Keyline Plowing with Compost Tea Application

Part I: Introduction

Employing the methods developed by P.A. Yeomans, keyline pattern plowing is a proven component in the job of revitalizing degraded soils. The plow performs deep ripping with minimal plant disturbance. At its most basic this offers many benefits, including opening compacted soils (without destructive tillage), breaking up the hard pan, allowing moisture and oxygen to re-activate soil life, thus restoring fertility.  When used in concert with controlled grazing or mowing through a managed cycle, top soil is built rapidly. 

In the related field of soil biology, Dr Elaine Ingham (the eminent biologist) has made breakthrough discoveries studying soil life and developing methods of brewing compost tea. Her work promotes the pressing need to re-populate our damaged soils with the necessary microbial biota. Without the essential micro organisms our soils cannot develop balance. A balanced soil offers fertility, that builds through the exchange for nutrients that is the tireless work of soil life. A multitude of symbiotic connections evolved in harmony.

With the generous support of the well respected compost tea educator and biological farming consultant, Paul Taylor (Trust Nature), I am developing a means to both inject compost tea into the root zone of pasture plants driectly, and perform a foliar (plant leaf) application while keyline plowing. The potential for this method to restore health and balance to soils is explosive.

I will therefore post a series of articles on detailing my development of this system so that others may be inspired to explore this exciting system (and perhaps make improvements).

Part II: Designing the Keyline Plow Frame Extension

Making Progress

I believe I’ve solved the tank (and equipment) frame extension question. The photos below mostly speak for themselves, although I’ll elaborate for the enthusiastic.

We made up a simple frame extension of welded steel box section that will form a platform for mounting the compost tea tank. In the photo below, you’ll notice I’m supporting the frame extension with timber, which obviously won’t do. So, next I’ll weld plate steel “L” brackets onto the extension where it meets the upper beam of the original keyline plow frame (positions A & B below). Then drill bolt holes so I can employ “L” shaped bolts. The same kind those used on the plow. I like standards and it makes everything multi-use, opening the door for more creative ideas.

Bolting onto the upper beam will support the extension, although it will not hold any significant weight. To solve this problem I will do the following.

Because the keyline frame is essentially a tool bar allowing great variation, it is essential to consider this variation when designing additions. To create a decent sized platform, my frame extension extends beyond the depth of the original frame, so it will require diagonal plate steel supports to bare weight. These will bolt to both the lower keyline beam and the new extension. This will give the extension support from below, as I intend to apply considerable weight to the platform above. As such I’ll need to make up at least two, maybe three supports.

A profile illustration of these supports is pictured left. To maintain a thin profile and not consume too much space on the rear keyline tool bar, I’ll most likely opt for plate steel. I must cut triangles out of each end of the plate piece to match the new frame extension and also the keyline plow. To sure this up, again, “L” constructs to bolt on.

These supports are then completely adjustable, which allows me to relocated the shanks and coulter beams without worrying about ‘permanent’ frame extension supports being in a fixed position. If they are in the way, I can just shift them, left for right. Total freedom. The general position is shown as dotted lines in the image below.

This extension also allows ample clearance beneath the tank platform should I need to access the shanks during plowing to change over a shear pin etc.

Part III: 1:1 Wooden Scale Model

Today I developed a 1:1 scale model of the platform supports. This allowed me to consider the design in more depth and get a feel for where the pressure points are. I constructed the model from cypress which obviously is much easier to work than box section or plate steel. I’ve established exact dimensions so constructing the steel version only involves cutting each ‘part’ of the assembly, then welding it together. All position issues, levels etc. are correct. No painful mistakes.


My only regret thus far, is employing non-standard box section steel for the frame extension. In the keyline plow, there are three sizes of box section employed. The main frame is constructed from 100×100mm RHS (Rolled Hollow Section). This is a very strong steel product. One that allows the frame to withstand extreme pressures during plowing. The coulter beams, which don’t experience the same stresses, are build from 75×75mm box section. Finally a smaller kind again is employed in the coulter assemblies themselves – the 50×50mm variety.

Since the frame extension was made up for a purpose other than its current application, I opted for 90×90mm. I briefly considered a ’sleeved’ design. Involving reversed coulter with a ’sleeve’ of 90×90mm over the 75×75mm. The intent – to create an extended rear platform. But the forces at play made me abandon it. If I had opted for 100×100, the platform supports would be fully reversible. A regrettable oversight.

For the supports, I’m using the same box section as the coulter beams. 75×75mm. Never to later to correct the course. I’m pleased with this design and look forward to creating the final steel versions.


The steel brackets are now complete and working exactly as intended, with strength to spare. I anticipated a measure of ’spring’ based on the design, but this doesn’t seem evident. They are extremely robust, and very straightforward to construct.

One of the completed steel support brackets.

As it appears, mounted on the plow.

Read Parts IV to VI here