Cover Crops/Rotations

Cover Crops at the Kerr Center

The bioextensive system in place on the Cannon Horticulture plots keeps half the ground in cover crops at any given time.  It’s meant to keep weeds in check and soil healthy – and it works.


Rotation Plan:

Summer cover crops on much of the acreage help suppress weeds and manage soil sustainably.



Three half-acre plots in rotation, with a fourth half-acre plot used for testing equipment and other purposes.


2011 – present:

4-field system includes all four plots part of a single planned rotation.

Growing mulch on-farm

  • reduces weed introductions and possible pesticide contamination
  • recycles nutrients on-farm

The mulches are grown primarily on the four fields and also in buffer zones.

Mulches grown in-field can be used in place in organic no-till.



The four-field rotation controls a wide range of crop pests and diseases.

  • Summer crops = crops planted in late spring and early summer (tomatoes, okra, corn, sweet potatoes, etc.)
  • Fall crops = crops requiring hotter planting weather (peanuts, southern peas, etc.) and crops planted late for fall harvest (after July 1: squash, pumpkins, etc.)

Segregating crops into these two groups ensures that timing of tillage and mowing varies over time on every plot. This aids in long-term weed management.

The current plan does not include early spring-planted crops due to difficulties working fields after wet weather, as normal in winter/early spring.



Rotating crop plantings within fields in effect creates an eight-year rotation. This is useful in controlling some especially persistent diseases.

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2017 National Conference on Cover Crops and Soil Health Presentations

via National SARE: Videos and presentations from the 2017 National Conference on Cover Crops and Soil Health sessions are now available. Held December 7-8, 2017 in Indianapolis, the conference highlighted insights from some of the nation’s most innovative producers,…

Case Studies Show Big Economic Benefits of Soil Health Practices

Soil health practices such as cover crops and no-till can result in an economic return of over $100 per acre, according to a set of case studies jointly released by the National Association of Conservation Districts and Datu Research, LLC.

Cover crops and no-till can limit soil loss, reduce run-off, enhance biodiversity, and more. Naturally, farmers who are considering adopting these practices are keen to know how they will affect their farm’s bottom line.

Cover Crop Report Documents Yield Boost, Soil Benefits

For the second year in a row, a national survey of farmers has documented a yield boost from the use of cover crops in corn and soybeans, as well as a wide variety of other…

Cover Crop Survey Reflects Enthusiasm for the Soil-Saving Practice

Insight from 2,020 farmers from across the country reflected enthusiasm for cover crops and—for the fourth year in a row—found a yield boost in corn and soybeans following cover crops. Multi-year data shows the yield boost increases as cover crops are planted year after year, a revelation that points to an appealing long-term benefit of the conservation practice.

Cover Crops as Beneficial Insect Habitats

This publication outlines thoughts on, and experiences with, using cover crops as beneficial insect habitat in organic farming.

Cover Crops for Soil Improvement in Crops

General overview of the benefits, considerations, and management of cover crops, including tables of planting and management information for both warm- and cool-season cover crops

Elements of Organic Farming: Putting Your System Together

This presentation gives an extensive overview of setting up an organic farming system.

Fall Cover Crops Are In!

This week we planted cool-season cover crops on the Cannon Horticulture Plots: a mixture of grain rye, hairy vetch and Alsike clover. For a wealth of resources on how and why we use cover crops,…

Farming with Native Beneficial Insects

The Kerr Center’s projects to provide habitat for beneficial insects in our certified organic horticulture plots, on the Kerr Ranch and in our office landscape are summarized in “Farming with Native Beneficial Insects: Ecological Pest Control Solutions,”…

Gardening in Goop

“Even in organic no-till,” muses George Kuepper, “you can still get caught.” He’s surveying a small plot of ground that was tilled up for a demonstration for the May 9 plasticulture workshop. Heavy rains forced…

Heirloom Variety Trial Report 2011: Organic No-Till Pumpkin Demonstration

This report presents the results of our 2012 no-till organic pumpkin/warm season cover crop trial.

Horticulture Main Demonstration Plot Scheme

This handout maps the Cannon Horticulture Plots, as well as the field within them where the 2013 warm-season cover crop trial was conducted.

How We Converted Bermuda Pasture to Organic Vegetables

This fact sheet describes how to eliminate bermudagrass from future vegetable fields using a sorghum-sudangrass cover crop.

Low-Till Vegetable Production: Cover Crops for Oklahoma

Rationale and preliminary results for using cover crops killed in place in raised beds as a low-till market vegetable production system

Market Farming with Rotations and Cover Crops: An Organic Bio-Extensive System

This report outlines how to control grasses and weeds, and build soil life, health, and fertility organically, using cover crops and rotations.

Native Plant and Pollinator Library

Learn about what plants to grow to attract a variety of pollinators throughout the season, including native bees, honey bees, butterflies (such as the Monarch), and other insect and bird pollinators. Check out our lists of...

New Studies: Cover Crops Insure Soils against Extreme Weather; Crop Rotations Boost Beneficial Soil Microbes

Two new studies show the beneficial effects of both cover crops and crop rotation on soil health and quality. These practices boost beneficial soil microbes and enhance the soil’s ability to withstand weather extremes like drought and flooding.

New Study: Best Time to Crimp-Kill Cover Crops Is…

Clair Keene, a researcher at The Pennsylvania State University, and her colleagues wanted to find the perfect time to crimp-kill a cover crop: grown long enough to make biomass adequate to suppress weeds, but not far enough along to make seeds.

Organic Bio-Extensive Management Revisited

This report recounts the lessons learned from nine years of organic management of the Cannon Horticulture plots.

Organic Soil-building

"Start with the soil." "Feed the soil, not the crop." "Weed the soil, not the crop." These are common catchphrases in organic agriculture - here are the dirt-under-the-nails details on how the Cannon Horticulture Program...

Perennials, Polyculture, and Pollinators

After several years of large-scale demonstration work for the Beginning Farmer Program and Resilient Farmer Project, the horticulture program is shifting gears. Three of the four fields in the Cannon Horticulture Plots will be moving…

Researchers Find Water Conservation Solutions in Cover Crops

via Southern SARE:

In a two-year graduate student study at Texas Tech University, funded through the Southern Sustainable Agriculture Research & Education (SSARE) program, winter cover crops – specifically rye – helped build healthy soils while preserving precious water for summer crops in minimally tilled forage-based grazing systems.

Rotations, Cover Crops, and Green Fallow on the Cannon Horticulture Project: A 2010 Status Report

This report outlines the “bio-extensive” approach to fertility and weed management used on the Cannon Horticulture Plots.

Scientists Document Benefits of Diverse Rotations

Anyone who’s attended a Kerr Center horticulture workshop in the last umpteen years has been exposed to the idea that crop rotations confer numerous benefits both on the soils they’re carried out on, and on the crops that grow in those soils. Studies hot off the academic presses have just added more support to the notion.

Sign up by March 31 for NRCS Conservation Stewardship Program 2016

USDA’s Natural Resources Conservation Service (NRCS) in Oklahoma plans to add an estimated 450,000 more acres to the rolls of the Conservation Stewardship Program (CSP) during fiscal year 2016. NRCS Oklahoma State Conservationist Gary O’Neill…

Southern Soil Health Conference Videos

Videos of several presentations from the January 2016 Southern Soil Health Conference in Ardmore are now available for viewing free online.  

Texas Farmers Learn to Build Soil Health Through No-till and Cover Crops

Just across the state line in Vernon… (via Southern SARE) Farmers tour cover crop research plots in north Texas. Photo credit: Southern SARE.   It’s a hot, dry, windy summer day on the plains of…