Strip-till basics

Benefits of tillage and no-till meet in this precision approach

Story by Dr. Paul Tracy

The past two field seasons provided challenging planting conditions. Excessive rainfall caused planting delays often extending into June and even July. In 2008, late planting did not hurt us too much because we had adequate August rainfall and an open fall. This year, it remains to be seen how the delayed planting conditions affected harvest and crop yield.

The benefits of no-till farming have been known for several decades. I cut my teeth on no-till as it was the key component of my doctoral research project back in the early 1980s. No-till reduces wind and water erosion, increases water infiltration, reduces soil water evaporation, increases crop water use efficiency, requires less fossil fuel, improves soil tilth, encourages root growth and has the potential to increase soil organic matter. I still strongly encourage producers to work within a no-till system whenever possible.

Starting in the 1980s, a hybrid tillage system was developed. Its purpose was to combine tillage and residue management to reap the benefits of both systems. Hence, strip tillage or strip-till was developed. In this system, the seedbed row is tilled in a narrow strip, leaving the majority of the soil surface covered with crop residue.

No-till systems are not without problems. They often require higher crop protection product use, lead to nutrient stratification and can increase soil compaction. By far, the two most common concerns that I’ve had to address with new no-tillers are 1) planting problems associated with excessive crop residue and 2) wet-cool soil conditions that delay planting. As mentioned earlier, wet cool springs have occurred in our region over the past few years.

Strip-till is very common in the northern and western corn belts. Expanding the growing season has pushed interest in the north. In the west, most interest is soil moisture conservation. Recently, reduced water erosion in the lower Midwest and better drainage in the Southeast, combined with the popularity of early planting in both regions, has led to an increase in strip-till acres. Even though our region has been slow to adopt strip-till, I expect the system to expand rapidly over the next five years, as its benefits are locally documented.

Accurate tillage/planting placement is essential in strip-till systems.

There are a variety of strip-till systems. One size does not fit all. Briefly defined, strip-till is a form of conservation tillage that tills a narrow row (4 to 8 inches wide) where the seed will be placed (see photo above and illustration below).

I am not an equipment specialist, but strip-till equipment generally consists of a coulter for cutting residue, a residue manager (row cleaner) for removing residue from the seed row; a shank for breaking a tillage pan and an optional fertilizer application; a hiller or ridger to raise the seedbed slightly; and a basket or disk to remove clods and better prepare the seedbed. There are several strip-till configurations, but they generally fall into three categories: 1) unit by itself, 2) unit with the planter and 3) unit with fertilizer rig.

Grain yield vs. driving error for irrigated strip-tilled corn in Western Oklahoma, 2007 Source(Oklahoma State University Extension)

Two-inch depth noon soil temperatures as influenced by surface residue at Albany, Missouri, 2009 Source(Missouri Historical Agricultural Weather Base)

Accurate tillage/planting placement is essential in strip-till systems. To borrow a quote from Dr. Gyles Randall from the University of Minnesota, “Without accurate auto-guidance or someone very competent to both create the strips and plant into them, yields will likely suffer.” The first chart on page 12 illustrates the importance of driving accuracy in terms of yield benefits associated with strip-till. I recommend strip-till farmers utilize the RTK guidance systems for repeatable multi-pass accuracy. 

Warmer temperatures and drier planting conditions are important, especially when planting early. The second chart on page 12 tracks noon temperatures at the two-inch soil depth during the 2009 field season at Albany, Mo. Please notice that in the early spring, bare soil is appreciably warmer than soil with corn or soybean residue on the soil surface. These warmer soil temperatures that occur in the strip-till zone will help an early planted crop germinate and emerge.

There is much debate concerning the best time to strip-till a field. In our region, I highly recommend strip-tilling in the fall. In the spring, it is often too wet to get the tillage work done. Strip-tillage at planting often causes problems with seedbed preparation that does more harm than good. My concept of an ideal system is to till the strips and apply fertilizer in a single fall pass, followed by spring planting using an RTK guidance system to ensure that seed is placed in the strips and near the applied crop nutrients.

Another consideration when initiating a strip-till system is potential incentive support from the Natural Resources Conservation Service. The agency funds incentives for the practice as addressed with Strip Tillage in Conservation Code 329. Incentive payments for starting strip-till vary between states and counties, but, depending upon acres enrolled, can go a long way toward paying for the system.

The many interwoven benefits associated with strip-till have been well documented. As harvest ends, this is a good time to consider trying it out in your farming operation.

Dr. Paul Tracy is director of agronomy for MFA Incorporated.

Strip-Till Equipment Manufacturers – Short List

Bigham Brothers Equipment	Blue Jet Equipment
Case IH	Dawn Equipment
DMI Manufacturing	Hiniker Equipment
John Deere	Orthman Mfg. Inc.
Progressive Farm Products	Redball Manufacturing
Reminger Equipment	Yetter Equipment
Unverferth Manufacturing

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