By Steve Hansen
QCS Managing Editor
Soybeans do not seem to respond well to irrigation with reclaimed wastewater. But Leonard Lauriault, superintendent of the New Mexico State University Agricultural Experiment Station, Tucumcari, is far from discouraged.
The first year of using reclaimed wastewater from Tucumcari’s wastewater treatment facility has shown it is an experiment that is working well.
Feed and forage crops like alfalfa, summer annual grass forages, and tepary beans can’t tell the difference between treated wastewater and irrigation water, Lauriault said. They grow just as well with either source.
Most gratifying to Dr. Steven Loring, who supervises NMSU’s agriculture experiment stations, is the wastewater is allowing crop experiments to be carried out at the Tucumcari station, since the station has not received irrigation water from the Arch Hurley Conservancy District, its usual source, for three years.
The conservancy district has not allocated water because its source, Conchas Lake, has lost too much water due to low rainfall and high evaporation as a drought continues.
The experimental station’s use of wastewater began in 2012 under a 20-year contract with the city signed in 2011. The pipeline was built during 2012.
The use of Tucumcari’s reclaimed wastewater is practical because the treatment facility is only two miles away, in the line of sight from many points at the science center. Lauriault said he is thankful the city and NMSU were willing to partner for the tests.
Wastewater experiments also have the potential to make the Tucumcari science center one of the focal points for research and development of agricultural applications of treated wastewater that could be applied around the world, Lauriault said.
In fact, Lauriault said, he is proposing that a specialist in wastewater’s agricultural uses join the experimental station’s faculty.
The center is currently seeking a specialist in semi-arid cropping to join the faculty. According to the job description, the position is needed because, despite the presence of the wastewater supply there is still a “declining availability of water for irrigation.”
The job description continues, “The need exists to initiate research in dryland and reduced irrigation cropping systems.”
At present, Loring said, the wastewater’s main role is allowing tests to continue at the Tucumcari station to help determine effects of different watering schedules on the growth rates of various forage crops, Lauriault’s specialty.
Lauriault has made sure the wastewater pipeline travels to many of the station’s fields and pastures on its 464-acre site. Some can now be watered from either Arch Hurley Conservancy District ditches, which are expected to run again this spring, or the treated wastewater.
Lauriault the two sources will enable studies comparing the effects of reclaimed wastewater and irrigation water.
Lauriault drives to a pasture where heifers that are part of an experiment at the Corona experimental station are grazing on stands of triticale (trit-i-KAY-lee), a rye and wheat hybrid. The grain is sprouting green in mid-February and seems to be thriving with wastewater irrigation.
In another field, alfalfa is growing, watered by treated wastewater, and at least one crop has been harvested.
In another planned test, Lauriault said, kochia, a tumbleweed species that can be used as forage feed for cattle, will be planted and watered with reclaimed wastewater.
Indulging in some speculation, Lauriault said he expects reclaimed water is likely to be expensive. Lauriault anticipates its agricultural use may eventually may have to focus on “high value” crops, like fruits and vegetables, for which the profit margin would justify the cost of the water. At present, it is illegal to use treated wastewater on crops for human consumption.
Lauriault said eventually, however, if perception issues about treated wastewater can be resolved, it might be used safely on tree fruits and nuts or crops like grapes that grow above the soil level.
Loring said logistical concerns are likely to limit treated wastewater’s use to urban applications and limited agriculture close to cities with ample wastewater supplies.
Orlando, Fla., Tucson, Ariz., and many California cities and counties have use treated wastewater to irrigate parks and open spaces for many years.