The Gordon Gnohm

Play along at home, read Future Farmer in The Braidwood Bugle every Wednesday. 

Passive Land Hydration Pt 2- Keyline Ploughing

Australians are famous for some pretty special inventions. Over the past century we have collectively invented humble items that changed lives. The Hills Hoist, the Victa lawnmower, the Ute to name but a few. When it comes to Passive Land Hydration, Australia provided the world with the Yeoman Keyline Plough.

Dry Times 

Contours, or keylines as we will refer to them this week, are positions that run level across your landscape. PA Yeoman developed his keyline plough to beat the compaction that had occurred as a result of misguided farming methods. In response to the significant drought and drought breaking events of the early 1900s, where it is estimated 1m of topsoil was lost through poor land management.

The land surface, and management techniques of the time, could not slow the flow. As we have discussed in previous articles, water will find the fastest way downhill and take your topsoil with it. 

Share the Water

His theory would prevent erosion and hydrate the whole paddock. To do this he would take the water from wetter spots on his property, like gullies, springs, and dams. He ploughed a deep narrow furrow across the landscape, on contour. This keyline rip would evenly distribute the water across the paddock. Designed to release excess water onto the ridges. The release point reduces erosion, as the water works its way downhill, across less fragile areas. 

A rip in the land is the smallest amount of disruption possible for the greatest effect. As it is still a form of ploughing, I’m guessing it was better received than modern no till methods. When farming with Hammers (industrial machines) everything looks like a Nail.

Just like a freshly mown lawn, there is plenty of satisfaction looking back at a well ploughed paddock, but as we have learned, the microbes and mycelium network don’t like it at all. Yeoman offers a great step forward for soil health, microbe husbandry and earthworms.

Whats Good

The main benefit of keyline ploughing is water infiltration. The deep rip on the keyline allows water running downhill to be captured, to soak into the subsoil. Rips can be placed 1-2m apart to capture water before it builds up speed.

Reducing the speed of the water starting at the top of the system is key. Erosion is reduced in the gullies, and some extra sediment is pushed out to the ridge for redistribution. Storing water made easy.

The practice of keyline ploughing has been used with mixed success for 70 years. There is plenty of anecdotal evidence, amazing claims about topsoil building and carbon sequestering but a significant lack of empirical data.

How Strange

PA Yeoman caught the attention of CSIRO in the late 1950s when Sir Ian Clunes Ross commenced a study to investigate the benefits of keyline ploughing on farming landscapes. The study had just started before Clunes Ross passed away. The new boss took over and the study was forgotten. 

Americans have also been using this practice for 50 years with great faith. A team of farmers approached their governing body (SARE) for a grant around 2005. They wanted to test the efficacy of keyline ploughing and its longterm benefits. The grant was dismissed on the grounds that the same research had already been completed. The research referred to has never surfaced.

If there is no research, no proof, then why are so many people using the system? 

Yeomans system provides hope for degraded farmland. It makes logical sense, and it’s a lot less work in the tractor than regular ploughing. 

An interesting technique to investigate if you are done with disk ploughing. The rewards are greatest on compacted, arid land, but there are other ways to work it. 

Ideal Use

If you’ve ever attended a tree planting event with Local Land Services, you will know the tell tale signs of subsoil ripping. Narrow furrows in the paddock to plant trees. Easier than digging holes with shovels, and after several rips in preparation the taproots can grow deep, quickly.

The rips tend to run along fence lines, uphill and over dale, with no consideration to the contour of the land. There is zero optimization of keylines and the pioneering work of this great Australian.

Ripping Off Contour

Its seems pertinent that Land Service Organisations in NSW, the home of PA Yeoman, adhere to his ground breaking concept. I mean why do ‘halfajob’ when the beneficial work could be completed with a simple adjustment.

Many hours of back breaking work go into planting, protecting and watering with varied results. The Scarlett Robin project didn’t perform as well as hoped using the halfa Yeoman technique. A lot of resources were mustered with little success. If only the trees were planted in contour rips, instead of in ripped drains, more trees would have survived with less input.

Where Does the Water Go?

Any water applied to the tree will fall to the bottom of the rip, remember gravity, and find its way downhill via the bottom of the rip. The easiest, fastest path. Trees in gullies and hollows perform better using the halfa Yeoman technique. It therefore stands to reason that trees planted in keyline rips would survive better, grow faster and need less tending. 

The Yeoman keyline system breaks up compacted land to allow water infiltration as it passes. Growth is increased by improved root penetration. Earthworms will inhabit the looser earth assisting microbes to bloom. Best of all productivity in the soil will increase, just like nature intended and you will reap the rewards by improving your land.

Whats Not Great

There are a few parts of the keyline system that I’m not as excited about living with in my paddock.

  1. It requires (bi) annual ploughing to keep the keyline open, ripping a bit deeper every time. 
  2. The keyline rips make for bumpy trips across the paddock in a vehicle.
  3. Walking in long grass across the rips can be quite the adventure too.

This Week

Im eating my second patch of corn. 25 plants in a square. Ive eaten several cobs tasting them to find the right time to pick, maybe 4. Today I ate 5 during harvest. The chickens got anything that was subpar. Maybe 8 and 24 corn cobs made it to the kitchen. 

That’s 40ish cobs off 25 plants! Sure, they weren’t all the same size, but they are tasty and juicy straight out of the husk. Too good to ruin with boiling water. 

A new discovery, the unfertilised 2nd ear. Usually, I chuck the unfertilised cobs to the chickens. To my surprise it was very corny and so sweet. I looked for more, but I only found one. 

Now that space is starting to free up in the garden, its time to start planning winter beds. If your tomatoes have been slow to ripen you are not alone, its been an unusual, tease of a summer. 

Stay Awesome

The Gordon Gnohm

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