MAKING ORGANIC ROTATIONS WORK FOR YOU

Dr. Erin Silva

University of Wisconsin-Madison

Assistant Professor

Organic and Sustainable Production Systems Specialist

“CERTIFIED ORGANIC”

• Indicates that the item has been grown according to strict uniform standards that are verified by independent state or private organizations

• includes inspections of farm fields and processing facilities and detailed record keeping

• 3 year transition period until organic

DEFINITION OF ORGANIC(NATIONAL ORGANIC PROGRAM)

• “A production system that is managed to respond to site-specific conditions by integrating cultural, biological, and mechanical practices that foster cycling of resources, promote ecological balance, and conserve biodiversity”

• “Organic” speaks to adherence to a certain set of production practices

• Does not speak to any other claims

What is Organic Agriculture?

Ecological-based management system – not just what you don’t use, but what you do

• Diversified crops – corn, soybean, wheat, oat, alfalfa

• Soil stewardship – maintaining and improving resources

• Animals must have access to pasture

• No antibiotic use on livestock

• Prohibits synthetic inputs

• Prohibits use of GMO crops

REGULATION ALLOWS FOR FLEXIBILITY

• Not a cookbook

• Management plans reflect unique characteristics of each operation

DISTRIBUTION OF ORGANIC FARMS

ORGANIC AGRICULTURE – NOT YOUR “GRANDFATHER’S FARMING

• Alternative approaches – not less inputs!

• De-emphasis on individual inputs, more emphasis on understanding the system

• Integrates science and technology to make decisions and to manage production

MINIMUM ROTATION FOR ORGANIC GRAINS

• Corn (interseeded with cover crops?)

• Soybeans (cover crop-based no-till?)

• Small grains (interseeded with alfalfa, clovers, and grasses)

• Legume-grass mix (essential for soil building, fertility, and weed management)

System

Crop

rotation

w/cover

crops

Years in

rotationTillage Fertility

Mean poultry

litter

application

rate (tons/

acre/year)

Weed

control

No-till

(NT)

Corn-rye-

Soybean- Wheat-

Soybean

3 None Mineral

fertilizers

NA Herbicide

Chisel

Till

(CT)

Corn-rye-

Soybean- Wheat-

Soybean

3 Chisel, Disk Mineral

fertilizers

NA Herbicide

Organic,

2-year

(Org2)

Corn-rye-

Soybean-

vetch

2 Moldboard plow,

Chisel, Disk,

Rotary hoe,

Cultivator

Legume and

animal

manure

1.0 Cultural

Organic,

3-year

(Org3)

Corn-rye-

Soybean-

Wheat-vetch

3 Moldboard plow,

Chisel, Disk,

Rotary hoe,

Cultivator

Legume and

animal

manure

1.3 Cultural

Organic,

6-year

(Org6)

Corn-rye-

Soybean-

Wheat- Alfalfa-

Alfalfa-Alfalfa

6 Moldboard plow,

Chisel, Disk,

Rotary hoe,

Cultivator

Legume and

animal

manure

0.7 Cultural

WEED PRESSURE

• In Org2, opportunities to kill weeds occur at the same time each year since the two cash crops, corn and soybean, are planted at similar times

• Summer annual weeds increase populations in this system.

• When wheat is added to the rotation (Org3), the summer annual weeds either do not germinate under the wheat canopy or do not reach reproductive maturity as they are cut prior to setting seed when the wheat is harvested, and killed when soil is prepared for planting cover crops after wheat harvest

• In Org6, a perennial forage crop, alfalfa, provides an additional level of phenological complexity that provides further weed control opportunities

• Alfalfa is cut three to five times per year, a disturbance regime that tends to favor perennial and annual grasses with a prostrate growth habit rather than annual broadleaf weeds

• Tillage prior to corn planting provides control of the grasses favored during the alfalfa phase of the rotation.

• Corn yield loss to weeds, as measured in adjacent weed-free and weedy plots, was reduced from 35% in Org2 to 14% in Org6

ECONOMIC PERFORMANCE

• When organic price premiums for corn, soybean, and wheat were included in an economic analysis for the years 2000 to 2002, net returns for the three organic systems were similar (mean, $286/acre) and substantially higher than for the conventional systems (mean, $78/acre)

• Economic risk, however, was 7.5 and 3.9 times greater for Org2 and Org3, respectively, than for Org6, indicating a substantial economic benefit to more phenologically diverse crop rotations, as risk is spread over crops growing and harvested during different parts of the year

NUTRIENT MANAGEMENT

• Increasing crop phenological diversity can benefit soil nutrient management

• While N mineralization potential, particulate organic matter N, and SOC were similar among the three organic systems and all were greater than in CT and NT

• Benefits were attained in Org6 with substantially fewer inputs of poultry litter than in the two shorter organic rotations (Org2 and Org3)

• Possibility of overloading soils with phosphorus, an important concern in many watersheds, especially when animal manures are applied, was reduced considerably with Org6 compared to the shorter organic rotations

CORN YIELD

• Corn grain yield in a six-year rotation (Org6), which includes summer annual (corn, soybean), winter annual (winter wheat), and herbaceous perennial (alfalfa for three years) cash crops was, on average, 10% greater than in a three- year rotation (Org3) that includes only summer and winter annual cash crops, and 30% greater than in a two-year rotation (Org2) that includes only summer annual cash crops

• Result of both increases in N availability and decreases in weed competition as crop rotation length and complexity increased

MANAGEMENT TOOLS FOR ORGANIC ROTATIONS

Tool Mode of Action

Rotations Biological

Cover crops Biological

Weed seed predation Biological

Tillage Mechanical

Tine weeding/harrowing Mechanical

Rotary hoeing Mechanical

Cultivation Mechanical

Hand weeding Mechanical

Mitigating compaction Biological

Soil temperatures Biological

WEED AND FERTILITY MANAGEMENT

• Biggest challenges for long-term, profitable organic production

• Site-specific – not a “cookbook” approach

• General principles can be applied

• Combination of biological and mechanical

SOURCES OF N FOR ORGANIC CROPS

• Biological N fixation (credits from legumes)

• Rotation effect: some N credit

• N scavenging cover crops?

• Livestock and poultry manure

• Blood meal, feather meal, fish products

• Chilean (sodium) nitrate

• Foliar feeds

OPTIMIZING N CYCLING

• Include legume crops in your rotation

• Grow high N-demand crops after a plow-down

• Use manure or other amendments as N sources only to provide additional N after accounting for legume N credits unless you also need to build up P and K levels

http://www.pivotandgrow.com/wp-content/uploads/2016/03/organic-wheat-price-history-1.png

SMALL GRAIN PRODUCTION CHALLENGES IN UPPER MIDWEST

• Quality

• Low protein (11.5-12.5%)

• Obtaining adequate test weights

• Moldy grain

• Low falling number (sprouting in head)

• Fungal issues

• Disease and head blight

• Vomitoxin

• Availability and identification of regionally adapted varieties

PROFITABLE SMALL GRAIN PRODUCTION

• Crop rotation strategy

• Field selection

• Soybean or plowed field – get in early, good seedbed, get them up

• Variety selection

• Resistance to diseases, winterhardiness

• Weed control strategy

• Early planting, good seedbed

• Leaf structure?

• Harvesting and storage strategy

• Manage quality

• Marketing strategy

• Commodity vs. quality

• Protein

OAT VARIETIES FOR UPPER MIDWEST

• Badger

• Spurs

• Sabers

• Deon

• Hayden

• Shelby 427

• Betagene

GOOD SITES FOR VARIETY TRIAL DATA:

• http://umaine.edu/localwheat/research/variety-trials/

• Smallgrains.cals.cornell.edu

• http://www.coolbean.info/small_grains/variety_trial_results_small_grains.php

TINE WEEDING AND HARROWING CEREAL GRAINS

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CROP TOLERANCE TO IN-ROW HARROWING

Crop Type (resistance to in-crop tillage decreases from left to right)

Pea and Chickpea

Sunflower LentilWheat and Barley

OatFlax and Canola

Estimated % of crop plant loss

Less than 20%

Less than 20%

30% 30% 30% 60 to 90%

FUSARIUM HEAD BLIGHT

• “Scab”

• Cause: Fusarium graminearum and other fusariums

• Overwinters on host residue (grasses, corn, wheat stubble)

• Inoculum also travels on wind

• Occurs during rain at flowering, fungus infects florets and later cuts off nutrients to the spikelet resulting in shriveled kernels “tombstones”.

FUSARIUM HEAD BLIGHT

• Severity of FHB varies greatly from year to year, but favored by

extended periods of high moisture or high (>90%) relative

humidity, and moderately warm temperatures (59 to 86°F)

• Conditions have to occur just before or during wheat flowering

(Feekes 10.5) and wheat can remain susceptible to infection

through the early dough stage (Feekes 11.2)

• If favorable weather conditions persist, flowering tillers can

continue to be infected

WHY IS FUSARIUM IMPORTANT?

• Fusarium fungus can produce vomitoxin (deoxynivalenol or DON)

• Strict limits on presence of DON in grain for feed and food, see quality testing

• Spikes will be partially white – either individual spikelets or top part if vascular tissue in the main rachis is blocked

• Seeds will be shriveled and lighter, can be pinkish if infection is severe enough

• Presence of pink color and degree of shriveling are NOT an indication of the amount of DON in the kernel. The fungus can produce varying amounts of toxin depending on the environmental conditions in the field.

FUSARIUM MANAGEMENT

• Avoid planting into or near corn stubble

• Plant resistant varieties if available (some new ones from UMN showing tolerance)

• Manage harvest carefully:

• Scout fields for signs of infection while wheat is still green and white heads can be seen

• Harvest fields separately, and consider not harvesting patches that were highly infected. Turn up air in combine if field looks infected

• Send a sample from each field into a lab for testing (see below)

• Keep fields separate until lab tests come back

• Cleaning can reduce the number of tombstone kernels, but don’t rely on cleaning as it will not always reduce the level enough to make grain marketable

COMBINE SETTINGS FOR SCAB FIELDS

• Properly setting combine to blow out lighter seeds and chaff

• Adjusting the combine’s fan speed between 1,375 and 1,475 rpms and shutter opening to 90 mm (3.5 inches) resulted in the lowest discounts that would have been received at the elevator due to low test weight, % damaged kernels, and level of the mycotoxin deoxynivalenol (DON; vomitoxin)

• Salgado et al., 2011, “Grain harvesting strategies to minimize grain quality losses due to Fusarium head blight in wheat,” Plant Disease, 95:1448-1457

TEST WEIGHTS

• How much a volumetric bushel actually weighs

• Measure of grain density

• Sound grain is denser than grain that has FHB infection or poor filling

• Higher protein grain has higher density than low protein grain

ACHIEVING BEST TEST WEIGHTS

• Adequate fertility. When available nitrogen is deficient (or too high), test weight will be lower.

• Insect pest management. When foliage or stems are eaten or damaged during grain fill, test weight will be reduced.

• Variety selection.Varieties showing superior test weight results in trials may be a good choice. However, other factors including yield and disease resistance are equally important.

• Avoid plant lodging. Avoid development of an overly dense canopy caused by excessive nitrogen rates early in plant development. Other causes of lodging include poor standability varieties, uneven fertilizer spreading equipment, stem-based diseases and poor plant anchorage resulting from poor soil structure

SMALL SCALE GRAIN DRYERS

SOME GENERAL GUIDELINES

• Apply manure before planting

• Watch your rotation. Do not follow corn with wheat (fusarium)

• Plant thick

• Be ready to harrow or tine weed, especially spring grains (3 leaf stage)

• Organic fungicides and foliar feeds?

• Watch the weather

• Harvest earlier at 18-20% and dry down

• Monitor moisture and humidity in stored grains

• Watch for insect infestation

CornSilage

CoverCrops

Soybean

Winter

Wheat

CoverCrops

Mid-Aug

Mid-early May

Mid-late Sept.

Mid-MayLaChance et al., courtesy of Murrell

COVER CROP OPTIONS FOR ORGANIC ROTATIONS

• Choose cover crops to best fit desired purpose(s) and niche (window) in system.

• “Green manure” crop—cover crop or forage grown to incorporate into soil while green or flowering, to improve soil

• “Catch” crop or “trap” crop—cover crops planted to reduce nutrient leaching following a main crop

• “Living mulch”—cover crop interplanted with cash crop

• Forage crop—can serve as green manure crop after grazing or haying is finished

https://web.extension.illinois.edu/smallfarm/downloads/56089.ppt

HOW TO CHOOSE COVER CROPS

FROST SEEDING RED CLOVER INTO WHEAT

• Red clover is “frost seeded” (10 lbs/ac) into dormant winter wheat in mid to late March after snowmelt, when low nighttime temperatures cause the soil to freeze and crack

• Warmer day time temperatures create thawing at the soil surface, and close the cracks

• The best time of day to broadcast the seed is early in the morning when the cracks are frozen open and the stiff soils support the application equipment.

ORGANIC COVER CROP-BASED REDUCED-TILLAGE

• Focused on limiting tillage in certain phases

• Soybean phase most reliable

• Corn phase possible?

• Use fall-planted cover crops to smother weeds

• Cover crops terminated in spring

• Rolled-crimped or mowed

• Cash crops planted following cover crop termination

• No or limited cultivation needed for weed control

CRIMPING RYE