As gasoline prices reach for the sky, so do fertilizer prices.

“We’re at the point of such high fertilizer prices that people are going to have to learn how to grow forage legumes and manage them properly,” said Gerald Evers, Texas Agricultural Experiment Station forage management expert at Overton.

Because nitrogen fertilizer production uses natural gas, its price increase is directly linked to higher fuel costs. Prices for other fertilizers, such as potassium, also climb as transportation costs from mining sites to the farm contribute to price increases. As with gasoline prices, the increase has been rapid and dramatic, Evers said.

In mid-July nitrogen – in the form of ammonium nitrate was about 40 cents per pound. By mid-August, it was 48 cents per pound.

“That’s a 20 percent increase in about a month, and who knows where it’s going to go next,” he said.

But before they give up on fertilizing, farmers should consider alternative sources of nitrogen.

Legumes can offset high fertilizer prices because they extract nitrogen from the air. As a bonus, legumes have a higher nutritive value than grasses. When over-seeded on warm-season grasses, they can extend grazing five to six weeks and lessen the need for supplemental feeding or hay during winter months, he said.

With adequate moisture and good management, a forage legume such as arrowleaf clover can make from 50 to 100 pounds of nitrogen per acre available for the summer bermudagrass pasture.

“Livestock graze the legume and return over 90 percent of the nitrogen to the soil as urine and manure,” Evers said.

Many producers, but not all, grow some sort of winter pasture already. The most common in East Texas is not a legume but ryegrass, he said.

Arrowleaf clover used to be widely grown but fell out of favor due to plant diseases. Arrowleaf seed was mixed with crimson clover seed and grown widely throughout many southern states from Texas to Georgia. By mixing the early-maturing crimson clover and late-maturing arrowleaf, ranchers and farmers could have forage from February through early June.

Multiple disease problems put an end to the practice. The most prevalent and damaging of the plant viruses and fungal rot was the bean yellow mosaic virus.

Apache, a relatively new arrowleaf clover developed by Ray Smith, experiment station legume breeder based at Overton, is highly productive and resistant to bean yellow mosaic virus.

But before farmers and ranchers rush out to plant Apache or any other clover, they should consider several issues, Evers said. First is soil pH. All clovers need a minimum soil pH of 6. Arrowleaf does better with a soil pH of 6.5 to 7.

As it takes four to six months to raise soil pH and pasture legumes must be planted in October, a lime application should be made no later than spring, he said. A standard soil test will tell producers not only their soil pH, but also the need for any soil nutrients.

The next step is to determine which forage legume to plant. When it comes to clovers, one size – or variety – does not fit all. Clover species are adapted to specific soil types, and don’t perform well on others.

There are about eight types of clover adapted and available for East Texas producers, but three most prominent ones – arrowleaf, crimson and white clovers – are adapted to most situations, Evers said.

Arrowleaf clovers do well on deep sandy soils. Crimson clovers are adapted to shallow sandy soils. White clovers are well adapted to loamy soils like those found in creek bottoms.

The National Resource Conservation Service can provide detailed soil survey maps of any farm, Evers said.

Planting rates vary with type of clover used, but all plantings should be preceded with a light disking to ensure seed has good soil contact. Any fertilizer called for by the soil test should be applied at planting or after legume seedlings emerge, he said.

Rhizobia bacteria are responsible for the nitrogen fixation in legumes and should be applied to the clover seed before planting. It’s also possible to purchase seed already inoculated with the bacteria, Evers said.

Farmers can use a planter or broadcast the seed. Either way, however, it is a good idea to mix the clover seed with ryegrass seed for two reasons. The clover seed is so small that most planters won’t have the correct setting for accurate seeding rates. Also, ryegrass makes a great mix with clover. The ryegrass will produce forage earlier and lessen the chance of cattle bloating on the rich forage produced by the clover, Evers said.

More information on planting legume forages and winter pasture can be found on the Web site of the Texas A&M University System Agricultural Research and Extension Center at Overton: http://overton.tamu.edu/clover/cool/. Agricultural producers may also contact the Texas Cooperative Extension office in their county.

e-mail: rd-burns@tamu.edu