Maximizing the Benefits of Zone Tillage, Coulter Tillage and Strip Tillage

Zone Tillage

Zone tillage is the indirect loosening of an area of soil between two coulter blades which are stagger mounted on either side of a planter row. The following are some key points to keep in mind when planning for a zone tillage setup.

• Zone tillage allows for effective loosening of the soil in the seed placement area while allowing for the use of a planter unit mounted residue clearing device. The residue clearing device will promote early germination due to soil warm up without the need for tillage.
• To effectively loosen the area of soil between the coulter blades without burying residue, it is recommended that narrow profile coulter blades be used. The narrow profile blades will fracture and lift the soil without causing excessive tillage of the soil.
• By using narrow profile blades to merely fracture the soil, moisture in the seedbed will be maintained.
• Excessive tilling and turning the soil will warm up the ground at a faster rate, however, much needed moisture will be lost due to soil being overly exposed to the air.
• Excessive tillage may bring weed seed to the surface where it can germinate causing future problems with weed control.

Coulter Tillage

Coulter tillage is the direct loosening of soil by a coulter blade. This can be accomplished using a single coulter or the combination of several coulters. The coulters should be able to accommodate a variety of blade styles to match changing soil types and soil conditions. The following are some key points to keep in mind when planning for a coulter tillage setup:

• Coulters operating directly in-line with the planter row unit should NEVER engage the soil at a depth below seed placement. There are several reasons for this:
  1. Loosened soil below the seed can develop air pockets which will affect seed germination because of poor soil to seed contact.
  2. Loosened soil below the seed may settle, especially after a rain, causing the seed to drop below the desired planting depth.
  3. Deeply working the soil in this area will reduce much needed moisture.
• Coulters operating directly in-line with the planter row should provide a wide enough area of loosened soil to overcome any potential compaction from the seed double disc openers and to allow for sufficient firming around the seed.
• Coulters mounted on the planter frame should be adjustable for variable depth settings in variable depth settings in varying soil conditions.
• Coulters mounted on the planter frame should in most installations be allowed to pivot. Rigid mounted coulters can undergo and transfer to the planter excessive amounts of stress, especially when negotiating a turn or upon encountering heavy obstructions such as rocks.
• Excessive coulter tillage can bury more residue than compensated for by soil conservation regulations.
• Coulter tillage with aggressive coulter blades can lead to soil erosion problems on contoured ground.

Fertilizer Applications in Zone Tillage and Coulter Tillage

In most cases, it is recommended that fertilizer be applied at a localized point slightly below and to the side of the seed placement area. Misplaced fertilizer could prove less effective or result in germination failure. The following are some key points to remember when applying fertilizer in the previously discussed applications:

• Fertilizer coulters should be equipped with narrow profile blades. These blades will provide a clean narrow slot in which fertilizer may be placed.
• Aggressive coulter blades are not recommended for fertilizer applications due to the following reasons:
  1. Insufficient penetrations may result in shallow placement
  2. Thrown soil may carry fertilizer out of the intended zone
  3. Overly tilled moist soil may build up under the seed double disc opener depth gauge wheels.
• Knife style applicators are generally preferred over injectors because of the following:
  1. Fertilizer knives ensure pinpoint placement
  2. Injectors apply fertilizer in a band (the lower the pump pressure, the poorer the accuracy range).
  3. Injectors which are supplied by low pressure pumps may dribble fertilizer on the soil surface instead of at the desired depth

Problem	Possible Cause in Zone Tillage	Possible Remedy
seed trench not closing	insufficient soil loosening	move coulters close together and ensure that in operation the planter is level
poor soil to seed contact	soil is being loosened below the seed	move the coulters farther apart, use less aggressive blades
excessive residue loss	aggressive coulter blades are burying residue	use narrow profile coulter blades
hairpinning of residue in the seed trench	residue is not being cleared	use a residue clearing device to move residue without engaging the soil
planter skipping, seed spacing, drive wheels lifting off the ground	planter lacks ballast to keep the coulters in the soil	add ballast to the planter
Problem	Possible Cause in Coulter Tillage	Possible Remedy
poor seed to soil contact	coulter mounted ahead of the planter row unit is running too deep	set coulter 3/8" shallower than planting depth
uneven planting depth and seed placement	excessive soil disturbance leaving rough, uneven path for row unit gauge wheels to follow causing row unit bounce	use less aggressive coulter blades or use planter unit mounted row cleaners to level the soil surface
	coulter mounted ahead of the row unit is running at inconsistent depths	use a planter unit mounted coulter that will maintain a consistent depth relationship to that of the row unit
weeds emerging in seedbed area	excessive tillage bringing weed seed to the surface where it can germinate	use less aggressive coulter blades or switch to a zone till system
poor seed germination	seed which is located too close to like residue may become subject to alleopathic poisoning (ex. corn following corn)	use a residue clearing device which moves residue instead of incorporating it into the soil
erratic fertilizer placement	injectors applying fertilizer in a band or on top of the soil	use a deep placement coulter equipped with a knife for pinpoint fertilizer placement
	overly aggressive blades are tilling the soil instead of opening a slot for fertilizer placement	use narrow profile blades to open a clean narrow slot
poor seed emergence on a dry year	excessive tillage causing additional moisture loss in the intended seedbed	use less aggressive coulter blades or switch to a zone till system
planter skipping, drive wheels lifting off the ground	planter lacks ballast to keep the coulters in the soil	add ballast to the planter
uneven seed spacing and depth	excessive residue in the seed trench	use a residue clearing device which moves residue instead of incorporating it into the soil

NOTICE - The information contained in this guide is offered in good faith by Yetter Mfg. Co. to further the understanding of no-till farming. However, the use of the information provided is beyond the control of Yetter Mfg. Co. and in no case shall Yetter Mfg. Co. or any seller of its products be responsible for any damages which may occur from the use of this information. All such risks shall be assumed by the user.

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Yetter Manufacturing Inc.
PO Box 358 • 109 S. McDonough • Colchester, Illinois 62326 USA
Phone: 309.776.4111• 800.447.5777       FAX: 309.776.3222
E-mail: info@yetterco.com

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