Relevance Of Keyline Techniques In Perennial-Dominated Environments?

Hello to all,

First-time poster in the Rainwater Catchment forum - hope this thread is on-topic (or at least, I hope it's less off-topic here than it would be elsewhere).

After reading 'The Keyline Plan' by P. A. Yeomans recently, the impression I have of the Keyline system of water conservation is that it is mainly applicable to large, open tracts of land which are tilled or mechanically cultivated on an annual basis. (I.e., it wouldn't be possible to implement Keyline techniques within, say, polyculture guilds which are mainly composed of perennials.)

Okay, then, here's a question... Would broadforking the soil along Keyline contours in an open meadow-type environment help to equalize soil moisture levels between the wetter and drier areas (at least over the space of a single wet/rainy season)? I'm specifically thinking about silty loams which do not have much organic matter and have low Ksat/saturated hydraulic conductivity.

Interesting: When I read the book, I have to say quite some time ago, I understood that Yeoman worked mainly with perennials (pastures and forests).

Did I misuse the term perennials? Oh....shoot. Well, I'm already aware that I don't know a whole lot...  How about my original question?

Yes, broadforking on keylines would help equalize moisture, if that is your scale.  Or small swales-more work up front but last longer.  Biggest thing to do is build organic matter.

Greetings R Scott,

Thanks for replying to this...pro'ly an oddball question.

I just keep thinking to myself that if broadforking frees up moisture to move between wet and dry areas, then (assuming the tine furrows left behind by this type of cultivation become the paths of least resistance) these should follow the Keyline for maximal effect.

The effect could well be too small to notice, of course (and would undoubtedly fade away as soil particles get moved around, etc.).

Anyway, Cheers!

Donner MacRae wrote:Would broadforking the soil along Keyline contours in an open meadow-type environment help to equalize soil moisture levels between the wetter and drier areas (at least over the space of a single wet/rainy season)? I'm specifically thinking about silty loams which do not have much organic matter and have low Ksat/saturated hydraulic conductivity.

As you already know, the idea of keyline ploughing is to follow the contours so moisture is captured and retained in the soil, leading to increases in soil ecology and therefore holding capacity.

Pasture/lawn aeration (plugging) works in a similar fashion, but keyline focuses on broad acre usage – futureproofing pastures and tree lines from drought/soil erosion, increasing clean surface water (creeks), and therefore maintaining water levels in dams.

On a small scale, broad-forking could work, though perhaps using a spade to prise small V-shaped trenches on contour would be more effective – backfilling the trench with compost would further benefit silty/sandy soils. Broad-forking only lasts a short time in most soils before it compacts again, the trench option should last years.


P.S. I have an urban backyard and a rural property and plan to do small keylines on the urban, keyline AND swales on the rural ... haven't been able to do either yet as we're experiencing a severe drought and high temperatures (it's 48 C today in the shade!), so disturbing the soil in these conditions - with near zero soil moisture - would do more harm than good. With the on-gong bushfires at least I won't need to use potash because it's falling from the sky!

Greetings F,

"On a small scale, broad-forking could work, though perhaps using a spade to prise small V-shaped trenches on contour would be more effective – backfilling the trench with compost would further benefit silty/sandy soils."

Apologes for the delay, I've been ruminating on a couple of your suggestions...

The area I will be prepping come spring will probably be too big to use the prising & backfilling technique over all of it. However, you've made me believe it is worth the additional time and effort to do it over the areas that I eventually plan to convert to food trees.

As for the methodology, I think it might be easiest to lay the composted organic stuff down first, then lever the soil open with a broadfork until it (the compost) falls down into the cracks...if I have time, I may even make two passes over these areas to get an extra shot of OM into the soil and working right away.

Heck, now I'm excited. =]  Thanks for this idea!

"I have an urban backyard and a rural property and plan to do small keylines on the urban, keyline AND swales on the rural...haven't been able to do either yet as we're experiencing a severe drought (...) With the on-gong bushfires at least I won't need to use potash because it's falling from the sky!"

Are the fires upwind of your place, then? Yikes, I haven't had time to follow the news... All I can say is stay safe, brother. I know bush fires can move quickly in your kind of country when the wind picks up.