Cover crops could be the best new trend to hit potato farming for years, farm researchers say.
Nagging diseases such as rhizoctonia and verticillium wilt can be suppressed better through the use of such cover crops as canola and sudangrass. And potato plants get a boost in nutrition, according to University of Idaho potato scientist Jim Davis.Davis said he's confident research on cover crops will have "a lasting and significant impact on agriculture as we know it today. We are moving forth quickly with rapid strides."
He will report details of his experiments at the University of Idaho's 23rd annual Idaho Potato School Jan. 22-24 in Pocatello.
Cover crops are those grown between regular cash crops to conserve and improve soil. Davis said prior cover crops of sudangrass have had outstanding success in controlling verticillium wilt.
Canola preceding potatoes shows good success in reducing the severity of rhizoctonia on stems and has brought almost complete control on the potatoes themselves. "We can wind up with potatoes that look rather clean," he said.
"These observations, combined with significant increases of beneficial organisms, lead us to believe that biological control can be achieved through the use of cover crops," Davis said. "We are excited."
Nutritional studies by Dale Westermann at the U.S. Department of Agriculture Agricultural Research Service, Kimberly, also indicate that potatoes following cover crops, especially sundangrass, take up more nutrients than potatoes following potatoes.
At Aberdeen, Davis has reproduced the "spudded out" effect farmers have noted for years by growing potatoes in experimental fields for five seasons in a row. The result was 200 fewer sacks per acre in the sixth year of continuous potato planting than was obtained by planting potatoes after corn, or after the land was allowed to lie fallow.
In the coming year, Davis will study carryover effects a second year following sudangrass, canola, Austrian winter peas, corn, rye and oats. He also will evaluate double-cropping, with sudangrass following either barley or peas.
Davis said he has no doubt that the practicality and efficiency of cover crops can be developed and accelerated so economic costs are reduced, but he isn't ready to recommend specific rotations or specific cover crops. "We have more work to do, but our work does point to the fact that these things may have enormous effects on the future production of potatoes," he said.