Researchers consider water conservation

TUCUMCARI - In the semiarid climate of northeastern New Mexico, farmers and ranchers have no guarantee of water for their crops or livestock. In the Tucumcari area, dry weather patterns can mean little or no rain for fields, and inadequate rain to replenish reservoirs that feed farmers' irrigation canals.

Water conservation is a priority not only in this part of the state, but across New Mexico where water seldom is plentiful.

Such extremes are the kinds of challenges that researchers at New Mexico State University's Rex E. Kirksey Agricultural Science Center at Tucumcari are suited to address.

The science center, one of a dozen off-campus science centers operated across New Mexico by NMSU's College of Agricultural, Consumer and Environmental Sciences, sits three miles northeast of Tucumcari.

Researchers at the science center approach water conservation in a variety of ways, and two recently published journal articles by associate professor Murali K. Darapuneni illustrate projects geared toward helping farmers use scarce water resources more efficiently.

One three-year study evaluated the effectiveness of three tillage strategies - conventional, strip and no-tillage - and two nitrogen rates on corn yield, water use and carry-over residual water and nitrogen characteristics.

"Successful corn production in the semiarid and arid southwestern United States is limited by available resources, especially water and nitrogen," Darapuneni said. "Management of such limited resources needs efficient on-farm tillage and nitrogen management decisions."

Darapuneni and his colleagues found implementation of strip tillage in semiarid regions offers farmers a significant advantage over other tillage practices in improving resource use efficiency in corn production.

The study, published in Agronomy Journal, was a collaboration between with Darapuneni and other researchers, including Omololu "John" Idowu, Leonard M. Lauriault, Syam K. Dodla, Kiran Pavuluri, Srinvasulu Ale, Kulbhushan Grover and Sangamesh V. Angadi.

A second study, published in the Soil & Tillage Research journal, looked at variations in plant and soil characteristics following the application of manure in strip-till zones of dryland farming fields.

"Utilizing manure as a cost-effective plant nutrient source under dryland farming is often undermined by transportation and application costs of large quantities of manure," Darapuneni said. "Our study compared the effectiveness of a one-time application of manure in the strip-till zone using dryland sorghum as the test crop."

The project, also a three-year study, determined that even three years after a single application of manure, significant agricultural benefits were evident.

Darapuneni collaborated on the project with Lauriault, Dodla, Idowu, Grover, Gasper Martinez, Koffi Djaman and Angadi.

Other projects at the center are focusing on summer and winter cover crops and the impact of the source of water - whether from an irrigation canal or from a municipal wastewater treatment plant - on alfalfa establishment and production.

"Municipalities seek uses for treated wastewater, which is generally safe to apply to animal feed and fiber crops, to minimize the release of potential pollutants into the surface and groundwater bodies," said Lauriault, who is leading the study.

In addition to his role as a forage crop management scientist, Lauriault is superintendent of the center. He notes with alfalfa being the most important forage crop worldwide, determining the potential effect of using treated municipal water could assist farmers with making good decisions.

"Preliminary results of ongoing research at the center has discovered a potential effect of wastewater on established alfalfa nutritive value and soil fertility characteristics," Lauriault said.

Research is ongoing on the wastewater project.

Another project at Tucumcari, published in Irrigation and Drainage Journal, with Darapuneni, Lauriault and Angadi as coauthors, found that farmers who had irrigated alfalfa through the growing season could skip irrigation for the harvest of fall growth without any negative effect, thus saving a tremendous amount of water.

"These research findings can have significant practical applications in budgeting annual water applications during the growing season in many semiarid regions to improve the dry matter yield and irrigation water use efficiency in alfalfa," Lauriault said.

For farmers, that can mean significant cost savings, whether their fields are in Tucumcari or elsewhere across the Southwest.