Water and Nitrogen Use Research

Andre Biscaro on Water and Nitrogen Use Research

By Charmayne Hefley, Associate Editor

Many jobs exist solely for the improvement of agriculture. Andre Biscaro, agriculture and environmental issues advisor at the UC Division of Agriculture and Natural Resources, Cooperative Extension, Los Angeles and Ventura Counties said his job is to find ways to improve water and nitrogen use in fertilizing crops such as strawberries and celery.

“We’re measuring how much nitrogen the plant takes in and at what time,” Biscaro said, “so we can make more accurate recommendations for nitrogen fertilizers. It’s the same for water. We’re monitoring the crop growth of the strawberry plants—how deep the roots go and how the canopy develops—so we can make more accurate water recommendations. We’re assessing fields in Santa Maria and we are implementing the second phase here in Ventura County, Santa Maria and Watsonville.”

Biscaro is researching in strawberries and celery how to push salts in the soil beyond the root zone, the point beyond which plants will generally seek water unless they are stressed. “It’s essential to install soil moisture sensors at the end of your root system,”Biscaro said, “to make sure the soil is saturated every time you irrigate and then you need to push the water down. And it’s also really important to calculate the amount of water you’re applying because a lot of growers are irrigating without knowing how much water they are applying.”

“We calculate the leaching fraction [the portion of irrigation water that infiltrates past the root zone] based on the sensitivity of the crop to salinity and to the salinity of the water,” Biscaro explained. “And by only knowing how much water you’re applying, you can add a certain leaching fraction to your crop,” Biscaro said.

Patrick Cavanaugh2016-05-31T19:27:09-07:00September 29th, 2015|

Celery Management Research

Andre Biscaro on Celery Management Research to Improve Water and Nitrogen Use

By Charmayne Hefley, Associate Editor

Ongoing research continually improves the agriculture industry. Andre Biscaro, agriculture and environmental issues advisor at the University of California, Division of Agriculture and Natural Resources, Cooperative Extension, Los Angeles and Ventura Counties, described current trials in celery management research, sponsored by the California Celery Research Advisory Board.

“We’re monitoring water and nitrogen use based on best management practices,” Biscaro said. “We evaluate ‘best management’ practices using the soil nitrate quick test. That gives us a really good estimate of how much nitrogen is in the soil, and we can accomplish the test in just about an hour.” The trial also incorporates data from weather stations to calculate the amount of applied water.

“This trial and research actually monitors the amount of water and nitrogen we’re using and how much yield we’re getting under various best management scenarios,” Biscaro said, “and compares our practices to what the grower usually does.” Ultimately, the trial will help determine the yield of a celery field using best management practices, and how much water and nitrogen are required to achieve that yield.

Biscaro said the grower he has been working with to conduct the trial was already highly successful with soil and water management in the specific celery field under study. “He really knew what he was doing, and the nitrogen management was quite decent as well. So I believe there are opportunities for improvement in the industry, but the grower was actually doing quite well in this particular field I monitored.”

Patrick Cavanaugh2016-05-31T19:27:09-07:00September 25th, 2015|

Plants Do Not USE Water…They Borrow it!

Plants Transpire Most of the Water They Use!

Editor’s note: California Ag Today interviewed Allan Fulton, an Irrigation and Water Resources Advisor, UC Cooperative Extension Tehama County, in Redbluff CA, to comment on the debate about the agricultural industry’s use of water and to focus on a critical but disregarded process—that all plants transpire, even plants cultivated for the crops we eat.

Allan Fulton, Irrigation and Water Resources Advisor

CalAgToday: We hear in the media that our crops are using too much water. And while all plants need water to grow food, we also know that a high percentage of water taken up by all plants actually transpires back into the atmosphere, to form clouds and precipitation, right?

Fulton: Yes, when plants transpire, the water just returns to the local hydrologic cycle, leaving the harvested crop that we distribute elsewhere in the US or in the world actually very low in water content.

CalAgToday: When we think about transpiration, are the plants actually “borrowing” the water?

Fulton: Yes. We get a lot of questions about why we irrigate our crops so much, and it comes from the general public not being as close to farming everyday. The truth is, plant transpiration is a necessary biological process. The water cools the tree so it stays healthy and exits the leaves through special cells called stomata. While the stomates are open to allow water to transpire, carbon dioxide enters and is used in photosynthesis, making sugars and carbohydrates for the plant to create the fruits and nuts that we eat. So, an inadequately watered plant cannot take in enough carbon dioxide during transpiration, resulting in defective fruits and nuts that are smaller, shriveled, cracked—all the things the typical consumer does not want to buy.

Plants cannot gain carbon dioxide without simultaneously losing water vapor.[1]

CalAgToday: Can we say 95 or 99% of the water that is taken up by the plant gets transpired and definitely not wasted?

Fulton: Definitely. We converted to pressurized irrigation systems, micro sprinklers and mini sprinklers, so we have a lot more control over how much water we apply at any one time. We do not put water out in acre-feet or depths of 4-6 inches at a time anymore. So, much like when rainfall occurs, we can measure it in tenths, or 1 or 2 inches at most. As a result, the water doesn’t penetrate the soil very deeply, maybe only 1 or 2 feet each irrigation.

We are very efficient with the water, but because we deliver it in small doses, we have to irrigate very frequently. That is why we see irrigation systems running a lot, but they are systems that efficiently stretch our water supply and do not waste it.

CalAgToday: But again, the vast majority of the water that the tree is taking up is being transpired, right?

Fulton: Yes, most of the time, at least 90% of the water that we apply taken up through the tree and transpired so that photosynthesis can happen.

CalAgToday: And transpiration increases on a hot day?

Fulton: Yes, we do get a little bit of loss from surface evaporation from wet soil, but we try to control that with smaller wetting patterns—drip-confined wetting patterns. When you think about it, the heat of the day is in the afternoon when many irrigation systems don’t run because of higher energy costs. There are incentives not to pump in the middle of the afternoon, but those who do try to confine the wetted area to limit evaporation. And the hot hours of the day make up about 4 hours of a 24-hour cycle, so we irrigate mostly during the nighttime and early morning hours to lesson evaporative loss.

CalAgToday: Growers are doing everything they can to conserve water. If the trees and vines are all transpiring most of their irrigated water, why is using water to grow food a problm?

Fulton: I think the emphasis throughout the United States has always been to provide a secure food supply. That security has many benefits, economically and politically; and in the end, we are trying to provide the general public with good quality, safe food at the best price possible.

______________________________________________

[1] Debbie Swarthout and C.Michael Hogan. 2010. Stomata. Encyclopedia of Earth. National Council for Science and the Environment, Washington DC.

The California Irrigation Management Information System (CIMIS) is a program unit in the Water Use and Efficiency Branch, Division of Statewide Integrated Water Management, California Department of Water Resources (DWR) that manages a network of over 145 automated weather stations in California. CIMIS was developed in 1982 by DWR and the University of California, Davis (UC Davis). It was designed to assist irrigators in managing their water resources more efficiently. Efficient use of water resources benefits Californians by saving water, energy, and money.

The CIMIS user base has expanded over the years. Currently, there are over 40,000 registered CIMIS data users, including landscapers, local water agencies, fire fighters, air control board, pest control managers, university researchers, school teachers, students, construction engineers, consultants, hydrologists, government agencies, utilities, lawyers, weather agencies, and many more.

California Ag Today2021-07-23T14:31:38-07:00September 23rd, 2015|

Bountiful Plant Transpiration

Guy Kyser on Plant Transpiration, Phytoremediation

By Patrick Cavanaugh, Deputy Editor

When plants get irrigated, not only do they provide food, but all plants transpire. Guy Kyser, a specialist at the UC Davis Plant Sciences Department, explained how plant transpiration transforms carbon dioxide into “food” for plants to grow.

“Water in the shallow soil is either going to evaporate, or it’s going to be transpired,” Kyser said, “which means it’s going to pass through a plant from the soil to the atmosphere. The transpiration process helps the plant fix CO₂ and convert it into food or plant material. The plant is really a little solar powered machine that catches CO₂ out of the atmosphere and turns it into something solid so it’s not a greenhouse gas anymore.”

Kyser also explained the phytoremediation* process that occurs in plants grown in less-than-ideal soil and water conditions, in which these plants take up polluted water from its roots while removing impurities from the soil, retain the impurities, and release pure water into the atmosphere. Kyser said, “So, with phytoremediation, you can use the plants to purify poor soil or water situations, then mow off the plant material when the process is done. All the toxins stay in the plant, and only the pure water goes through.” Despite being a slow process, phytoremediation is effective in toxin removal, environmentally friendly, and does not harm soil health.

*Phytoremediation: Ancient Greek for “plant” and Latin for “restoring balance”

California Ag Today2016-05-31T19:28:07-07:00August 13th, 2015|

Subsurface Drip in Alfalfa

Subsurface Drip in Alfalfa–A Growing Interest

By Laurie Greene, Editor

Dan Putnam is a faculty member and Cooperative Extension specialist at UC Davis with a statewide responsibility for alfalfa and forage crops. He said there has been an increased interest in subsurface drip irrigation in alfalfa, which is usually flood-irrigated. Alfalfa is a key forage source for the state’s top agricultural product, dairy, to the tune of more than $7 billion per year.

“It does come with some challenges,” but he said, “the growers who have really treated this as an educational experience are continually learning how to manage this system; not only the gophers, but the irrigation management component as well. To establish a crop with drip irrigation, growers need to plant in early fall and use sprinklers to germinate the seeds. A lot of growers fail on agronomic issues, like not planting at the right time of year rather than on drip irrigation issues,” Putnam said.

Putnam noted that growers are more interested in learning about subsurface drip irrigation because of increased yields. “I think over time, we are going to see a greater adaptation of this technology in California,” Putnam explained, “particularly in areas that have very high yield potential. For example, in the San Joaquin Valley and the Imperial low desert areas where the crop is actually capable of 12-16 ton yields, our yields average about 7-8 tons per acre. And so,” he added, “we do have a yield potential that we are unable to achieve, and part of that is in the limitation of surface irrigation.”

Putnam also noted one advantage of drip irrigation is efficient nutrient delivery, which in turn fosters increased uniformity across the system. “Growers can ‘spoon-feed’ the crop rather than inefficiently apply it on the surface,” stated Putnam. “I think a lot of growers have figured this out, although alfalfa does not have a nitrogen issue. Nevertheless, we have to apply significant phosphorous, potassium and several other nutrients in some deficient soils.”

As with most things, there are drawbacks, and Putnam outlined two. “One is an increased cost of the drip line and filtration system,” Putnam said. “Growers who are considering subsurface drip need to wrestle with the cost to be sure they can increase yields enough to justify the cost. In most cases, growers have been able to substantially increase yields in their systems to pay for the $1500-2500 per acre upfront investment in the technology,” he said.

“The other drawback is maintenance,” Putnam continued, “particularly with regard to rodent infestations. We’ve seen gophers, in particular, ground squirrels and meadow voles absolutely devastate drip-irrigation fields. As our vertebrate pest specialist at UC Davis says, ‘It is essentially an ideal habitat for gophers as they have plenty of food, plenty of shelter, plenty of water, and they are able to reproduce pretty readily.’ ”

“You should consider this system only if you are willing to accept a very high level of maintenance and no tolerance for rodent infestation because, if left unchecked, they will chew on the tapes and ruin the system,” he said.

Putnam reported there are strategies to get around gophers and other rodent issues, “You have start clean and do some deep tillage. We also recommend retaining the capability of flood irrigation in those fields to use once in a while because it reaches the furrows very effectively,” he noted.

For those gophers, Putnam recommends every trick in the book. “There are traps organic farmers are able to use, flood irrigation, and boxes to help control the population,” Putnam said. “There are products available for baiting and other types of control measures that should be used. It is really too expensive a system to allow the gophers to have their way with it, so we need to have a high level of management,” he concluded.

California Ag Today2016-07-30T21:43:15-07:00August 3rd, 2015|

UC Davis to Host Beef Cattle Conference

Reproductive Strategies in Beef Cattle

UC Davis to Host National Conference August 17–18

The latest technologies and techniques in beef cattle reproduction will take center stage at UC Davis in August at the 2015 Applied Reproductive Strategies in Beef Cattle Symposium.

Cattle producers, veterinarians, faculty, UC Cooperative Extension specialists, students, and more are welcome at the national event, which will be held August 17 and 18 at the UC Davis Conference Center.

“Speakers from multiple states will outline approaches to improve the efficiency and success of beef cattle reproduction,” said Alison Van Eenennaam, a UC Cooperative Extension specialist in the UC Davis Department of Animal Science, which is hosting the annual beef cattle conference. It’s the first time the symposium has been held in California.

Participants will explore key topics in beef cattle reproduction, including physiology, genetics, management, marketing, and strategies for coping with drought.

“Dr. Eric Scholljegerdes from New Mexico State University will deliver a particularly timely talk entitled, ‘Drought: Devastating natural event or a wakeup call for better cattle management,’” Van Eenennaam said.

Heifer development will also be addressed, along with the role maternal nutrition plays in fetal development. For a full list of speakers and topics, visit the Beef Reproduction Task Force website.

American Registry of Professional Animal Scientists, as well as Veterinary Medicine continuing education credits are approved for the meeting.

The Registration fee of $250 includes one dinner and two lunches. Students can attend for $100.

For additional information, visit the conference website at or contact Alison Van Eenennaam at alvaneenennaam@ucdavis.edu or 530-752-7942.

Patrick Cavanaugh2016-05-31T19:28:09-07:00July 23rd, 2015|

Location! Location! Location!

UC ANR Research and Extension Centers Strategically Located

By Charmayne Hefly, Assistant Editor, California Ag Today

Bill Frost is the director of the University of California, Division of Agriculture and Natural Resources’ Research and Extension Center System that has nine different research and extension centers located throughout the state.

UC ANR Research and Extension Center System

Describing the strategy in their geographic placement, Frost said, “We have located them in different growing zones, climates and environments. We have chosen everything from the desert region in El Centro, to cropland here in Kearney, to livestock grazing in both our Hopland and Sierra Foothill Research and Extension Centers, all the way up to Intermountain in Tulelake, where we research potatoes, garlic and crops that can be grown in that fairly short growing season.”

The goal, according to Frost, is to solve local issues from a local or regional perspective. “Each one of our centers has different environments, crops and pest issues to address,” he explained. “These diverse locations are critically important to us because we can do localized, applied research and get useful information out to people, whether they are homeowners in their gardens or growers managing a thousand acres of a crop.”

Frost noted the UCANR Research and Extension Center System has been actively seeking new personnel to better meet the needs of growers. “Just in the last four years,” he said, “we’ve hired almost one hundred new cooperative extension advisors and specialists around the state—many of whom are housed here at the Kearney Research and Extension Center. They are also housed on UC campuses and in our county Cooperative Extension offices.”

Frost commented, “We continue to be relevant. We continue to do cutting-edge applied research. Our programs provide information to everyone; from our youth development program in 4-H and our nutrition education, to master gardener programs that help homeowners with pest problems and water management.”

“And of course, we serve the agricultural community. We have a lot of good research going on and we’re generating lot of good information in commodity production, pest management and water management,” Frost said.

The nine UC ANR Research and Extension Stations are:

Desert Research & Extension Center in El Centro
Hansen Research & Extension Center in Santa Paula
Hopland Research & Extension Center in Hopland
Intermountain Research & Extension Center in Tulelake
Kearney Agricultural Research & Extension Center in Parlier
Lindcove Research & Extension Center in Exeter
Sierra Foothill Research & Extension Center in Browns Valley
South Coast Research & Extension Center in Irvine
West Side Research & Extension Center in Five Points

Featured Photo: UC ANR

Patrick Cavanaugh2016-05-31T19:28:10-07:00July 20th, 2015|

UC ANR Horticulture Advisor Retires After 28 Years

John Kabashima wrapped up his horticultural career on July 1, after 28 years with University of California Agriculture and Natural Resources. Nursery professionals lauded the UC Cooperative Extension advisor’s service to the nursery and landscape industry and to homeowners in Orange and Los Angeles counties.

“He’s one of the few people who could translate science into business with a sense of candor and fact-based conversation,” said Robert Crudup, president of Calabasas-based Valley Crest Tree Company, of Kabashima.” John has long-term vision, which he used throughout his career to move the nursery industry forward.”

John Kabashima, UC ANR

“He is smart about political science as well as plant science,” Crudup said. On a regular basis, Kabashima would warn growers about emerging issues that were likely to affect the nursery industry, such as regulations to control the spread of polyphagous shot hole borer, red imported fire ant and palm borer.

“He’s been very, very valuable,” said retired nurseryman Gary Hayakawa, noting that Kabashima not only contributed research on pest control and water issues for the nursery and landscape industries, but also persuaded people from UC campuses, the California Department Food and Agriculture and industry to work together. “Before he was involved in issues, the work was all separate. Industry didn’t have input,” Hayakawa said. “What John has done is to work with all three to form a coalition.”

Crudup, whose company has nursery operations in Los Angeles, Ventura, Alameda and San Joaquin counties, agreed.

“John’s biggest contribution was his work with the glassy-winged sharpshooter subcommittee,” said Crudup, who served on the subcommittee. “He brought a voice of reason that helped counterbalance emotional sides of the discussion.”

“His ability to act as the primary liaison between the nursery industry, CDFA, the UC, the county agricultural departments and the wine and grape industries was the primary reason this part of the GWSS (glassy-winged sharpshooter) program was so successful and, more importantly has resulted in the continued viability of the California nursery industry in light of significant regulatory pressures,” said Bob Wynn, who was statewide coordinator of the CDFA Pierce’s Disease Control Program and who continues to oversee the program as senior advisor to Secretary Karen Ross.

“The CDFA, with advisement and counseling from John, developed what is known as the Approved Nursery Treatment Program, which allows nurseries in the infested areas of the state to ship by merely treating the plants with an approved treatment,” Wynn said. “John was the primary author in the development of the nursery ‘Approved Treatment Best Management Practices’ document published in 2008. The use of this document has allowed the nursery industry to save millions of dollars in regulatory compliance costs over time.”

A native of Los Angeles, Kabashima says he started working in his family’s nursery business as soon as he was tall enough to water 1-gallon nursery plants. “After killing thousands of plants, I was finally allowed to manage the family business from 1970 to 1976,” he quipped.

In 1976, his family sold the nursery and Kabashima enrolled at California Polytechnic University, Pomona. After he earned a B.S. in agricultural biology from Cal Poly Pomona in 1979, he was hired by UC Riverside horticulture entomologist Pat Morishita as a lab technician. While working at UC Riverside, Kabashima earned a master’s degree in pest management. He would later complete a Ph.D. in entomology at UC Riverside.

Kabashima earned his MBA at Pepperdine University in 1986 while managing the Ornamental Horticulture Division at Target Specialty Products. In 1987, the UC Division of Agriculture and Natural Resources recruited him to become a UC Cooperative Extension environmental horticulture advisor in Orange and Los Angeles counties.

Over the years, he has studied the management of insects, diseases and weeds in horticulture production systems, biological control of exotic pests, and water-related problems in landscapes, golf courses, nurseries, municipalities and watersheds.

In 1998 Kabashima took over the fledgling UC Master Gardener Program in Orange County, which as of now has trained more than 300 UC Master Gardener volunteers to extend research-based information on gardening and horticulture to the public.

The UCCE environmental horticulture advisor has also served as director of UC Cooperative Extension in Orange County and interim director of the UC ANR South Coast Research and Extension Center.

In 1994, when Orange County filed for bankruptcy and the Board of Supervisors voted to discontinue funding and housing for the local UC Cooperative Extension, Kabashima worked with Gary Hayakawa to keep UCCE in the county.

“When Orange County cut Cooperative Extension’s budget, we found out that without extension you don’t have 4-H or Master Gardeners,” Hayakawa said. To preserve the UC Cooperative Extension programs, Hayakawa, who was an Orange County Fair Board member, helped Kabashima secure office space in trailers on the fairgrounds. In 2014, the UCCE office moved from the fairgrounds to UC ANR South Coast Research and Extension Center in Irvine.

Kabashima belongs to many professional organizations including the Entomological Society of America, California Association of Nurseries and Garden Centers, Nursery Growers Association, Western Chapter of the International Society of Arboriculture, United Agribusiness League, and San Diego Flower and Plant Association. The scientist has served on numerous government and industry advisory committees.

Throughout his career, Kabashima’s achievements in education and research have been recognized by various organizations. To name a few, he received the 1987 Education and Research Award from the Orange County Chapter of the California Association of Nurseries and Garden Centers (CANGC), 1993 CANERS Research Award from CANGC, 2002 Nursery Extension Agent Award from the American Nursery and Landscape Association, 2008 Western Extension Directors Award of Excellence, 2010 Entomological Society of America’s National IPM Team Award and the 2011 California Agriculture Pest Control Advisors Association Outstanding Contribution to Agriculture Award. In 2014, he and his friend Hayakawa were inducted into the Green Industry Hall of Fame.

Being a UCCE advisor has suited Kabashima. “I love learning new things, sharing that information with others, and using my skills to solve problems facing California, such as the ever-increasing arrivals of exotic and invasive pests,” he said. The avid photographer has been able to unite his avocation with his vocation. His photographs of insects have been used to illustrate textbooks, websites and news articles.

“Success in one’s field is often a combination of natural ability, informal and formal training and education, being mentored, and networking with collaborators and colleagues, all sprinkled with a little bit of luck and support from one’s family and friends,” Kabashima said.

In retirement, Kabashima plans to seek new culinary experiences with his wife Janet and daughter Misa, at home and in their travels together. He has been granted emeritus status by UC ANR and he will continue his efforts to help UC Irvine save trees on its campus that are infested with polyphagous shot hole borer.

UC Agriculture and Natural Resources researchers and educators draw on local expertise to conduct agricultural, environmental, economic, youth development and nutrition research that helps California thrive. Learn more at ucanr.edu.

California Ag Today2016-05-31T19:28:11-07:00July 12th, 2015|

CROPS ACTUALLY BORROW WATER VIA TRANSPIRATION

Almonds and All Other Crops Borrow Water Via Transpiration

By Patrick Cavanaugh, Associate Editor

Editor’s note: We interviewed Allan Fulton, UC Cooperative Extension Irrigation and Water Resources Farm Advisor, Tehama County, on an important, yet overlooked, process of a plant’s water use in agriculture. We zeroed in on a major process all plants have called transpiration in which crops borrow water.

Allan Fulton, UC Cooperative Extension Irrigation and Water Resources Advisor,
Tehama County

California Ag Today (CAT): We hear in the media that our crops are using too much water. And while all plants need water to grow food, we also know that a big percentage of the water taken up by all plants actually transpires out of the plant, back into the atmosphere, to form clouds and precipitation, right?

Fulton: Yes, the water just returns to the hydrologic cycle. Most of the crops we are distributing, whether within the US or globally, are actually very low in water content.

CAT: When we think about transpiration, the plants are actually borrowing the water. Isn’t that true?

Fulton: We get a lot of questions from the general public about why we irrigate our crops so much.

The truth is, plant transpiration is a necessary biological process. The water cools the tree so it stays healthy. The water exits the leaves through special cells called stomata. While they are open, stomata allow water to transpire and carbon dioxide to enter the plant for photosynthesis, making sugars and carbohydrates, which, in turn, are used to make the fruits and the nuts that we eat.

So if we don’t have an adequately watered plant that is allowed to transpire, the plant won’t get enough carbon dioxide. The plant will grow defective fruits, and nuts—smaller, shriveled, cracked, all the things that the typical consumer does not want to buy.

CAT: Now, when we are talking about transpiration, can we say most of the water taken up by the plant ends up being transpired back to the environment for reuse? So the water transpired by the plant is definitely not being wasted?

Fulton: Definitely. Since we converted to pressurized systems, micro-sprinklers and mini-sprinklers, we have a lot more control over how much water we apply at any one time. We no longer measure water output in depths of acre-feet, or even 4-6 inches at a time anymore. Much like rainfall, we measure it in tenths of an inch, or 1 or 2 inches at most.

As a result, we use less water, so it doesn’t penetrate the soil very deeply, maybe only 1 or 2 feet each irrigation. We are very efficient with the water; but, we have to irrigate very frequently because we apply it in small doses, and we run our irrigation systems a lot. So, we are definitely using systems that stretch the water supply, not waste it.

CAT: But again, the vast majority of the water that the tree takes up is transpired, right?

Fulton: Yes. Most of the time, at least 90% of the water we apply is taken up through the tree and transpired for photosynthesis to occur.

CAT: Does transpiration increase on a hot day?

Fulton: Yes, plus the plant looses a bit from surface evaporation from the wet soil, but we try to control that with smaller wetting patterns and drip-confined wetting patterns.

When you think about it, the heat of the day occurs in the afternoon, and many systems don’t run because of energy costs. There are incentives not to pump in the middle of the afternoon; but for those who do, try to confine the wetted area to limit evaporation. The hot hours of a day comprise about 4 hours of a 24-hour cycle, so a lot of irrigation occurs at night-time or in the early morning hours to lesson evaporative loss.

CAT: Growers are doing everything they can to conserve water. If the trees and vines are all transpiring most of the applied water, what is the problem with using water to grow food?

Fulton: I think the concept throughout the United States has always been to secure our food supply. That security has many benefits—economically and politically. In the end, we are trying to provide the general public with great quality, safe food, at the best price possible.

CAT: And nutritious food. We are growing the food people need more of.

Patrick Cavanaugh2016-05-31T19:28:11-07:00July 10th, 2015|

UC Cooperative Extension Farm Advisor in Ventura County

By Laurie Greene, Editor California Ag Today

Ben Faber, UC Cooperative Extension Farm Advisor in Ventura County, works with growers who farm a variety of different crops including blueberries, raspberries, blackberries and strawberries as well as lemons and avocados.

Faber is developing new approaches for better avocado pruning to increase yield. “We have not done a lot of pruning on avocados in the past,” Faber said, “because this plant species responds to pruning in a very rapid fashion with a lot of shoots and water sprouts, so people have been scared to prune avocados. Over time, we have learned how to prune avocados somewhat differently than other tree crops.”

Faber said the two pruning choices are a heading cut and a thinning cut. “A heading cut,” he explained, “is often what you see peach growers doing, indiscriminately cutting into a branch. Well, they are actually doing is selecting the branches that will be the fruiting branches for the next year. Whereas, if you do that in avocados, you just get a lot of wild regrowth.”

So Faber believes the strategy in avocados has to be a thinning cut, “where you prune back to a sub-tending branch or a crotch so the remaining branch continues growth. This method controls growth lower down in the branch. It has taken a long time to discover this, though it seems simple now.”

He added, “Thinning cuts are all about keeping the tree from ‘crowning out,’ which reduces yield. As neighboring trees start shading each other, the flowering and fruiting spreads to the very top of the tree. This is where you see significant yield reduction because instead of having fruit form all over the tree’s canopy, fruit and flower production forms only on the very top of the canopy.” Faber said.

“Keeping the avocado fruit lower in the tree is better for harvesters to grab,” Faber commented. “So, growing fruit high in the tree presents not only yield loss, but a worker safety issue as well.”

California Ag Today2016-05-31T19:28:11-07:00July 9th, 2015|