The Crush June 2023 - 2

cover crops, and biochar. (Biochar Zoom virtual workshop
is on July 13.) The Soil Hub held a field day workshop
on May 5 at the Santa Rosa Junior College Shone Farm
in Sonoma County called, " Clear as Mud: Soil Health
Technical Assistance for Ag Professionals, " which focused
on soil health assessment.
Soil Health Assessment
The NRCS created a " Cropland In-Field Soil Health
Assessment Worksheet " as a basic in-field visual
assessment of 11 soil health indicators. It can be
performed by request as a service by local RCD or NRCS
staff, but the instructions and worksheets are relatively
easy to use by growers on their own farms. NRCS soil
health specialist Dr. Josh Beniston provides training to
USDA personnel and demonstrated in-field protocols
at the Soil Hub workshop. Beniston said, " This soil
health assessment doesn't require much technology or
equipment, or a lot of money, you mostly need to use
your hands, feet, and eyes. " He added, " This helps
evaluate the condition of the soil as a habitat for living
things. " A good time to assess soil health in California is
mid- to late-spring, when soils are not too wet or too dry.
Indicator assessments include Soil Cover, Residue
Breakdown, Surface Crusts, Ponding, Penetration
Resistance, Water Stable Aggregates, Soil Structure, Soil
Color, Plant Roots, Biological Diversity, and Biopores.
In addition, NRCS identifies four main soil health
concerns: Compaction, Soil Organic Matter Depletion,
Aggregate Instability, and Soil Organism Habitat Loss
or Degradation. See the NRCS assessment guide,
worksheet, instructions, and definitions.
More specific soil health lab tests are available from
commercial and service laboratories. Soil scientists/
researchers Dr. Chelsea Carey and Dr. Erika Foster
of Point Blue Conservation Science, which provides
research, planning, and services for ag lands in
California, offered advice on selecting soil health lab
tests at the Soil Hub workshop. They cited The Soil
Health Institute recommendations to assess soil organic
carbon, soil respiration/carbon mineralization, and
aggregate stability as a cost-effective minimum suite
of soil health indicators for North America. Carey said,
" Soil organic carbon is one of the most important tests
to provide an indication of carbon sequestration and
how much organic matter is in the soil. " The percent
of organic carbon is an indicator of a soil's ability
to regulate nutrient cycling and support ecosystem
functions. Soil tests/indicators should be selected based
on management goals and factors related to the site and
crop. Researchers recommend using the same lab over
time for consistent testing and results. An indicator/test
is only useful for decision-making if it can be interpreted.
Healthy Soil for Winegrape Production
A current SARE project by UC Davis researchers Dr.
Cristina Lazcano, Dr. Mallika Nocco, Dr. Kerri Steenwerth,
and graduate student Noely Gonzalez-Maldonado seeks
to develop a definition of soil health for winegrape
vineyards that meets their unique production goals, and
to assess the variability of soil health indicators across 32
Napa Valley vineyards. This study interviewed 16 grower
participants about factors they viewed as important
for soil health. A healthy soil for winegrape production
was defined as one that: allows adequate vine vigor
control, produces high quality grapes, maintains vine
health, allows reaching yield targets, has adequate water
holding capacity and good infiltration, has " balanced "
fertility, resists erosion, and needs minimal inputs
and interventions. The most important soil properties
highlighted by growers were: coarse soil texture;
adequate water holding capacity; good infiltration;
adequate (not high) levels of nutrients, especially
nitrogen; and sufficient (not excess) organic matter.
Soil health analyses and lab tests were performed under
three main categories. Soil Physical Properties analyzed
were gravimetric soil moisture, water holding capacity,
and soil texture. Soil Chemical Properties analyzed
were soil pH, electrical conductivity (EC), soil organic
matter, and permanganate oxidizable carbon to estimate
the active carbon pool of the soil organic matter. Soil
Biological Properties analyzed were microbial diversity
and activity by measuring soil microbial respiration,
potentially mineralizable nitrogen, and phospholipid
fatty acids. Soil biodiversity indicates the types of
organisms present and the functions they could perform
with different impacts on nutrient cycling and availability,
soil carbon, and overall soil health. The researchers
believe soil organic matter is one of the main drivers of
soil health with the ability to positively influence water
infiltration, soil erosion, microbial diversity, and crop
yields. See a progress report here.
CA Healthy Soils Program
The California Department of Food and Agriculture
(CDFA) administers the Healthy Soils Program (HSP)
to provide grant funding for eligible agricultural
practices that sequester carbon, reduce atmospheric
greenhouse gases (GHGs), and improve soil health.
Eligible vineyard practices include compost application,
conservation cover, cover crops, mulching, hedgerow
planting, nutrient management, and residue and tillage
management. The HSP administers three types of grant
programs. Individual growers can apply directly under
two programs during specified open solicitation periods.
Agencies or organizations can apply for the Block Grant
Pilot Project program (currently accepting applications
until June 19) that serve as regional grant administrators.
More information can be found here.
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The Crush June 2023

Table of Contents for the Digital Edition of The Crush June 2023

The Crush June 2023 - 1
The Crush June 2023 - 2
The Crush June 2023 - 3
The Crush June 2023 - 4
The Crush June 2023 - 5
The Crush June 2023 - 6
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The Crush June 2023 - 12