Posts Tagged: soil

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 4^th 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

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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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Soil Health Assessment Report

Soil Biodiversity in California Agriculture: Framework

               and Indicators for Soil Health Assessment

Prepared by: California Department of Food and Agriculture Below Ground Biodiversity Advisory Committee

 

Soil health depends on soil biodiversity.

However, external pressures from land-use change, climate change and certain agricultural practices threaten the biotic networks that underpin the delivery of soil's many ecosystem services. Yet measuring soil biodiversity is a complex task, with a wide variety of possible indicators, and methodologies that are evolving with recent technological advances. This report, prepared by the Belowground Biodiversity Advisory Committee (BBAC) convened by the California Department of Food and Agriculture (CDFA), focuses on how best to assess soil biodiversity in the context of working lands and considers current and future challenges faced by California agricultural producers, policy makers, governing agencies, and related stakeholders. The report presents information on the taxonomic and functional diversity of soil organisms, ecosystem services they provide, threats to soil biodiversity, assessment frameworks, and biodiversity indicators. Examples of how biodiversity indicators can be applied to specific use cases provide insights for soil health, sustainable and climate-smart agriculture, and biodiversity conservation in California.

Soil biodiversity is the interconnected ‘social' network of numerous species of living organisms that contribute to soil functioning. As these organisms grow, die, and interact with soil's abiotic components, they perform essential functions in carbon, water and nutrient cycling and plant growth, collectively described as multifunctionality, benefiting ecosystems and humans alike. Comprehensive assessment of soil biodiversity involves measurements of organism abundance, identity, and functional diversity or traits, ideally in tandem with measurements of soil processes, as well as interactions among organisms. Soil biodiversity and soil processes vary in space and time due to factors like location, climate, vegetation, and land management practices across California's diverse landscapes.

Soils are incredibly biodiverse habitats, containing a vast array of organisms ranging from macroscopic organisms like gophers to microscopic worms, fungi, and billions of bacterial cells. The physical and chemical properties of soils – soil texture, pH, water and oxygen content, salinity, organic matter inputs, and nutrients – determine the types of organisms found in a particular habitat. The array of organisms inhabiting soil spans over six orders of magnitude in size, and includes microorganisms (viruses, bacteria, archaea, and fungi); microfauna (protists, nematodes, and tardigrades); mesofauna (mites and springtails); and macrofauna (earthworms). Life in soil exists in ecological communities that are complex and interconnected. These interconnections provide stability to soil functions. Soil organisms are critical to regulation of greenhouse gases, both by consuming and producing gases such as nitrous oxide, carbon dioxide, and methane. Mycorrhizal fungi in symbiosis with most plant species promotes root growth and availability of water and nutrients. A broad range of soil organisms mediate the decomposition of organic inputs and enhance nutrient cycling. Other functions of biodiverse soils include soil structure formation, organic matter formation, carbon storage, water regulation, and pathogen suppression. But despite these critically important functions, the diversity and complexity of soil biodiversity makes it challenging to decipher these intricate relationships and understand the impact of human activities.

Soil biodiversity faces many of the major threats from human activities and global change that also impact soil health and sustainability of California's agroecosystems. Land use changes, intensive agriculture, climate change, pollution, invasive species, overexploitation, and loss of habitat connectivity all pose risks. These threats disrupt soil biological networks, reduce biodiversity, impair ecosystem functions, and degrade soil structure and fertility. Soil biodiversity loss reduces multifunctionality and the provision of ecosystem services, highlighting the need to recognize the value of belowground communities to overcome challenges such as climate change, land degradation, and overall biodiversity loss. Addressing these challenges through sustainable land management, agroecological approaches, and awareness campaigns is crucial for preserving belowground biodiversity to maintain provision of essential ecosystem services.

READ ALL ABOUT SOIL DIVERSITY in the Report:

https://www.cdfa.ca.gov/oefi/biodiversity/docs/Soil_Biodiversity_California_Ag_July_2023.pdf

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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)

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