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!