When USDA scientists wrote about cotton in the late 1800s, they considered it a more forgiving plant when it came to nutrient needs. They wrote that most of the fertilizer available at that time went to fields with corn and other grain crops and not on cotton fields.
In the decades after chemists found they could produce fertilizer commercially, agronomists recommended higher and higher amounts of nitrogen for all crops. Somewhere along the way, says Cotton Incorporated's Kater Hake, cotton got included in those recommendations.
Now, researchers are finding the nitrogen needs of the cotton plant may have been over-stated and that less may mean more when it comes to applying the optimal amount of nitrogen for high-yielding cotton fields. Hake discussed the situation in a presentation titled "Fertilizer efficiency leads to both profitability and environmental stewardship" at the National Conservation Systems Cotton and Rice Conference.
The discovery of a method of producing nitrogen fertilizer revolutionized crop production. Until the early 1900s, farmers’ only source of plant nutrients was from animal and human wastes. The Haber-Bosch process changed that and made it possible for growers to significantly increase yields with commercial nitrogen products.
“Berrye Worsham (Cotton Incorporated’s CEO) was the one who identified the organic era,” said Hake, citing a slide labeled “N Fertilizer – A Global Balancing Act.” “The organic era started 10,000 years ago when we first began growing crops, and it continued up until this inflection point that establishes the beginning of commercial nutrient usage.”
Yields were flat during this period, said Hoke, noting that yields for cotton changed little during that period prior to the advent of fertilizer nitrogen. “The graph looks the same for other crops such as corn. Then, all of a sudden, you begin to see a steady increase in yields as more fertilizer becomes available.
“Cotton has a unique, positive story from the standpoint of nutrition,” says Hake. “It starts with a very efficient plant. We’ve got tools; we’ve got expertise; and grower dedication to be bolder and more efficient in fertilizing the crop.”
Hake showed data from the USDA U.S. Cotton Nitrogen and Phosphate balance sheet for 2010. On average, growers applied 77 pounds of nitrogen per acre and removed 63 pounds of nitrogen in the cotton crop that was harvested that fall.
“That is darn good,” he noted. “We’re getting back about 85 percent of what we’re putting in. Phosphate is not as good. We’re putting in 41 pounds per acre and getting back 29. It’s OK, but not as good as what we’re doing with nitrogen.”
Earlier in the conference in Tunica, Miss., Cotton Incorporated's Worsham introduced attendees to the new COTTON LEADS program, CI and the National Cotton Council are partnering with Australia’s cotton industry.
“It’s all about bragging about efficient cotton, sustainable cotton, responsible cotton grown in the U.S. and Australia and taking back that high ground from the organic industry without adding to our cost,” said Hake. (For more information on the program, visit www.cottonleads.org.