Posts Tagged: drought
This week much of California is under a heat advisory or excessive heat warning, with high temperatures estimated to range from 90 to 108 degrees. Many home gardeners are wondering how they can help their plants, trees or shrubs survive the intense summer heat.
“We are getting a lot of inquiries around the state from people worried about how the extreme temperatures are going to affect the plants or trees in their yards,” said Missy Gable, director of the UC Master Gardener Program. “With a little extra planning, you can help your garden beat the heat and survive the hot summer weather.”
UC Master Gardener volunteers are available to help answer gardening questions and provide advice on gardening during the hot summer months. Here are four quick and easy ways to help make sure your plants and trees not only survive, but thrive.
- Don't fertilize plants or trees during hot summer months
Fertilizers aim to increase the growth of plants and trees. When a fertilizer is applied, especially one that is high in nitrogen, a plant is triggered to produce more green growth. An increase in growth means an increase in water and nutrient needs. During hot spells, it is especially hard to keep up with plant water and nutrient needs as soils dry out quickly and water may not be readily available. Save your plants (and yourself!) from stress by stopping fertilizer application before hot weather hits.
- Water trees deeply and less frequently
It sounds counter intuitive to water trees less frequently, but this is exactly what UC environmental horticulture experts recommend. “When watering trees you want to consider the roots below the tree and you want to encourage a network of deep roots. If you are only watering for short periods at a higher frequency, the roots will remain shallow since that is where the tree finds its water supply,” said Janet Hartin, UC ANR environmental horticulture advisor. “Deep roots mean a healthier tree that is less susceptible to disease.”
How much water a plant needs depends on the specific plant, how long it has been in the ground, and the type of soil where it is planted. In general, young plants or newly planted plants require more water than older more established plants. Clay soils absorb water slowly so watering can take longer but is typically done less frequently. This is in contrast to sandy soils that moisten and drain quickly. Typically, watering sandy soils take less time but has to be done more frequently. A Landscape Irrigation Scheduling Worksheet from the California Center for Urban Horticulture (CCUH) can be used to help calculate and determine an annual irrigation schedule for one irrigation zone.
- Mulch, mulch, and more mulch
When temperatures get extreme, having a good layer of mulch prevents soil from heating up excessively and loosing water to evaporation. Apply 4 inches of a medium shred bark mulch to insulate the soil. This protects the fine roots that plants use to feed from the surrounding soil. Mulch also helps maintain healthy soil ecology with earthworms and other de-composers that promote nutrients and oxygen in soil. Finally, mulch will pay for itself by maintaining a more consistent soil moisture so you can water less and have better success with your plants. Be sure to maintain the depth of your mulch to ensure you can benefit from all the services it provides.
An important part of gardening is planning for activities in the garden for future months. When the temperatures are too hot to spend outdoors, you can always start to develop a garden or planting plan. (Photo: Melissa Womack)
- Wait to introduce new plants or trees until the fall
In gardening, timing is everything. New plants, whether grown in ground from seed or planted in your landscape from a container, have smaller root systems than more mature plants or plants that have been growing in your landscape for some time. Because root systems on new plants are smaller and need time to develop, these plants require more water more frequently. New plants introduced into a landscape during hot summer months have a significantly higher rate of failure. In California, it is best to introduce new plants in fall when the weather gets cooler. Winter rains can help keep new plants watered so they can establish and thrive in the future when temperatures are high and rainfall is scarce.
Always remember that you should take precautions for yourself while gardening in the summer months, especially during a heat wave. Remember to drink plenty of water and always have at least one quart of water per hour of outdoor activity. Limit time spent outdoors during peak temperatures and schedule any active time during cooler portions of the day. Always wear light loose clothing, a brimmed hat, and sunscreen as protection.
Thankfully we're not trying to garden on the surface of the sun. Unfortunately, sometimes it can feel like it for us and for our plants. Stay cool with these tips and consider planning for the fall to be an important part of your summer gardening activity.
As sorghum plants cope with drought conditions, the plants' roots and adjoining microbial communities are communicating in a chemical language that appears to improve the plants' chances under water stress.
“It's amazing,” said Peggy Lemaux, UC Cooperative Extension specialist. “We know there are lots of microbes in the soil and, for the most part, ones in the surrounding soil stayed the same under drought conditions. We only saw changes in those microbes closely associated with the roots.”
The role of drought in restructuring the root microbiome was the first published discovery to come out of a sweeping drought research project underway since 2015 in the fields at UC Kearney Research and Extension Center in Parlier. The five-year study, funded with a $12.3 million grant from the Department of Energy, aims to tease out the genetics of drought tolerance in sorghum and its associated microbes. Using sorghum as a model, scientists hope the research will help them understand and improve drought tolerance in other crops as well.
The new research results from the lab of USDA's Devin Coleman-Derr at UC Berkeley, published April 16, 2018, in the Proceedings of the National Academy of Sciences, document the fate of microbes associated with sorghum roots under three distinct irrigation regimens. Because the San Joaquin Valley generally sees no rain during the growing season, it is the ideal place to mimic drought conditions by withholding irrigation water.
All plots received a pre-plant irrigation to initiate growth. In the control plots, sorghum was irrigated normally, with weekly watering through the season. In the plot simulating pre-flowering drought stress, the plants received no additional water until flowering, about halfway through the season. The third treatment was watered normally until it flowered, and then water was cut off for the rest of the season.
Beginning when the plants emerged, the scientists collected samples from each plot on the same day and time each week for 17 weeks. In a mini, in-field laboratory, roots, rhizosphere (zone surrounding the root), leaves and soil samples from 10 plants in each plot were immediately frozen and transported to Berkeley, where they were disseminated to collaborators, who investigated the plant and microbial responses at the molecular level.
“When a sorghum plant is subjected to drought, it starts sloughing off metabolites, nutrients and amino acids from the roots. The compounds appear to communicate to the neighboring microbial community that the plant is under stress,” Lemaux said. “That selects out a certain population of microbes. Certain types of microbes increase, others go away. When you add water back, the microbial community returns to its pre-drought population in just a few days.”
The researchers cultured two specific microbes that were enriched in the rootzone under drought conditions. They coated sorghum seeds with the microbes and planted them under drought conditions in a growth chamber. This treatment encouraged the plant to grow more roots.
“The microbes appear to improve plant growth during drought,” Lemaux said. “Those microbes appear to be helping plants survive drought. We didn't know that was happening before we got these results.”
Lemaux said the research might lead to future field use of the research breakthrough.
“A lot of companies are interested in the microbiome,” she said. “Some are already selling microbes to coat seeds.”
“Sometimes we don't see the farmers that often. They are busy on the farm,” Yang said. “But when they hear something (important) like this on the radio, they show up.”
UC Cooperative Extension office staff - including UCCE advisor Ruth Dahlquist-Willard, Yang, part time staffer Xia Chang, Fresno State student volunteer Sunny Yang, and research assistant Janet Robles from Fresno State's Center for Irrigation Technology – are working with small-scale and socially disadvantaged farmers one-on-one to line up the necessary paperwork and information to submit successful grant applications. (Read more about UC staffer Xia Chang, millennial Hmong farmer.)
“We helped eight farmers submit applications in the last two rounds, and seven received grants,” Yang said. “The money is significant.”
The grants allowed the farmers to make improvements in energy efficiency and water savings, Dahlquist-Willard said.
“This can make a huge difference for the profitability of a small farm,” she said.
The application requires energy bills from the previous growing season, a pump test and a plan for redesigning the irrigation system to result in reduced water use and reduced greenhouse gas emissions.
“There are a lot of calculations to do,” Yang said. “It's very complicated, and no one is available to help underserved farmers.”
While assisting farmers with applications for other programs is not usually part of UCCE's extension efforts, the small farms program in Fresno County has identified this form of assistance as crucial to the success of small-scale and minority-operated farms.
Help with the State Water Efficiency and Enhancement Program (SWEEP) grants is one in a series of outreach efforts for Hmong farmers spearheaded by Dahlquist-Willard since she was hired in 2014 to work with small-scale farmers in Fresno and Tulare counties. After just two weeks on the job, she was invited to an emergency meeting with the National Hmong American Farmers and USDA's Farm Service Agency to address the challenges faced by Hmong farmers as groundwater levels continued to drop during the drought.
“Wells were starting to dry up. Some Hmong farmers were reportedly calling suicide hotlines,” Dahlquist-Willard said. “We knew we had to take action.”
Dahlquist-Willard and her staff began researching programs that could offer the farmers financial assistance. They identified a free PG&E rate analysis, which could help the farmers choose the best electric rate for their irrigation practices to minimize charges. They searched for financing to deepen wells for farmers who had difficulty qualifying for existing USDA loans. And in 2015, they began helping farmers with applications for the State Water Efficiency and Enhancement Program.
The dire circumstances also prompted Dahlquist-Willard to commission a survey of Hmong farmers to see how they were impacted by the drought. Documenting their plight would be useful in seeking support. The survey was conducted in conjunction with outreach efforts with Fresno Regional Workforce Investment Board and Jennifer Sowerwine, UCCE Cooperative Extension specialist in the Department of Environmental Science, Policy and Management at UC Berkeley. The survey was funded with a grant from the USDA Office of Advocacy and Outreach and with support from UC Agriculture and Natural Resources via Sowerwine.
Sixty-eight farmers were interviewed by phone or in-person. Twenty-two percent said their wells had dried up, and 51 percent reported a decreased water flow.
“For the ones with dry wells, it could be $20,000 to $50,000 to drill a new well,” Dahlquist-Willard said. “A lot of them cannot get access to loans.”
To deal with irrigation water limitations, some farmers told interviewers they reduced acreage or changed the time of day they irrigate. Some stopped farming all together.
“One farmer told us he was irrigating his crops with his domestic well,” Dahlquist-Willard said.
Energy efficiency programs turned out to be very important for this population of farmers. Eighty-seven percent said their utility bills increased during the drought. As a result, UCCE has been promoting PG&E programs for energy efficiency as well as the SWEEP program.
The survey also showed the power of radio in reaching the Hmong farming community. Eighty percent of the survey respondents said they were regular listeners to Michael Yang's Central Valley Hmong Agriculture radio show.
Xia Chang: Millennial Hmong farmer
Chang attended college, but his financial aid was depleted before he earned a degree. In addition to part time work with UCCE, Chang is now farming.
“Last year we expanded our farm from 4 acres to 14 acres, with a new three-year lease,” Chang said.
The family's many technical agricultural questions led to Chang's frequent visits to the Cooperative Extension office, and ultimately to his being hired to help conduct the Hmong farmer survey.
“I spend a lot of time speaking Hmong on this job,” Chang said. “I've had to learn a lot of new vocabulary.”
He said he's also learning a lot about new farming techniques that he wants to apply on the family farm. However, there are obstacles.
“My dad is not open to new ways because he is afraid it would not be as successful,” Chang said. “But, in everything you do, you learn.”
Chang is now looking into a career in plant sciences. He is working with Dahlquist-Willard and Kent Daane, UC Cooperative Extension biological control specialist based at the UC Kearney Agricultural Research and Extension Center in Parlier, testing integrated pest management techniques in Southeast Asian vegetable crop production. In time, Chang plans to return to Fresno State to complete a degree in agriculture.
Presenters will explore research, farmers' practices, and commercial products that aim to make California agriculture more resilient in the face of drought, weather extremes, and uncertain water allocations. Presentations from researchers in the morning will be followed by lunch and a panel discussion with area growers.
The field day is free for farmers, $5 for students, and $10 for the general public.
Russell Ranch is a unique 300-acre facility dedicated to investigating irrigated and dry-land agriculture in a Mediterranean climate. The ranch is run like a commercial farm and features a variety of research activities by UC faculty and UC Agriculture and Natural Resources researchers, with the aim of informing California agricultural practices. Russell Ranch is home to the flagship 100-year Century Experiment, an ongoing mega-experiment focusing on sustainable agricultural practices in California.
Since 1994, Russell Ranch has hosted an annual field day to share research findings related to pressing topics in California agriculture. This year's event will focus on a common challenge of farm fields across California: how to ensure healthy crops when the availability of key resources is uncertain.
The field day includes tours of Russell Ranch, in-field presentations, panel discussions with growers, and a poster session to learn about the variety of research and outreach on the topic of water management and scarcity.
The schedule of events is as follows:
8:30 – 11:30 a.m. Presentations from researchers
11:45 a.m. – 12:15 p.m. Lunch; view research posters and exhibitions from vendors of commercial irrigation products
12:30 – 1:15 p.m. Farmer panel discussion: Water Management on Farm: Challenges and Opportunities
The field day features presentations from:
Olivier Jerphagnon, PowWow Energy, Inc.
Stan Knutson, PowWow Energy, Inc.
Teresa Carillo-Cobo, Agricultural Sustainability Institute post-doctoral scholar
Amelie Gaudin, Assistant professor, Dept. of Plant Sciences at UC Davis
Martin Burger, Associate Project Scientist, Dept. of Land, Air, and Water Resources at UC Davis
Mark Lundy, Assistant Cooperative Extension Specialist, Dept. of Plant Sciences at UC Davis
Dan Putnam, Cooperative Extension Specialist, Dept. of Plant Sciences at UC Davis
Daniele Zaccaria, Assistant Cooperative Extension Specialist, Dept. of Land, Air, and Water Resources at UC Davis
Tim Hartz, Cooperative Extension Specialist/Agronomist, Dept. of Plant Sciences at UC Davis
Toby O'Geen, Cooperative Extension Soil Resources Specialist, Dept. of Land, Air, and Water Resources at UC Davis
Graham Fogg, Professor of Hydrogeology, Dept. of Land, Air, and Water Resources at UC Davis
Darren Drewry, Research Scientist, Climate Physics Group, NASA Jet Propulsion Laboratory
Russell Ranch's Annual Field Day
Farm Water Management in Times of Scarcity
June 8, 2016, 8 a.m. to 1:30 p.m.
Register at: https://registration.ucdavis.edu/Item/Details/246
recently received a $1.69 million grant to use several UC agricultural research stations to study an often overlooked tool to fight the drought: soil.
The team, led by Samantha Ying, an assistant professor of environmental sciences at UC Riverside, received the grant from the University of California Office of the President.
The funding will allow for the establishment of the University of California Consortium for Drought and Carbon Management (UC DroCaM), which will design management strategies based on understanding soil carbon, the soil microbiome and their impact on water dynamics in soil.
The researchers will conduct field and lab research on microbiological, biophysical, and geochemical mechanisms controlling soil formation and stability under different row crops (tomatoes, alfalfa, wheat), farming practices (carbon inputs and rotations) and irrigation methods (furrow and flood, microirrigation).
Field research will initially be conducted at three UC Research and Extension Centers (Kearney, West Side and Desert) the Russell Ranch Sustainable Agriculture Facility near UC Davis.
Recommendations will then be made for broader monitoring and field experiments throughout the state based on input gained from local growers and citizens at workshops at the agricultural research stations. Ultimately, the hope is to expand and involve all nine research and extension centers from the Oregon border to the Mexican border.
“Having agricultural research stations throughout the state is a huge part of this project,” Ying said. “It is going to help us create one of the best research centers in the country focused on soil and drought.”
There is also a public engagement component. Citizens will be recruited to participate in workshops to learn how to monitor and sample their local soils. Information will then be imputed into an online soils database that will help create a map of the biodiversity of agricultural soils in California.
Ying's collaborators are: Kate Scow and Sanjai Parihk (UC Davis); Eoin Brodie and Margaret Torn (UC Berkeley); Asmeret Berhe and Teamrat Ghezzehei (UC Merced); and Peter Nico and William Riley (Lawrence Berkeley National Laboratory).
The grant is one of four awards totaling more than $4.8 million from University of California President Janet Napolitano's President's Research Catalyst Awards.