What is in this article?:
- Subsurface drip irrigation increases alfalfa yields
- Water use is reduced
- Capital investment recovered through improved yield and reduced water use
Steve Maddox Jr. uses the latest technology, including a weather station connected to a subsurface drip irrigation system to water some of his alfalfa in central Fresno County, Calif.
Soil cracking problem
Another issue Maddox deals with in fields is soil cracking common in the heavy clay soil where the alfalfa is grown. Some of these two-inch cracks, which can reach a five-foot depth, pull apart the root systems in the alfalfa. Not only does this affect the alfalfa stand, but the next irrigation has to fill in the cracks, leading to an inefficient use of water.
Overall, the SSDI system places the water where the plants need it the most.
“This is important since it reduces water evaporation,” Maddox said.
The heavy soil cracking has not been completely eliminated with the SSDI system. Soil cracking is still enough to pull apart drip lines at the connections, causing leaks and the need for repairs.
“When you dry down before harvest, it has a tendency to pull the couplers apart,” he said. “Every time we start back up we find four-to-five leaks.”
To work around the problem, Maddox keeps some water in the SSDI system to maintain soil moisture around the tape and prevent soil cracking.
“We feel pretty confident that this will solve our problem,” he said. “It’s still a learning process for us.”
Water use during the spring months did not seem to change from the flood system to irrigating by SSDI, Maddox said. He suspects the summer months where the soil tends to crack more will result in an appreciable savings of water.
“They say we ought to save 20 percent (on our water use),” Maddox said. “I don’t think that is out of the realm.”
Maddox uses water sensors in the two fields where the SSDI system is located. The sensors link to a computer program to provide real-time water-use information. Attached to one sensor is a weather station assessable with a smart phone app.
The app and weather station have proven useful as workers can monitor the wind speed prior to baling. Too much wind can dry the hay during baling.
One water sensor reads every foot down to five feet. The other sensor reads every four inches down to 20 inches. The later sensor is not as useful as visually checking the field for soil moisture, he said.
Irrigations in the system are timed to run two hours on one set, and then switch to another set for two hours. Maddox says this pulsing system of irrigation allows for total coverage quicker and more efficiently.
“We are consistently feeding the plant all the way through and not stressing the plant.”
The results are increased tonnage and an improved stand.
Other benefits with SSDI include reduced weeds. Soil amendment treatments are more efficient.