Precision fertilizer rates may help sugarcane farmers save money

Kenneth Gravois, Hoy, Jeffrey W., Bogren, Richard C., Tubana, Brenda S.  |  7/17/2008 1:15:08 AM

News Release Distributed 07/16/08

ST. GABRIEL – Sugarcane growers can reduce the cost of producing their crops by following new fertilizer recommendations, researchers said today (July 16) at a sugarcane field day at the LSU AgCenter’s Sugar Research Station here.

Nitrogen fertilizer, which is made from natural gas, has increased significantly in price during the past year, said Dr. Brenda Tubana, a researcher in the LSU AgCenter School of Plant, Environmental and Soil Sciences.

Tubana has been studying how fertilizer rates affect yields by using sensor-based technology that can help farmers make fertilizer decisions based on what the crop needs in a particular location.

She has developed a calculator that growers can use to collect data and estimate the nitrogen requirements for a particular field to produce optimum yields.

“You can use this technology to maximize economic and agronomic returns,” she said.

Nitrogen fertilizer recommendations have been based on historical research dating back to the 1960s and 1970s, said Dr. Rich Johnson, a research agronomist with the U.S. Department of Agriculture’s Agricultural Research Service Sugarcane Research Laboratory in Houma.

Johnson said earlier recommendations were based on the use of anhydrous ammonia, the common nitrogen source 40 to 50 years ago. Because anhydrous ammonia is a gas that’s injected into the soil, some of the nitrogen is lost during application and some is lost in the soil.

The current fertilizer source of nitrogen is a liquid solution that is more stable in the soil.

The scientists are now recommending to sugarcane farmers that they can reduce the amount of nitrogen they apply to their crops because newer sugarcane varieties are more efficient in their use of the nutrient and because new sources of fertilizer are more efficient.

Johnson distributed new nitrogen fertilizer recommendations that represent decreases of approximately 15-20 percent in nitrogen rates across soil types and crop ages.

By using less, growers are able to reduce their fertilizer costs, which is particularly important as fertilizer prices are climbing as a result of rising energy prices, Johnson said.

The field day was the 26th annual event held at the LSU AgCenter’s Sugar Research Station, said Dr. David Boethel, AgCenter vice chancellor for research.

Since 2003, eight sugarcane varieties and two energy cane varieties have been released for Louisiana growers through a partnership of the LSU AgCenter, the USDA Sugar Research Unit in Houma and the American Sugar Cane League, located in Thibodaux, Boethel said.

The vice chancellor said that despite rising market prices for sugar, Louisiana growers are facing extremely high input costs for fertilizer and transportation.

“We’re trying to find ways to help farmers manage their crop,” Boethel said. “Variety development is the mainstay of the program.”

In other presentations, Dr. Jeff Hoy, an LSU AgCenter plant pathologist, presented preliminary results of his research using fungicides on sugarcane rust, a leading disease of the plant.

“Rust can hurt yield and overcome varietal resistance,” Hoy said. “Under the right conditions, fungicide can be a useful tool.”

The best way to control rust is to plant varieties with resistance, he said. “It doesn’t cost you anything.”

Hoy said he is interested in finding out if using fungicides for rust will yield an economic return for growers.

Other researchers at the field day presented information on new research on insect resistance and weed control. In addition, plant breeders reviewed the different varieties currently available for growers to plant.

This year, the variety HoCP 96-540, which was released in 2003, is growing on 45-50 percent of the Louisiana sugarcane acreage, said Dr. Kenneth Gravois, LSU AgCenter sugarcane breeder and resident coordinator of the Sugar Research Station. “This is the first new leader since 1998,” when the variety LCP 85-384 was becoming the leading variety in the state.

Gravois gave a pitch for the newest variety, L 01-283, which was released this year.

It stands well, stubbles well, has good disease resistance and resistance to sugarcane borer, he said. The drawback is that it can’t be propagated successfully by tissue culture, as most now are.

“Mix and match to tailor your needs,” the sugarcane breeder told the growers. “Diversify risk by trying new varieties.”


Contacts: Brenda Tubana at (225) 578-2110 or

Jeff Hoy at (225) 578-1464 or

Kenneth Gravois at (225) 642-0224 or

Writer: Rick Bogren at (225) 578-5839 or

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