ARS | Publication request: THE ECONOMIC IMPACTS OF DISEASE SUPPRESSIVE ROTATIONS IN MAINE POTATO CROPPING SYSTEMS

Submitted to: Crop Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 29, 2008
Publication Date: September 12, 2008
Publisher's URL: Http://www.plant managementnetwork.org/sub/com/research/2008/potato
Reprint URL: Http://www.plant managementnetwork.org/sub/com/research/2008/potato
Citation: Halloran, J.M., Larkin, R.P., Honeycutt, C.W., Griffin, T.S. 2008. The economic impacts of disease suppressive rotations in maine potato cropping systems. Crop Management. On-Line.

Interpretive Summary: Potato growers in Maine have identified the need for profitable rotation crops as well as rotations that reduce the incidence and severity of soil borne diseases as two of their most pressing needs. Researchers at the New England Plant, Soil and Water Laboratory, Orono, Maine have been conducting experimental trials addressing both issues. Eight different 3-year rotation sequences were examined, including continuous potato. The rotation crops included barley, canola, clover, green bean, soybean, and sweet corn grown in different combinations before the potato crop. Based on two 3-year trials it was found that all rotation sequences significantly lowered disease incidence and severity relative to continuous potato. With respect to profitability, all rotations had a significantly lower percentage of misshapen tubers compared to continuous potato. Given that these tubers are unmarketable, net income also increased as compared to continuous potato. Furthermore, the introduction of rotation crops, especially high-valued crops, led to large reduction in income variability and in the likelihood of negative earnings over the entire rotation sequence. These results provide support for the use of a wider range of rotation crops in potato cropping systems. However, producers will need to identify markets for some crops (sweet corn, green bean) before they enter production.

Technical Abstract: Soilborne diseases can greatly reduce marketable yields and are a major concern to Maine potato producers. Control of these organisms is difficult as they can persist in the soil for several years and symptoms typically worsen each year. Depending on the specific pathogen, different mechanisms for moderating soilborne disease can be employed, such as breaking the host-pathogen cycle, stimulating beneficial microbial activity, and direct inhibition of the pathogens. Current research at the USDA¿ARS, New England Plant, Soil, and Water Laboratory is investigating the effect of rotation crops and rotation sequences on the incidence and severity of soilborne diseases in the following potato crop. These results (incidence, severity, and potato yield) are incorporated into an economic simulation model to determine the impact of rotations on profitability, level of income risk, and probability of economic loss for different rotation sequences and rotation lengths. The results show that several rotation sequences can increase profitability and reduce economic risk when compared to continuous potato or to the standard barley-potato rotations.