Posts Tagged: Climate

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."

$1.7M granted for climate-smart planning led by UC ANR scientists

Cover crop from a UCCE led research project focused on adapting to climate change using smart land management practices. Photo courtesy of Cristina Murillo-Barrick.

In California, natural and working lands make up 95 million acres of the state and play a vital role in building resilience to the impacts of climate change. University of California Agriculture and Natural Resources was awarded $1.7 million for the California Next Generation and Equitable Climate Action Plan, as part of the state's Natural and Working Lands Climate Smart Strategy and California's 30x30 Initiative, an effort to conserve 30% of the state's lands and coastal waters by 2030.

Natural and working lands include both unmanaged and managed areas actively used for agriculture, forestry or production purposes.

Chandra Richards, UC Cooperative Extension agricultural land acquisitions academic coordinator for Southern California, and Cristina Murillo-Barrick, UCCE's Black, Indigenous and People of Color community development advisor for the Bay Area, are leading the California Next Generation and Equitable Climate Action Plan project.

To build capacity and technical assistance for climate-smart action planning, Richards and Murillo-Barrick will use the Climate Smart Land Management Program funding, awarded through the California Department of Conservation, to focus on two of the most pressing climate action issues: equitable land access and land management diversification.

According to the 2022 U.S. Department of Agriculture census, demographic data indicates that California agricultural land ownership and production is concentrated within an aging and mostly White demographic. However, research suggests diverse management practices promote healthy landscapes. This has been shown to benefit the environment, human health and climate resilience in multiple ways.

For this reason, this project centers on “historically underrepresented communities,” a term that includes California Native American Tribes, communities of color, landless farmers, immigrant and non-English speaking communities and other agency-designated minority groups (racial, ethnic and non-male groups, socially disadvantaged farmers and ranchers, and California designated severely disadvantaged communities).

Focusing on Southern California, UC Cooperative Extension scientists will identify barriers to land access, management and opportunities to increase land manager diversity. They also will engage historically underrepresented communities in coalition building, capacity assessment and climate action planning.

Within the last few decades, Californians have faced increased ecosystem stressors and decreasing diversity of natural systems. This pattern continues to damage already-vulnerable communities (disproportionately historically underrepresented communities), while also worsening and intensifying climate impacts, including drought, wildfire, flooding and disease. Overcoming these kinds of systemic and structural challenges will require the next generation of land managers to reflect California equitably, while preparing them to take on climate resilience. The project will determine clear solutions and plans that enable long-term, strategic land use and protection.

To do this work, UCCE is collaborating with the Community Alliance with Family Farms (CAFF), California Association of Resource Conservation Districts (CARCD) and the California Bountiful Foundation, all of whom serve as subgrantees and will deepen connections with communities.

Organizations like CARCD have long served as “boots on the ground” personnel and have close relationships with landowners and land managers. “RCDs have been hearing the land equity need for a long time and are actively collaborating with different partners to tackle this pressing issue,” said Qi Zhou, program manager of Justice, Equity, Diversity and Inclusion at CARCD and member of the Strategic Growth Council Land Equity Task Force.

“California RCDs are excited about this project because it will allow major California agriculture and conservation partners to collaboratively develop plans and implement projects centering on equity land access and land management diversification,” Zhou added.

Project lead Richards said $270,000 of the grant will be reserved for new partnerships with organizations in Southern California that have experience with, and strong ties to, historically underserved communities.

UC ANR is collaborating with the California Department of Food and Agriculture as well as California Climate and Agriculture Network (CalCAN), and World Be Well, a Southern California nonprofit.

Tawny Mata, CDFA's director of the Office of Environmental Farming and Innovation, described technical assistance providers as being grounded in their local agricultural communities and recognized their importance to partners in the success of CDFA's incentive programs.

“When we do succeed in reaching historically underserved farmers and ranchers with our grant programs, it is often with the thoughtful support and planning of a technical assistance provider,” Mata said. “I look forward to this project helping us refine our own technical assistance funding programs and bringing technical assistance providers together to network and share best practices for improving land access and promoting climate-smart agriculture.”

“The successes of this project will elevate the voices of historically underrepresented communities, strengthening efforts in these communities to support climate action,” said Richards. Additionally, the project will increase sharing of regional reports, needs assessments and community plans surrounding climate-smart management practices. Finally, it will boost technical assistance for these groups specifically.

To learn more about the  Climate Smart Land Management Program and this year's awardees, visit:

https://www.conservation.ca.gov/index/Pages/News/California-award-8-5-million-climate-action-natural-working-lands.aspx.

Climate-smart crop production workshops March 5-7 in Ventura, Salinas and Tulare

Workshops will cover the latest research and advances in managing risks to agricultural production that can result from climate change and climate variability.

Growers invited to learn how to manage risks to fruit, nut, vegetable production

UC Cooperative Extension is offering workshops in Ventura, Salinas and Tulare to help growers adapt their fruit, nut and vegetable production practices to variable climate conditions.

"Growers, farm and ranch managers, and technical assistance providers can learn about the latest research and advances in managing risks to agricultural production that can result from climate change and climate variability,” said Daniele Zaccaria, associate professor in agricultural water management for Cooperative Extension at UC Davis.

Tapan Pathak, UCCE specialist at UC Merced, will speak about climate change trends, potential impacts on agricultural production and decision support tools. Zaccaria and local experts will discuss cover cropping, pests and other issues.

During a roundtable session, participants will discuss their own production challenges resulting from climate change and variability.

“Participants will also learn about tools available to aid manage climate change and climate variability risks," Zaccaria said. 

The Climate-Smart Agricultural Production Practices workshops will be held in three locations: 

Ventura: Vegetable and Berry Production

March 5 (8 a.m.–1:30 p.m.)
669 County Square Dr., Suite 100

Speakers include UCCE advisors Andre Biscaro, Ben Faber and Mark Battany, and other scientists and experts from Ventura County Resource Conservation District and Land IQ. Register at https://bit.ly/VenturaCrops.

Salinas: Vegetable, Berry and Grapevine Production

March 6 (8 a.m. –2 p.m.)
1432 Abbott St.

Speakers include Daniel Hasegawa and Eric Brennan of USDA-ARS and UCCE advisors Larry Bettiga, Michael Cahn and Mark Bolda. Register at https://bit.ly/SalinasCrops.

Tulare: Fruit and Nut Production

March 7 (8 a.m.–2 p.m.)
4500 South Laspina St.

Speakers include UCCE advisors Jhalendra Rijal, Mark Battany, Mohammad Yaghmour, Sandipa Gautam, Brent Holtz and other scientists and experts from USDA-NRCS, Almond Board of California; California Pistachio Research Board and Land IQ. Register at https://bit.ly/TulareCrops.

Workshops are free and include coffee breaks, lunch, workshop materials along with the presentations. Registration is required. 

These workshops are supported by grants from the California Department of Food and Agriculture and USDA's National Institute of Food and Agriculture.

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.

No-till annual wheat better for soil health in California’s climate

From left are researchers Mark Lundy, Kalyn Taylor and Taylor Becker, at the time all in the UC Davis Department of Plant Sciences, observing plots of wheatgrass. The photo was taken in 2019, during the second year of a three-year experiment to compare the benefits and disadvantages of perennial wheatgrass with tilled annual wheat and no-till annual wheat in California's Central Valley. Photo: UC Davis Department of Plant Sciences

One more reason to adopt sustainable cultivation

California wheat farmers could both maintain their yields and improve soil health by growing annual wheat without tilling the soil year after year.

This could be one more encouragement to farmers to adopt a sustainable practice commonly called conservation tillage, no-till or minimum-till cultivation, impacting how we grow a grain that supplies about 20 percent of the calories and protein for people around the world.

A new study, by a team led by Mark Lundy, University of California Cooperative Extension specialist in UC Davis' Department of Plant Sciences, offers new insight for decades-long discussions around soil conservation, sustainable agriculture and climate-warming emissions related to growing our food. The study has been published in the journal Soil and Tillage Research. For the first time, researchers have shown that annual wheat that is not tilled each year is better for stashing carbon in the soil than perennial wheatgrass, while still yielding more crop in Central California.

Previous studies have looked at annual wheat that is tilled each year, annual wheat that is not tilled, and a cousin species, perennial intermediate wheatgrass (trademarked Kernza), which also is not tilled. But until now, no one has looked at all of the benefits and trade-offs together. Most importantly, “no one has ever controlled for tillage,” Lundy said. “And, no one has compared annual wheat to perennial intermediate wheatgrass over multiple years in a Mediterranean climate, which is what we have in California.”

At the left is perennial intermediate wheatgrass (Kernza), and at the right is no-till annual wheat in experimental plots west of UC Davis in June 2019. Photo courtesy: Kalyn Taylor

This study also is unique because it delves into the deeper question of what is going on in the soil that drives the different results for carbon there. Soil carbon reflects various processes linked to plant activity and soil health. Measuring the different forms of soil carbon may also signal whether a farming system is accumulating carbon in the soil over time – a plus for reducing climate-warming gases in the atmosphere.

“Measuring soil carbon is complex and nuanced,” said Kalyn Taylor, the lead author on the paper. “We started this experiment because we wanted to know whether and how plant activity and tilling or not tilling would affect the carbon story belowground in California's climate.”

“When we started this study, we thought the crop being perennial or annual would drive the differences in carbon storage in the soil,” Lundy added. Specifically, they had expected perennial wheatgrass would lead to more carbon in the soil because of its deeper, better-established root system. “But that's not what we found,” he went on. “What we found was, it was the lack of tillage, plus the level of productivity of common annual wheat, that made the difference in soil carbon here in California.”

Soil carbon in annual vs. perennial grain

In 2017, Lundy, then-graduate-student Taylor, UC Davis Professor Emeritus Kate Scow and others on the team started measuring different forms of soil carbon in test plots at Russell Ranch, west of campus. Plots were planted with annual wheat that was tilled each spring, annual wheat that was not tilled and perennial intermediate wheatgrass (Kernza) that also was not tilled.

Each year, the researchers measured the carbon present in the soil, the amount of soil organisms (which have carbon in their bodies) and the amount of material the plants created.

At the experimental wheat field west of Davis in March 2019 are, from left: Kate Scow, of the UC Davis Department of Land, Air and Water Resources and co-principal investigator on the wheat study; Liz Carlisle, from UC Santa Barbara; Kalyn Taylor, of the UC Davis Department of Plant Sciences and lead author on the recent paper; and Bob Quinn, who earned a doctoral degree at UC Davis, then returned home to Montana to run the family's wheat farm. Photo by Daniel Rath

At the end of three growing seasons, they found that land planted with no-till, common, annual wheat had the highest amount of soil organisms, measured as biomass, of the three treatments.

The researchers also found soil carbon is more likely to remain stable in the no-till, annual plots, compared to both tilled wheat and wheatgrass.

In addition, the no-till, annual wheat produced plant material more consistently than the perennial wheatgrass across the three years, which saw variation in rainfall.

“Overall, annual wheat grown without soil disturbance or tillage had both higher productivity and higher potential for storing carbon in the topsoil than perennial wheatgrass in our Mediterranean climate,” Lundy said.

Related research

“No-till annual wheat increases plant productivity, soil microbial biomass, and soil carbon stabilization relative to intermediate wheatgrass in a Mediterranean climate,” is online now and will be published in the January 2024 edition of Soil and Tillage Research.

The team also found that tilled annual wheat vs. Kernza stores total carbon at different depths in the soil profile and hosts distinct soil fungal communities, primarily in the root zone and topsoil: Taylor, K., Samaddar, S., Schmidt, R., Lundy, M. and Scow, K., 2023. Soil carbon storage and compositional responses of soil microbial communities under perennial grain IWG vs. annual wheat. Soil Biology and Biochemistry, p.109111.

Previous work comparing the perennial grain known as intermediate wheatgrass (trademarked Kernza) to annual wheat had not distinguished the extent to which soil health benefits are a function of the perennial nature of the crop. Read the story here.

This story was originally published on the UC Davis News site.

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