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• The point is, there appears to be very little difference in wheat, regardless of which seeding rate was used. On average that’s correct, but the averages can be deceiving and costly for wheat growers.
RANDY WEISZ explains seeding rate results during recent field day in Rowland, N.C.
Extra cost of seed
“By over-seeding the grower has a similar potential for yield loss as he does with 600,000 seed per acre, but he has the extra cost of the wheat seed. So, it could be a double-edged sword with losses in both yield and dollars spent producing the crop,” the North Carolina State specialist says.
“From a yield perspective, and based on our tests in North Carolina, I believe a seeding rate of 1.1 to 1.5 million seed per acre is optimum. However, farmers don’t usually look at optimum yield, they look at optimum profit,” he adds
“Based on 2011 wheat prices, the optimum seeding rate for optimum profit dropped to a range of 1 to 1.3 million seed per acre. The ideal comfort level may be higher, but the optimum sweet spot for profit appears to be at the lower seeding rates.
“Putting optimum yield and optimum profit together makes an on-time seeding rate of 1.3 million seed per acre look pretty good,” he says.
Just when it appears growers have an ideal seeding rate for maximizing profit, in comes some variables.
One of the biggest variables to seeding rate optimization is planting date.
If wheat is planted in the optimum time frame of late October to early November in the southern end of North Carolina, and if you look at the same seeding rate chart and the planting date is late November, then the optimum seeding rate for either comfort or profit is significantly different, Weisz says.
“If you are planting later than what is deemed the ideal planting date, seeding rate has to go up,” the North Carolina State specialist says. If you miss the optimum late October planting date by a month, the optimum seeding rate for top yields is going to be somewhere between 1.5 to more than 2 million seed per acre, he adds.
“Based on several years of looking at seeding rates and planting dates, it seems that every week late that wheat is planted, seeding rates should be increased by 5 percent per week.
“On a profit per acre base, being a month later than optimum planting will require about 1.5 million seed per acre, Weisz says. From a comfort standpoint, the optimum rate may be closer to 2 million seed per acre.”
While researchers deal in number of seed per acre, most growers calibrate planters and deal more frequently with pounds of seed per acre.