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S.D. Study Supports Change in RMA Planting Date

Monday, February 1, 2010
filed under: Marketing/Risk Management

Three years of planting date studies in South Dakota should aid the effort to extend the final planting dates for crop insurance coverage eligibility in that state.

Currently, producers cannot fully insure sunflower planted after June 10 in the northern portion of South Dakota, or that planted after June 15 in the southern portion of the state. Many growers believe they can safely plant after those dates without major yield or quality losses. With approximately 95% of South Dakota sunflower covered by some form of federal crop insurance, it is an issue of considerable importance.

For USDA’s Risk Management Agency (RMA) to change the current final planting date requires on-farm data. To assist, the National Sunflower Association and the South Dakota Oilseeds Council funded a three-year (2007-09) planting date study headed by South Dakota State University oilseeds breeder Kathy Grady.

The study was designed to encompass seven locations each of the three years. Due to logistical complications, however, it ended up including five locations in 2008, four harvested locations in 2008 and two locations in 2009. Sites were located on the farms of cooperating growers. These farms were concentrated in leading South Dakota sunflower production areas: in the northern region, at Eureka (McPherson County), Java (Walworth County) and Bison (Perkins County); in the southern region, at Onida (Sully County), Miller (Hand County) and Martin (Bennett County).

Four planting dates were used, per zone, with plot size ranging from 0.5 to 1.8 acres. In the northern “June 10” zone, the study’s planting dates were June 10, 15, 20 and 25. In the southern “June 15” zone, planting dates were June 15, 20, 25 and 30. (Actual dates varied slightly, depending on grower scheduling logistics.)

Results from the three-year study were as follows:

June 10 Zone — Averaged across five environments, yield of sunflower planted on June 15 equaled that of sunflower planted on June 10. While sunflower planted June 20 averaged 371 lbs/ac less than that planted June 10, it still exceeded average T-yield. Oil content remained stable at all four dates of planting, and test weight did not differ for the June 10, 15 or 20 plantings.

June 15 Zone — Averaged across six environments, sunflower planted on June 20 and 25 yielded slightly less than sunflower planted on June 15 — but still exceeded the average T-yield across locations. There was a small decrease in oil content when planting was delayed to June 20, but no further decreases when delayed to June 25 or June 30. The test weight was lower on sunflower planted on June 25 and 30 compared to the 15th.

The South Dakota planting date study’s authors concluded that “final planting dates could be moved five to 10 days later in each zone without significantly impacting crop insurance payments to growers.” They add the following points:

• In South Dakota, planting dates of from May 15 to June 20 will generally give the best yield and oil content.

• Soil temperature must be above 50°F for seed germination.

• Growers should adjust planting dates for the season.

• Seed moisture at harvest may be higher for late-planted sunflower, thus increasing drying costs.

• Select early maturing hybrids for late planting or replanting.

John Sandbakken, NSA marketing director, says RMA routinely needs three years of planting data in order to consider a change in the final planting date. Those data are now available for South Dakota, so the NSA will be submitting a request to RMA this spring to make the change for the 2011 crop year. It is too late to make the change for 2010, Sandbakken says.

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