UC ANR Strategic Initiatives
University of California
UC ANR Strategic Initiatives

SI-related Blogs

University researchers and organic farmers to build soil as nature intended

A USDA grant will allow a group of California organic farmers to team up with researchers from the University of California, Chico State and Fresno State to determine whether tilling less soil on the farm will improve production of vegetable crops.

The aim is to duplicate the soil environment found in natural areas – typically concealed by plants, leaves and other organic debris – to improve agricultural soil health, increase production, reduce water use and avoid leaching nutrients out of the root zone.

“Tilling the soil is common on farms, but our research shows that it often isn't necessary, and can even be detrimental,” said Jeff Mitchell, UC Cooperative Extension agronomy specialist. “In nature, organic matter on the soil surface creates a protective layer and promotes biological activity that is beneficial to plants and the environment.”

A group of organic farmers, shown above, are working with UC researchers to minimize tillage and optimize soil characteristics on their farms.

The three-year project, funded with $380,000 from the USDA Natural Resources Conservation Service's Conservation Innovation Grant program, involves six organic farmers who are already experimenting on their own with cover crops, compost and minimum tillage to grow high-quality organic produce.

“This is a group of outstanding farmers,” Mitchell said. “It's very encouraging to see this sort of care for the soil. They recognize that taking care of the soil biology is useful to produce crops.”

One of the participants, Scott Park of Meridian, Calif., 50 miles north of Sacramento, has been building the soil on his farm for 38 years.

“We put 10 to 15 tons of biomass on every acre every year,” Park said. “This has given me good soil structure, water percolation and water retention, and we're having some really good results.”

Park said he tweaks his farming practices each year. To date, he has tinkered with reduced tillage, but isn't sold on a no-till system.

“I'm doing minimum till now, but it can be better,” Park said.

Teasing out those improvements is a goal of the project, which includes trials on four farms and two 12-acre demonstration plots, one at the UC West Side Research and Extension Center in Five Points and the other on the Chico State campus.

“Each of us will be trying to get closer to the goal of reducing tillage to promote soil health. We all want to develop strategies that might work, and not repeat mistakes,” Mitchell said.

The USDA grant funds will enable the farmers and researchers to gather accurate data about the agronomic and economic impacts of the new farming systems and use state-of-the-art equipment and technologies as they experiment with new techniques.

For example, the team is working with a Salinas company that is bringing a Spanish transplanting technology to California. The company, Tanimura & Antle Produce, will allow a demonstration of a plant tape that holds sprouts spaced ideally for a broccoli field planting in the West Side REC plot. (See video below or on YouTube at https://youtu.be/6pkmQVNjH1I .) The technology holds promise for reducing tillage, cutting back on labor, using less seed, and bringing the crop into production earlier in the season.

Planting cover crops is another way farmers and researchers will seek to improve soil health, though this process is a challenge in organic farming systems. On conventional no-till and minimum-till farms, the cover crop may be sprayed with an herbicide before planting seedlings in the cover crop residue. Possible solutions are chopping up the cover crop or using a roller-crimper machine.

“These technologies would provide considerable advantages in organic systems, but very little research has been done to quantify how these practices might influence soil function and cropping system resilience in California,” Mitchell said.  

As part of the project, a farmer network will be developed for information sharing, 18 public extension events will be held, six videos will be created and curriculum will be developed to extend the research outcomes.

For more information, contact Jeff Mitchell at jpmitchell@ucanr.edu, or (559) 303-9689.


 

In the video below, see an overview of transplanting technology developed in Spain that will be part of the soil building research.

Posted on Thursday, August 16, 2018 at 8:34 AM
Tags: CASI (5), Jeff Mitchell (16), organic (14)
Focus Area Tags: Agriculture Environment

Why 'AA' is for Avocado Addict

Avocado addicts know the avocado as a veritable green goddess that never disappoints, never deceives, never dissatisfies. (Photo by Kathy Keatley Garvey)

If you're like most of us, you “go bananas” for a banana for breakfast.

It's healthy, nutritious and packed with potassium.

But wait! You should probably go bananas for another fruit--that pear-shaped avocado. Did you know the avocado provides more potassium than a banana?

It does. A medium-sized banana yields 422 milligrams of potassium, while a medium-sized avocado, a whopping 708 milligrams.

Dietitian Linda W. Adams
Dietitian Linda W. Adams of UC Davis Occupational Health Services (among her responsibilities: teaching a 52-week UC Davis Diabetes Prevention Program) says “I think my favorite part about avocados, in addition to their wonderful flavor, is that they are full of monounsaturated, heart-healthy fat AND have more potassium than bananas! These two nutrients are lacking in many Americans' diets.”

“Eating more unsaturated fats -- as opposed to saturated fats and processed carbohydrate -- is a delicious step we all can take to maximize cardiovascular health,” Adams says. “Avocados are such a delicious way to do that!"

We love our avocados, our veritable green goddess that never disappoints, never deceives, never dissatisfies, whether we “butter” them on toast in the morning for breakfast, or slice or chunk or cube them for our salads at lunch and dinner. Health-conscious folks call them a superfood, and even mash and freeze them to ensure a steady supply in the winter. There's even a website on “50 Things to Love About Fresh Avocados.” 

This year, California's 2000 avocado growers anticipate a yield of 374.6 million pounds. That crop forecast, according to Tom Bellamore, president of the California Avocado Commission, is nearly double the yield of the 2017 crop and “despite the ravages of Mother Nature in California's avocado growing regions.”

UC Cooperative Extension adviser and avocado researcher Ben Faber of Ventura and Santa Barbara counties, points out that the avocado is really a fruit, not a vegetable. “The Supreme Court classified the tomato in 1920 or so as a vegetable because that's the way people think of it and it was taxed differently for tariffs. Politics or botany separates a lot of things in our lives.”

“The avocado is an amazing fruit,” Faber says. “It grows on a tree and comes to maturity, reaches certain oil content and a stage at which it will ripen, but it does not ripen on the tree. It needs to be removed from the tree before it will soften. If the fruit is removed before it has reached maturity it will not soften, and will remain rubbery and inedible.”

“One of the problems is that the fruit will hang on the tree for an extended period of time and it is hard to know when they are mature,” Faber points out. “Avocados are not like apricots where you have about two weeks to get the fruit off before it falls off. As the fruit stays on the tree, it gradually develops more and more oil content and has a richer flavor.”

What if the fruit stays on the tree too long? “It can develop an almost rancid flavor,” Faber says. “So it is good to know when the best, acceptable flavor is. Avocado varieties fall into general seasonal periods when they are mature, such as ‘Fuerte' and ‘Bacon' in winter, ‘Hass' in spring/summer, ‘Lamb-Hass' in summer/fall.”

An avocado must be removed from the tree before it will soften, says UC Cooperative Extension advisor Ben Faber. (UC ANR Photo)
We've all had our share of rock-hard avocados that seem as if they will never ripen. Sometimes they're as hard as the pits within! “Given time, they all soften,” Faber says. “But they all don't soften evenly, which is a reflection of their maturity or how they were handled in the food chain, stored at the wrong temperature or with too many bananas.”

The fruit will typically be ripe in seven to ten days, Faber advises. “If you want to speed things along a bit you can take three or four avocados and place them in a loosely closed paper bag with two or three Red or Golden Delicious apples or ripe kiwifruit. The purpose of the apples or kiwifruit is that these fruit produce a natural plant hormone, ethylene, that will help stimulate the avocado to produce its own ethylene. Apples and kiwifruit are known to produce lots of ethylene. The Delicious apples are varieties that produce more ethylene than other apple varieties. You can keep them even after they are shriveled and they will be producing ethylene.”

Never place your avocados in a plastic bag “unless you keep it open since the fruit needs to breathe during this process,” he says. “Just keep the fruit on your kitchen counter or in a warm place; 68F is the ideal temperature. Lower and higher temperatures both actually slow the process.”

Plant scientists trace the origin of the avocado (Persea americana) to south central Mexico. The avocado belongs to the flowering plant family, Lauraceae. Growers and gardeners glean tips on pest management from the industry and from the UC Statewide Integrated Pest Management Program.

Of the many known varieties, avocados fall into three broad categories based on whether they are of the Mexican, Guatemalan or West Indian races of Persea americana, the avocado species and the crosses that occur between these races. Generally speaking, California varieties have been the result of crossing between the Mexican and Guatemalan races. West Indian race varieties are not common here because of their generally lower cold tolerance.”

Ben Faber, like Linda W. Adams, enjoys avocados. He usually buys them “whenever they are reasonably priced.”

“One of the reasons I do research is that all the downed fruit is not salable because it is against food safety restrictions to introduce it into the food chain and all that fruit either gets eaten by coyotes or me,” he quips, adding “The tree is too big to fit into my backyard.”

The avocado, often thought of as a vegetable, is really a fruit and it's packed with potassium. (Photo by Kathy Keatley Garvey)

Looking for a great recipe? The California Avocado Commission offers many recipes, including what it calls “The Best Guacamole Ever."  

Dietitian Adams shares one of her favorites at https://www.delish.com/cooking/recipe-ideas/a19872947/avocado-tomato-salad-recipe/.

Avocado Tomato Salad
Ingredients

1/4 cup extra-virgin olive oil
Juice of 1 lime
1/4 tsp. cumin
Kosher salt
Freshly ground black pepper
3  avocados, cubed
1 pint cherry tomatoes, halved
1  small cucumber, sliced into half moons
1/3 cup corn
1  jalepeño, minced (optional)
2 tbsp. chopped cilantro

Directions
In a small bowl, whisk together olive oil, lime juice, and cumin. Season with salt and pepper. 

In a large serving bowl, combine avocados, tomatoes, cucumber, corn, jalapeño, and cilantro. Gently toss with dressing and serve immediately. 

Enjoy! The avocado keeps good company!

Posted on Wednesday, August 15, 2018 at 8:22 AM

Program Highlights August 4- 10

Throwback to the 2016 statewide conference closing ceremony where we collectively

Learn more about Point Reyes National Seashore in ways the casual visitor cannot, exploring in areas less traveled and alongside some of the...

Posted on Saturday, August 11, 2018 at 1:48 PM

Cities in California inland areas must make street tree changes to adapt to future climate

Many common street trees now growing in the interior of California are unlikely to persist in the warmer climate expected in 2099, according to research published in the July 2018 issue of the journal Urban Forestry & Urban Greening.

“Urban foresters in inland cities of California should begin reconsidering their palettes of common street trees to prepare for warmer conditions expected in 2099 due to climate change,” said the study's co-author, Igor Lacan, UC Cooperative Extension environmental horticulture advisor in the Bay Area.

Common trees in Coastal California cities appear to be better suited to withstand the 2099 climate.

Urban foresters in inland cities of California should begin reconsidering their palettes of common street trees to prepare for climate change.

“Our research shows that some trees now lining the streets of cities like Fresno, Stockton and Ukiah are likely to perform poorly in 2099,” Lacan said. “Those cities need to look at the conditions – and trees – now found in El Centro, Barstow and Fresno respectively.”

To reach these conclusions, Lacan and co-author, professor Joe McBride of UC Berkeley, used space-for-time substitution. They compared the most common street tree species in cities representing each of the 16 California climate zones with trees in cities that currently have climates that approximate the expected warmer conditions in the 16 cities 80 years from now.

For example, Eureka can expect a climate like Berkeley's today; Fresno's climate will resemble the climate of El Centro today. (Find the complete list of cities below.) The corresponding cities were determined with climate predictions from Cal-Adapt, which synthesizes California climate change scenarios to reach a consensus view of the magnitude of climatic warming.

Igor Lancan, UC Cooperative Extension urban horticulture advisor. (Photo: Evett Kilmartin)

“We used the mid-range models,” Lacan said. “It's very reasonable to say the warming predicted by the model we used is already ‘baked in,' regardless of any mitigation efforts. While we should take measures to prevent even greater warming – mostly by reducing the use of fossil fuels – this study aims to help adapt California urban forests to the warming that can be reasonably expected to occur.”

Lacan said he and McBride were surprised to find that coastal cities and their warm equivalents contain most of the same common urban tree species, while the warm equivalents of inland cities seemed to lack most and, in some cases, all of the common trees there today.

“It's really a sharp distinction,” Lacan said. “Perhaps they were lucky, but coastal cities are better positioned for the climate of 2099 than the inland cities.”

Climate zone

City

Corresponding city
(approximates climate
in 2099)

1

Eureka

Berkeley

2

Ukiah

Fresno

3

Berkeley

Santa Ana

4

King City

Stockton

5

Santa Maria

Santa Ana

6

Santa Monica

King City

7

San Diego

Santa Ana

8

Santa Ana

Burbank

9

Burbank

Fresno

10

Riverside

Barstow

11

Yuba City

El Centro

12

Stockton

Barstow

13

Fresno

El Centro

14

Barstow

El Centro

15

El Centro

Furnace Creek

16

Susanville

Barstow

For a copy of the complete research report email Igor Lacan, ilacan@ucanr.edu.

Posted on Friday, August 3, 2018 at 8:38 AM
Focus Area Tags: Environment

Program Highlights July 28- August 3

Fire retardent on California Laurel (Umbellularia californica) leaves

Many of our CalNat friends and colleagues and the places they hold dear are being heavily impacted by statewide wildfires. We wish you all the best...

Posted on Friday, August 3, 2018 at 8:00 AM

Next 5 stories | Last story

 
E-mail
 
Webmaster Email: mozbell@ucanr.edu