Field Crop Production
Mulch Tillage

Mulch Tillage

Mulch tillage leaves at least 30% of the soil surface covered by crop residue. In this section, we look at how practices change when moving from conventional systems into mulch tillage. Other terms that are sometimes used for this system include: reduced tillage, minimum till or conservation tillage.

Mulch tillage is the ideal system to use if you want to reduce tillage but have forages or manure to worry about. This system allows you to leave residue on the soil surface and work manure into the soil.

Equipment

Mulch tillage calls for modification to all production equipment, including harvesting, tillage and planting equipment.

Choosing the right tool for soil conditions and amounts of residue is a high priority. When the primary tillage implement is changed, it sets off a chain reaction through the whole system. As more residue is left on the surface, secondary tillage implements may have to be adjusted or traded in for better clearance tools. Planting equipment may not be able to handle the high residue conditions left by mulch tillage, so you may have to add weights, heavy down-pressure springs, coulters, trash whippers, etc. If your planter is very light, it may not have the frame strength for modifications. Be prepared for changes throughout the system.

Mulch tillage can be achieved with many different tillage tools that leave various amounts of residue.

Chisel Plows

Chisel plows are used for primary tillage. There are several types available. The coulter-chisel plow is the most common in Southern Ontario. It combines a gang of discs or coulters in front of the chisel teeth to work in all residue conditions. The cutting action of the coulters/discs is necessary for handling corn stalks. This makes it easier for secondary tillage. After one pass, 30 to 75% of the residue is left.

The plows are solidly constructed with high clearance and shanks spaced 30 to 40 centimetres (12 to 16 inches) apart. This usually prevents plugging but in high residue or wet conditions, it can still be a problem. Spring-mounted chisel shanks vibrate and shed residue better than rigid shanks. They also last longer in stonier soils.

This coulter-chisel plow has a gang of coulters ahead of the chisel teeth.

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Discs

Discs are used for both primary and secondary tillage. Residue is mixed into the soil about three-quarters of the depth of tillage. It will leave 30 to 70% of residue after one pass. It breaks up the residue and loosens the soil surface. Use of the disc in wet soil conditions can lead to compaction at the tillage depth. This is caused by pressure exerted by the curvature of the blade. This problem can be minimized by varying the depth of tillage every year, or by altering primary tillage tools every few years. If poor root growth or surface ponding is seen after a few years if discing, using a chisel or moldboard plow to a depth of three or five centimetres (one or two inches) below discing depth, will usually ease the problem. If the problem is back in a year or two, consider a permanent change to a chisel plow.

Rotary Till Implements

A rotary till implement (e.g. Aerway) is a primary/secondary mulch tillage implement you can use on lighter soils. Its success has been limited on heavier soils due to problems getting adequate penetration. It is a single tool bar equipped with non-powered rotating knives. The frame is heavy enough that extra weights can be attached. This implement can be used for one pass tillage, although it is more common to make two passes. It will leave considerable residue on the soil, while leaving the surface relatively level. Material which survives the winter should be killed, as rotary tillage may not destroy all plants.

Rotary till implements will leave a high percentage of crop residue on the soil surface.

Secondary Tillage

Secondary tillage should be kept to a minimum to conserve residue. It should be sufficient to mix in fertilizers, work in pre-plant herbicides and level the surface. Heavy residue, like corn stalks, can cause plugging problems. Field cultivators may need to have a few tines removed and others re-spaced for better residue flow. An overall spacing of 13 to 15 centimetres (five to six inches) between tines should give the best compromise between residue flow and a level seedbed. It may be necessary to trade in the S-tine cultivator for a high clearance C-shank cultivator. C-shank cultivator frames are stretched and raised to make residue flow easier.

Planting Equipment

When planting into tilled soil, aim for residue levels between 30 and 40% after planting. To get uniform stands in mulch till fields, planters must:

• Clear or cut residue ahead of the seed opener
• Open a narrow trench in firm, moist soil
• Maintain accurate depth control and seed placement
• Press seed into the soil, cover and firm soil over the seed.

Planting equipment may need modifications in high-residue situations. If you are in the market for a new planter, look into some of the conservation models which have heavier frames and down pressure springs for better soil penetration, coulters to remove residue, offset double disc seed openers, gauge wheels at the seed opener for better depth control and press wheels for improved seed trench closing.

Chisel plow at a slight angle to old corn rows to prevent plugging problems.

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Best Management Practices for Mulch Tillage

• Match tillage implements to tractor horsepower. It's better to use a smaller implement on a larger tractor than the other way around.
• Only till when the soil conditions are right. Avoid wet fields.
• Only till when necessary. No-till planting wheat into bean stubble may be an option.
• Till across slopes to cut erosion losses. Chisels and discs are quite capable of working on gentle curves, but do not make right turns with the implement still in the ground.
• Set coulters on chisels just deep enough to cut residue to avoid excessive wear.
• Chisel plows and discs perform better in corn residue if the field is worked at a slight angle to the old rows.
• Make sure that right and left throwing twisted shovels are alternated on chisels.
• Both chisels and discs should be checked for level operation.
  

Implementing a Mulch Tillage System - A Five-Year Plan

The following is a plan to implement a mulch tillage system over a period of five years. You may be able to speed up or slow down the process depending on your farm situation.

Year 1

• Identify your soil types from a county or regional soil map.
• Make a rough map of your farm, locating buildings, fencelines, woodlots, wet areas and slopes. Make several copies of the map.
• Keep field-by-field records.
• Scout your fields, noting locations of weed problems and identifying weed species.
• Test the soil in your fields if you have not done so in the past three years.
• Plan to correct any drainage problems before starting a mulch tillage program.
• Outline your crop rotation on paper. Plan to start your system after a bean or after a cereal crop, if straw is removed.
• Check tine spacing of your secondary tillage equipment for proper residue flow. Tines should be about 15 centimetres (six inches) apart.
• Locate mulch tillage equipment available for rent in your area, including secondary tillage equipment. Look for a variety of types and configurations to experiment with.
• Evaluate your planter and drill's ability to operate in residue. Locate conservation planters and drills available for rent.
• Read up on mulch tillage in farm papers, OMAF factsheets, attend soil and crop project tours and consult with extension staff.
• Talk to successful mulch tillage farmers, find out what similarities you have and what your differences are. Choose farmers with similar soil conditions if possible. See what mistakes they made and learn from their experience.

Year 2

• Fertilize according to soil test recommendations.
• Keep up field records of problem areas, weeds and other pests. Plan your control options for all crops in your rotation.
• Adjust the straw spreader on your harvest equipment or find a custom operator who has a good straw spreader on his.
• Start with a small area of 2 to 4 ha (five to ten acres) with a rented piece of equipment.
• Work the chisel or disc across the slope, regardless of row direction to prevent water running down the furrows.

Year 3

• Continue to keep field records and evaluate crop progress on small plots.
• Secondary tillage and planting should be timed according to your soil conditions, not according to what your neighbours are doing. Working or planting the ground when it is too wet will result in a cloddy seedbed and a reduced stand. You may plant a day or two later than you would under conventional systems. Be patient.
• Expand the acreage worked to include more types of residue.
• Try different teeth on the chisel plow or a combination of twisted shovels and sweeps to see what works best for your soil and residue type.

Year 4

• Continue monitoring crop progress and keeping field records.
• Evaluate weed control and pest management. Get advice if necessary to make changes.
• Prepare a budget for buying conservation equipment. Find out the value of equipment to be traded in. Check the prices of available equipment. You may continue renting for a few years.
• Make needed adjustments to planting equipment to handle more residue.
• If all your equipment will handle residue, mulch till corn ground.

Year 5

• Evaluate program and make changes as necessary
• Assess your need for new equipment and make the necessary purchases. Modify existing equipment if possible.
• Continue to update your crop and pest management skills.
• Keep field records up-to-date.

By following this plan, keeping good records and monitoring your progress you should be able to implement mulch tillage successfully.

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Available in Published Version of Field Crop Production

• Soil Management
  • Erosion Control
  • Soil Temperature
• Residue Management
• Crop Rotation and Cover Crops
• Nutrient Management
  • Placement
  • Manure
• Pest Management
  • Crop Diseases
  • Insects & Slugs
  • Weeds
• Equipment
  • Chisel Plows
    • Chisel Teeth, Soil Penetration, Set up and Operation
    • Chisel Teeth Selection - Chart
  • Discs
    • Offset vs. Tandem Disc
    • Blade Selection and Spacing
    • Set up and Operation
  • Planting Equipment
    • Seed Openers, Coulters, Trash Whippers, Press Wheels
    • Seeding Rate
    • Planter Set-up / Field Operation
  • Harvest Equipment
• Getting Started
• Trouble Shooting - Chart

Tillage Options - cont'd.

| Introduction | Understanding the Basics | Approaching Change | Tillage Options | Non-tillage Options |
| Table of Contents |

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