By Jeff Moyer

This article is an excerpt from Roller/Crimper No-Till: Advancing Organic Agriculture: Crops, Soils and Equipment (available from the Acres U.S.A. bookstore) Copyright 2021.

As with any field operation on any farm, you need the right piece of equipment to accomplish the task effectively and efficiently.

This is especially true in a cover crop system where every operation has an impact on the success of crop yield and quality. These ramifications are particularly evident in organic systems where every part of the system is closely interconnected to every other part.

Organic farming needs to be considered as a holistic system.

Adopting organic no-till methods creates a dynamic change to this holistic system. It’s hard to make one change without affecting the whole farm management plan. As we discuss organic no-till, we need to be especially mindful of how it will impact every other part of the system. The impacts can be seen from an agronomic perspective through changes in weed species and location, from a soils perspective as you’ll see changes in the soil’s ability to retain water and support greater microbial diversity, and from an energetic perspective since there will be tremendous reductions in the amount of embodied energy in the production process.

Through some experimentation with organic no-till, it became obvious that we needed a specialized tool to do the job. The roller/crimper is the tool that makes organic no-till possible because it does just that.

Although there are other similar tools available, the roller/crimper is the one that is currently best suited for managing cover crops in organic no-till. Tools don’t have to be that different to be revolutionary. Small modifications can make the tool perform much better. Any tool that will save you time and energy will be a good investment and pay for itself.

Essentially, the roller/crimper is a drum or cylinder with curved blades, which when operating, lays the cover crop over in one direction and crimps or crushes its stems. The combination of these two actions kills the cover and turns it into a thick, weed suppressing mulch in a single pass. You won’t need herbicides to provide 90 to 100 percent knockdown. Farmers can use the roller/crimper as part of an organic operation, or as part of a conventional one to reduce the use of herbicides and improve the bottom line.

Design & Development

The design and development of the roller/ crimper at Rodale began with an examination and analysis of many another tools including rolling stalk choppers, rolling harrows, and even flail mowers. These tools were already in use on our farm. Although they were designed for other functions, they appeared to adapt well to managing cover crops. However, none of these tools were designed specifically to roll cover crops and each had drawbacks. So we sought to develop a specialized tool for the job of rolling and crimping cover crops, instead of using a modified implement intended for another purpose.

Let’s start with the example of the rolling stalk chopper. The rolling stalk chopper consists of eight rolling drums (in a 4 row unit) arranged in two parallel rows. The implement is rear mounted on a tractor. As with any farm tool, some things about the rolling stalk chopper worked well, and some things didn’t. The rolling stalk chopper has two big drawbacks. First, the machine is rear mounted on the tractor, which leads to some problems in completely killing the cover crop. As the tractor tires pass over the cover crop, they knock down the cover crop and make an indentation in the ground.

This is especially true if the soil is wet. This means that the implement can’t do its job effectively — the cover does not receive the full impact of the rolling stalk chopper. The stems of the cover crop remain uncut and often have a tendency to stand back up. This defeats the purpose of the operation and eliminates the mulching effect of the cover crop.

Also, since the rolling stalk chopper is rear mounted, the planting must be done in a separate pass. This two-pass operation increases the time and energy invested in establishing the cash crop.

With the thick mat of rolled cover crop covering the ground, it can be difficult to see where the planter has already been. Traditional row markers can’t make a good line in the thick residue and foam markers would be a necessary option.

Another issue with rolling stalk choppers or mowers, as well as some other tools that have been used for organic no-till, is their tendency to cut the cover crop into small pieces. The cutting creates several problems. First, the cover crop breaks down faster and is less effective for weed control.

Second, when the cover crop is cut, it is no longer anchored in place by its roots. Consequently, it ends up in all kinds of places it shouldn’t. For example, it can get dragged by the planter and clog the machinery. In addition to the problems with the machinery, it creates bare patches that can become weedy later on in the season. The mulch is not distributed evenly across the field, with some thick areas and some thinner ones.

There are several other key design points that we considered important when reviewing existing equipment and the creation of our own roller/ crimper. One of those was the number of moving parts — in other words, the number of points where the cover crop could get tangled in the machinery as the rolling operation takes place. By creating a roller with only two bearings we were able to minimize both wear points as well as reducing the areas where wrapping of the cover crop might take place. We also wanted to design the blades in a way that would prevent them from ripping or pulling at the cover crop. This pulling action would create bare patches in the cover thereby providing an opportunity for annual weeds to germinate. This was accomplished by mounting the blades onto the cylinder at an angle of 7 to 10 degrees off of perpendicular. We’ll discuss this in more detail later in this chapter.

Design Elements

The design flaws we saw in using existing equipment were the impetus for developing a completely new implement — the roller/crimper.

As the roller/crimper developed, the following elements were incorporated into the design.

These elements addressed some of the problems with other tools, which were never really meant to roll thick stands of cover crops. The end result is a specialized tool that provides a 90 percent to 100 percent knockdown for cover crops, even for tough combinations like rye and vetch.

The Rodale roller/crimper design features one large drum with blades that cover the width of the planter (in our case 10 feet 6 inches for a 4 x 30 inch row planter), instead of the eight rollers in the rolling stalk chopper. These rollers can be built in gangs mounted separately on the planter frame to create larger roller/crimpers to accommodate wide planters. To date I know of several 30 foot rollers in use with great success.

With fewer sets of bearings, the Rodale roller/ crimper is easier to maintain, and has fewer moving parts which could get clogged with heavy residue.

This is especially important for vining crops like vetches or peas. The roller/crimper’s bearings on each end are inset by three inches and fronted with a smooth shield. Shielding the bearings is crucial to successfully rolling thick dense cover crops. The shields prevent the plant material from wrapping around the bearing and quickly tearing large patches of cover from the field.

The roller/crimper was designed to perform a specific function. As such, it can be scaled up or down to suit the particular needs of many growers.

In its simplest form it doesn’t need to even be a roller. A handheld version using human foot pressure on a crimping blade can work in tight spaces like a greenhouse floor. On a larger-scale a roller can be built to run in front of the very largest planters or grain drills.

Jeff Moyer has been working in organic agriculture all his life. For over 30 years he was the farm manager/director for the Rodale Institute in Southeastern Pennsylvania where he managed the farm operations department and conducted his own research. For the past 5 years Moyer has been the Executive Director/Chief Operating Officer (CEO) overseeing strategic planning and growth of Rodale Institute.