Moisture Sensors Are Key Part Of Efficient Irrigation

MISSISSIPPI STATE, MISS.
   If Jason Krutz could put one item on the Christmas list of every row crop farmer in Mississippi, Santa’s elves could not make enough soil moisture sensors to keep up with demand.
   Krutz, Mississippi State University irrigation specialist at the Delta Research and Extension Center in Stoneville, wants producers everywhere to approach irrigation with scientific accuracy.
   “We’ve been charged by you to make you better irrigators, and the only way we think we can do that is to have you purchase soil moisture sensors and put them in the field,” Krutz told about 400 producers, crop consultants and specialists at the 2013 MSU Row Crops Short Course. “It’s the only way that we can feasibly make you better irrigators.”


Jason Krutz, an irrigation specialist with Mississippi State University, holds a portable soil moisture meter, one of the tools needed to help producers make irrigation decisions with scientific accuracy.
Photo by MSU Ag Communications/Bonnie Coblentz

   Krutz works with the MSU Extension Service and the Mississippi Agricultural and Forestry Experiment Station to support growers with their irrigation needs.
   “Up and down the U.S., we irrigate willy-nilly,” Krutz said. “We use a screwdriver to dig down, kick the bed with our boots, maybe take a shovel out and go a few inches deep to look for soil moisture. That’s not going to cut it in the future when we’re running out of water not only in Mississippi but around the globe.”
   To both research and demonstrate irrigation efficiency, Krutz uses the Row-crop Irrigation Science and Extension Research, or RISER, program. Through RISER, MSU scientists partner with corn, cotton, soybean and rice producers using existing on-farm management systems to promote good irrigation management practices.
   “I’d go to a farmer and say, ‘You give us a 40-acre field and you keep a 40-acre field.’ I have the farmer irrigate according to his regular decision-making process, and I use the tools we have to determine when it was time for irrigation,” Krutz explained.
   Fifteen Mississippi producers took part in the RISER program in 2013. In each case, both fields showed similar yields, but the MSU-controlled field used from a quarter to half as much water as the neighboring plot irrigated using traditional decision-making processes.
   “It sounds absurd to say that you can apply half the water you normally apply and we can maintain or improve your yield almost guaranteed and improve your profitability by cutting way down on your water cost,” Krutz said.
   The tools to make this happen, Krutz said, are soil moisture sensors, surge irrigation and the computerized program Pipe Hole and Universal Crown Evaluation Tool. Known as PHAUCET, this program calculates the proper hole size and distribution for polypipe to furrow irrigate row crops efficiently.
   Tom Eubank, an Extension soybean agronomist and MAFES researcher in Stoneville, has evaluated PHAUCET for four years under a grant from the Mississippi Soybean Promotion Board.
   “Our research has shown that PHAUCET reduces water, fuel and irrigation usage by 20 percent versus conventional irrigation sets in regular-shaped fields,” Eubank said. “In irregular-shaped fields, PHAUCET could reduce water use as much as 50 percent.”
   Krutz said furrow irrigation controlled by PHAUCET that uses surge valves is the most efficient form of irrigation in the Delta. Surge values increase irrigation efficiency by evening the distribution of water across a field.
   “If you are operating in the Delta and using polypipe and not using PHAUCET, you are leaving money on the table,” Kurtz said. “For a moment, set aside the water use issue. This is real money, and this can save you a lot of money. It’s that simple.”
   The final tools are soil moisture sensors placed at 6, 12, 24 and 36 inches deep. These take the guesswork out of determining how much moisture the soil has available to plants. Portable soil moisture meters allow a producer to spot check a field at will, confirming the data being received from the soil moisture sensors installed in the field.
   “By just looking at the sensors twice a week, a producer can tell three days in advance when they need to pull the trigger on their irrigation,” Krutz said.
   Most traditional irrigation is done on a schedule that is based on soil type and the water demands of the crop at a particular maturity point. Rain alters the situation, making it more difficult to properly time the next irrigation application. Krutz said sensors allow producers to “see” the active rooting zone and water use within that rooting zone throughout the season.
   “I promise that you will recoup the money the first season. You might be able to do that the first time you run irrigation,” Krutz said.∆