For the better part of the last decade, farmers in eastern New Mexico have had to plan for their summer growing season without knowing how much water - if any - will be available for irrigation, due to severe water limitations.

To help farmers make smart decisions about their crops before planting, researchers at New Mexico State University are evaluating late-planted, short-season annual forage crops for adaptability and yield potential in the Southern High Plains.

"Water is a limited resource, and is expected to be more limited in the future," said Rex Kirksey, superintendent of NMSU's Agricultural Science Center at Tucumcari. "This project is evaluating a number of forage crops for adaptation to lesser amounts of water than is normally considered full irrigation. It is developing strategies for obtaining high forage yields, per unit of applied water, when water for irrigation is limited and uncertain."

Most farms within the Arch Hurley Conservancy District are completely dependent on surface water from Conchas Reservoir for irrigation. Even with limited or no water in the spring, there is a good chance that spring and summer rains in the watershed will provide lake inflow to provide at least some late-season irrigation.

"The decision to evaluate late-planted crops was made with the purpose of allowing growers an opportunity to delay cropping decisions as late in the season as reasonably possible," Kirksey said. "Planning for crop establishment in late June or early July provides an opportunity for increased water storage in Conchas Reservoir and allows for the accumulation of soil moisture following early summer rainfall events."

Millets and forage sorghums comprised the majority of crops selected for this project that began in 2010. For their test, researchers at the science center selected annual forages that had the potential to produce a marketable yield in less than 100 days. The crops also had to be heat- and drought-tolerant, and they needed to be productive with limited irrigation but capable of responding to increased water availability.

The crops for the study were planted in July 2010. The entire test was swathed in October—97 days after planting—as a single-cut hay harvest; baling took place, by species, based on curing time. Bales were weighed by plot and hay core samples were collected, oven dried and analyzed for nutritive quality by near-infrared reflectance spectroscopy.

Kirksey said that so far, they have found that multiple annual forages offer potential for producing hay in late-planted, water-limited situations. Traditional crops for hay production—sorghum x sudangrass hybrids and forage sorghums—were among the most productive. Pearl millet provided the best combination of forage yield and quality when grown as a monoculture or in combination with selected annual legumes.

Researchers at the science center plan to repeat the experiment this year and possibly in 2012, to confirm their observations.

For more information on the project, contact Kirksey at 575-461-1620or rkirksey@nmsu.edu.