Team conditioning for plowing

[Tim Harrigan]

There have been questions about plowing with a walking plow. If you have a young team one thing you want to do is prepare your team to pull against the resistance of the plow. If they are not prepared they may become discouraged and jump the furrow or refuse to pull. Plow draft can be quite variable depending on soil type, moisture, whether recently tilled cropland or hay or pasture ground, etc. Usually, I expect plow draft to be in the 600 to 800 lbf range. You can condition your team and prepare for the resistance of plowing by working with a sled or stoneboat ahead of time. Typically, the pulling force of a sled or stoneboat on firm, level hay or pasture ground will be about 40% of the weight of the sled. So if the expected plow draft is 600 lbf, you can create or work up to an equivalent load with a sled loaded to a weight of 600 lbf / 0.40 = 1500 lb. Forty percent of 1500 lb is 600 lbf resistance for the sled.

The attached graph demonstrates this with actual measurements I made while a friend was plowing with a walking plow. The average plow draft was 522 pounds force. The pulling forces were measured 5 times per second with a hydraulic pull meter in the towing chain. This was in a sandy loam soil and was somewhat low because the ground had been plowed in the fall, overwintered and was plowed again in late spring. Plowing was how my friend conditioned his team for the county fair. The horizontal axis of the graph shows the pulling forces for the plow and a 1200 lb sled grouped in 100 lbf increments. The vertical axis shows the frequency of the pulling forces as a percent of all the forces measured with each implement within each of those 100 lb increments. For instance, nearly 50% of the measured pulling forces for the sled were between 500 and 600 lbf. About 85% were between 400 and 600 lbf. About 75% of the plowing forces were between 400 and 600 lbf.

Notice that the frequency and magnitude of forces were quite similar for the sled and stoneboat. Using the 40% of load rule-of-thumb to create an equivalent load with a 522 lbf plow draft, a 1300 lb sled would create an equivalent load (522 / 0.4 = 1305 lbf). An average draft for the 1200 lb sled was 543 lbf.

This is how you can use a sled or stoneboat to condition your team and prepare them for the resistance of a moldboard plow or other heavy load. The plow draft in this situation was lower than I would generally expect for typical plowing conditions. A well-conditioned team makes plowing look easy, but it is not. To be on the safe side, work up to and then build condition and endurance with a sled with a total weight of 1500 to 2000 lbs.

[Andy Carson]

Tim, this is a fascinating and extremely useful chart… I noticed that the chart plots everything above 700 lbf as one event. I am curious what the maximum force you recorded in this run or other runs… In the same vein, it seems that a spring hitch (like the ones used on some of the pioneer sulky plows) could “smooth out” some of those higher draft spots. I am interested in hearing opinions about the use of these springs and if they help much in the real world…

[jac]

The late Charlie Pinney of the UK developed draft springs for the trace ends, I havent tried them myself but i think a few of the horse loggers over here use them so i recon they must be of benefit. Mabey Simon can chip in if he has come across them. I ordered the spring hitch on my plow from pioneer so will find out how that goes soon i hope..
John

[Tim Harrigan]

Countymouse;17237 wrote:

I noticed that the chart plots everything above 700 lbf as one event. I am curious what the maximum force you recorded in this run or other runs… In the same vein, it seems that a spring hitch (like the ones used on some of the pioneer sulky plows) could “smooth out” some of those higher draft spots. I am interested in hearing opinions about the use of these springs and if they help much in the real world…

The maximum pull with that plow on that day was 821 lbf. Your question made me think of some plowing we did with a 14-inch sulky plow in the fall one year after it had been really dry for an extended time. It was on a Kalamazoo loam but I am sure it would texture out as a sandy loam. The average draft in this case was 1002 lbf and the maximum pull was 1692 lbf. We used two teams of oxen and they had their work cut out for them and they did a great job. I will attach two images, one is a draft map showing the spatial distribution of forces across the field, the other is a graph of the frequency of forces similar to the one for the walking plow. This is based on 5,100 measurements of the plow draft.

Notice the pulling forces for the plow on this hard, dry soil. The highest forces for the walking plow were in the 700 lbf range, the lowest forces for the sulky plow were in this range. I would normally expect the average plow draft to be in the 700 to 800 lbf range on this soil. Plow draft is hard to predict because it is so strongly influenced by soil conditions.

This is why a team has to be prepared to pull a plow. An equivalent sled or scoot load would be 2500 lbs.

[mitchmaine]

tim, i can’t see how in any heavy soils, the spring would help too much. wouldn’t you just stretch the spring out to the resistance of the soil and the draft would remain th same? farmers used springs up here on boney, rocky soil to protect the point from ledgeoutcrops and stones too big to give. in clay or sand, just hook direct to the plow. the spring also adds length to your plow rig, requiring more adjustment for depth.

[Tim Harrigan]

I agree that the greatest benefit of the springs is to protect the equipment from shock loads such as when hitting a rock when plowing or maybe when catching a root when skidding a log. I have not seen any evidence that they do much to reduce high-end draft forces under normal conditions. I have compared draft forces for standard harness (horses) and tow chains (oxen) with nylon tow rope and generally I have measured higher forces with the nylon tow rope (I am not referring to the nylon rope and pulley systems). Why this is so is sort of a long story but I will get into it later when I have more time.

I think the buffer springs can be a good idea but you do not want to see them extending very often.

An example of the higher draft with the nylon tow ropes is in the graph and picture I posted some time ago in the Sustainable Forestry section under ground skidding. We did some side-by-side skidding over a ton on a scoot uphill, on level ground and downhill with standard traces and the nylon rope. It is surprising how much higher the average draft is with the nylon. If you look closely in the picture you can see the nylon traces.

[mitchmaine]

thanks tim, are you saying then that the spring, with stretch somewhat like the nylon, might develop a higher draft? i guess that kinda makes sense if it is always giving and taking. in regards to the original thread, i think our horses might look at plowing as a break after coming out of sugaring. a full load of sap is about 1600. and 40% makes 640 lb of draft on a scoot, except its over roots and boulders and into gullies, on snow, ice, and mud. thanks again, mitch

[Tim Harrigan]

mitchmaine;17251 wrote:

are you saying then that the spring, with stretch somewhat like the nylon, might develop a higher draft?

I suspect it will based on what I have seen with the nylon rope system. I am not speaking against the spring buffers, it is just that they are best selected to protect against shock loads. That means occasional and uncharacteristically high loads such as hitting a rock when plowing. So if you are using one and you see a lot of spring compression or extension, depending on the type of buffer you have, perhaps it is undersized for the operation you are doing.

[Andy Carson]

Maybe there might be a use for springs to equalize the required power is some instances, but Tim’s field chart on his second post convinces me that plowing is probably not one of them. The fact that areas of high draft often boarder other areas of high draft means the spring is going to do just as Mitch suggested, extend for long periods of time and the draft will be the same as with no spring. If the draft for a particular application fluctuated widely over the span of inches, the spring could extend and slow progress through these tough spots, which would in turn, reduce the power (force x velocity) required to go through this area. This would then be followed by the return of the spring in a lower draft area which would increase the power required in these low draft areas (as compared to no spring) and might serve to equalize the power required. When the load is sped up following an area of high draft, some work must be done to overcome innertia. If the load is heavy, or if it completely stops in the area of heavy draft, you would probably loose a lot of efficiency. Perhaps this is why the average draft is higher with the nylon rope compared to the standard traces? I am not sure I can think of an application where the power required might fluctate wildly over the course of a few inches, but logs hitting roots and plows hitting rocks would be a pretty good guess. Oh well, another intellectual exercise to confirm what others already knew… Maybe these thoughts are helpful to others who might have innitially thought in the same vein as I did.

[near horse]

My understanding was that the springs reduced the “shock load” that the horses might experience when hitting the “immovable object” (like a rock, root etc). If you’ve ever hit something solid, even in a tractor, it can be a bone jarring experience – I can’t imagine how bad it could feel on a horse’s shoulders.

[Tim Harrigan]

OK, this discussion is drifting off topic so I will take this to a new thread.

[TBigLug]

To comment on the original topic, I believe conditioning on a stone boat or working sled is a great idea for starting young horses. Add to this, dragging tires behind a forecart, one of my past times after the plowing’s done and before I can use them to rake hay. Also, for a first time team, I would drive them (hooked on th forecart) with one horse in the furrow (opened up with a tractor or older team perhaps) to give them an idea of what is expected of them (as far as where to walk). I’ve always done this and it’s worked out spectacularly for me.

[mstacy]

@Tim Harrigan 17214 wrote:

The pulling forces were measured 5 times per second with a hydraulic pull meter in the towing chain.

Tim,

This answers one of my questions from the “load buffering” thread. Your team is towing a relatively sophisticated data aquisition system. You have a pressure transducer coupled to a hydraulic cylinder, sampling at 5Hz? Very impressive.

Are you recording axial loads, or just the useful forward component thereof? It would be extremely interesting to combine your data with trace angle and ground speed to evaluate power, efficiency and other factors. Fascinating!

Regards,

Matt

[Tim Harrigan]

Spring tillage work is just about started in this part of the country so I thought I would revive this thread on conditioning draft animals for the work at hand. Many teams do not get the work they need throughout the winter to be in shape for pulling a plow or other tillage tools. Some work early on with a sled or other resistance can help you make sure they are ready to go.

A week or so ago Carl started an interesting post about foundational communication in response to some behavioral and other issues that had been brought up. Presenting your team with a task they are not well prepared for can give rise to a range of problems that I would describe as ‘a failure to communicate’. If they are not prepared for the effort of the work they may become discouraged, jump the furrow or refuse to pull.

I have developed the concept of equivalent loads in other threads here on DAP and I think it is really important when preparing for spring work. Plow draft can vary quite a lot depending on soil type, moisture, whether recently tilled cropland or hay or pasture ground, but a good guess for a 12 inch, single bottom plow at 6 inch depth is in the range of 600 to 800 lbs pulling force. The pulling force to move a sled or stone boat on firm, level pasture ground will be about 40% of the total weight of the sled. So if you want to create a pulling force with the sled equivalent to what you expect with the plow, say 600 lbs force, the total weight of the sled needs to be about 2.5 times (1/0.4) the pulling force of the plow, or about 1500 lbs. With this load, the pulling force needed to pull the 1500 lb sled will be nearly equivalent to the pulling force needed to pull the plow, about 600 lbs force.

This is how you can use a sled or stoneboat to condition your team and know when they are prepared for the resistance of a moldboard plow or other heavy load. Start with lighter loads and increase the weight as the team becomes hardended to the task.

[blue80]

I recently read that a furlong is a measurement which originated by the distance a team of horses could plow before needing a break; 660 ft. if I remember correctly…

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