zero-waste Watering


Growing food is a delicate balancing act. Water, soil moisture, fertilizer, and, of course weather, all play their role. Thankfully, the introduction of precision agriculture—including GPS, GIS and remote-sensing technologies to aid in farm management—has made this balancing act a little easier, and researchers continue to develop new solutions. 

Forrest Melton, executive director of the Agricultural Center for Education and Research at CSU Monterey Bay's School of Natural Sciences, has partnered with the UC Cooperative Extension to develop precision ag software called CropManage that uses information about soils, crop type, weather and satellite imagery to allow farmers to use water and fertilizer more efficiently while still increasing their crop yield. Growers in California's Salinas Valley are using the software already on more than a dozen different crops, including lettuce, broccoli, strawberries and spinach.

“Using a more dynamic data-driven approach to irrigation management can reduce the use of applied water [irrigation] by as much as 20 to 40 percent," says Melton, who is also a researcher with the NASA Ames Co​operative for Research in Earth Science and Technology (ARC-CREST) and a leading expert in the field of satellite data for precision agriculture.

“Use of these crop-management software tools in production trials of lettuce and broccoli has also shown that we can sustain crop yield and quality, while reducing loss of nitrates below the root zone by up to 75 percent," he explains. When nitrates (which come from fertilizers) are kept in the root zone where plants can use them, the amount that leaches into the soil and groundwater is reduced.

Another cutting-edge area of research—and one with the biggest potential impact for sustainable water management—is measuring the amount of water lost through evapotranspiration (the process by which water is transferred into the atmosphere from the ground and plants). Melton, along with colleagues from CSUMB and other organizations, is leading OpenET, a western-states effort that should make it easier and less costly to track water lost to evapotranspiration. Farmers and water managers across the west will be able to access the free data, he says, which will provide a shared basis for decision ​making about groundwater management, support the development of incentive-driven conservation programs and help California manage its most limited and valuable resource. ​

Agriculture accounts for approximately 80 percent of all the water u​sed in California, so even small increases in efficiency can have a huge impact.

Fruit and vegetable growers around the state are​ already using precision ag software that helps them make better use of limited water resources. Above:  Anthony Mele, a Fresno State Jordan College dean medalist, inspects broccoli on a campus irrigation research plo​t. Below (left and bottom): Fresno State plant science student Javier Herrera works on irrigation at the horticulture nursery. Below (top right): Staff inspect almond blossoms at the Fresno State campus orchard.