for all rotations under strongly risk averse conditions. The relative ranking among the other three cover crop treatments depended on the rotation and risk preferences.