The Organic Horticulture Production System Heather Friedrich University of Arkansas [email protected]
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 & weeds Rule of Thumb: No synthetic fertilizers or pesticides (including urea or Round-Up™); few exceptions eg. pheromones Rule 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 crops Tillage Fertilizers Mulch Irrigation Weed management Insect, 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 N Manure: cannot be applied less than120 days prior to harvest for a food crop Cover crops: Legume/Grass mixtures Fish emulsion, seaweed Plant based fertilizers Alfalfa meal Soybean 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 soils Slow-release of nutrients May 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 Organics Can be applied to a crop at any time if it was composted according to NOP rules: Made with plant or animal materials No biosolids or any other unapproved inputs (refer to National List) C:N ratio of 15:1 to 40:1 In-vessel or static aerated pile system must reach a minimum of 131F for at least 3 days A windrow system must reach at least 131F for 15 days and be turned at least 5x so that that all materials reach temp must 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 fertility Interrupt insect, weed and disease cycles Pests unable to find hosts when crops are changed Change the crop ecology: shallow/deep roots, cold/warm season, row/drilled crops, foliage density, heavy/light feeders
10 Year Rotation Scheme Alex 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 flowers 5 Flowers- overwintered Sudangrass-soyb. Rye-hairy vetch 6 Peppers Wheat-crimson clover 7 Flowers -summer Oat-crimson clover 8 Mixed spring veg cowpeas Fall planted flowers 9 Flowers- overwintered Sudangrass-soyb. Oat-crimson clover 10 Flowers-summer Wheat-hairy vetch
Planting Diversity Efficiency: space soil water reduces insects pressure increases beneficial insects Early season spring greens and garlic
Mixed lettuce greens & gladiolas
Perennial Crops Soil building & Biodiversity Groundcover management – mixed spp Mulches Cover crops in strips Insectary plantings
WEEDS Understand the biology of weeds: annual, fixed perennial, wandering perennial, the lifecycle, establishment Good soil for crops = good for weeds Action Remove or Prevent establishment --change the environment “Many little hammers approach”
Mechanical Weed Control Cultivation (timely&shallow): hoe, cultivators - dust mulch Push-pull hoes ergonomic handles Hand scrapers and cultivators for tight spaces Rototilling, multivators, tine & basket weeders – can get close and in-btw plants Exhaust root system (perennial weeds)– deplete storage reserves Requires 6-8 timely treatments in yr 1, then 3-5 the following year
Tillage & Soil Health Criticism of organic agriculture is use of tillage Negative 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-till Must 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 herbicides Matran , Burnout II, Green Match, others Phytotoxic – burn plant tissue Thoroughly coat weed Non-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 canopy Use transplants vs direct seeding for crops if possible Transplant 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 rotation Time & 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 Fall Hairy vetch Crimson clover Subterranean clover Austrian winter pea Grain rye, wheat, oats Brassicas (radish, turnip) Summer cover crops – plant after frost Annual lespedeza Soybeans Southern peas Buckwheat lespedeza Sorghum-Sudangrass Crimson clover
Insect Management Crop rotation – healthy soil Enhance natural plant defenses Prevention - clean up after harvest & destroy all infested fruits/vegetables Row covers - keep pests out; put over plants when young and remove at flowering Companion planting and trap crops Harvest early – variety selection Know your pest--life cycle, natural enemies, relationship with climatic conditions--and manage at vulnerable period
Biological Control Critical component of organic insect management Natural enemies (predators, parasites, nematodes and pathogens) exist for nearly every pest Conservation of beneficials is key Augmentation (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 landscape Insectary plants: buckwheat, clovers, herbs-dill, mint, yarrow; flowers- gaillardia, allysum, daisies Use of toxic pesticides limited to outbreaks
Approved Treatments Use as last resort--may affect beneficials Check with Certification Agency Check with National List Check with Organic Materials Review Institute (OMRI) www.omri.org Bacillus thuringiensis (Bt), lepidopteran specific Botanical insecticides: pyrethrum, sabadilla, neem Other natural treatments: D.E., garlic, hot pepper, vegetable oils and soaps
Disease Management Susceptible host Favorable environment Virulent pathogen Disease Triangle: for disease to occur, all 3 must be present
Disease Management Crop rotation – healthy soil Disease resistant/tolerant cultivars; breeding programs Pruning & spacing- promote air-flow Removal of diseased leaves/plants - sanitation Compost application; compost tea Organic fungicides – baking soda, garlic, milk – efficacy dependant on several things Serenade Bacillus subtilis – powdery mildew, early & late blight, gray mold
Compost for Disease Suppression
Organic Breeding Seed breeding under organic conditions Organic Seed Alliance, Abundant Life, Save Our Seeds, Cornell - Public Seed Initiative, Seeds of Change Organic producer involvement Organically bred varieties can thrive under less than optimum conditions -seedling vigor, efficient nutrient uptake Have multiple gene resistance -cuticle thickness, trichomes , phenols
Resources NCAT-ATTRA, www.attra.org Ag groups: SSAWG Annual conf Resources www.ssawg.org/ed-resources.html Local Extension office Field days Local Farmers Market Internet 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 Arkansas Obadiah Njue , University of Arkansas at Pine Bluff Jeanine Davis , North Carolina State University Geoff Zehnder , Clemson University Charles Mitchell , Auburn University Rufina Ward , Alabama A&M University Ken Ward , Alabama A&M University Karen Wynne , Alabama Sustainable Agriculture Network