Posts Tagged: soil health
CASI’s Mitchell announces long-term NRI Project publication in Cal Ag on Don York’s KMJ580 AM morning “Ag Report” radio program, May 23, June 4, and June 6, 2024
In an effort to extend information on CASI's twenty-year conservation agriculture study that has been conducted at the University field station in Five Points, CA and that has been recently published in the journal, California Agriculture, Jeff Mitchell provided three radio interviews on the morning Ag Report that Don York produces for KMJ580 AM each morning out of Fresno. The segments aired on May 23rd and on June 4th and 6th, 2024 and are available below. Mitchell shared findings of the long-term “NRI Project” that since 1998 has examined four production systems – standard tillage without cover crop, standard tillage with cover crop, no-till without cover crop, and no-till with cover crop.
The NRI Project started as an effort to determine the potential of reduced disturbance tillage in terms of generating or producing less dust and in the early 2000s found that dust can be significantly reduced by as much as 80% with a variety of reduced tillage practices relative to standard tillage techniques that have been widely used in annual crop fields throughout the San Joaquin Valley since the early 1930s. The recent findings from the unique long-term study have shown that several soil health indicators including aggregation, water infiltration, biodiversity, and surface carbon were improved through the long-term use of cover crops with reduced disturbance tillage.
In the interviews, Mitchell points out that the systems that were evaluated and developed in the NRI Project were not at all easy to implement and required considerable trial-and-error effort to achieve. Yields, for instance, of cotton in the early years under the high residue, no-till cover crop system lagged behind the standard tillage, however once effective planting techniques were learned to establish the cotton crop. There were no yield differences between the two tillage systems for the next several years.
The results of this study that included 18 coauthors can be seen at https://doi.org/10.3733/001c.94714
Jeff Mitchell on KMJ Ag Report 5-23-24
Jeff Mitchell on KMJ Ag Report 6-4-24
Jeff Mitchell on KMJ Ag Report 6-6-24
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20-year summary of soil health research in Five Points, CA published in California Agriculture!
May 17, 2024
Findings from twenty years of soil health research in Five Points, CA have been published in the University of California's California Agriculture peer-reviewed journal's May 1, 2024 issue. https://doi.org/10.3733/001c.94714.
This work has been a large collaborative effort involving twenty-one UC and non-UC coauthors. It began in 1998 initially as an effort to evaluate the potential of reduced disturbance tillage systems to reduce dust emissions from annual cropping systems that are common in California's San Joaquin Valley. It long-term nature however, allowed it to become a unique site for also monitoring changes in soil properties and function under four experimental systems: conventional tillage with no cover crop, conventional tillage with cover crop, no-till with no cover crop, and no-till with cover crop. Crops rotated between tomato and cotton initially, but later during the study, the rotation was diversified to include melons, sorghum, and garbanzo beans.
The work involved the Soil Health Institute's Shannon Cappellazzi, who sampled at the site in 2019. That sampling event led to the site becoming part of a multiple-publication series of articles that reported on soil health impacts in 124 long-term study sites across North America.
https://soilhealthinstitute.org/news-events/a-minimum-suite-of-soil-health-indicators-for-north-american-agriculture/
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CASI hosts the Soil Health Institute's US Regenerative Ag Cotton Program leaders - April 11 and 12, 2024
April 12, 2024
The UC ANR CASI Center hosted five members of the Soil Health Institute's US Regenerative Ag Cotton Program in the San Joaquin Valley on April 11th and 12th, 2024. The Soil Health Institute (SHI) is a non-profit organization based in Morrisville, NC that conducts research and extension education related to soil health management. Five SHI members, Diana Bagnall, David Lamm, Jessica Kelton, Emily Ball, and Nate Looker, took part in the two-day tour of six San Joaquin Valley farms and the California Cotton Ginners and Growers Associations. San Joaquin Valley farmers who hosted the SHI members included Mark Borba of Borba Farms in Riverdale, CA, Mark McKean of McKean Farms also in Riverdale, Tony Azevedo of Stone Land Company in Stratford, CA, Cannon Michael and Derek Azevedo of Bowles Farming in Los Banos, Gary and Mari Martin of Pikalok Farms in Mendota, and Gary Smith of Ingleby Farms in Burrel. Roger Isom, President of the CCGGA in Fresno, also hosted the SHI guests.
SHI requested help from CASI with the cotton tour and discussions that took place as an effort to expand their national Regenerative Ag Cotton Program to California in 2024. The tour provided excellent opportunities for SHI to learn about California cotton and to make connections with leading cotton farmers in the San Joaquin Valley who may become part of the baseline soil sampling project that SHI is looking to conduct with cotton producers this year.
In addition to the farmers who generously hosted the SHI guests, several other local California folks including Cary Crum, Kimber Moreland, Rob Roy, Jacob Wright, and Olivia Peters helped CASI's Jeff Mitchell in sharing information about California cotton systems.
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How Many Earthworms are Enough?
Perhaps you've seen them. You're digging into the soil to plant something and as you dig you run across a few earthworms. Most of us have heard from childhood that worms are good for the soil. You may also be aware of vermiculture, or worm composting, using worms to help turn organic waste into nutrient rich compost for the soil. When you see earthworms in your garden, what does their presence suggest about the soil health? Should you add more?
Earthworms and Wigglers
The earthworms you typically see in your garden are considered "migratory" which means they will travel to find the habitat best suited to their success. They tend to cluster in the top 6 to 8 inches of soil around the roots of plants where they feed on decaying material and the fungi and other organisms that live there. As they travel through the soil, they drag leaves and other litter down into their burrows where soil microorganisms also begin digesting the material. These worms can tolerate colder temperatures through the winter months when they burrow deeper into the soil.
Earthworms need a light airy soil and rely on decaying organic material for nourishment. Introducing these earthworms to an inhospitable environment such as heavy clay, or compacted and/or dry soil, will result in them either leaving or dying. Where they flourish, however, they are important in mixing the dead surface litter with the main body of the soil. If you regularly add compost and a layer of mulch to your garden to improve the soil you may find the worms 'magically' appear, attracted to the habitat you are creating. In turn their constant burrowing and feeding activities help mix and distribute organic matter throughout the soil, improve soil aeration and water penetration, promoting a healthier root environment for your plants. Their excrement, known as castings, is richer in nitrogen, potassium carbon, sulfur, and other minerals than the rest of the soil, and acts as a natural fertilizer.
There is a second type of worm which lives close to the soil surface in areas of abundant organic material. These worms, including the popular species red wigglers, reproduce rapidly and thrive in warm, crowded conditions. They are less likely to survive in your garden environment, particularly during cold weather. Instead, these worms are ideally suited to worm bins, and you will usually find them for sale for use in vermiculture. In a bin they can rapidly break down food scraps and other organic waste materials, and their castings also act as a natural fertilizer when collected and added to garden soils. Think of these worms as composting specialists.
A Note of Caution
There is a type of worm known as a jumping worm, an invasive species capable of harming native forests which has been seen in California and many other states. It is recognizable by a milky-white band wrapping all around its body near the head. When disturbed, jumping worms have been known to throw themselves into the air and thrash around. It is very difficult to eliminate these worms once established, so make sure to check new mulch, compost, and potting soil for the worms, as well as soil in nursery pots. Because they live close to the surface their castings are often visible as a coffee-ground-like substance on the soil. Don't use these worms for fishing, vermiculture, or gardening. You can learn more about jumping worms at https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=56929.
The Bottom Line
Should you add worms to your garden soil? Ultimately, it's a chicken and egg situation. Do earthworms create healthy soil or are they attracted to healthy soil? Few valid studies have been done to link the presence of earthworms with improved plant growth. However, both plants and earthworms need temperatures between 60°F and 100°F, water (but not too much or too little), oxygen, and a soil that isn't too acidic, basic, or salty. It's clear the conditions that are good for plants are also good for earthworms, and improving your soil by regularly adding compost and mulch ends up supporting a thriving community of both healthy plants and earthworms.
Help Desk of the UC Master Gardeners of Contra Costa County (RDH)
No-till annual wheat better for soil health in California’s climate
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.”
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 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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