Keyline Plow

[earthwise]

There has been some discussions about using a Keyline plow on another discussion list that I am on, and a question was raised as to whether anyone has used this kind of equipment with a team of horses, and if so, how many horses were needed.

A Keyline plow (for those not familiar) is a rigid-tined subsoil plow that can decompact abused soils, dramatically enhanc water infiltration and oxygenate subsoils. In practice, when drawn through the soil, subsoil plow shanks (the deep ripping components of a subsoil plow) create minimal surface disturbance and mixing of soil layers while shattering compacted soils, thereby setting the stage for the development of a healthy biological soil community.

thanks,
Lisa McCrory

[Carl Russell]

Here is a link with related discussion, sweetie;)

http://www.draftanimalpower.com/showthread.php?t=1673

Carl

[Tim Harrigan]

I have never measured the pulling force but I am familiar with that type of tillage tool. I would guess a horse-drawn, single shank keyline plow would pull in the range of 1000 to 1800 lbs force at 14 inches or so. So if you expect a team to work right along I would say at least three but probably 4-6 . It is really hard to say because soils can be so different and it depends on the nature of the restrictive layer that is to be disturbed. And how much lifting the plow is designed to do. Even a moldboard plow draft can vary by a factor of six to eight from sandy to clay soil, moist to dry etc. First, get a shovel and dig. Find out if deep compaction is really the problem. Deep compaction gets a lot of attention and in my estimation in a lot of cases is not the real source of the problem.

The role of such a tillage operation in building soil quality is debatable and is worthy of discussion.

[Carl Russell]

Tim Harrigan;14961 wrote:

I have never measured the pulling force but I am familiar with that type of tillage tool. I would guess a horse-drawn, single shank keyline plow would pull in the range of 1000 to 1800 lbs force at 14 inches or so. So if you expect a team to work right along I would say at least three but probably 4-6 . It is really hard to say because soils can be so different and it depends on the nature of the restrictive layer that is to be disturbed. And how much lifting the plow is designed to do. Even a moldboard plow draft can vary by a factor of six to eight from sandy to clay soil, moist to dry etc. First, get a shovel and dig. Find out if deep compaction is really the problem. Deep compaction gets a lot of attention and in my estimation in a lot of cases is not the real source of the problem.

The role of such a tillage operation in building soil quality is debatable and is worthy of discussion.

I agree entirely. This is from discussion on organic dairy farms. In my estimation it is a typical discussion taken from the standpoint of a mechanized operation trying to find out how well animal power could perform.

Truly functional animal powered operations will require that the tasks are energy appropriate, and certain tools and their benefits may never be effective in animal based enterprises.

I have attached the article from the NODPA (Northeast Oragnic Dairy Producers Alliance) Newsletter that started this discussion on the O-Dairy discussion forum.

Carl

[goodcompanion]

Carl and Tim, I imagine you are right. Farming mostly with grass as I do, I’d always wondered about this implement and whether doing this job or having it done, even just once, would be worthwhile.

Maybe in a cheap-energy economy it might make sense for me at some point. From a strict energy standpoint,though, I doubt it could make sense at all, there being so many other things you can do to promote healthy soil that don’t use energy quite so prodigally.

Got me thinking, anyway.

[jac]

An interesting discussion guys. Deep compaction ? Is this problem only a tractor based issue and is it possible to compact the soil next to the subsoil while still having the surface apparantly ok.. I have read in various farming mags over here that the use of liquid slurry changes the soil structure and makes it greasy for want of a better word but thats a surface problem. It would be good to find two farmer neighbours.. one a modern tractor based farmer and his neighbour working a historicaly horse based farm and compare soil structure. Do horses or cattle grazing cause deep compaction or is it just the surface that gets pounded ? I’ve often wondered what does most damage.. a tractor with wide tyres that weighs 8 or 9 tons but a pounds/square ins of 26 or a horse with a much higher poundage/square ins…I have heard a figure of 56… but less all up weight ? Is the horses weight only tranfered so far into the ground ?
John

[Carl Russell]

Soil compaction is not just a surface traffic issue, but is related to the mining of organic material and soil supporting microbial communities. I am just a hill farmer, and work on extremely long term solutions, accepting the current productivity and condition of the land I have to work with. I am not at a point where I feel that I need to have an opinion about the value of these processes, but I just try to see things from the standpoint of starting with animal power, not moving toward it from a mechanized operation.

Carl

[Gabe Ayers]

It seems only necessary to sub soil when a mold board plow has been used for several years. If you drive a soil probe and to a profile it is usually just compacted at the plow shear level and loose under that.

The freezing and resulting heaving of the soil seem to take care of compaction on the surface, and deeper when it freezes deeper – for the most part, depends on where you live.

Sub-soiling certainly increases water penetration and we like to do it before liming and at some point on all long term pasture land, on the contour.

I really don’t think there is much increase in top soil depth from doing this, since that builds from the top. It always seems that when the top soil is thin or the plowing is to deep and sub soil is brought to the surface and if you are growing without chemical fertilizes you will see a reduced yield. There is no biotic life in the sub-soil it is mostly mineral.

They do have some nice horse drawn sub-soilers that have break away features. They do pull hard. We had a three point hitch cart and used one a few backs. It had a breakaway foot on it and we broke it on tight rock several times.

~

The idea is don’t moldboard plow except to break sod, then use the animals and other tillage tools.

Jason

Not a HHFF post…just an old farmer thinking out loud….

[OldKat]

@jac 14975 wrote:

An interesting discussion guys. Deep compaction ? Is this problem only a tractor based issue and is it possible to compact the soil next to the subsoil while still having the surface apparantly ok.. I have read in various farming mags over here that the use of liquid slurry changes the soil structure and makes it greasy for want of a better word but thats a surface problem. It would be good to find two farmer neighbours.. one a modern tractor based farmer and his neighbour working a historicaly horse based farm and compare soil structure. Do horses or cattle grazing cause deep compaction or is it just the surface that gets pounded ? I’ve often wondered what does most damage.. a tractor with wide tyres that weighs 8 or 9 tons but a pounds/square ins of 26 or a horse with a much higher poundage/square ins…I have heard a figure of 56… but less all up weight ? Is the horses weight only tranfered so far into the ground ?
John

John et al,

I know an Amish produce farmer in South Texas that told me a couple of years ago that he owns about 115 acres. He bought it sometime after 1999 when his community relocated from Tennessee. He said that at the time, exactly 2 years ago, that he was farming about 12 acres of the place with his horses; the other roughly 100 acres was leased out to a conventional farmer who grew corn, milo and cotton in rotation. He said that each year he adds about an acre or two to his production by cutting back on what he leases out.

I asked him what differences he could see in the land that he had been farming with his horses and that the other guy had been farming with his tractor. He said that the land that was farmed with tractors was so hard that he had to apply manure and compost on it for about a year before he could even get it to break. He uses a single bottom moldboard to break this land. I never saw him breaking any new land, so I don’t know how many horses he put on the plow. He had 3 Belgians, but his dad has probably a dozen Percherons so horsepower probably isn’t an issue.

He said that after about three years of adding manure and compost the land “mellows out” enough that subsequent tillage is with a disc plow. He said it takes about 3 to 5 years for the land to get as mellow and as productive as what he was already farming. The soil is a coastal prairie clayish loam, semi-arid climate. He irrigates from a deep well using a submersible pump powered by a diesel engine.

[jac]

Pretty compelling evidence there Oldcat..It makes me wonder if the modern tractor plow that is taking 18″wide and going down 9 and 10″ is HAVING to do that to break up its own damage.. after all barley roots dont go any deeper now than they did 80yrs ago so why the deeper plowing now than in the horse era ? and what forces are at play to create a hard pan at the point of shear and not below? Over here the big arable farmers use a chisel plow every year on the tramlines that the sprayers use. I knew a farmer a few years back that took advice from the ag college to chisel plow his land.. and burst every clay drain in the field !! Seems to me anuther good reason to farm with horses .
John

[Tim Harrigan]

OK, I read the article that Carl posted. There is a lot of room for interesting discussion but I will not be able to add to it for a few days. One thing I like about these approaches is that they challenge us to think through the parameters of a balanced biological system and the most efficient way to achieve it. One thing we need to do is develop an attitude of experimentation and apply these types of treatments in defined areas where we can observe and measure the impacts compared to alternatives. If we till the entire field, or not till the entire field, how do you measure the value of what you did or did not do?

[Tim Harrigan]

I am pretty practical in my approach to these solutions to perceived problems. Landscapes and soils are so variable that management needs to be on a field specific basis. These subsoil plowing operations are power intensive but if the results justify the effort that is OK. My only requirement is that there is a clearly defined problem that the plowing will solve. That could be breaking a plow pan such as Jason mentioned although in the northern states we have annual freezing and thawing that help alleviate that problem. Some soils have natural restrictive layers that might limit infiltration and root growth. The coastal plains soils in the southeast have a distribution of soil particles that cause them to set up pretty tight and require deep tillage on an annual basis, at least for row crop production. So there are cases when deep tillage is justified.

Tillage is a physical intervention with rapid effects. Is it possible to oversell it? The discussion often turns to soil quality and the need for robust microbial communities. No question that biological activity is important, biological activity builds soil aggregates which allow soil to carry vehicle and animal traffic, convert organic matter and mineral nutrients to plant available form, provide a balance of pests and pathogens and other benefits that build soil quality. Do we need to loosen and oxygenate the subsoil? Jason is correct, the subsoil is not particularly biologically active, at least not compared to the topsoil where the nutrients and organic matter are concentrated. Microbial communtities are dynamic and arise in response to specific favorable conditions. Tillage can provide rapid and desireable changes in the physical environment, but we can not assume the effect on microbial communities will be the same. A rapid change in temperature and oxygen may cause a flare-up of microbial respiration that quickly consumes available nutrients. Like fanning glowing embers to a flame only to quickly die out when the fuel is gone. The changes are unlikely to be sustainable as the change in environment causes one community to die-off and perhaps be replaced by another less desireable one. And, tillage induced physical changes are not particularly structurally stable. There will be ongoing changes in the microbial community as the soil reverts to the initial conditions over time.

In pasture and hay ground tillage may have a role but it should be secondary to enhancing the natural conditions that build soil quality and sustain microbial and biological communities. Obvious things are earthworm activity, freezing and thawing to alleviate soil compaction, root growth and the addition of organic carbon from compost and manure to feed biological activity and build soil organic matter, and pasture management that sustains botanical diversity including a mix of grasses and legumes.

The rhizosphere is the area at the interface of the soil and plant root under the influence of the root. This is the zone of intense microbial and biological activity. Manure, compost, a diverse plant community, managing animals to maintain a dense vegetative cover, a diverse mix of grasses and legumes, these are the things that are critical in sustaining biologically active soil. Roots support biological activity and when they die and decay they create channels for water infiltration and oxygen penetration. Tillage induced pores are immediate but not structurally stable. They will collapse easily when retrafficed by animals or vehicles. Natural pores develop more slowly but are stable and give the soil carrying capacity. It is best to not make simple assumptions about the effects of tillage on biological activity in soil, particularly the ability to create favorable changes in the microbial community.

I am not endorsing or discouraging the use of subsoil tillage tools. I am suggesting that is easy to fall into the over-tillage trap if tillage is not focused on solving specific and measureable problems. Restrictive soil layers can be located with a shovel. If the only benefit of deep tillage is to improve infiltration and reduce runoff that is fine but subsoil tillage is not a replacement for managing the pasture. Over-grazing and allowing too many animals on saturated soils are two of the most detrimental things for pasture ground. If you pasture animals east of the Mississippi you can’t get away with not having a sacrifice lot for holding animals at certain times of the year.

If you farm with draft animals, subsoil tillage will challenge the ability of your animals. If it moves your soil quality ahead, that is fine. But if there is not a clear reason for doing it then it might be recreational tillage. I suggest dragging pastures for that. Even if you identify a problem that subsoil tillage might alleviate you should still seek proof of the benefits. Subsoil one-half of the field, or better yet make 4 or more strips of alternating plowed and unplowed land. If you fertilize, treat the plowed and unplowed areas the same. Then observe closely over the year for evidence of better infiltration, greater growth, drought tolerance, greater botanical diversity etc. One more thing. In many areas of the northeast the topsoil is shallow and overlays bedrock. Subsoil plowing may improve infiltration and in doing so provide a straight shot for manure nutrients and other contaminants to move directly to groundwater. So be careful if there is anything in the pasture that you do not want in your well water.

[Carl Russell]

Thanks Tim for taking the time to post such a thorough review.

This echoes to some degree how I am looking at this. One of the questions that brought the discussion here was about the use of animal power to perform these tasks. I can see that if you already have a financial investment in tractors and modern farm equipment then under taking sub-soiling may have some merit as another way to utilize that investment. I also question whether the result is the function of increased biological activity, or primarily a result of the degree of change that is made possible by the available power.

When using animal power my first thoughts tend to be “What natural processes am I trying to replicate, and can I utilize them instead of trying to artificially augment them with power needs that are either beyond what I have available, or require financial investment?” The other part of this is the question about the sustainability of trying to maintain the result of such disturbance, if the disturbance is required to provide the result.

Animal power has limitations, but enveloped in there is the response of the “farmer” to work with/around/through those limitations. Using animal power in support of a farming system requires a level of awareness about subtle ecological factors that govern that living system. People still assume that farmers are so aware of nature, working with the seasons,but more and more these days they are merely watching the weather. Machinery and enhanced cropping techniques have allowed modern farmers to overcome the limitations that the environment throws in the path of production.

I realize that there are those who just want to use animal power as a replacement for petroleum based machinery. For some the use of animal power leads to a sensitivity to the permanent ecosystem that leads to a development of craft. In this instance farming is more than methods of harvest, and enhancing production, it also has its roots in walking the line where human interests meets ecological parameters.

When I think about the values that sub-soiling and Key Line techniques bring to modern production-based agriculture, I can’t help but think about the patient and subtle moldering growth that is already in place in a natural system. It isn’t really as simple as reducing traffic, or increasing amendments, but in part must be a willingness to let nature take it’s course.

As I am clearing a 60 year old forested plantation back to pasture, and eventually cropland, I wonder about the value that the large root structures as they pertain to this issue. Over the lives of these trees, there has been organic material deposited on the site, and the roots have penetrated the soil and pulverized it to some degree. We are not going to de-stump the land, but intend to allow the stumps to rot in place, allowing a whole host of biological activities to occur within the soil. It makes me think about the type of rejuvenation that soils receive from reforestation. I just wonder what agriculture would look like if all of our soils were allowed to go through some regular reforestation, if only to a pioneer sapling stage.

This obviously would require tremendous change, and sub-soiling is probably the best type of mechanism to perform these functions, especially considering where modern methods have taken us. I am just trying to illuminate some of the thought processes that may work at the foundation of permaculture and animal powered farming, and in my mind will support a much more sustainable system.

Carl

[near horse]

Again, lots of food for thought here so I’ll try and add something. First – since soil microbial activity seems to be pretty important, do we know which groups or species predominate in “healthy” soils w/ good tilth? And, if so, how easy would it be to do an estimate of soil microbe presence or populations – instead of having an N P K soil test (probably better in conjunction with NPK)? Kind of like thinking of your soil like your compost pile – is it active? why or why not? what needs to change? ….

The other part of this is the question about the sustainability of trying to maintain the result of such disturbance, if the disturbance is required to provide the result.

This kind of speaks to the dilemma of farming and harvesting in general. These actions aren’t natural. For example, the nutrients in a hayfield or a tree would never leave the site en masse as when we harvest those materials and it is also highly unlikely that fields would naturally be plowed and turned over in such short order (like a few days when we plow). So, what to do? We can try, as Carl says, to mimic natural processes as best we can and I think some of the forestry practices discussed on this site are great examples. But it us truly THE challenge before us to

walking the line where human interests meets ecological parameters.

.

In “The Plowman’s Folly” (mentioned here at DAP by others), the effect of inverting the topsoil with a moldboard plow is unnatural, even if it doesn’t bring up subsoil. Instead, they encourage using a disc plow or now, a chisel plow. But they require increased HP in their use. The same can be said of the “No-till” drilling systems being pushed out here in the west. I think the engineering has come from the top down – in other words, “here’s this problem with moldboard plowing AND we have a 350 HP tractor at our disposal, so what can we do?” WE need to think, as Carl mentioned he does, “here’s this problem and I have draft animal power at my disposal, what can I do?”

People still assume that farmers are so aware of nature, working with the seasons …

I have to add that “if that’s the case, why are they trying to keep all that nature off of them in their A/C cab with digital surround-sound stereo and plush bucket seats, riding 8 feet off the ground at 8 mph?”:(

I guess my point in this is we are changing an ecosystem by doing what we do. We are continually resetting “natural succession” to a stage more desirable for our needs. For example, the 60 yr old forest plantation Carl mentions wouldn’t become a pasture or cropland on its own. It would likely become a climax woodland of whatever species fit in that area. But that’s not what he needs it to be and that’s fine and I’m sure he recognizes this.

Unfortunately, as bad a rap as moldboard plowing gets, it’s still something I really enjoy doing with my team. Perhaps I can keep it to skimplowing in green manure crops or something?:o

[goodcompanion]

The thing that gets me about the keyline argument is a sort of messianic tone that tends to go along with it. That using this one particular technique in conjunction with this one particular method of grazing will send your pasture productivity through the roof, fix enough carbon to cool the planet, cure cancer, and lead the white sox to win the world series. And any other approach makes you a stick-in-the-mud luddite idiot.

I guess I really have to believe that most of the tools we need to create a durable agriculture are already at our disposal. Using them appropriately depends on years of patient observation, and reliance on what we have in the way of accumulated wisdom for our particular place.

Back when Bill Mollison first started to disseminate Permaculture I was living in Australia. The vision then, don’t know if it’s changed much, entailed the modification of Australian flash-flood hydrology in a way that would ideally green the entire continent. An Aussie friend I was staying with then suggested there might be more than a little hubris in the idea. The aboriginals had lived perfectly well for 40,000 years without feeling the compulsion to re-engineer water distribution on the continent. Plus, every agricultural scheme the white man had brought to make Australia look more like Europe had made things worse.

Keyline is (someone please correct me if I’m wrong) also part of this thread of attempts to retool Australia’s arid landscape into something more of our liking, and more capable of supporting our numbers. But which is the real problem, the landscape, or the numbers?

[Author]

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