By Dennis Pollock, Ag Alert
When a rare heavy rain used to fall on Jim Chew’s Madera County farm, the water would just roll off his pistachio orchard, uncaptured as it drained down a slight slope.
Then came the ground cover between his rows of trees.
Now the perennial grasses he planted about five years ago “act as a dam,” Chew said. They slow the movement of water and keep it in the orchard where it can infiltrate into his sandy loam soil.
Chew farms 10 miles south of Chowchilla in the Dairyland area. He believes the groundcover—including Cucamonga California Brome and Blando Brome annual grasses—helps infiltration of water and keeps insects at bay. That’s because pests gravitate to the groundcover instead of into his trees, he said.
Photo/Natural Resources Conservation Service
Chew said mowing the ground cover helps control pistachio mummies, which may be infested by the navel orangeworm, as the grass clippings cover up what’s left of felled mummies.
His drip lines are spaced away from trees and near enough to the groundcover that they provide moisture to keep it alive in the valley’s searing heat.
Priscilla Baker, with the U.S. Department of Agriculture’s Natural Resources Conservation Service, and others helped Chew with technical assistance and some funding.
Baker, acting district conservationist for Madera County, recently discussed such efforts—”practices to sink water on your farm,” she called them— at a meeting at the Madera County Farm Bureau. It was a discussion aimed at encouraging local growers to find places on their land where they may capture excess rain water for long-term needs.
She posed these questions: “In a big water year, can you take additional surface water after your ground is saturated? Where can you put it? Does your soil infiltrate heavy rains, or does it pond and evaporate or run off? Can you use more surface water instead of groundwater?”
Across the San Joaquin Valley, groundwater is severely overdrafted, and California’s 2014 Sustainable Groundwater Management Act is imposing rules aimed at replenishing aquifers and maintaining consistent water resources going forward.
Baker said “landscape features” already in place could become places to sink water back into the ground. They include ponds, wetlands, sloughs, tailwater sumps and reservoirs. Or growers may need to create such features to deposit water.
Baker said she hopes to motivate people to think of how they can better position themselves to deal with the challenge of drought and stepped-up regulation under SGMA rules.
Baker said some pilot projects are being put in place in Madera County and elsewhere to corral excess water, and they have added benefits that include improved wildlife habitat, for example.
One project involved connecting an existing pond that has been mostly dry since the region’s Friant Dam was put in place. It’s on land owned by Pat Emmert Manning, where crops include walnuts, Thompson seedless grapes for juice and merlot and syrah wine grapes.
The pond is about half a mile from the San Joaquin River near Gravelly Ford. Pipes have been added to take water from the river into the pond.
Manning said the project began in part to create wildlife habitat.
“It’s a good environment for nesting birds and waterfowl,” she said, “and has a lot of cattails and lily pads.”
Partially funded by the National Resources Conservation Service, the pond that Manning sometimes refers to as “a lake” will have the dual purpose in wet years of serving as a recharge basin.
On Kole Upton’s farmland in Merced County, the NRCS has helped fund creation of small irrigation reservoirs that also serve double duty by providing wildlife habitat.
Upton, who is chairman of the board of the Chowchilla Water District, said the small reservoirs attract birds. He’s hoping that in time those birds will include tricolored blackbirds.
NRCS funding helped create sumps and supported use of plants to attract wildlife to the low spaces that gather water on Upton’s farm, where he grows corn for corn nuts, along with wheat, almonds, pistachios and cotton.
Another grower’s project will involve removal of an orchard. The land will then be kept open for two years, after which the property will be replanted with fewer trees on leveled ground with added pipes, a pump and a cover crop. Ultimately, a sump area will be created at a lower end of the field to collect water.
Floodwater will circulate and aerate soil, and the land can take on-farm recharge water.
At the Oct. 28 “Irrigation & Nutrient Management Workshop”in Madera County, Baker joined numerous presenters on water recharge efforts. They included speakers from American Farmland Trust, the Sierra Resource Conservation District and the University of California Kearney Agricultural Center. The Madera/Chowchilla Resource District posted the presentations on its YouTube page.
Khaled Bali, with the Kearney center, gave a primer on irrigation scheduling. He offered insights on improving irrigation efficiency, regulating deficit irrigation and creating new cropping systems.
Bali explained that applying the right amount of water to meet crop water requirements is key. Doing that means drawing on a wide array of information, knowing soil types and making adjustments based on soil moisture and plant health, he said.
Rex DuFour, with the National Center for Appropriate Technology, emphasized understanding and investing in soils. He said high-tech irrigation is “important and needed.” But he said soil surfaces will not allow good infiltration or water storage if the soil is poor shape.
“Ignoring soil health while investing in irrigation infrastructure is like putting a $100 saddle on a $10 horse,” he said.
DuFour said well-managed soils infiltrate, store and cycle water and nutrients more effectively and help protect water quality above and below ground. He said he believes adding organic matter is important to provide better infiltration and increase water storage capacity of soils.
Dominic Rossini, team leader for Agronomy West with Netafim USA, stressed the importance of vigilant maintenance of irrigation systems. He said system design and performance is critical throughout the growing year—from start-up, through the harvest, the end of season and winterization.
