Economic and Risk Effects of Rotation Based on a 14-Year Irrigated Potato Production Study in Manitoba

Citation

Khakbazan, M., Mohr, R.M., Huang, J., Campbell, E., Volkmar, K.M., Tomasiewicz, D.J., Moulin, A.P., Derksen, D.A., Irvine, B.R., McLaren, D.L., Nelson, A. (2018). Economic and Risk Effects of Rotation Based on a 14-Year Irrigated Potato Production Study in Manitoba. American Journal of Potato Research, [online] 95(3), 258-271. http://dx.doi.org/10.1007/s12230-017-9627-8

Plain language summary

Crop rotations can be used to optimize economic return by preserving or enhancing soil quality and reducing pest pressure including diseases insects, and weeds. A study of two two-year potato rotations (potato-canola and potato-wheat), two three-year rotations (potato-canola-wheat and potato-oat-wheat), and two four-year rotations (potato-wheat-canola-wheat and potato-canola (underseeded to alfalfa)-alfalfa-alfalfa) was carried out in Manitoba, Canada from 1998-2011 to analyze the profitability of potato in each rotation. Potato grown in two-year rotations was found to be more profitable in the first few years of the study. However, over the course of the entire fourteen year study, three- and four-year crop rotations for potato were found to be more profitable than shorter rotations. This is because the benefits of growing potato in two-year rotations are eventually outweighed by its negative consequences, including higher disease levels and lower soil quality, which in turn decrease the amount of potato grown and sold and lower profits for farmers. The results of this study encourage the adoption of longer potato rotations, such as potato-oat-wheat or potato-canola (underseeded to alfalfa)-alfalfa-alfalfa, in order to maintain soil and plant quality and maximize long-term profits.

Abstract

Crop rotations can be used to optimize economic return by preserving or enhancing soil quality and reducing pest pressure. A field experiment consisting of six rotations of potato with canola (P-C), wheat (P-W), canola-wheat (P-C-W), oat-wheat (P-O-W), wheat-canola-wheat (P-W-C-W), and canola underseeded to alfalfa-alfalfa-alfalfa (P-C(A)-A-A) organized in a Randomized Complete Block Design was established on a clay loam soil in Manitoba, Canada and monitored for fourteen years to assess the relative economic performance of potato in each rotation. A stochastic budget based on returns and risk of returns trade-offs was used to determine each rotation’s profitability. While differences in average annual net income of all crops between rotations were not significant, the P-C-W rotation was the most stable. Despite the economic advantage of P-C in the first two cycles, longer P-C-W or P-C(A)-A-A rotations are recommended, as two-year rotations increase plant disease and decrease economic viability in the long run.