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Organic Field Crop Production and Marketing in North Carolina

     
Organic No-till Roller System
Alternative Grain Crops
Organic No-till Roller System

No-till production offers many soil conservation benefits. Over the last 20 years, many conventional famers in the Southeast have turned to no-till production to take advantage of these benefits. However, until recently it has been nearly impossible to implement any kind of no-till production in organic field crop production. Tillage, or cultivation, has been a critical component of organic weed management. With a focus on conseravation, organic farmers have been interested in ways to reduce tillage in their organic production. Farmer-directed research has helped develop a reduced tillage technique (organic no-till roller system) that can be used in organic production, providing weed control and soil conservation. The basic concept is that a cover crop (rye or legume) is planted in the fall, is rolled down and killed in the spring, and corn or soybeans are planted immediately into the roll-killed cover crop. The cover crop acts as a mulch and few weeds make it into the crop canopy.

Research on this system in NC looked at many aspects of managing the cover crops and planting corn or soybeans including, cover crop varieties, bloom time, effectively killing the cover crops, secondary weed control techniques, N-fixation by legume cover crops,equipment to kill cover crops, and planting adjustments.

Below is basic information about how to implement this production system in NC, as well as links to more detailed articles on aspects of this sytem in NC.

Soybeans (information on this system specific to soybeans)

Corn (information on this system specific to corn)

Cover Crop Bloom Chart (when certain types of cover crops are ready to roll-kill)

Extension Bulletins

Links to more information and research on this system

 

 

Soybeans: The roller system for soybeans continues to show incredible promise for the region. Here are some tips that are important to know for using this in NC.

  • You need a lot of rye.  For this system to work, we are recommending over 8,000 pounds of rye dry matter per acre.
  • Plant the rye early.  Your chances of getting over 8,000 lbs DM are greatly improved by planting rye in September or October.  We have occasionally gotten enough from November plantings but that is rare.
  • Make sure the rye has enough nitrogen.  Fertilizing the rye and tissue testing for N may be called for.  This may sound like overkill, but the roller system demands we think about the cover crop differently.  The rye cover crop represents your entire weed control program; it will save you all the costs associated with spring tillage and cultivation. 
  • Wait until the rye is in the milk or soft dough stage before rolling.  Roll too soon and it will stand back up and will not die.
  • Rolling and planting on the same day makes it more likely you are planting into dry soil.  Rye cover crops are really effective at depleting soil moisture.  Other states are recommending that planting occur about 2 weeks after rolling or after enough rain has fallen to recharge soil moisture.  So far we have had remarkably good luck with same day planting, with only one stand out of 10 failing to emerge.
  • Weed control and yields in this system are higher than the standard organic practices being utilized in NC.  Organic soybean yields are highly variable because of weed control issues.  In years with wet springs, missed passes with a rotary hoe or spring tooth harrow have led to in-row weed problems. 
  • Lodging is worse in the roller system.  We have a lot of theories so far, and very little data.  Lateral roots on the soybeans appear to be shallower in the mulched system.  Mulched soybeans were taller this year with pod set higher on the stem.  Both observations could be part of the problem.  We will be trying some new ideas on planting this spring to see if we can prevent the lodging.
  • Almost any type of roller seems able to kill the rye, though this has not been researched here yet.  By waiting until the rye is in milk or soft dough, the rye is well on its way to senescence.  Several farmers have tried cultipackers with good success.
  • Try it on a small piece of land first.  Make sure you can get your planter through the residue.
  • Anyone wanting to try this system can call anytime for advice and help. 
    Phone:  919-515-7597; email:  chris_reberg-horton@ncsu.edu

Cover Crop Bloom Chart for NC:

These tables estimate the time of full bloom, or ideal time for rolling the crop in order to fully kill the cover crop so that corn or soybeans can be planted into the rolled mulch.

Table 1. Roll times for legume cover crops.

MATURITY

TIME

SPECIES

CULTIVAR

Early

Mid-April

none

none

Mid

Late-April/ Early May

Crimson clover

AU Robin Dixie

AU Sunrise Tibbee

Late-April/ Early May

Hairy vetch

AU Earlycover

Late

Late-May

Hairy vetch

AU Merit Experimental USDA line

Winter hardy Earlycover

Late-May

Winter pea

(unstated) and Whistler

Early June

Common vetch

(unstated)

Early June

Berseem Clover

Bigbee

Mid June

Sweet clover

Hubam

Hard-to-kill

Sub clover

Denmark

Not winter hardy

Blue Lupine

Tifblue 78

Table 2. Roll times for rye (Secale cereal L.) cover crops.

MATURITY

TIME

CULTIVAR

Early

Late April

Wrens Abruzzi

Wrens 96

MatonII

Mid

Early May

Aroostook

Late

Mid to late May

Rymin

Wheeler

One unifying factor for most of the cover crops is that it must be heavily flowering to kill with the roller. For instance, in crimson clover, we estimate that flowers must be on average 80% up each head before the cover crop can be killed (Figure 1). Vetch must have a few green pods with unfilled seed on the lower stems, and rye needs to be in the milk stage of development. We are putting together a guide for knowing when these crops are ready to roll which will be available by next year. The subterranean clover was impossible to kill with the roller and died on its own sometime in late May after seeding out. Subterranean clover flowers underground, making it an ideal reseeder. Whether this is an advantage or disadvantage depends on the crop rotation.

 

More information and research on the organic no-till roller system

USDA, Agricultural Research Service Fact Sheets. This site has fact sheets on cover crops, roller equipment, and modifying equipement for high residue planting.

Rodale Institute: No-till Revolution. This site has a variety of information about no-till organic production, including farmer profiles and stories of success and challenges.

eXtension: What is "organic no-till" and is it practical? Article from eXtension on no-till organic vegetable and field crop producitons. Includes considerations for trying organic no-till.

 

 

 

     

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