Replacing Metam Sodium Use with Green Manure Cropping in Potato Production
Potato growers across the Pacific Northwest are increasingly interested in transitioning away from metam sodium use, especially as EPA completes its review of fumigants in the re-registration process. Re-registration may result in changes to metam sodium use, thus encouraging growers to seriously consider alternatives. While Pacific Northwest university researchers have shown green manure cropping as an effective control for some potato pests, many growers remain reluctant to transition to this time-, labor- and input-intensive practice. Potato growers in Idaho have repeatedly expressed a desire for information on green manure best management practices and weed and wireworm control before they commit to transitioning. The value of this project is the focus on reducing green manure input costs and identifying the weed and possibly wireworm control, thus resulting in grower adoption and on-the-ground changes. Potatoes are grown by 600 farm operations on 325,000 acres in Idaho. More than 50 potato growers on the Fort Hall Indian Reservation and 90 in the S. Bingham and Power Soil Conservation Districts in eastern Idaho will assess their readiness to implement the practice. Of the 81,000 acres on the Fort Hall Indian Reservation and S. Bingham and Power Soil Conservation Districts, 2,500 acres are regularly planted with green manures and 5,000 acres will be planted with green manures because we can provide growers with solid recommendations for growing a successful green manure crop and by showing them the costs and benefits for their potato crop. Green manures will replace 600,000 pounds of metam sodium use.
Project goals and objectives
1) Through the incentive program, this project will directly implement green manure cropping on at least 500 acres. As a result of the project’s education outreach to growers, we expect transition to green manure on an additional 4,500 acres.
2) There will be a 100% reduction in the use of metam sodium on these acres.
3) This project will leverage $134,980 of in-kind support from our participating growers and project collaborators.
4) The current level of pest management on the SAI Transition Index is 2. Following completion of this project, growers planting a green manure will move to a SAI Transition Index of 7.
Proposed: Of the 81,000 acres on the Fort Hall Indian Reservation and S. Bingham and Power Soil Conservation Districts, 2,500 acres are regularly planted with green manures and 5,000 acres will be planted with green manures (and consequently reduce herbicide and fertilizer use on potatoes by 25%) because we can provide growers with solid recommendations for growing a successful green manure crop and by showing them the costs and benefits for their potato crop. Green manures will replace 600,000 pounds of metam sodium use.
Achieved: Growers on the Fort Hall Indian Reservation and adjacent soil conservation districts tripled the number of acres planted with green manure. According to lease checks conducted by the Bureau of Indian Affairs, 3,500 acres were planted in 2007 on the Reservation. Additionally, Idaho NRCS reports that farmers in Bingham and Power County planted 4,415 acres of green manures in 2007, with support of the NRCS EQIP cost-share. This represents a potential savings of up to 949,800 pounds of metam sodium, if all of these growers who planted 7,915 acres of green manure crops had originally planned to use metam sodium. Overall, interest and adoption of green manure cropping as an alternative to metam sodium has grown throughout southern Idaho. Based upon seed sales, one seed dealer estimates that 35,000 acres of green manure were planted in southern Idaho in 2007.