By Linda Fresques
Using remote sensing to improve irrigation
Practically any road traveled along the meandering Mesilla and Rincon valleys is graced by the leafy canopy of pecan orchards. Dotted in between are fields of chile, alfalfa, cotton, corn and other crops.
Agriculture is big business in Doña Ana County, stretching from Hatch to Las Cruces. The majority of New Mexico’s 36,000 acres of pecan trees are here. In 2009 the state ranked first in value of production of pecans in the United States, resulting in 70 million pounds valued at about $133 million in net sales going directly to the growers, reports the New Mexico Department of Agriculture.
Key to the success of local growers is the efficient use of a most precious commodity in the region – water. And a team of researchers at New Mexico State University is investigating the use of new technologies to improve irrigation management with the goal to help farmers increase the yield of their crops. Local farmers may soon be able to observe real-time data about their crops via the Internet.
The project team includes Zohrab Samani, civil engineering professor; Salim Bawazir, civil engineering associate professor; Max Bleiweiss, science specialist and adjunct professor in the department of entomology, plant, pathology and weed science; and Rhonda Skaggs, agricultural economics and agricultural business professor.
By using data available from satellites, the group has developed techniques to estimate water loss by evaporation from the soil and transpiration from plants into the atmosphere, making it possible to calculate water consumption.
“Plants are like humans,” Bawazir said. “They transpire and when they are not doing well, this is reflected in their rate of transpiration. A farmer can use this information to identify problems and take corrective action, such as test soil for salinity, increase fertilizers or check for disease.”
The team uses real-time Landsat satellite data collected by the Center for Applied Remote Sensing in Agriculture, Meteorology and Environment.
“We collect atmospheric and climate data from our own satellite and information that we get over the Internet,” said Bleiweiss, who is also director of CARSAME. The center, a cooperative effort among the College of Agriculture, Consumer and Environmental Sciences, the New Mexico Space Grant Consortium and the U.S. Department of Agriculture Jornada Experimental Range, gathers more than 30 gigabytes of data per day.
The information is augmented with images from video cameras on a college airplane.
The researchers use NMSU’s super computing capabilities to create mathematical models showing evapotranspiration rates in the region based upon the satellite data. Evapotranspiration rates are indicated by variations in color on the satellite imagery. This is validated with data from climate stations in the fields.
“Prior to this, we had to look at individual crops,” Bawazir said. “Now we can look at the entire valley and get a more accurate understanding of water consumption and how we can help farmers increase the yield of their crops.”
Skaggs is using the data to look at the socioeconomic issues related to crop water usage. She points out the strong relationship between water consumptive use and yield, or value of crop, which ultimately influences the economic output of the region.
“I’m using the data to look at the spectrum of water use across different crops and sizes of farms,” Skaggs said. “There is a huge range for consumptive water usage for the same crops in the same region during the same time period.”
Local farmers are working in cooperation with the team, including Stahmann Farms, the largest pecan-producing farm in the U.S., along with other farming enterprises. They allow climate stations to be placed on their property and the information is shared with them.
“We are currently in the ‘truthing’ stage, to see if the technology works,” Bawazir said. “So far, our results have been very positive.”
They are also working to make the data available via the Internet and making the interface more user-friendly. They anticipate making the system available to farmers within two years.
“I envision that someday, a farmer in his truck out in the field can access this information on his cell phone in real time,” Bawazir said.
The team began this research in 2002 and their work has received various sources of funding, including the federally funded Rio Grande Basin Initiative, the Governor’s Water Innovation Fund and the Office of the State Engineer.