Ray Weil Main Points Soil Health is Key to Sustainability: - - PowerPoint PPT Presentation

Ray Weil

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Soil Health is Key to Sustainability: Physical/Chemical/Biological Cover Crops: Tools for sustainability Ag Revolution: new interest in / applications

• f soil health lead by “rock star farmers”

Positive Environmental Impacts: Carbon sequestration, energy efficiency, clean water, better food, fewer chemicals

Main Points



Farmer = Ecologist. Managing Millions of “Moving Parts”: both above and below ground

• 1. Plants: Crops , forages , green manures,

weeds.

• 2. Animals: Cattle, wildlife, soil fauna.
• 3. Microbes: Pathogens, soil food web
• 4. Physical /chemical environment: Weather,

soil structure, texture, pH, fertility.

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Typical dung beetle in cow manure

Buries manure Conserves Nitrogen and

• ther

nutrients

Keystone Species: a Dung Beetle

Earthworms - Ecological engineers

Photo by Steve Groff

Anecic earthworms under no-till: reconnecting topsoil and subsoil

CANSIS

Soil core Heat source Cold water

The Actors: Meso-fauna

Bacterivore Fungivore Plant Parasitic

Nematodes play diverse roles within the food web

Omnivore Predator

Photos: Lisa Stocking Gruver, U of Md

Plant parasite

The Soil Food Web Matters!

From Omay, et al. 1998.

Margaret McCully.

Wheat root covered with rhizobacteria

Plant – microbe partnerships

• Acid conditions
• Untilled soil - Residues on

surface

• Woody, resistant materials

Microorganisms: Fungi

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Absorb, hold and release water Breath -- exchange gases Cycle nutrients - mineralization Assimilate carbon into humus Resist raindrop erosion Allow root penetration Suppress pathogens Sustain genetic diversity

A Healthy Soil Will….

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Soils from the rotation plots after drying.

25 yrs of conventional tillage corn. 1.2 % SOM 20 yrs of bluegrass, then 5 yrs conventional

• corn. 2.0% SOM

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Organic v Conventional: False Choice The agricultural cropping efficiency (ACE)

The agricultural cropping efficiency (ACE) coefficient is defined as the total sweet corn yield per unit of pollutant lost, with greater coefficient values indicating higher yields with less pollution. Normalized to No- Till/Conventional

SWEET CORN PRODUCTION SYSTEM (North Carolina) ENVIRONMENTAL IMPACTS EROSION (SEDIMENT LOSS) TOTAL PHOSPHORUS TOTAL DISSOLVED NITROGEN 2011 2012 2011 2012 2011 2012 CONV TILL /Conventional 2b 6c 6c 17b 16b 24 CONV TILL /Organic 4b 10b 4c 9b 14b 44 NO-TILL /Organic 37a 16b 14b 11b 26b 33 NO-TILL /Conventional 100a 100a 100a 100a 100a 100 P value <0.001 <0.001 <0.001 <0.001 <0.05 >0.05

Edgell, J., D.L. Osmond, D.E. Line, G.D. Hoyt, J.M. Grossman, and E.M. Larsen. 2015. Comparison of surface water quality and yields from organically and conventionally produced sweet corn plots with conservation and conventional tillage. J Envir Qual.

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Planting

Cover crops can utilize

• therwise wasted resources

The sun shines, the rain falls and microbes work 10-12 months a year, but this typical Indiana grain farm captures only 3-4 months of this activity.

Harvest

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Cover Crops Liberate Farmers from Market Dictates on What to Plant

• 1. Cool season

grasses

• 2. Cool season

Legumes

• 3. Cool season

Brassicas

• 4. Warm season

grasses

• 5. Warm season

legumes

• 6. Warm season

broadleaves

Increased infiltration Soil Cover Soil

• rganic

matter Nematodes Food web activity Labile C Soil Aggregation Nitrogen fertility Weed suppression Soil water Soil temperature

Cover crops

Enhanced crop growth Bio-drilling Reduced erosion loss Nutrient capture (N, P, S, K, etc) Rhizobial associations P- fertility Reduced evaporation Reduced leaching loss (N) Mycorrhizal associations

By increasing bio-diversity and keeping living roots in the soil year-round ….

Following winter cover crop No winter cover crop

Water dynamics: usually bio-drilling combined with surface mulch can be a water life saver during summer!

Comparison on PA farm of Steve Groff, a leading no-till cover cropper.

Cover crops can improve structure deeper in the soil

Bouwman, L.A., and W.B.M. Arts. 2000. Effects of soil compaction on the relationships between nematodes, grass production and soil physical properties. Applied Soil Ecology 14:213-222.

Compaction tripled plant parasite nematodes (herbivores) but didn't change total nematodes

Reclaimed polder with calcareous sandy loam (30% silt, 5% OM) dug 60 cm deep, compacted and planted to perennial ryegrass.

Investigating roots with fiber optic camera: minirhizotron

Bio-drilling- the cover crop answer to compaction

45 cm2

Chen and Weil, unpublished

Roots of corn following rye, radish or no winter cover crop Compacted layer

Plow depth

Another major cover crop function: enhanced nutrient management

Reduce losses Enhance availability Add nitrogen Recover deep nutrients

Nutrient capture: nitrogen in fall

Unpublished data of Weill and Fisher

By March-April, radishes are long dead and its residue is mainly gone, but its nitrogen capture effects are still evident.

1 2 3 4 5 6 7 8 No cover Oat Radish Rad + Oat Fresh spinach, Mg/ha Roto tilled No-till

16 14 12 10 8 6 4 2

Organic no-till, no-herbicide veggies using cover crops

Lounsbury, N.P., and R.R. Weil. 2015. No-till seeded spinach after winterkilled cover crops in an organic production system. Renewable Agriculture and Food Systems 30:1-13.

No-till corn, after radish cover crop No-till corn, after rye cover crop

Nitrogen captured in fall can reduce the need for fertilizer in spring

Example of more advanced cover cropping: Zoned cover crop mixtures

Photo by Natalie Lounsbury

Thank-you! Any questions?