While carryover nutrients may be available to crops next spring, one expert predicts that high crop prices for corn and soybeans will also play a major role in farmers’ nutrient use.
Nutrient carryover in a year following drought is an important consideration for farmers. That’s certainly true as farmers evaluate their crop fertility needs for 2013. For Larry Mussack’s part, he plans to apply only the nutrients he knows his corn crop needs.
"Soil test, don’t guess," recommends the Decatur, Neb., farmer.
Research by Harry Vroomen, vice president of economic services for The Fertilizer Institute, shows that while drought does impact the ability of crops to absorb nutrients in a given year, thus contributing to carryover, that fact doesn’t automatically mean farmers will decrease fertility applications the following year. His research over a 30-plus year period bears out that fact.
Vroomen notes that between 1970 and 2011, a significant drought occurred seven different years in the United States. He defines a drought as a year in which corn yields dropped by more than 15% in a given season, due to inadequate moisture. In each case, he looked to determine the impact on fertilizer applications the year following drought.
What Vroomen learned is that in the years following those seven drought years, average nitrogen application rates fell only twice while they increased five times. Application rates for phosphorus and potash fell three times and increased four times in years following drought.
In 1988, the year most comparable to 2012, Vroomen says corn yields dropped by nearly 30% due to drought. He reports that average fertility application rates the following year, 1989, fell 4% for nitrogen, 9% for phosphorus and 8% for potash.
He doubts a drop in fertility applications will occur in 2013 like it did in 1989. He explains that’s likely because 2012-13 corn prices are forecast at $7.10 to $8.50 per bushel (based on a mid-October 2012 USDA forecast) with a 5.6% stocks-to-use ratio. Whereas, in 1989, corn prices were closer to $2.50 per bushel and the stocks-to-use ratio was about 20%. Stocks-to-use ratio is a measurement of supply and demand interrelationships for commodities.
High crop prices encourage growers to apply higher application rates as greater yields bring about higher additional revenue at higher crop prices; on the other hand, carryover nutrients will bring those higher application rates back down so the net effect is difficult to predict, notes Vroomen.
On top of that, he adds that 2013 planted acreage of corn, soybeans and wheat, the top three fertilizer using crops, is expected to increase by several million acres. Despite the uncertainty, Vroomen is expecting little change in total U.S. nitrogen use next year; however, phosphate and potash use may decline somewhat, depending on the eventual level of nutrient carryover.
"If a farmer is expecting $7.50 or $8 for corn next year, he won’t take the chance of missing out on that potential income," Vroomen says. His prediction for 2013, regarding fertilizer application rates, goes back to Larry Mussack’s recommendation. Notes Vroomen: "I think we’re going to see soil testing like crazy."
John Lory, University of Missouri nutrient management specialist, explains how this year's drought might affect next year's fertilizer needs.