Vegetable Crops – PLSC 451/551Lesson 10, Organic Strategies

Instructor:Stephen L. LoveAberdeen R & E Center1693 S 2700 WAberdeen, ID 83210Phone: 397-4181 Fax: 397-4311Email: slove@uidaho.edu

Choosing a Production Location

Concepts and Objectives

Minimize the need for unwanted inputs

Avoid serious production barriers

Choosing a Production Site

Strategies

Choose property that is located near the market delivery point

Seek soil with high levels of natural fertility and good textural and structural characteristics

Select a site that is free from serious chronic weed, insect, or disease problems

Choosing a Production Site

Specifics – market location

Owner-operator marketing

Best located near a major population center

Access to farmer’s market

Vegetable stand on major travel route

Local grocer, restaurant, specialty market

Wholesale or cooperative marketing

Best located near produce collection point

Choosing a Production Site

Specifics – soil characteristics

Naturally high in organic matter

Naturally high in P, K, S

Good water holding capacity in infiltration

Loams, sandy loams, silt loams

(Avoid heavy clay or very sandy soils)

Choosing a Production Site

Specifics – chronic pest problems

Low weed seed bank (historically good control)

Free of perennial, deep-rooted weed problems

(e.g. bindweed, quackgrass, nutsedge, etc.)

Free of consistent, chronic insect or disease problems that affect the intended crops

(e.g. nematodes, soil wilt diseases, cutworms, wireworms, etc.)

Plant and Seed Selection

Concepts and Objectives

Use crop and variety choices to enhance production capabilities and market options

Utilize genetic resistance for controlling common problems

Avoid “importing” problems

Plant and Seed Selection

Strategies

Select crops and varieties that provide a market identity

Choose crops and varieties that are adapted to local conditions and organic techniques

Traditional

Unique and unusual

Traditional

Unique and unusual

Traditional

Unique and unusual

Plant and Seed Selection

Strategies

Select varieties that are biologically competitive and resistant to locally common disease and insect problems

Purchase “organic” seed and transplants from a reputable producer

Inspect all seeds and transplants

Potato Variety Comparison

Variety Vert Eblt Lblt PLRV PVY

R. Burbank S MS S VS S

Defender VR R R MR MR

Important to have resistance to pathogens that require intense management inputs

Soil Management

Goals

Create a “healthy” soil

Maintain and/or increase organic matter

Improve soil structure and tilth

Supply nutrients with minimal added fertilizer

Improve water holding capacity and infiltration

Soil Management

Healthy Soils

Biologically active

Flourishing micro-organism population

Rapid breakdown of organic residues

Natural nutrient availability

Attractive to earthworms and other “aerifiers”

Suppressive to soil diseases

Suppressive Soils

Verticillium wilt incidence on potatoes

Treatment % Vert Wilt

Non-suppressive 62.6

Suppressive (OM added) 16.5

No soil fumigant 36.6

Soil fumigant 42.5

From Davis et al. (unpublished)

Soil Management

Sources of organic matter

Animal manures (cow, sheep, poultry, swine)

Compost (manure or plant residue based)

Green manures (grains, grasses, legumes, mustards, etc.)

Cover crops (winter grains, grasses, hardy legumes)

Crop residues (leftover or added)

Soil Management

Sources of organic matter

Animal manures (cow, sheep, poultry, swine)

Compost (manure or plant residue based)

Green manures (grains, grasses, legumes, mustards, etc.)

Cover crops (winter grains, grasses, hardy legumes)

Crop residues (leftover or added)

Soil Management

Sources of organic matter

Animal manures (cow, sheep, poultry, swine)

Compost (manure or plant residue based)

Green manures (grains, grasses, legumes, mustards, etc.)

Cover crops (winter grains, grasses, hardy legumes)

Crop residues (leftover or added)

Soil Management

Sources of organic matter

Animal manures (cow, sheep, poultry, swine)

Compost (manure or plant residue based)

Green manures (grains, grasses, legumes, mustards, etc.)

Cover crops (winter grains, grasses, hardy legumes)

Crop residues (leftover or added)

Soil Management

Sources of organic matter

Animal manures (cow, sheep, poultry, swine)

Compost (manure or plant residue based)

Green manures (grains, grasses, legumes, mustards, etc.)

Cover crops (winter grains, grasses, hardy legumes)

Crop residues (leftover or added)

Fertility Management

Soil testing

Zone sampling

Evaluate:

N, P, K, S, micronutrients (Zn, Mn, Mo)

pH

Organic matter content

Cation exchange capacity (CEC)

Fertility Management

Organic matter as a nutrient source

Nutrient release delayed – 20-50% first year

Not effective as a short-term nutrient source

Required in large amounts

Acts as a complete fertilizer, including micronutrients

Fertility Management

N requirement of selected crops

Low requirement - <120 lb/A

greens, beans, peas, squash

Medium requirement – 120-200 lb/A

carrots, corn, melons, onions, tomatoes

High requirement - >200 lb/A

cole crops, celery, potatoes

Fertility Management

Nutrient content of manures (lb/ton)

Type N P2O5 K2O

Beef 21 18 26

Swine 6 7 7

Horse 14 4 14

Sheep 14 9 25

Poultry 33 48 34Composts are generally lower but vary by source

Fertility Management

Nutrient contribution of green manures (lb/A)

Crop N P2O5 K2O

Hairy vetch 141 18 133

Clover 115 16 143

Austrian pea 144 19 159

Rye 89 18 108

Sullivan, 2003

Fertility Management

Other contributions of green manures and cover crops

Suppresses weeds

Minimizes soil erosion

Serves to capture nutrients

Improves soil structure

Enhances the growth of beneficial soil flora

Fertility Management

Crop residues

Important contributor to soil nutrition

Should be incorporated or left on surface

Contribution varies widely by crop

Fertility Management

Nutrient contribution organic fertilizers (%)

Fertilizer N P2O5 K2O

Bone meal 2 15 0

Blood meal 13 0 0

Fish emulsion 4 2 2

Soybean meal 7 2 2

Corn gluten 10 1 1Jett, 2004

Low nutrient content means high shipping and handling costs?!

Organic Vegetable Production

Fertility management – approved products

Algae Blood mealBone meal Chilean nitrateCompost CyanobacteriaDolomite Epsom saltsFish emulsions* Grape or apple pomadesGuano Hoof and horn mealHumic acids (nonfort.) Kelp meal

Organic Vegetable Production

Fertility management – approved products

K-mag Peat mossPhosphate rock Sodium nitrate (20%)Sugar beet lime Zinc or iron sulfateWorm castings Animal manureChelates EnzymesFish meal Gibberellic acidGreensand Gypsum

Organic Vegetable Production

Fertility management – approved products

Humates Kelp extracts

Kieserite Limestone

Mined material Mushroom compost

Perlite Potassium sulfate

Ground shells Elemental sulfur

Wood ashes

Organic Vegetable Production

Fertility management – prohibited products

Ammonia products Calcium nitrateSewage sludge Hydrated limeFortified humic acid Leather mealMagnesium nitrate Muriate of potashPhosphoric acid Potassium nitrateSuper phosphate Triple phosphateUrea Vitamin B-1

Weed Control

Cultural weed control

Rotate with competitive cropsEmploy incorporation of green manuresUtilize drip irrigationPlastic or organic mulches and/or row coversPlant crops at high population levelsUse competitive varieties

Weed Control

Mechanical weed control

Pre-irrigate and till prior to plantingPractice frequent cultivationUse flame-weedersEmploy hand labor (hoe, hoe, hoe)

Weed Control

Herbicidal weed controlThese products have been shown to provide some

control (finicky and not consistent)

Herbicidal soapsAcetic acidCitric acidCorn gluten

Weed Control

Weed control – prohibited products

Carrot oil

Synthetic growth regulators

Herbicides (all synthetic classes)

Weed oils

Insect Control

Control techniques

Plant resistant crops/varieties

Utilize beneficial insects and parasites

Plant borders with trap crops

Schedule planting to avoid damaging stages

Use approved insecticidal products as needed

Practice sanitation/fall plowing

Organic Vegetable Production

Beneficial insects and the pests they control:Lacewings thrips, aphids, mites, eggsLadybugs aphids, mites, eggsMinute pirate bug thrips, eggsBig-eyed bug thrips, aphids, eggsDamsel bug thrips, aphids, eggs, othersAssassin bug thrips, eggsSyrphid fly thrips, aphids, eggsParasitic wasps aphids, caterpillars, othersTwo-spotted stink bug Colorado potato beetle larvae

Organic Vegetable ProductionApproved insecticides:Bacillus thuringiensis Boric acidCryolite Dormant oilsHerbal preparations NematodesPyrethrums (natural) RyaniaSoaps GarlicDiatomaceous earth Insect extractsPheremones RotenoneTrapping substances Neem oilSpinosyn A&D Spinosad

Organic Vegetable Production

Prohibited insecticides:

Chlorinated hydrocarbons Carbamates

Methyl bromide Nicotine

Moth balls Methyl sulfoxide

Organophosphates Dimethyl sulfoxide

Pyrethroids (synthetic) Plant protectants

Organic Vegetable Production

Production methods – Disease control

Practice sanitation

Rogue infected plants

Control disease vectors

Utilize extended rotations

Maintain plant health/natural defenses

Use approved fungicidal compounds

Organic Vegetable Production

Disease control – approved products and practices

Natural antibiotics Copper hydroxide

Dormant oils Lime sulfur

Hydrogen peroxide Tree waxes/seals

Soil pasteurization Elemental sulfur

Organic Vegetable Production

Disease control – prohibited products and practices

Soil fumigants

Sterilants

Synthetic fungicides

Bactericides

Postharvest Management

Controlling postharvest rots/breakdown

Minimize injury during harvest

Harvest during cool temperatures

Employ proper cooling techniques

Remove damaged/rotting produce

Sanitize all handling equipment surfaces

Postharvest Management

Approved sanitizing or disinfecting products

Acetic acid

Organic ethyl alcohol

Quaternary ammonium salts

Bleach

Hydrogen peroxide

Postharvest Management

Prohibited products

Synthetic fungicides

Bactericides

Non-organically produced waxes and alcohols