[Andy Carson]

After much thought, I have decided to go with this concept. It’s going to be a process that takes many years to get going, but I’ll try to post periodic updates. I have devoted about 2.5 acres to this, so I think it’s enough to be a good sample and also be productive enough to be worthwhile. Here’s what I’m planting and why:

30 White Russian Mulberries: Productive trees with a somewhat extended and generally early fruiting season and good wintering ability

30 Sweet Crabapples: Productive and hold onto fruit into winter (which will provide forage in an otherwise difficult season -if the wild animals don’t eat them first)

30 Seguin Chestnuts: PRoductive and blight resistant. Provides a dense high carb diet in the fall for finishing hogs (too much fat in the finishing diet is supposed to lead to soft pork)

12 Wild Yellow Sweet Cherries: First tree to fruit, so that I can extend the “tree crop season” a bit -The timber value is also attractive (even though I might not live long enough to see it)

8 Honey Locust: Good productivity, I am using this in higher traffic areas where I hope the thorns will keep the pigs from “messing” with them too much

30 Black Walnut: I went with black walnut rather than english walnut because I was worried about the hardiness of the english tree. Maybe I didn’t need to (as peaches can grow here) but I figured that I should play it safe on such a long term project. The walnuts are high fat, so I am planning on using these to provide dense nutition to lactating sows and overwinter breeding stock. The timber value of the walnuts is attractive too (even though I might not live long enough to see it).

All these trees will be planting in different sections so that I can rotationally graze different crops when the fruit is in season (and thusly limit damage). Late winter and early spring is still a difficult time from a planning point of a view, so I am planning on 1) carrying only breeding stock during this time and 2) planting field crops which can be grazed during these lean times.

I ended up buying tree shelters for all these trees, as I am convinced the deer will eat them if I don’t. I may end up building cages around some of them too, if the rubbing is bad. I am still on the fence about investing in tree mats, and haven’t yet. I would be curious about other’s experience with them.

[Andy Carson]

That is a pneumatic collar. In theory, the air cushion accomidates the movement of the horses shoulders, which prevents rubbing of the neck and shoulders. In addition, there is some cushioning in case the pulled object hits a solid obstruction. I had done some reading about these when I was doing a little background reading about draft buffers. There was a company created in WV in 1898 to manufacture these collars and they recieved praise in very non-scientific tests (I have added a link below). I love inventions from this time period, where engineering was advanced and widespread enough to really improve things, but internal combustion hadn’t taken everything over yet. I bet someone could make some substantial contributions to animal power today if they simply “mined” that period of history for animal-related inventions and tested them.

http://books.google.com/books?id=14vmAAAAMAAJ&pg=PA45&lpg=PA45&dq=pneumatic+collar+for+horse&source=bl&ots=5gdOvOWAId&sig=Fi4hxndxTMlp_Kxj_jw9Awxo_HY&hl=en#v=onepage&q=pneumatic%20collar%20for%20horse&f=false

[Andy Carson]

I have gotten less flack about this whole farming thing than I expected… It’s even kinda “trendy” in certain circles and sometimes I feel very undeservingly popular. Even outside those circles, pointing out a few examples of people who are successful makes a strong argument. Ultimately, you aren’t going to be able to change everyone’s mind, but differences of opinion make the world more interesting anyway… A little success changes a lot of minds.

[Andy Carson]

Thanks Geoff,
I would think that these kinds of fungal infections would be most common in situations where there is a significant amount of manure (probably enough that it doesn’t dry out) or where the manure sits for a long time without being cleaned up. I would guess that if there isn’t enough manure to “make a stink” and/or it hasn’t sat around long enough to “make a stink” the risk is probably minimal… I just wanted to check if anyone out there had any experience with illness that may have been attributed to this cause…

I am still going to scrape it out of the feed trough, though, probably because I would want the done for me! 🙂

[Andy Carson]

@Tim Harrigan 28364 wrote:

Andy, how about a ramp and a bucket on a frame with a wheel on the front and two handles in back? 🙂

Very inventive, Tim :rolleyes:

[Andy Carson]

1. The “chisel” would need to go 4 inches minimum (6 would be better), and be able to deal with substantial crop residue without clogging
2. The row marker is probably more difficult than you are thinking, this would be for a min till situtation where there is alot of crop residue. Marks are hard to see when you are planting only one row at a time, especially with residue obscuring your view, are using somewhat limited animal power to make your mark, are distracted by working your animal, and are walking at ground level (gives you poor perspective). Geoff made a prototype foam marker, I think this would be a good starting point.
3. A “bucket” that could scoop manure up about 3-4 feet and dump it would be awesome. No need for telescoping on anythign “fancy.” I will be curious to see what you come up with (if you pick up this concept). I have sketched something like this out before, but it always got too far-fetched looking. At least a few people who use draft animals almost exclusively keep a tractor just for the bucket. It’s definately a need that hasn’t been filled.
4. I am also curious about the other concepts and the gearbox you come up with. I have to admit I wonder if animals have the raw power to brush hog or thresh grain unless you get alot of them together… You might want to check out the power requirements of these types of things just to see how many horses (or anything else) would be required to do the work at hand. If the answer is 100 horses, for example, you will probably end up changing things…

[Andy Carson]

Hi Douglas,
Here’s a quick wish list… Maybe something will peak your interest…

1. Something animal powered that would substitute for a chisel to allow for min-till with animals
-This is going to challenging because of high draft for tractor type chisels
2. Something animal pulled that can substitute for a brush hog
-I am not opposed to mounting a motor on this, but wouldn’t it be great if you didn’t have to???
3. Some type of simple reliable row marker system that would work for organic farmers
4. Small scale thresher that would be able to handle a wide variety of crops
-I expect to mount a motor on this, it would be great if it was light enough to be mobile
5. Something animal powered that would substitue for a tractor’s bucket
-Lots of room for creativity here, but would need to be relatively simple and reliable (slip scoops just don’t reach out in front!)

These are just off the top of my head, I am sure you’ll find many other ideas.

[Andy Carson]

This might be a strange thought, but I think one of the groups that ought to be concerned about the use of round-up resistant bluegrass in lawns are big commercial farmers who use round-up ready crops. Here’s why…

I bet most lawn owners who opt for this grass will only use round-up when they see a fair amount of weeds. Then, they will probably only use enough round-up to get rid of “most” of the weeds. Next time they see weeds, they will probably use the same application rate, and if this fails to kill most of the weeds, they will use a little more (just enough to kill most weeds). You couldn’t come up with a better plan to select for round-up resistant weeds. Couple this with the fact that not all these lawns will be sprayed at the same time and are close to other lawns, allowing for easy dissemination of weed seeds. Add to this the fact that most landowners cannot and/or will not perform any sort of tillage to remove round-up resistant weeds and are also pretty resistant to reseeding. Also, the wide adaptablity and desirablility of bluegrass means it will likley populate large swaths of the country. Also the perineal nature of lawns gives a home to both annual and pereinial round-up resistant weeds. All together, I bet all these lawns will provide sources and refuge for roundup resistant weeds throughout the country. The seeds of which will blow back into roundup resistant corn, soybeans, and everything else. Jeesh, you almost couldn’t design a better system to breed for round-up resistance weed development. And the system is voluntary, self sustaining, and self funding. I seriously doubt round-up ready crops are long for this world, but is the the enemy of your enemy your friend??? Maybe, but I suspect Monsanto will “deal” with the resistant weeds by developing and selling otehr herbicide reistant crops (such as Glufosinate). Possibly Monsanto will run the whole gambit of herbicides and herbicides resistance gene combinations until they run out of drugs or genes or both. That would be pretty much what happened with antibiotics… It will definately be interesting to see what happens and I bet is won’t take long to find out. I don’t see why a round-up resistant weed would be any more difficult to control by mechanical or organic means, so if you are not “bugged” by the engineered genes this might simply be an “interesting state of affairs,” mattering only to people needing to use the herbicides. I know that is a matter of much debate but that is largely how I look at it.

[Andy Carson]

@Tim Harrigan 28162 wrote:

I have thought about changing the surface material but not the shape of the runners. You rockered the runners, but you also seemed to describe a natural process of wear whereby the runners took on a rockered profile. So do the runners seek a low-draft profile? Are you suggesting we need to be more attentive to the shape of worn runners when we replace them with new runners? That makes sense to me.

i hadn’t really thougth of watching the runner wear as a practical tool, but yes, that would definately be a good idea. An ideal runner would wear evenly over the entire contact surface. If one notices that an area wears more than any other, that area should be smoothed or back off whenever the runners are replaced. You know, not only would that reduce the force required to move the sled, but also would save on steel… That’s a great thought!

I would be curious about the results of pulling different weights over the same surface too. The compressibility of the soil has been a difficult thing for me to model completely, because soil behavior seems to vary alot by soil type and moisture content. Not only is the compressiblity variable, but also the dampening effect varies. At very high dampening rates, one might see a reduction in the apparent friction coefficient at high weights, because the soil doesn’t have time to compress fully during the time the sled is acting on it. I really don’t know if the dampening effect is significacnt in something like a pulling contest. There are just so many unknown and important variables in this analysis that even I won’t hazard a guess.

[Andy Carson]

Sorry Erika,
sometimes I get excited and do a bunch of modeling, thinking, and writing and don’t stop to explain why I’m doing it in the first place…

Basically, I think that Tim’s data in this post and others can be partially explained by having greater drag from the front of the sled or log than from the back. I think this makes some intuitive sense and matches with experience and observations but it is difficult to explain exactly why that is. I am interested in trying to figure out “why” because whatever is causing the additional drag might be able to be “fixed.”

Most of the math is me coming up with theories of what might be causing the additional drag in the front, and seeing if this math matches with measured values. The idea is that if the math predicts values that are far from the measured values, than the model/theory is probably wrong. I created a model based on different coefficients of friction that explained the values in this thread alone. Tim pointed out (very gently I might add) that although it does match the value in this post, the coefficients of friction are hardly believable and it the model doesn’t match measurements in post #26 of the draft buffer thread. So, I came up with a different way to explain exactly how the drag might be higher in the front than in the rear, based on the compressibility of the soil. I think it makes sense, and explains the data in this post and most of post 26, but we’ll see what people have to say… It sounds like whatever the explaination is, it is probably going to be somewhat theoretical. That’s what’s nice about the sled runner shape test. If a theory can’t be tested somehow, there’s no way to know if it’s true. Also, the runner design is a practical application of the concept, if it does indeed work. There will probably be some batting back and forth of ideas to come, that is if anyone else wants to be nerdy.

[Andy Carson]

Draft buffer post #26 has made me think a lot. One of the things that this brings to mind is that we have been modeling the soil as an incompressible substance, even though we know better. Now when I say compression here, I don’t mean irreversible compression, just the “give” that you feel when you step on soil versus say concrete. I think this is an important factor, and here’s why. I think Tim is right when he points out that my friction coefficients for the front of the log are too high to be reasonable. And yet experience, observation, and Tim’s tractor+sled data (post 26) would indicate that weight in the front somehow causes more drag than weight in the back. If one doubts this, one can also look at the wear on sled runners. I have had to replace mine several times, and the most wear is invariably at the leading edge of the runner right where soil contact is made. There’s a good bit of wear at the very rear of the runner too, but the middle of the runners always holds up a lot better. Now every part of those runners sees exactly the same terrain, travels the same distance, and is made of identical materials, but the wear pattern is dramatically different. On my sled, I bet the leading edge wears at twice the rate of any other area. Maybe even more than twice… So, because the friction coefficient is probably almost the same (soil vs steel), there must be more weight on the leading edge somehow. With even or variable loads, that can’t make sense without some degree of soil sinkage. With soil sinkage, the front of the sled would be thrust up onto upcompressed ground and be briefly suspended between the leading edge of a flat runner and the trailing edge. At this point, weight from the front half of the sled will compress the soil along the leading edge, and the trailing edge will sit on already compressed soil at the rear of the sled. The elevation of the sled’s front may or may not be noticeable (just like you can’t always see the front of an icebreaker elevate) but the concept of “lift and fall” still applies.

So, I’m going to see if vertical lift and the work of compressing soil can account for the increased drag from the front of the sled in this test (and see if this also works for the sled in draft buffer post #26). During the “lift” component a pull into compressible soil with a flat bottom sled, all weight will be suspended between the leading sled runner edge (or other contact point) and the trailing rear edge. The downward force on the leading edge has to overcome the compressibility of the soil at a rate proportional to the angle of the leading edge. Half the load in Tim’s example weighs 613 lbs (1225/2), which is elevated by the the 15 degree total pull of 392 lbf. The vertical component of this pull is 101 lbf, leaving 511 lb on a 10 degree incline (estimated angle of attack) and a horizontal pull of 379 lbf. Moving 511 lb up a 10 degree incline takes 89 lbf along at a 10 degree angle. That equates to a 90 lbf horizontal pull. So 90 lbf out of 379lbf might used up compressing soil along a 10 degree leading edge of a sled. That leaves 289 lbs remaining. There is still 511 lbs in the front and 613 lbs in the rear, which if applied equally would yield friction coefficients of 0.26. Now these friction coefficients are really quite low, but this is analysis models this interaction as non-compressing, non-tilling, and smooth, and takes the leading edge into account separately, so maybe this isn’t stange… Overall, using this analysis the front edge is responsible for about 60% of the draft and the rear is responsible for about 40%. This general pattern explains some of the patterns seen in post #26, where loading up the front of the sled resulted in higher draft forces than loading the rear. It’s really pretty tough to do these analysis in great detail, because so much depends on the exact angle of attack at the leading edge, the length of the sled, and soil properties (such as compressibilty and dampening). Because of these complications, I can’t compared exact numbers, I can really only see if the trends match, which they do.

There are practical applications of this modelling. One aspect that comes out to be important is how critical a shallow angle of attack is on sled runners. Also, it would be advantageous to extend the runners out in front of the load so they are not as weighted while they are being “lifted.” Lastly, having a very shallow rounded bottom to the runners (very slightly higher in the middle) will prevent much of the the deleterious loading of the front end. I bet a runner such as the top runner in the photo below would be much more efficient than the runner below. Maybe as much as 10% improved with respect to draft for a given weight… Now, there’s something to test! 🙂

[Andy Carson]

Yes, post #26 is very interesting… I will have to give this a good think and see if this data contradicts or supports my modeling… I agree that without “real” measurements, we are kinda arguing about how many angels can dance on the head of a pin. I think this kind of data analysis is sometimes (maybe even often) useful though, because it can identify which parameters are most interesting to test in the field. Sometimes, too, the mathmatical modelling can suggest interesting and potentially useful modifications. I am sure I will have more thoughts when I think through and compare post #26.

[Andy Carson]

Hey, who’s calling me a nerd! Need I point out the you just performed calculus on a trigometric function, and in public??? 😀

Thanks for the thoughts, numbers, and math, Tim. It is interesting that we come up with functionally similar angles using different methods. Getting similar answers with different methods definitely gives more confidence. I am probably picking a nit, here, but I like an analysis that treats the front of the log differently than the back of the log because the front can dive into the ground and till while the rear cannot. Because of this fundamental and important difference, I think the friction coefficient for the front of the log will be different from the rear. Also, I don’t think that a lift to one side of a log will necessarily shift that same weight to the rear. A lift of 525 lbs on one end, for example, doesn’t make the other end weigh 1050 lbs… So, I’ll rework this with the additional information. I kinda wonder why, because I’ll probably end up with the same take home information as in our previous two posts, but let’s see…

Sled: As the front of the sled can’t till and the rear of the log is off the ground anyway I’ll estimate draft without reguard to front and rear ends. For a pull of 392 lbf at 15 degrees, the horizontal component is 379 lbf (cos15degrees*392), and the vertical component is 101 lbf (sin15degrees*392). The vertical component removes 101 lbs from the weight of 1225, yielding an applied weight of 1124. This gives a friction coefficient of 0.34. with this friction coefficient, one can plot the resulting forces (shown in the graph below). I get a minimum draft force at 19 degrees, which is damn close to Tim’s 18 degrees, but what really jumps out at me in this plot is just how flat it is. All resulting draft forces from an angle of 7 degrees to 29 degrees are within 2% of the minimum. So, for all practical purposes, the angle of draft doesn’t matter for a sled.

Tongs: I am going to model the rear of the sled as having a friction coefficient of 0.4 (slightly more than the sled) because it can’t till and has a rough surface (and because I’m a stubborn bastard). The downward force of the rear half is still 525 lb, resulting in horizontal drag is 210 lbf. For a pull of 549 lbf at 15 degrees, the horizontal component is 511 lbf (cos15degrees*549), and the vertical component is 137 lbf (sin15degrees*549). The vertical component removes 137 lbs from the front weight on 525, yielding an applied front weight of 388. As the horizontal component of the pull is 511 lbf, and the rear takes up 210 lb of this, the resulting friction coefficient is 0.78. Wow, can the front dig in! With the friction coefficients of the front and rear, one can plot the resulting forces (shown in the graph below). I get a minimum draft force at 38 degrees, which is a ways away from Tim’s number due to substantial lift on the front (not the rear) of the log. This probably doesn’t matter is practice, though, because either angle is challenging to achieve. Here the graph illustrates how much more sensitive this setup is to draft angle, with a 2% increase over minimum draft at 27 degrees, a 5% increase over minimum draft at 20 degrees, and 10% increase at 13 degrees.

Chain: similar to the tongs, I am going to model the rear of the sled as having a friction coefficient of 0.4. The downward force of the rear half is still 525 lb, resulting in horizontal drag is 210 lbf. For a pull of 565 lbf at 15 degrees, the horizontal component is 546 lbf (cos15degrees*565), and the vertical component is 146 lbf (sin15degrees*565). The vertical vector yields an applied front weight of 379. As the horizontal component of the pull is 546 lbf, and the rear takes up 210 lb of this, the resulting friction coefficient is 0.89 for the front end of the log (which is similar to the friction of a car tire on pavement). Wow again! Just as in the other examples, I can use the friction coefficients to plot total forces at different draft angles. For the chain, I get a minimum draft force at an impractical 42 degrees. This type of hitch is even more sensitive to draft angle, with a 2% increase over minimum draft at 30 degrees, a 5% increase over minimum draft at 23 degrees, and 10% increase at 16 degrees.

[Andy Carson]

One of the interesting things about this group of measurements is that as all three of these twitching methods are applied to the front end of the log, one could assume with some confidence that the drag on the rear of the log remains constant. This allows one to tease out the relative contributions of the front and rear of the log towards total draft. Perhaps this will be interesting…

One could model the total drag on the log as the weight of the front end*friction+weight of rear end*friction. Previous work from Tim shows that stoneboat friction is approximately 0.4x weight. I think this is a good approximation of friction at the rear of the log, which can slide over ground without digging in and tilling it. For this particular log, this would be 1050/2*0.4 or 210 lbf (I am assuming the rear and front halves are approximately the same weight). With a sled under the front end of the log, the average draft is 392 lbf, with only 182 lbf coming from the front end (392-210). One might be surprised that the draft of the front end here is lighter than the rear. I think this is totally due to the angle of draft. The vertical component of a 10 degree angle of draft with a total force of 392 lbf is about 68 lbf (sin10 degrees*392=68). The vertical component would reduce the total applied weight of the front end of the log from 525 lb (1050/2) to 457 (525-68). 457*0.4=183 lbf, which is damn close to 182 lbf.

So, the drag applied by the rear end of the log in this case is about 210 lbf. As the front of the log does not physically lift of the ground in any of these pulls, and the geometry of the rear of the log remains constant, the drag applied by the rear of the log would be the same (210 lbf) in these different situations. I am going to assume the angle of draft also remains constant in these situations. That means the applied force of the front end is sin10degrees*total draft in all cases (which is 92 and 97 lbf for the tongs and chain respectively).

Here’s where the differences really stand out. The average force of the log skidded with tongs is 530 lbf and the chain is 546. That means the drag from the front end of the log is 320 lbf and 336 lbf, respectively. These represent friction coefficients of 0.74 (320/((525-92)) for the tongs and a whopping 0.78 (336/(525-97)) for the chain, which is almost double that of the sled or the rear of the log. Pretty dramatic difference when you dig into the numbers.

I think this is also a great illustration of why getting lift on the front end of a log is important. Actually, these numbers give is a way to determine the optimal amount of lift to apply to this particular log in these different situations. To do this I determined the upward vector of the total draft at 10 degrees, as I did previously. This gives the downward force at the front of the log (525-sin10degrees) and horizontal component of the vector that must be exerted to overcome drag in the front end which is equal to the downward force times the friction coefficient (0.4 for sled, 0.74 for tongs, and 0.78 for chain). The horizontal component of the rear of the log we already know will always be 210 lbf, so we add the horizontal frorce vectors together and use trigonometry to determine the total force vector. One can then use excell to plot all required draft forces at these different angles and get an idea of the ideal angle of draft for these different situations (I have attached the plots below). Interestingly, the optimal angles are not identical. One can tell from the plot below that a sled isn’t very sensitive to draft angle, but is the angle is optimal at about 20-25 degrees. The tongs and choker chain are much more sensitive to draft angle with an optimal angle of around 35-40 degrees. As this angle is probably not achievable with standard hitching methods, the recommendation would be to hitch as short as possible if you are using a chain or tongs. Or you could simply use a sled and not have to worry about angles and such. I think we already knew this, but it’s nice to see the math too.

Interesting stuff, and fun to think about! 🙂

PS. This post contains substantial edits from my previous post due to a few math errors… These were actually pretty important math errors and they changed my overall conclusions.

[Andy Carson]

One thing that could be done with these tests would be to compare the average and peak pulling forces. I am sure this is useful information (and might be the most useful information possible), but I wonder about the possibility of other tests. I wish there was some way of determining not only the force exerted, but also how “easy” and “comfortable” it is for the animal to exert that given force. From a human example, we all know there are “easy” and “hard” ways to lift a heavy weight and/or pull a heavy load. Sometimes the “hard” ways are difficult short term (like lifting with your arms only versus bending your legs) and sometimes they are easy short term, but can cause long term damage (like beindg you back to lift instead of bending your legs). Long term damage is probably impossible to do anything other than speculate on, but I wonder about shorter term “efficiency” tests. I have seen measurements of oxygen consumption of horses treadmills that were pulling draft loads, and these would certainly tell you how many calories are consumed with these different hitching configurations. I suppose also that some some of blood test for lactate could also tell you if there was alot of anaerobic work going on, which might shed light on how different hitch configuations can help of hinder animal performance. A hitch configuration that resulted in higher lactate levels after equal work, would be less efficient than one resulting in lower lactate levels, despite equal work (for example). These tests are probably too difficult to be of practical utility in the field though… I wonder if anyone out there has thoughts on what types of tests might be done to objectively determine the different efficiencies of hitching arrangements. Particularly tests that would answer the question, “how comfortable and easy is it for an animal pull pull an equal load with different hitching arrangements?” If the loads or pulling forces are indeed different, this observation probably “trumps” the “comfort and ease” test, but if the loads were similar, I think some test would be very interesting (if the test itself was practical).

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