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Water risks to agriculture: Too little and too much

"To make agriculture resilient to climate risks, we need to engage in holistic solutions that integrates environmental, social, economic and policy considerations," said Tapan Pathak, left, shown adjusting moisture sensors in a strawberry field.

Water is among the most precious resources on the planet. Some areas don't get enough; some get too much. And climate change is driving both of those circumstances to ever-growing extremes.

Two UC Merced experts in civil and environmental engineering took part in a recent report by the Environmental Defense Fund examining the issue and potential solutions. Associate Professor of Extension Tapan Pathak and Professor Josué Medellín-Azuara co-authored the report, "Scarcity and Excess: Tackling Water-Related Risks to Agriculture in the United States," and wrote the section pertaining to California.

In addition to climate change, disruptive human interventions such as groundwater over-extraction, sprawling drainage networks and misaligned governance are driving up water-related agricultural costs, particularly in midwestern and western states, the researchers found.

The problem is magnified in California, which hosts the largest and the most diverse agricultural landscape in the U.S., Pathak and Medellín-Azuara wrote, with gross revenues from farms and ranches exceeding $50 billion.

"Due to the favorable Mediterranean climate, unique regional microclimate zones, a highly engineered and developed water supply system, and a close connection between producers and research and cooperative extension institutions, California's agricultural abundance includes more than 400 commodities, some of which are produced nowhere else in the nation," the UC Merced researchers wrote.

Policies and funding are needed to support farmers’ efforts to adapt to drought and flood risks, write the report authors.

But the state's varying climate and water needs pose a challenge. Though most of the precipitation falls in the northern part of California, the southern two-thirds of the state account for 85% of its water demand. And all of those crops must be watered in the summer, when there is little, if any, rainfall.

Some of the water comes from snowpack developed through winter storms and stored in reservoirs as it melts. Much of it comes from the Colorado River.

"Substantially less water is captured and stored during periods of drought, imperiling California's water supply and putting agricultural water needs at risk," Pathak and Medellín-Azuara wrote.

Climate change, with increasing periods of drought between excessively wet winters, magnifies that risk.

"Further, the rate of increases in the minimum temperatures in the Sierra Nevada is almost three-fold faster than maximum temperatures, resulting in potential decrease in the snowpack, earlier snowmelt, and more water in liquid form as opposed to snow," the researchers wrote. "According to the California Department of Water Resources, by 2100, the Sierra Nevada snowpack is projected to experience a 48% to 65% decline from the historical average."

Climate change is also expected to affect the availability of water from the Colorado River.

Climate extremes such as heat waves, drought and flooding - giving rises to increased weeds, pests and disease - are already significantly impacting agriculture and the broader economy, Pathak and Medellín-Azuara wrote.

The state's drought from 2012 to 2016 led to about 540,000 acres of fallow farmland in 2015, costing the state's economy $2.7 billion in gross revenue and 21,000 jobs. With the lack of precipitation, farmers increasingly pumped groundwater to irrigate crops, depleting those resources.

The report goes on to recommend policies, programs and tools be developed for agricultural resilience, including:

  • Changing land use and crop management practices to support a transition to an agriculture footprint that can be sustained by the available water supplies.
  • Increasing farmer and water manager access to important data and innovative technological tools to support their efforts.
  • Reimagining built infrastructure and better using natural infrastructure so regions are better equipped to handle weather extremes.
  • Developing policy and funding mechanisms to support mitigation and adaptation to water-related risks, avoid maladaptation and ensure food and water security.

"California's innovative agriculture needs to rapidly adapt to more volatile water availability, climate-driven higher water demands, and regulation protecting groundwater reserves, communities and ecosystems," Medellín-Azuara said. "The early adoption of more sustainable practices in agriculture will likely pay off dividends both in the short and long terms."

Added Pathak, "California faces significant challenges related to climate change, but it also presents opportunities for innovations, collaborations and sustained growth. To make agriculture resilient to climate risks, we need to engage in holistic solutions that integrates environmental, social, economic and policy considerations."

 

Posted on Monday, March 18, 2024 at 11:44 AM
  • Author: Patty Guerra, UC Merced
Focus Area Tags: Agriculture, Natural Resources

Fighting fire with feeding

Researchers, including UC Davis and UC ANR scientists, calculated the greenhouse gas emissions of cows consuming vegetation that would otherwise burn in wildfires. Photo by Elena Zhukova

Are cattle a secret weapon for taking on California wildfires?

California's cattle ranchers contribute a significant amount to the region's culture, economy and food supply, but do they also inadvertently help to temper the wildfires that have been plaguing the state? And if so, is it a better alternative – environmentally speaking – to letting grasslands burn?

A new study published in the journal Sustainability delves into the topic, weighing the advantages – and disadvantages – grazing cattle bring to the table. Researchers, including scientists from University of California, Davis and UC Agriculture and Natural Resources, set out to calculate the greenhouse gas emissions of cows consuming vegetation that would otherwise burn in wildfires. Then they estimated the GHG emissions that would result should that forage be untouched and therefore, consumed by fire, eventually comparing the two.

Feeling the burn

Given the severity of California's recent wildfires and the belief they will continue and even escalate in the near future, it's a discussion worth having, said Frank Mitloehner, an expert in animal agriculture and air quality from UC Davis, director of the CLEAR Center and one of the researchers who contributed to the peer-reviewed article.

“Each year from 2010 to 2020, California lost on average 89,000 acres of grassland to wildfires,” said Mitloehner, who is also a Cooperative Extension specialist. “In addition to the obvious disruption and devastation they caused, the fires spewed greenhouse gases and harmful particulate matter such as black carbon into the air and into our atmosphere. Those alone threaten climate health and human well-being.”

A fast and furious gas

Cattle are adept at eliminating herbaceous fuel as they graze. However, at the same time, their specialized digestive system produces methane that is expelled most often in the form of enteric emissions … more commonly known as belches. By way of background, methane is a potent greenhouse gas that warms the atmosphere at 25 times the rate of carbon dioxide over 100 years. But it's only in the atmosphere for 10 to 12 years after it's emitted. Following that, it's broken down into carbon dioxide and water vapor.

For that reason, Mitloehner refers to methane as a “fast and furious” gas. Furious because it warms with a vengeance and fast because it does so for only a short time, especially when compared to carbon dioxide. Furthermore, because of the biogenic carbon cycle, whereby plants extract carbon dioxide from the atmosphere for photosynthesis, the warming of methane and its byproducts can end entirely when it's hydrolyzed and used by plants.

How researchers calculated emissions

In order to determine if grazing, methane-emitting cattle are better for the atmosphere than burning grasslands, Mitloehner and the other researchers employed a method known as “Monte Carlo simulation,” a mathematical technique used by scientists to predict outcomes of an uncertain event.

Looking exclusively at methane emissions, they found it's better to have cows eat vegetation than to have wildfires burn it. Granted, it's only marginally better, but when one considers other advantages of animal agriculture and conversely, other disadvantages of widespread, uncontrolled fire, the conversation suddenly shifts.

“Even if cattle provided no other benefit to us, which certainly is not true, we can now make the case that they are helpful to us in yet another way,” Mitloehner said.

Friends or foes?

It goes without saying that one would be hard pressed to find much good to say about wildfires, but that doesn't hold true for animal agriculture. The industry provides jobs and supports the economy in other ways as well. Plus, it is a major source of protein-rich food that is in increasing demand as the world's population continues on a trajectory toward 10 billion people by the year 2050.

Where global warming is concerned, the industry is in the unique position of being able to reach net-zero warming, also known as climate neutrality, if it continues to aggressively chip away at its methane emissions, which Mitloehner asserts is of critical importance to the planet. “Few other sectors can reduce its warming to net zero and still be of service to society, but agriculture can because of the way methane behaves in the atmosphere,” he says.

To be clear, grazing cows are no match for wildfires. Yet, in addition to everything else the sector does for us, slowing the burn and keeping relatively more methane from entering the atmosphere are not nothing.

In addition to Mitloehner, authors of the study are Cooperative Extension advisors Sheila Barry, Devii Rao and Theresa Becchetti; Rowan Peterson, Ermias Kebreab and Minju Jung of UC Davis; and Felix Ratcliff and Kaveh Motamed of LD Ford. 

This article was first published on the website of the CLEAR (Clarity and Leadership for Environmental Awareness and Research) Center at UC Davis.

Posted on Monday, January 22, 2024 at 10:07 AM
  • Author: Mary Burich, CLEAR Center
Tags: cattle (22), cattle grazing (1), CLEAR (1), climate (14), Devii Rao (7), Frank Mitloehner (16), GHG (1), grassland (1), Greenhouse gas (10), livestock (15), methane (4), Sheila Barry (7), Theresa Becchetti (6), wildfire (179)
Focus Area Tags: Agriculture, Environment

Climate change to drive surge in insects that attack almonds, peaches, walnuts

Oriental fruit moth is a major pest that damages peaches. Photo by Jack Kelly Clark

UC study predicts three major pests to emerge earlier, produce more generations

As a result of climate change, the Golden State's farms are expected to face a surge in agricultural pests, which poses a threat to California's specialty crops industry. Populations of three major insect pests – codling moth, peach twig borer and oriental fruit moth — are projected to increase mainly due to rising temperatures, according to a study recently published in the journal “Science of the Total Environment” by a team of researchers at University of California Agriculture and Natural Resources and the U.S. Department of Agriculture California Climate Hub.

“These three pests are notorious for infesting most of the walnut, almond and peach orchards of California, causing extensive damages by reducing quality of fruits and nuts,” said study co-author Jhalendra Rijal, UC Cooperative Extension integrated pest management advisor and entomologist for Stanislaus, San Joaquin and Merced counties.

Climate change can lead to shifts in the timing of seasons, including warmer winters, earlier springs and hotter summers, and these conditions can disrupt the natural life cycles of pests.

 The California research is supported in part by USDA's National Institute of Food and Agriculture. NIFA National Program Leader Amy Ganguli said the California project is a strong example of the  work being done through AFRI's Extension, Education & USDA Climate Hubs Partnership.

 “A key element of this grant program to link critical research findings like this with timely education and outreach efforts to producers and the public to encourage nimble responses to the challenges climate change pose,” Ganguli said.

The new research, led by Prakash Jha, UC Agriculture and Natural Resources assistant project scientist based at UC Merced, compared pest populations in recent and future climates. The scientists used temperature projections from the latest generations of scientific models to predict the potential impact of climate change on codling moth (Cydia pomonella), peach twig borer (Anarsia lineatella) and oriental fruit moth (Grapholita molesta). Before using the model, the model predictions were verified using field data of these insect pests from various parts of the Central Valley.

The peach twig borer damages peaches. Photo by Jack Kelly Clark

The UC study revealed that due to increases in temperature, these insects are expected to appear up to 28 days earlier in the spring and the time between generations is expected to shorten by up to 19 days. The changes may be gradual, but the study predicts that we may see up to a half-generation of these pests added within the next 20 to 30 years.

The increase in these pest populations poses a serious threat for future pest management, which would subsequently affect the state's economy and employment related to specialty crops, warns Rijal.

“Codling moth is the primary pest of California's walnuts, which occupies over 365,000 acres,” Rijal said. “Similarly, peach twig borer and oriental fruit moth are two major economic pests of peaches. Growers must control almost every generation of these pests to protect the fruit.

“Additional generations of these pests within the same growing season will likely increase crop damage. It certainly increases the number of sprays needed to control these pests, increasing the production cost for growers. Plus, more use of insecticides has consequences for beneficial insects and the environment.”

Codling moth larvae inside a walnut. Photo by Jack Kelly Clark

Growers may need to adapt their pest management strategies to address the impact of climate change on these pests. 

For years, the UC Integrated Pest Management guidelines have suggested putting oriental fruit moth traps out in peach orchards by Feb. 15 in the San Joaquin Valley and Feb. 20 in the Sacramento Valley.

“In the last seven years, likely due to warmer winter, as suggested in this study, we observed the beginning of the moth's activity in traps (also called biofix) as early as Feb. 14,” Rijal said, “meaning that the trap placement date must move earlier to capture the first moth activity. We are revising the guidelines to change the trap placement date to Feb. 7 for the entire Central Valley.”

Developing a holistic climate-smart pest management strategy will build resilience, Jha said. This approach combines pest control with prevention and reduction, such as planting pest-resistant crop varieties, sanitizing the orchards during the winter, harvesting early to avoid later pest generation infestation, using biological control such as natural enemies, and deploying mating disruption techniques.

“More importantly, adoption of pest forecasting – including the long-term prediction and short-term potential outbreak, pest-scouting and early detection – will be essential to combat the growing threat posed by these pests,” Jha said. 

Research will be crucial to provide growers support and guidance about the latest developments in pest management and how to adapt their practices.  

“Climate change impacts on pests and resulting impacts on agricultural production are significant but not often researched or quantified,” said Tapan Pathak, UC Cooperative Extension specialist in climate adaptation in agriculture based at UC Merced.

“Information from this research will not only help farmers to understand impacts for strategic planning, but also will inform the agricultural industry to invest in making varieties more resilient to these damaging agricultural pests,” Pathak added. “We will use this information to update the CalAgroClimate tool, which informs farmers on the progress of these pests during the season so that they can take steps for effective pest management.”

Ganguli added the partnership between the University of California and the California Climate Hub embodies the goal of this funding program.

“The incorporation of this research into the existing CalAgroClimate decision support tool accelerates the ability of this information to be publicly used in the development of appropriate pest management or adaptation strategies,” she said.

In addition to Jha, Rijal and Pathak, the study was co-authored by Ning Zhang, Lauren E. Parker and Steven Ostoja of UC Davis Institute of the Environment and U.S. Department of Agriculture California Climate Hub.

The article “Climate change impacts on insect pests for high value specialty crops in California” can be accessed for free online at https://doi.org/10.1016/j.scitotenv.2023.167605.  

Dec. 8, 2023: This story was updated to add comments by NIFA National Program Leader Amy Ganguli.

 

 

 

Posted on Wednesday, October 25, 2023 at 11:23 AM
Tags: almonds (0), climate chance (0), peaches (0), pest management (0), walnuts (0)
Focus Area Tags: Agriculture

Farmers save money, water by adopting climate-smart agriculture practices

With the help of a Climate Smart Agriculture community education specialist, vegetable grower Rosie Lee was able to get a grant and install solar panels to power her irrigation system. Photos by Caddie Bergren

CDFA, UC ANR help farmers access $36 million in grants to improve water-use efficiency, reduce greenhouse gas emissions 

A Hmong small-scale farmer in Merced County has saved about 14.4 acre-inches of water annually and reduced greenhouse gas emissions by 12.406 MTCO2e per year (equivalent to the greenhouse gas emissions produced from burning 1,396 gallons of gasoline) after upgrading her farm. Rosie Lee – who sells Asian greens, green beans, corn, strawberries and other produce at her farm stand and to Asian markets – is one of hundreds of growers benefiting from California Department of Food and Agriculture incentives and funds with the assistance of Climate Smart Agriculture community education specialists.

“She is one grower who would not have access to those funds without my bringing my computer out to the field,” said Caddie Bergren, a Climate Smart Agriculture community education specialist who has been working with growers in Merced County since theprogram's launch.

Drip irrigation has saved Lee about 14.4 acre-inches of water annually.
To make it easier for farmers to adopt new practices, CDFA and UC Agriculture and Natural Resources partnered to create the Climate Smart Agriculture program.

"Since 2019, UC ANR's Climate Smart Agriculture Team has provided in-depth technical assistance to more than 1,300 farmers and ranchers in 25 counties,” said Hope Zabronsky, academic coordinator for UC ANR's Climate Smart Agriculture team. “Through their strong relationships with diverse farming communities, they support the implementation of soil health, water efficiency and manure management practices that optimize climate benefits for all growers and Californians.”

The program's community educators work with farmers and ranchers in 25 California counties to get CDFA-funded grants and implement Climate Smart Agriculture projects. These efforts, which emphasize outreach to underserved farmers and ranchers, have resulted in a total of $36.5 million invested from the State Water Efficiency and Enhancement Program or SWEEP, the Healthy Soils Program, and the Alternative Manure Management Program.

“Agriculture is an important part of the climate solution,” said CDFA Secretary Karen Ross. “This funding enables CDFA and UC ANR to partner with farmers and ranchers to scale up climate-smart agricultural practices. This is essential as we contend with our hotter, drier future.”

Lee, the Hmong grower, had been growing 18 acres of vegetables by flood irrigating with groundwater. To save water and reduce pumping costs, she asked Bergren to help her apply for SWEEP funds to convert to drip irrigation and install solar panels. Bergren brought her laptop to the field to help Lee pull together the necessary information for the application. After Lee received funds for the project, Bergren assisted her with the technical logistics of installing the irrigation and solar equipment.

“I called vendors and we were able to complete the project on time,” Bergren said.

Through the Climate Smart Agriculture program, Lee, shown holding a soil moisture sensor, received help to apply for grants and complete the energy and water-saving project.

CDFA and UC ANR have published an impact report highlighting the results of the multi-year partnership focused on increasing adoption of climate-smart agriculture practices to reduce water and energy use. 

The investments have funded more than 420 projects, so far. The projects are expected to save an estimated 8.3 billion gallons of water during their lifetime, enough to supply over 75,000 typical homes in California with water for a year. Additionally, there are projected reductions of more than 355,000 metric tons of carbon dioxide-equivalent, as much as would be achieved by removing 79,110 gas-powered vehicles from roads. 

The report highlights the importance of providing tailored outreach, education and technical assistance to small-scale, non-English speaking, and otherwise underserved farmers and ranchers.

To find the full details of the report, please visit https://ucanr.edu/climatesmartag2023.

[Updated Sept. 29 to show UC ANR's Climate Smart Agriculture Team has provided technical assistance to farmers and ranchers in 25 counties, not 24 counties.]

Posted on Wednesday, September 13, 2023 at 3:15 PM
  • Author: Pamela Kan-Rice
  • Author: Josh Staab, California Department of Food and Agriculture
Focus Area Tags: Agriculture

UC awards Brodt $2M to advance soil health, climate-smart farming practices

Orchard growers learn about cover crops at an almond orchard in Colusa County. Photo by Evett Kilmartin

Regional farms will demonstrate practices such as cover cropping, reduced tillage, compost and mulch use, hedgerow planting, optimized irrigation systems

To accelerate adoption of climate-smart farming practices, the University of California Office of the President has awarded nearly $2 million to a team of UC Cooperative Extension scientists and community partners working on a network of farm demonstration sites. The project will be led by Sonja Brodt, coordinator for agriculture and environment at the UC Sustainable Agriculture Research & Education Program. This UC Agriculture and Natural Resources project is one of 38 funded with $83.1 million allocated to UC by the State of California for climate action research and innovation.

Scaling up soil health and other climate-smart agricultural practices to sequester carbon, increase water and nutrient use efficiency, and improve the resilience of farms to climate-related threats like drought and floods is a core pillar identified in California's Natural and Working Lands Climate Smart Strategy

Sonja Brodt
Climate-smart agriculture is a systems-based approach that requires localized adaptation across the diverse soils, cropping systems, socioeconomic and cultural contexts throughout California.

“Our project will strengthen the nascent California Farm Demonstration Network for on-the-ground, regionally specific demonstration of a range of climate-smart practices,” said Brodt. “Regional farms will demonstrate practices such as cover cropping, reduced tillage, compost and mulch use, hedgerow planting, irrigation system optimization and more.”

The $1,999,524 project will pilot a participatory partnership extension model that allows farmers to learn from their peers to reduce adoption risks and adapt knowledge to an ever-changing environment, increasing the likelihood of farmer success and accelerating long-term uptake of complex, place-specific practices. 

Building on the capacity of local trusted organizations, project collaborators will be organized in a hub-and-spoke network with three regional Farm Demonstration Hubs (Sacramento Valley, North Coast and Central Coast), a pilot Hmong/Mien Demonstration Hub, and a statewide Organic Demonstration Hub.

Collaborators at each hub will be responsible for identifying and nurturing farm demonstration sites, and conducting demonstration trials and farmer-to-farmer outreach activities. Centralized organization and capacity building will be provided by UC SAREP, UC Organic Agriculture Institute, the California Association of Resource Conservation Districts, the Community Alliance with Family Farmers, and the California Farm Demonstration Network Advisory Panel.

In addition to several UC Cooperative Extension advisors and specialists across the state, partners include the UC Hansen Research and Extension Center and the Rodale Institute California Organic Center, both in Ventura County, and the UC Climate Smart Agriculture Program. Eight Resource Conservation Districts will also be involved in leading Farm Demonstration Hubs.

Hope Zabronsky of the UC Climate Smart Agriculture Program shows the importance of soil structure at a cover cropping workshop.

The project will also conduct soil health assessment activities to inform soil health and resilience monitoring protocols in future research and extension efforts. Since many existing soil health metrics were designed for agroecosystems in the Midwest and Eastern U.S., this project aims to lay the groundwork for research to adapt soil health metrics to the arid and Mediterranean climates of California.  

“By utilizing relationships built between demonstration hub managers and demonstration farms across different cropping systems, we will gather quantitative and qualitative soil health data, information about growers' management practices as well as their own perspectives of what they really need to know about their soils in order to better manage for climate resilience and mitigation,” said Brodt.

Ultimately, the project partners aim to establish an enduring on-farm extension and research system that will help thousands of farmers adopt climate-smart practices tailored to their farms.

Other grant-supported projects focus on water access, conservation

The largest of the Climate Action Matching Grants, an $8.2 million investment, supports the development of planning tools to advance sustainable, inclusive and equitable water distribution for California's 39 million people. The project is led by Ted Grantham, a UC Cooperative Extension specialist in the Department of Environmental Science, Policy and Management at UC Berkeley. Kristin Dobbin, UC Cooperative Extension specialist in the Department of Environmental Science, Policy, and Management at UC Berkeley, and Erik Porse, director of the California Institute for Water Resources are collaborating on the project.

Three other projects involving UC ANR researchers received California Climate Action Seed Grants and Matching Grants subawards:

  • Development of a hydrogel that can work as a soil amendment to help small-scale vegetable farms conserve water led by UC San Diego associate professor Shengqiang Cai with Ruth Dahlquist-Willard, UC Cooperative Extension small farms advisor and interim director of UC SAREP; Mallika Nocco, UC Cooperative Extension specialist; and Matthew Gilbert, UC Davis professor of whole plant physiology. $297,979
  • Development of a tool for predicting climate-water variation led by UC Irvine professor Isabella Velicogna with Tapan Pathak, UC Cooperative Extension specialist. $199,531
  • A study of urban stream corridors led by UC Davis professor Gregory Pasternack with Igor Lacan, UC Cooperative Extension environmental horticulture and urban forestry advisor. $33,824
  • A study of how California's housing crisis affects the growth of the wildland urban interface (WUI), where the fringes of development reach into natural areas led by UC Santa Cruz professor Miriam Greenberg, with Barb Satink Wolfson, UCCE fire advisor, Devii Rao, UCCE livestock and natural resources advisor, and the Central Coast Prescribed Burn Association.

Updated 8/31/23 to add the wildland urban interface study.

Posted on Wednesday, August 23, 2023 at 9:30 AM
  • Author: Kristen Farrar, SAREP
Focus Area Tags: Agriculture, Natural Resources

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