With a potential seed shortage for some rice varieties and rising seed costs, growers may want to consider reducing seeding rates this year — and they may be able to do that without sacrificing yield potential, say rice specialists across the belt.
“We've reduced seeding rates almost 25 percent and maintained yield in Arkansas,” says Chuck Wilson, University of Arkansas rice specialist, who with counterparts from other rice-producing states, exchanged production ideas and updates recently at a Valent-sponsored rice seminar at San Antonio.
Wilson said Arkansas changed its seeding recommendation last year, dropping rates from 90 pounds per acre on silt loam soils to 70 pounds.
“We need to adjust upward for clay soils,” he says. “We've recommended 120 pounds per acre in the past; now we're down to 90 to 95 pounds.”
He says early season insect damage may be a concern for some growers. “They can lose stand, so seed treatments could be an advantage with reduced seeding rates.”
Growers in Northeast Arkansas are still looking at seeding rates. “We're evaluating varieties and looking at row spacings.”
Narrow row planting may offer some advantage. “We saw a significant yield advantage the first year in narrow row. Last year, we didn't see much difference.”
Tim Walker, Mississippi State University, says lodging problems were not as bad with lower seeding rates. He looked at two varieties, Wells and Francis.
“Wells, at 40 pounds per acre, was one of our best-yielding treatments. With the seed situation this year, lower seeding rates could be a benefit.”
He says growers should consider “how much risk they are willing to take” with lower seeding rates. “With a full gamut of seed treatments, they might be more willing to cut rates.”
Lee Tarpley, Texas A&M, says reduced rates, 40 pounds per acre, with CL171, showed yields on the main crop to be about the same. “The ratoon crop was significantly better.”
Walker says seeding rates that optimize main crop yields appear to optimize ratoon yields as well.
Seeding method also affects rate; if growers water-seed, they use about 30 percent more seed than in drill-seeding.
Texas studies showed Cypress variety, at 40 pounds per acre, as the best yield in one year's test.
Studies also showed that a 20-pound per acre seeding rate resulted in 100 percent of seed producing seedlings. At 120 pounds per acre, that percentage dropped to 50 percent.
Karen Arthur, a Valent product development manager, said ongoing development of seed treatments should produce options that combine insect, disease, and nematode controls with growth regulators, herbicide safeners, and fertilizer polymer coatings.
“For now, we're screening a lot of fungicides.”
She said commercial products will not be available for “several years,” but that several products look promising. Rice water weevil and stem borers are primary insect targets.
Specialists said seed treatments for water weevils would provide benefits for growers. They said early tests show excellent results and good yield responses.
M.O. Way, Texas entomologist, said improved seed treatments for rice would be a welcome addition to growers' pest management programs. “We want to test the efficacy of new products on stem borers, and we hope something is available in a year or two.”