The Arkansas winter wheat crop is a “good news/bad news” situation, according to William Johnson, wheat specialist with the University of Arkansas Cooperative Extension Service.

The good news is that the market price is about 50 cents a bushel better than at this time last year, while fuel and nitrogen fertilizer prices are less than last year.

The bad news is that as much as 25 percent of the crop is suffering from phosphorus deficiency, and a possible leaf rust epidemic is just around the corner.

The 10-year average value of the Arkansas wheat crop is $142 million, according to the Arkansas Agricultural Statistics Service. The 10-year average size of the crop is 1.06 million acres. This year's crop is about 1 million acres.

“The United States has the smallest planted wheat crop since 1971, and that has resulted in a market price of around $3.15,” Johnson said. “Last year at this time, it ranged from about $2.45 to $2.65.”

Johnson said the price of urea, the main nitrogen fertilizer source, skyrocketed last year to $260 a ton. “This year, we've had a much warmer winter and fuel prices are down, so urea prices are about $160 a ton.”

But for farmers to benefit from better market prices and reduced costs, they have to get past a couple of hurdles.

“A lot of our acreage has received 15 to 30 inches of rain since it was planted in the fall. Southeast Arkansas is the hardest hit, especially Ashley and Chicot counties,” Johnson said.

He said the rain has reduced the plants' root systems, thereby reducing phosphorus uptake from the soil, especially in wheat planted following the rice crop harvest. The main symptom of this deficiency is a purpling of the leaf tissue, and “in some cases, the entire plant is purple.”

This condition shuts down the ability of the plant to tiller, delays its maturity, and reduces yields.

The treatment for severe phosphorus deficiently is to apply 100 pounds of diammonium phosphate (DAP) per acre. For less severe situations, Johnson recommends 50 pounds an acre.

“A hundred pounds of diammonium phosphate contains 18 pounds of nitrogen, which should be applied to the crop's typical nitrogen fertilizer budget of 120 pounds an acre,” Johnson said.

A potentially worse problem than phosphorus deficiency is an epidemic of leaf rust, according to Johnson. “We've got more rust in the state than we've ever had before.”

Leaf rust is a fungal disease that reduces the size of the leaf, ultimately resulting in yield loss. Many wheat varieties in a University of Arkansas performance test at Lewisville in Lafayette County are already infected.

“That part of the state is normally where rust first appears. We've not had enough freezing temperatures to destroy the fungus.”

Farmers don't need to take any action now.

“Scouting programs will be important in mid-March to get a handle on how bad it is,” Johnson said. He said farmers should treat for rust immediately before the wheat heads in mid- to late April.

Fortunately, Johnson said, farmers have an array of good fungicides available, and new fungicide makers have entered the market, so “rates are a lot more reasonable.”

Since leaf rust can cost a farmer up to 15 bushels an acre, fungicides are cost-effective. He urged farmers to read an Arkansas Extension publication, MP 158, to help them make good economic decisions about fungicide applications.


Lamar James is an Extension communications specialist with the University of Arkansas.