Gaining an edge in today’s vegetable production system is not easy, and while water is perhaps the most talked-about topic, some researchers and growers are looking at air to boost yields and quality.
At Fresno State University’s Center for Irrigation Technology (CIT), research is under way to test the practicality of injecting air into subsurface drip lines to improve plant performance.
“We’ve seen as much as 50 percent improvement in root growth in vegetables when air is injected through a subsurface drip line along with the irrigation water,” says David Zoldoske, CIT director.
“It’s actually a simple concept. When you irrigate the soil, you temporarily diminish the aerobic component of the soil/root environment. To function properly, roots need air as much as they need water.”
Several commercial vegetable producers are already using air injection systems.
“It’s not a cheap application, but it’s effective,” says Chuck Dees, irrigation manager for Stamoules Produce at Mendota. “It’s so effective on cantaloupes that we have to shut it off. You can get about 8 percent to 15 percent more benefit out of a crop if you use this product properly.”
Dees is using a system from Mazzei Injector Corporation, Bakersfield, Calif. It uses venturis to mix atmospheric oxygen with irrigation water as it is applied through the drip line 12 inches below the soil surface.
“For us, the most effective use has been on cantaloupes and honeydew melons,” Dees says. “It prolongs the period of time we can harvest. Normally, when we pick cantaloupes, we turn water off and it puts sugar into the fruit because the plant thinks it is dying.”
Bringing the plant back after irrigation has been shut down has always been a challenge for growers who are trying to optimize yield, quality, and the length of their marketing window.
“With air injection through the drip system, we’ve been able to pick, then turn the irrigation back on and rejuvenate the plant,” Dees says. “About two or three weeks later, we can pick again. That’s something we haven’t been able to do in the past.”