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New Mexico State University

New Mexico State University

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NMSU researchers examine forage production during drought

TUCUMCARI - A growing dairy industry in the Southern High Plains and the Rio Grande and Pecos River valleys brings with it increased demands for forage crops that provide feed for dairy cattle. But drought conditions, declining aquifers, urban growth and other factors can limit the amount of water available for irrigation of alfalfa and corn.

Researchers at New Mexico State University's Agricultural Science Center at Tucumcari are examining alternative crops that could produce dairy-quality feed with less water.

"New Mexico's number one cash crop is alfalfa, a high quality perennial legume, because we can grow lots of high quality alfalfa in the state," said forage agronomist Leonard Lauriault of the Tucumcari center. "But, although alfalfa is one of the most water use efficient forage crops, it still requires a lot of water to maximize production. Because of the declining availability of water for agriculture, producers need alternatives to alfalfa that can still produce sufficient forage to meet the demands of New Mexico's growing dairy industry using less water."

Lauriault and fellow researcher Rex E. Kirksey, superintendent of NMSU's agricultural science centers at Tucumcari and Clovis, wrote a paper on this topic that was published in the American Society of Agronomy's Agronomy Journal.

"Annual crops are valuable in semiarid regions, such as New Mexico, because they can be planted to take advantage of seasons of high precipitation," Lauriault said. "In New Mexico, while our high precipitation generally occurs in July and August, we use both small grains such as wheat and triticale, which are winter annual grasses, and sorghum forages, which are summer annual grasses. Both of these grasses are usually lower in quality than alfalfa in regard to protein levels and digestibility. Thus, planting an annual legume with the annual grass can be used to increase the protein content. Hairy vetch and Austrian winter pea, both winter annual legumes, are widely adapted to environmental conditions in New Mexico and the Texas Panhandle where the dairy industry is booming."

The yield and quality of each species, whether grass or legume, is determined by maturity. So researchers needed to plant different combinations of grasses and legumes to find the best match, Lauriault said. Researchers also needed to make sure any possible yield decrease of the mix due to competition by the legume was not significant to reduce the overall value of the increase in forage quality.

"Neither legume made a significant contribution to early maturing small grains forage like rye and barley," Lauriault said. "Forage quality was improved for wheat and triticale, which matured at about the same time, and for oats, which was the latest to mature. Wheat and triticale forage yields were decreased in the mixture compared to the monoculture small grain forage, but oat yields were unaffected. Still, yield of wheat or triticale mixed with Austrian winter pea was greater than the other small grains species, whether grown as monocultures or in mixtures."

The research covered two growing seasons in a small plot study at the Tucumcari science center. The first growing season saw average precipitation, while the second received a little more than half the average annual precipitation, so drought played a role.

"Alfalfa is still the dairy forage of choice and it has versatility beyond that industry," Lauriault said. "So, hopefully, the drought will end and alleviate the need to seek alternatives to alfalfa. In the meantime, and anytime water is limited, producers can increase quality of wheat, triticale and oat forage by planting it with Austrian winter pea. We're continuing to seek a warm-season legume to plant with the sorghum forages to improve quality of that forage."