a new look at cover crops and carbon management in our local agricultural systems glenn mcgourty,...
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A new look at cover crops and carbon A new look at cover crops and carbon management in our local agricultural management in our local agricultural systems systems
Glenn McGourty, Farm Advisor
UCCE Mendocino and Lake Counties
Ecological Services of Your Vineyard and Property
Watershed Habitat for native species Pollinators Carbon sequestering and cycling Nutrient cycling Energy cycling through photosynthesis,
production of O2 Urban separation and viewshed
Vineyard Floor Management ObjectivesVineyard Floor Management Objectives Be cost effective Enhance vine health Increase or decrease vine growth by management
practices Improve soil health (bio activity, soil structure,
water retention, water infiltration) Firm footing for vineyard operations Control weeds
In the beginning…
Negative Effects of Tillage: Loss of OM Decreased infiltration
of air and water Loss of soil structure Loss of soil
biological activity and diversity
Carbon Sequestering and Climate Change:Carbon Sequestering and Climate Change:
Increase of atmospheric CO2 from human activity
Loss of carbon from soil by tillage = 30% of total
CO2 generated
Farming for Carbon
Emphasis on managing soils to accumulate stable carbon
Focus on natural processes Soil amendments may also be needed Changes in tillage practices Don’t add more CO2 from soil or fossil fuels Possibility of carbon credits?
Goals in Improving Soil Chemistry and Goals in Improving Soil Chemistry and Fertility with Organic MatterFertility with Organic Matter
Increase in soil N Improved availability of K, S, and P Improved availability of micronutrients
(especially if composts used) Increased soil buffering capacity Increased soil CEC Increase bio activity, both macro and micro
Vineyard Organic Matter Vineyard Organic Matter Per Year, lbs /acre Per Year, lbs /acre
Item Conventionally Farmed
Organic/ BD . Farmed
Prunings 900 lbs. 900 lbs.
Leaves 1200 1200
Weeds/cover c. 1000 1000-10,500
Compost 0 2000
Total, tons/acre 1.5 1.5—7.5 t
North Coast Soil Issues:North Coast Soil Issues: Problems:Problems: Low pH Low Calcium High Magnesium Low Potassium High clay, poor soil
structure Phosphorus deficiency
Solutions:Solutions: Apply Gypsum or Lime “ “ Potassium sulfate Initial ripping, cover
crops, reduced tillage Rock phosphorus,
compost high in P
Soil Structure and Organic Matter
Improving Soil Physical QualityImproving Soil Physical Quality You can manage soils to increase SOM Increased SOM often means improved soil
structure Change soil structure from blocky to granular Increased soil porosity and lower bulk density
with more carbon Improved water holding capacities, infiltration
rates
Thanks to those you don’t even see…
Deep Tillage is Important InitiallyDeep Tillage is Important Initially Rip to rooting depth Don’t destroy soil structure Apply nutrients and
amendments that are difficult
to leach before ripping
Vineyard Floor Management: Vineyard Floor Management: TillageTillage Disking Spading Under the vine cultivation Mowing
Alternative Cultivation EquipmentAlternative Cultivation Equipment
Cover crops and their effects in vineyards
Cover Crops Cover Crops
Increase organic material Increase organic material and soil fertility and soil fertility
Prevent Prevent erosionerosion
Improve soil Improve soil structure structure
Retain soil moisture Retain soil moisture
Attract benefical Attract benefical insects insects
Increase diversity Increase diversity of soil organisms of soil organisms
Affect micro-climate Affect micro-climate
Source: A. Thrupp
Soil Protection With Cover Crops
Cover crop foliage shields soil from rain splashing, slaking of aggregates
Water infiltration rates stay elevated Improved water storage, water quality OM conserved by preventing erosion Mulching effect keeps soil cool in summer,
protects OM from oxidation
Immediate Effects of Cover Crops Plant tissue is the primary source of SOM Soil life is stimulated Cover crops serve as food source for
vertebrates, invertebrates and microbes Soil respiration rates and microbe numbers
increase
SOM Forms Quickest Under Sod Culture
Root biomass cycles annually Mulching effects conserve moisture, protect the
SOM from sunlight and oxidation
Summer Vineyard Floor Management
Cover Crop Types
Grasses and Legume Mixes Complimentary in
growth Good for improving
soil structure, tilth May also improve
soil fertility
Grasses: Fibrous RootsGrasses: Fibrous Roots
Peas, Vetch, Bell Beans and Oats Cover Crop
Fitting the Architecture of the Vineyard
vs
Self Reseeding Annual Legumes
Protect the soil and help water qualityProduce N (15-30 lbs/acre)Self Reseeding, no tillage neededHabitat for beneficialsPotentially good forage for grazing Works best in higher rainfall areas, or vineyards with sprinklers to help germinate seed
Crimson Clover Trifolium resupinatum
Subterranean Clover Trifolium subterraneum
Bur Medic Medicago polymorpha
Balansa Clover Trifolium michelianum
Well Mixed Sward
Spring Dry Down
Seed Production
Perennial Cover Crops Can greatly reduce vigor Recommended for fertile sites Grass and legume mixes useful, but not annual
and perennial species Grasses: turf-type tall fescue, sheep fescue,
creeping red fescue, hard fescue, perennial ryegrass
Legumes: white Dutch clover, Ladino clover, strawberry clover—watch out, gopher magnets!
Tall FescueFestuca arundinacea
California bromeBromus carinatus
What is right for your vineyard or farm? Sprinklers available? What will grow on native rainfall? What will tolerate cold weather and
dryness?
Insectary Plantings
Habitat For Beneficials Shelter Nectar Alternate prey Pollen Can assist your
vineyard in creating self-regulation for pest control
Dedicated Insectary RowsDedicated Insectary Rows
Parasitoids
Predators
Wild Carrot or Queen Anne’s LaceDaucus carota
Compost and Organic Matter—Compost and Organic Matter—Helping Your Soil Come AliveHelping Your Soil Come Alive
Recycled Pomace Manure, lime,
gypsum Produced on Farm
or Winery Process takes about
one year Applied at one or
two tons/ acre
Nitrogen in CompostNitrogen in Compost Available N = mineral N in the root zone Mature composts: typically 1 - 3% N= 20 -60 lbs of N Unincorporated materials: Effective applied
to cover crops before rains Incorporated materials: may release N or
immobilize N in short term
Other Minerals in CompostOther Minerals in Compost .5-1.0% P (10-20 lbs per ton) .5-3 % K (10-60 lbs per ton) Numerous micronutrients
Compost Applications: Beneath vines or across the vineyard floor
Vineyard Floor Management: Wooly Mowers
Useful Tools for Maintaining Sheep
Leaf Pulling by Sheep
Aggressive Leaf Pulling by Sheep
Helpful Resources
Available: UC ANR Press:Available: UC ANR Press:http://anrcatalog.ucdavis.edu/http://anrcatalog.ucdavis.edu/
Thanks for your attention!