The Organic Horticulture Production System

Heather FriedrichUniversity of Arkansas

heatherf@uark.edu

Organic Production Principles

Defined according to the National Organic Program (NOP) as:

an ecological production management system that promotes and enhances biodiversity, biological cycles and soil biological activity. It is based on minimal use of off-farm inputs and on management practices that restore, maintain and enhance ecological harmony.

Production is based on a holistic biological system & not input substitution Soil based system

Organic Production Principles

Management-intensive: Routine observation of plant health & weedsRule of Thumb: No synthetic fertilizers or pesticides (including urea or Round-Up™); few exceptions eg. pheromonesRule of Thumb: Only naturally based products, few exceptions eg. lead, arsenic, nicotine No GMO seeds or irradiated products

“Feed the soil to feed the plant”Build/maintain healthiest soil possible through:

Crop rotation including cover cropsTillageFertilizersMulch IrrigationWeed managementInsect, Arthropod & Disease management

What goes on in the soil that is so important?

Elaine R. Ingham The Soil Biology Primer 

Soil Fertility Management

Compost: animal-based provides more NManure: cannot be applied less than120 days prior to harvest for a food cropCover crops: Legume/Grass mixturesFish emulsion, seaweedPlant based fertilizers

Alfalfa mealSoybean meal

Field pea-oat-mustard cover crop

Soil food web!!

Benefits of Compost

Nutrient recycling cornerstone of ecologically-based farming

Assists in moisture retention in soilsSlow-release of nutrientsMay reduce disease incidence due to an increase of microbial populations• may out-compete disease causing

organisms

Benefits of Compost

• Helps reduce odors of original feedstocks

• Destruction of weed seeds and pathogens

• Destruction of potentially harmful microorganisms such as E.coli 0157:h7 or salmonella

Compost Rules for OrganicsCan be applied to a crop at any time if it was composted according to NOP rules:

Made with plant or animal materialsNo biosolids or any other unapproved inputs (refer to National List)

C:N ratio of 15:1 to 40:1In-vessel or static aerated pile system must reach a minimum of 131F for at least 3 daysA windrow system must reach at least 131F for 15 days and be turned at least 5x so that that all materials reach tempmust be cured or aged

If compost does not meet standards, follow the same rules as raw manure

Crop Rotations – annual crops

Rotation must include a cover crop and work to maintain or improve soil organic matter Consider crop nutrition, soil fertilityInterrupt insect, weed and disease cycles

Pests unable to find hosts when crops are changedChange the crop ecology: shallow/deep roots, cold/warm season, row/drilled crops, foliage density, heavy/light feeders

10 Year Rotation SchemeAlex and Betsy Hitt, Chapel Hill NC; http://www.ssawg.org/hitt.html

YR

Spring Summer Fall

1 Tomatos & leeks Oat-crimson clover

2 Flowers-cool seas. Sudangrass-soyb.

Oat-crimson clover

3 Spring lettuce Flowers, summer

Rye-hairy vetch

4 Squash Fall planted flowers5 Flowers-

overwinteredSudangrass-soyb.

Rye-hairy vetch

6 Peppers Wheat-crimson clover7 Flowers -summer Oat-crimson clover8 Mixed spring veg cowpeas Fall planted flowers9 Flowers-

overwinteredSudangrass-soyb.

Oat-crimson clover

10

Flowers-summer Wheat-hairy vetch

Planting Diversity

Efficiency: space soilwater reduces insects pressure increases beneficial insects

Early season spring greens and garlic

Mixed lettuce greens & gladiolas

Perennial CropsSoil building & Biodiversity

Groundcover management – mixed sppMulchesCover crops in stripsInsectary plantings

WEEDSUnderstand the biology of weeds:annual, fixed perennial, wandering perennial, the lifecycle, establishmentGood soil for crops = good for weeds

ActionRemove or Prevent establishment --

change the environment“Many little hammers approach”

WEEDS! “Little Hammers”

Crop rotation & cover crops-remember crop ecologyCultivation (timely): hand-hoe, rototilling, cultivators, hoeing - dust mulchMulches: straw, fabric, wool, flax, plastic (landfill issues)FlamerOrganic herbicidesBiodiversity: insects, animals eat weed seeds

Mechanical Weed Control

Cultivation (timely&shallow): hoe, cultivators - dust mulchPush-pull hoesergonomic handles Hand scrapers and cultivators for tight spacesRototilling, multivators, tine & basket weeders – can get close and in-btw plantsExhaust root system (perennial weeds)– deplete storage reserves

Requires 6-8 timely treatments in yr 1, then 3-5 the following year

Tillage & Soil HealthCriticism of organic agriculture is use of tillageNegative effects of tillage, offset by the use of cover crops and additions of organic matter (compost, manures, mulch, etc) USDA-ARS research showed organic methods can increase Organic Matter more than conventional no-tillMust use caution against excessive tillage

Mulches

• Prevent seeds from germinating, can smother out some weeds

• Conserve water, minimal soil disruption,

• Use local resources: straw, fabric, wood, newspaper, plastic/landsc. fabric

• Be careful of weed seeds in straw• Especially good for perennial systems:

blueberries, blackberries, flowers, trees

• Living mulches – eg plant fall clover crop, mow at flowering to kill it, plant into residue

Paper mulch in lilies & snapdragons

Rowcover over tomatoes and landscaping fabric between rows

Wood chip mulch laid over newspapers in walk way

leaf mulch applied in fall to perennial flowers

Wood chip mulch, possibly free resource

Other methods of weed control

Organic herbicidesMatran, Burnout II, Green Match, othersPhytotoxic – burn plant tissueThoroughly coat weedNon-selective

• Flamer – especially handy during wet conditions – no mechanical tools• Broadleaf weeds more susceptible to flaming

Crop selection

Some crops are more competitive against weeds than others

Rapid germination, growth, dense canopyUse transplants vs direct seeding for crops if possibleTransplant or plant into a clean bed

Allow a flush of weeds to emerge then till under

Insect – Weed Interaction

Cover crops in Weed Management How do they work?

• Smother weeds by out competing: light, water, nutrients

• Release allelopathic chemicals that suppress weed germination

• As they decompose, abundant microbial communities suppress germination

• prevent soil erosion• aka – “green manure”• Recycle and scavenge nutrients• Provide organic matter

Cover crops

How to incorporate into annual rotationTime & Space niches

Time - plant cover crop before or after harvest of main crops (eg. plant buckwheat between spring greens and fall tomatoes)

Space – plant low growing cover crop within main crop, after establishment (eg. plant legume into sweetcorn)

Cover crops for Southeast

Winter cover crops – plant in FallHairy vetchCrimson cloverSubterranean cloverAustrian winter peaGrain rye, wheat, oatsBrassicas (radish, turnip)

Summer cover crops – plant after frost• Annual lespedeza • Soybeans • Southern peas • Buckwheat• lespedeza • Sorghum-Sudangrass

Crimson clover

Insect ManagementCrop rotation – healthy soil Enhance natural plant defensesPrevention - clean up after harvest & destroy all infested fruits/vegetablesRow covers - keep pests out; put over plants when young and remove at floweringCompanion planting and trap cropsHarvest early – variety selectionKnow your pest--life cycle, natural enemies, relationship with climatic conditions--and manage at vulnerable period

Biological Control

Critical component of organic insect managementNatural enemies (predators, parasites, nematodes and pathogens) exist for nearly every pest Conservation of beneficials is keyAugmentation (purchased beneficials) can work in certain cases (e.g. greenhouses)

Trichopoda pennipes

Michigan Field Crop and Pest Ecology and Management , 2000

Conservation of Beneficials

Maintain adequate supply of food (prey, pollen, nectar) through plant diversity in the farm landscapeInsectary plants: buckwheat, clovers, herbs-dill, mint, yarrow; flowers- gaillardia, allysum, daisiesUse of toxic pesticides limited to outbreaks

Approved Treatments

Use as last resort--may affect beneficials Check with Certification AgencyCheck with National ListCheck with Organic Materials Review Institute (OMRI) www.omri.orgBacillus thuringiensis (Bt), lepidopteran specificBotanical insecticides: pyrethrum, sabadilla, neemOther natural treatments: D.E., garlic, hot pepper, vegetable oils and soaps

Disease Management

Susceptible host

Favorable environment

Virulentpathogen

Disease Triangle: for disease to occur, all 3 must be present

Disease ManagementCrop rotation – healthy soilDisease resistant/tolerant cultivars; breeding programsPruning & spacing- promote air-flowRemoval of diseased leaves/plants - sanitationCompost application; compost teaOrganic fungicides – baking soda, garlic, milk – efficacy dependant on several thingsSerenade Bacillus subtilis –

powdery mildew, early & late blight, gray mold

Compost for Disease Suppression

Organic BreedingSeed breeding under organic conditions Organic Seed Alliance, Abundant Life, Save Our Seeds, Cornell - Public Seed Initiative, Seeds of Change Organic producer involvementOrganically bred varieties can thrive under less than optimum conditions -seedling vigor, efficient nutrient uptakeHave multiple gene resistance -cuticle thickness, trichomes, phenols

ResourcesNCAT-ATTRA,

www.attra.orgAg groups: SSAWG

Annual confResources www.ssawg.org/ed-resources.html

Local Extension officeField daysLocal Farmers MarketInternet

www.attra.org www.ams.usda.gov/nop/indexIE.htm www.extension.org www.ofrf.org ; Organic Farming Research Foundation

Acknowledgements

This presentation address general organic production practices. It is to be to use in planning and conducting organic horticulture trainings. The presentation is part of project funded by a Southern SARE PDP titled “Building Organic Agriculture Extension Training Capacity in the Southeast”Project Collaborators• Elena Garcia, University of Arkansas CES

Heather Friedrich, University of ArkansasObadiah Njue, University of Arkansas at Pine BluffJeanine Davis, North Carolina State UniversityGeoff Zehnder, Clemson UniversityCharles Mitchell, Auburn UniversityRufina Ward, Alabama A&M UniversityKen Ward, Alabama A&M UniversityKaren Wynne, Alabama Sustainable Agriculture Network