Keyline Plow

Here is a link with related discussion, sweetie;)

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

Carl

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

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

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….

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

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.

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