- Author: Saoimanu Sope
Historically, date palms are grown along riverbeds or in areas with groundwater because they require an abundance of water to produce a good crop. Unlike lettuce or table grapes, date palms are deceptive in that they do not immediately wilt if underwatered. Eventually, however, the lack of water hurts yields and fruit quality.
The default for date growers is to apply excessive water, but doing so is neither economically nor environmentally sound. To help growers, Ali Montazar, UC Cooperative Extension irrigation and water management advisor for Imperial, Riverside and San Diego counties, has developed knowledge that enables growers in the region to establish irrigation guidelines they can use with confidence.
“Water issues in California's desert are very different than in the Central Valley,” said Montazar. “There is no groundwater to recharge so growers in the desert only have the Colorado River.”
Since 2019, Montazar has been focused on irrigation management for date palms in the Coachella Valley, the largest producer of dates in the United States. Montazar's research identifies how much water is needed for the crop and the best water delivery method according to location, soil type and conditions, and date cultivars.
“Dates require a lot of heat and light, which is why they do well in the desert. But they also need a fair amount of irrigation,” said Robert Krueger, a U.S. Department of Agriculture horticulturist and Montazar's co-author of a paper on date palm irrigation management.
Much of what we know about date palm production comes from the Middle East, which has a climate similar to the low desert of California. “That information is from many, many years ago though,” explained Montazar, whose research shows that drip irrigation cannot be the only form of irrigation for date palms.
“Ali is the first to really look at micro-sprinklers and flood irrigation for date palms,” said Krueger, adding that the other advantage of Montazar's research is that it prepares growers for production during times of reduced water supply.
Albert Keck, president of Hadley Date Gardens, Inc. and chairman of the California Date Commission, described Montazar's research efforts as “subtle yet incredible and profound,” adding that his findings not only benefit other farmers but also cities relying on water from the Colorado River.
Keck, one of the largest date growers in California, is well aware of how disruptive, expensive and time-consuming irrigation for date palms can be. Montazar has enabled growers like Keck to irrigate less without sacrificing yield or quality.
“Ali might save us a tiny percentage of the amount of water we're using. It might be a 5 or 10% savings. It doesn't seem like much, but it's an incremental improvement in efficiency,” said Keck. “And if you add all of these improvements up, say, along the U.S. Southwest, then that has a pretty profound impact.”
Montazar recommends that date growers in his region use a combination of drip and two to three flood irrigation events to manage salinity levels derived from the Colorado River. “We cannot maintain salinity issues over time if we're only relying on drip irrigation in date palms,” explained Montazar.
Flood irrigation pushes the salts below the root zone, when they would otherwise build up within the root zone preventing efficient water uptake. It also aids in refilling soil profiles quickly and more effectively since drip has a lower capacity of delivering sufficient water.
“Growers know what they need to water their crop within a broader parameter. But Ali has narrowed that window and helped us become more precise with our irrigation,” Keck said. “There's still room for improvement but we're spending less money, wasting less time and using less water now, and we're still getting the same positive results.”
Currently,Montazar is collaborating with the California Date Commission on developing guidelines for best irrigation management practices in the desert for date palms, which should be available by the end of 2023. These guidelines are based on a four-year data set from six monitoring stations and extensive soil and plant samples from commercial fields located in theCoachella Valley, Imperial Valley and near Yuma, Arizona. Additionally, Montazar is working to quantify how water conservation impacts growers economically.
“Growers from United Arab Emirates, Egypt, Tunisia and Mexico have already reached out asking for this information,” Montazar said, while reflecting on a presentation he made to a group of international date growers in Mexico late last year.
To read the paper on date palm irrigation, published in MDPI's Water journal, visit: https://www.mdpi.com/2073-4441/12/8/2253.
- Author: Mike Hsu
Light irrigation before flooding stimulates microbes to remove nitrates from soil
With California enduring record-breaking rain and snow and Gov. Gavin Newsom recently easing restrictions on groundwater recharge, interest in “managed aquifer recharge” has never been higher. This process – by which floodwater is routed to sites such as farm fields so that it percolates into the aquifer – holds great promise as a tool to replenish depleted groundwater stores across the state.
But one concern, in the agricultural context, is how recharge might push nitrates from fertilizer into the groundwater supply. Consumption of well water contaminated with nitrates has been linked to increased risk of cancers, birth defects and other health impacts.
“Many growers want to provide farmland to help recharge groundwater, but they don't want to contribute to nitrate contamination of the groundwater, and they need to know how on-farm recharge practices might affect their crops,” said Matthew Fidelibus, a University of California Cooperative Extension specialist in the UC Davis Department of Viticulture and Enology.
A recently published study by UC scientists sheds new light on how nitrates move through an agricultural recharge site and how growers might reduce potential leaching. Researchers analyzed data from two grapevine vineyards at Kearney Agricultural Research and Extension Center in Fresno County – one flooded for two weeks, and other for four.
Understanding initial nitrate levels crucial
A key factor in mitigating contamination is understanding how much nitrate is in the soil at the outset, said study author Helen Dahlke, a UC Davis hydrologist and leader of UC Agriculture and Natural Resources' strategic initiative on water. In areas with little precipitation and cropping systems that require greater amounts of synthetic fertilizer, the accumulation of residual nitrate – resulting from nitrogen in the fertilizer not taken up by the plants – can be quite high.
“The percentage of nitrates in some soils can really increase over the years, particularly if you have many dry years in a row where you don't have access to irrigation water or natural precipitation flushing some of those nitrates out of the soil,” Dahlke said.
While intense rains in recent weeks have helped dilute nitrate concentrations naturally, farmers looking to participate in recharge during the dry years ahead should consider flooding their fields with greater volumes of water.
“If you're doing this for the first time – on-farm recharge in the winter – check your residual soil nitrate levels because if they're very high, you should apply a lot of water in order to make sure that the residual nitrate is diluted down,” said Dahlke, who also added that growers should check their soil properties for suitability of recharge projects.
She recommended using, as a “good first approximation,” the online Soil Agricultural Groundwater Banking Index map, a project led by Toby O'Geen, a UC Cooperative Extension soil resource specialist.
Researchers looking at other ways to reduce nitrates
Even before flooding the fields for recharge, there are several practices that can lower initial nitrate levels and risk of leaching. Cover crops such as alfalfa and triticale, for example, can help take up residual nitrates that accumulate from fertilizing a main crop over time.
Dahlke and Fidelibus – a co-author of the San Joaquin Valley vineyard study – both pointed to pre-flooding irrigation that encourages denitrification, a process in which soil microbes transform nitrates into gaseous forms of nitrogen.
“Those denitrifying microbes need to be stimulated to do the work,” said Dahlke. “What we have found is that if you do a little bit of irrigation before you start the flooding, increasing the soil moisture can get those microbes started and they can take out more nitrate from the soil.”
The timing and quantity of fertilizer applications are also major factors in reducing leaching. Although more growers are following high-frequency, low-concentration practices to maximize uptake by crops, Dahlke said there needs to be more emphasis on incorporating nitrogen transformation processes – such as denitrification – in the nutrient management guidelines that farmers follow.
“Implementing thoughtful nutrient management plans will play a particularly important role in participating farms,” Fidelibus added.
A more holistic view of groundwater recharge
In short, choices made during the growing season can affect those in the winter recharge season – and vice versa. For example, applying compost or other organic amendments to soil can give microbes the “fuel” they need for sustained denitrification.
“What we have found is that our denitrifying bacteria often run out of steam because they don't have enough carbon to do the work,” Dahlke said. “Like us, microbes need energy to do the work, and for microbes this energy comes from soil carbon.”
Then, adding moisture via recharge to that field with high organic content can stimulate mineralization and nitrification, processes in which microbes transform the organic nitrogen into ammonium – and subsequently nitrates – that the plants can then take up. Those naturally occurring nitrates would thus reduce the need for the grower to apply synthetic fertilizer.
“The winter on-farm recharge experiments have shown that altering the moisture regime in the winter has consequences for the nitrogen budget in the summer growing season,” Dahlke explained. “Theoretically, what we need to be doing is better integrating both seasons by keeping an eye on the soil-nitrogen balance across the whole year so that we can ensure, at the end of the growing season, the residual nitrate in the soil is minimized.”
The study, published in the journal Science of The Total Environment, was part of the post-doctoral work of former UC Davis researcher Elad Levintal. In addition to Fidelibus and Dahlke, other authors are Laibin Huang, Cristina Prieto García, Adolfo Coyotl, William Horwath and Jorge Rodrigues, all in the Department of Land, Air and Water Resources at UC Davis.
/h3>/h3>/h3>/h3>- Author: Ben Faber
The USDA's Farm Service Agency and Natural Resources Conservation Service will have workshops to aid agricultural producers; including cattle, tree, nursery, vegetable, and berry farmers in filing for federal assistance programs. Appointments can be arranged now for filing applications during these workshops.
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- Author: Ben Faber
Fire, Flood, Freeze, Fytophthora. It seems like there is disaster around every corner these days. This can be tough for tree growers with a lot of investment in the ground. There has been a special USDA crop insurance available for ‘Hass' avocado growers for several years. For a reasonable amount, a considerable amount of disaster insurance can be obtained:
https://www.rma.usda.gov/fields/ca_rso/2018/caavocado.pdf
This program is not available for non ‘Hass' avocado, although that may change in the future. It is also not available for many other perennial crops like pomegranates and persimmons and may only be available for some crops like blueberry and citrus in some counties and not in others.
However,there is disaster insurance available for many fruit crops in all counties in California. This program is The Noninsured Crop Disaster Assistance Program (NAP), administered by the U.S. Department of Agriculture (USDA) Farm Service Agency (FSA). It provides financial assistance to producers of noninsurable crops against natural disasters that result in lower yields or crop losses.
The 2014 Farm Bill specifies that an individual's average adjusted gross income (AGI) cannot exceed $900,000 to be eligible for NAP payments.
Noninsured Crop Disaster Assistance Program
Tree Assistance Program
2018 NAP Application Closing Dates
Unfortunately, the closing dates for crops like pomegranates, persimmons, and blueberries closed October 1, 2017 for this year, but avocados and citrus are still open until February 2018.
For more information about the program, contact:
*ù...Daisy Banda¶ù*.
Program Technician
Santa Barbara-Ventura County | Farm Service Agency
920 East Stowell RD | Santa Maria, CA 93454
(: (805)928-9269 Ex. 2 |Fax: (844)206-7008
Insurance Survey
The National Center for Appropriate Technology (NCAT) is seeking input from growers across the nation concerning crop insurance. NCAT is hosting an online survey, which takes 20 – 30 minutes to complete, that will compile grower and rancher opinions, attitudes and concerns regarding crop insurance. The results will remain anonymous and will be used to shape crop insurance recommendations that NCAT, in partnership with a number of other agricultural organizations, will present to the United States Department of Agriculture concerning organic, diversified and specialty crop producers.
NCAT will pay those who complete the survey $20.
Growers interested in participating in the anonymous crop insurance survey can do so by clicking on this link.
- Author: Glen Martin
Reprinted from California Magazine
With perhaps one of the most intense El Niño ever recorded simmering like a massive coddled egg off the coast, Californians are bracing for precipitation on an epic scale. More than that: They're hoping for it. There is a general sense that even the rampaging floods that can result from a full-blown El Niño-driven winter would be tolerable as long as our reservoirs fill and aquifers recharge and we can get back to long showers and adequately watered hydrangeas.
This is a good place to insert a couple of caveats. First, choose your wishes carefully. Recall, if you were in California at the time, the great El Niño of 1997-98, and the vivid images it provided of nature running amok: Highway 70 disappearing into the vast, churning inland sea that was once the Yuba River, with dead cows, outbuildings and giant hissing propane tanks bobbing downstream. That was the year the dikes failed on the Feather River, and thousands of Yuba City residents fled the rising waters. After it was all over, one staffer with the U.S. Army Corps of Engineers chatted off the record, and said there had been very real fears that Folsom reservoir could have overtopped its dam. If that had happened, much of Sacramento would have flooded. People would have died. Four years of drought may have made people forget that California can be blighted by too much water as well as too little.
Second, observes Doug Parker, the director of UC's California Institute for Water Resources, the rain and snow may fizzle. A robust El Niño is no guarantee of record rainfall and snowpack.
“In fact, the research indicates a wet year for Southern California, but there's less confidence about a lot of precipitation for the north state, particularly in terms of snow,” says Parker.
And we need snow more than we need rain. Parker notes that intense rainfall can produce too much water too fast at the lower elevations and melt snow at the higher elevations. In such cases, the state's dams and reservoirs have to function as flood control structures; much or most of the water is shunted rapidly to the sea, not stored.
One wet winter could put a lot of water in our reservoirs and maybe help replenish some aquifers, but it will do nothing to address demand.
Further, cautions Parker, even an optimal El Niño that dumps heaps of snow in the Sierra without swamping the lowlands with Pineapple Express deluges may not get us back to “normal.” That's because surface water is only part of the issue. Brimming reservoirs alone cannot slake the state's thirst. According to theCalifornia Department of Water Resources, groundwater constitutes between 30 to 46 percent of the state's total water supply. Despite recent legislation to monitor and control groundwater withdrawals, pumping remains largely unregulated, and many of the state's aquifers are in “overdraft,” with more water being sucked up and out than trickling back underground. The results of this excessive pumping are particularly evident in the San Joaquin Valley, where massive ground subsidence—a sudden sinking or gradual sinking of the Earth's surface— is occurring as groundwater is withdrawn.
These effects are not temporary. Ground subsidence can destroy aquifer structure, reducing long-term storage capacity. And while heavy rains and deep snowpack are essential for recharging aquifers, the process isn't necessarily a rapid one.
“There are some areas where recharge happens fairly quickly, particularly if combined with decreased pumping,” Parker says. “But other areas may require decades or centuries to replenish. Also, you have to consider what you mean when you say ‘recharge.' In the Tulare Basin, the water table has fallen by hundreds of feet, it keeps dropping, and the pumping continues. So what does ‘recharge' mean? Getting water back up to 300 feet from 400 feet? What's your baseline? When water is that deep, it's unlikely you could get any significant or long-term replenishment from one year, especially considering the ongoing demand.”
And that may well be the ultimate rub: Demand. The problem with a state that has so many people and so much intensive agriculture is that water demand is by no means static. It's constantly moving, but it only moves one way: upward. No matter how much water we get, there will always be someone clamoring for it. Water rights claims exceed the amount of the state's developed water—the water controlled and distributed by government agencies—by 5.5 times. Even during the last four years of devastating drought, thousands of acres of new almond orchards have been planted in the Sacramento and San Joaquin Valleys, and almonds are a water-intensive crop, each tree requiring heavy irrigation for its entire productive span.
“One wet winter could put a lot of water in our reservoirs and maybe help replenish some aquifers, but it will do nothing to address demand,” says Parker, “so ‘getting back to normal' doesn't really speak to the biggest issues. People will always have a use for any water that's available. If we want a truly sustainable water policy, we can't be reactionary. We can't look at this from the perspective of one year, or a few years. We have to take a long-term view.”