Selecting the right tool for a job is essential. When that tool is as important and expensive as a farm implement, the same holds true—you want to buy farm equipment that does what you want; is strong, durable, and reliable; and is generally the best value for your money.
Tillage options require careful consideration before purchase. In addition to common methods involving a combination of a chisel plow, disk, and field cultivator, growers also have two conservation tillage equipment options available: no-till and strip-till. No-till is used extensively on soils and landscapes that have erosion potential. Strip-till was developed to provide some tillage below the seedbed for soils that need residue for erosion protection. Both no-till and strip-till, however, have been proven methods across a wide range of soil types and cropping systems.
Strip-tilling carries out two important functions: deep tillage using a ripper shank and seed zone preparation in a narrow strip. Strip-till should not be confused with using subsoiling as a stand-alone practice. In contrast to strip-tilling, the shanks of the subsoiler may not line up with the planted row and may even be run at an angle to those rows.
One of three different designs of strip-till rigs with noticeable differences in construction. Source: Alan Meijer, NC State University, Soil Science
One of three different designs of strip-till rigs with noticeable differences in construction. Note the heavier construction compared to the next image. Source: Alan Meijer, NC State University, Soil Science
One of three different designs of strip-till rigs with noticeable differences in construction. Notice the small clamps and lighter gauge metal holding the rolling baskets. Soruce: Alan Meijer, NC State University, Soil Science
Many companies have at least one type of strip-till unit in their product lineup, and they will each claim to offer the best tool for your farm situation. Manufacturers may even provide videos demonstrating what their respective products can do. Such an important purchase, however, requires understanding what you want and what you need in a strip-till unit as you set out to obtain one.
If you’ve been strip-tilling for a while, you may already know what changes you want to make in your next implement. If you’ve never strip-tilled, you might be unsure of what to look for in a strip-till unit. Read on for some key insights into a strip-till unit’s features and design that will help ensure you choose the right unit for your needs.
Construction and Durability
Simply put, not all tillage equipment is created equal! Tillage equipment takes a beating, being dragged across and through the soil. Examine the construction of the tool and consider how it will hold up in your fields. Are you dealing with a thick plow layer or rocky soil? Examine what you know to be weak links in any piece of equipment, such as bearings, bolts, coulters, and chains.
Points are available in a variety of shapes and designs. The shape and width of the points attached to the shank have the greatest effect on both the upheaving of soil and the zone of soil loosening. A wider point, perhaps with wings on each side, will create a wider zone of soil loosening than a smaller, narrower point. Some manufacturers will explain the correct combination of point and shank that will accomplish your goals in soil loosening and residue management. When you look to replace points, be aware of the range of cost among different types. Ask about the wear resistance of the points because some are manufactured for increased durability.
The shape of the subsoiling shank can also affect the fracturing of soil and can range from vertical to dramatically angled forward. A vertical shank typically has a narrower soil fracturing width but tends to leave more residue on the soil surface, which is beneficial for promoting infiltration, reducing wind and water erosion, and increasing organic matter in your soil. As the angle of the shank becomes more severe (approaching 45 degrees), the amount of soil fracturing is greater, extending wider on either side, but it will bury more residue and leave the ground surface rougher.
There’s a good chance your strip-till shank is going to hit something hard enough that you will feel it in the cab. Whether you have a broken shank or not will depend on whether the shank is designed to “trip.” Shank reset mechanisms vary, and the ability to trip and then reset has been a learning experience for the industry. Initially, shear bolts were used to hold shanks in place. While still present in some designs, shear bolts can be troublesome even if they are infrequently broken. Newer models have “trip-reset” shanks that require lifting up the implement to reset the shank, while “spring-trip” setups reset on the fly. There are potential cost differences associated with the various shank reset options, so consider these accordingly.
Strip-till is an important conservation tool, providing an element of tillage (deep and shallow), while maintaining much of the surface cover between rows. Early adopters of strip-tillage tilled an area up to 12” across largely due to the initial equipment’s limitation to till only that width at the surface. Some modern strip-till rigs affect a very narrow zone of tilled soil, up to 6” wide, allowing even more residue to remain in place.
Don’t expect a strip-till rig to do what a v-ripper might do. Strip-till shanks typically do not run as deep as a traditional ripper. Look for models that feature an adjustable depth setting on the shank. Confirm that the model you are purchasing will go as deep (or shallow, in certain soils) as you hope it will. If you browse the online literature, you’ll notice that many companies do not list the depth their unit will go beneath the soil surface, so call them to find out.
The amount of horsepower required to pull strip-till rigs varies with soil type, sampling depth, and soil moisture. Horsepower options will also differ among brands and models of these units. You can typically consider about 40 hp per row unit as a good starting point. A common consequence of being underpowered when performing deep tillage is raising the unit to reduce pulling resistance. The end result is that soil is not loosened to the targeted depth—a waste of time and money. Consult the specifications of each unit, and take into account your field situations on the farm to accurately assess your horsepower needs.
The soil is finely tilled and possibly more susceptible to crusting. Source: Alan Meijer, NC State University, Soil Science
The disturbed soil has been mixed less and pressed down by rubber press wheels, as opposed to chopped up as seen with a rolling basket strip tiller. Source: Alan Meijer, NC State University, Soil Science Options
Many implements come with different options regarding shank shape, points, row firmers or soil conditioners, and fertilizer delivery systems. Research what is available before you buy.
- Row firmers or soil conditioners: The trailing end of each row unit will consist of a row firmer or soil conditioner. Row firmers may consist of rubber press wheels that merely press down what was heaved up. A “rolling basket” is a common type of soil conditioner that breaks up clods, and prepares an ideal seed zone for planting.
- Fertilizer application system: While you might be able to create your own fertilizer application system in the shop, look into options available, or included, with some implements. Some units feature stainless steel tubes behind the shank that may be depth adjustable and able to deliver liquid fertilizer below the seeding depth for use by the plant as roots move deeper into the soil profile.
This document is not intended to recommend strip-till as necessarily the right practice for your cropping system, nor is it intended to describe recommended practices for performing strip-till in your fields. Those topics are or will be discussed in other publications available through North Carolina State University Soil Science and Cooperative Extension available at http://www.soil.ncsu.edu/publications/extension.html. If you would like more information, please call your local NC Cooperative Extension agent.