Draft Animal Power – Draft animals and sustainable land stewardship › Forum › Sustainable Living and Land use › Sustainable Farming › Energy efficiency of horses vs tractors
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- May 3, 2013 at 11:49 am #79405
I might be late to the party but I just saw this paper posted over on RH. A 10 yr study in Kansas using horses and calculating the enrgy efficiencies — pretty detailed. My take is that draft animals “lose” some of their “efficiency” when not being used (the still consume) while tarctors – not so much. So to maximize – use them a lot!
Attachments:You must be logged in to view attached files.May 3, 2013 at 1:19 pm #79407
But you still get manure and that should count for some energy even if they are idle.May 3, 2013 at 11:07 pm #79414
The energy it takes to get the fuel for tractors from the ground to the tank also needs to be taken into account. Remember there is a difference between efficiency and convenience: it is very convenient to fill the tank and turn the key, but in reality it is not efficient. We tend to forget this in the States.May 4, 2013 at 12:00 am #79415
Read the paper – they have taken a lot of this into account. As I read it, they even included the energy needed to build the tractor ….May 4, 2013 at 1:10 am #79416
Well I wanted to edit but my time limit expired …. Another calculation that makes things look significantly worse for horses is in labor. They calculated GJ of energy produced per hour of labor ….. so even with the same level of “production” (tons of hay, bushels of grain etc) the fact that the horses aren’t as fast is considered a detriment. That seems like an unfair assessment.May 5, 2013 at 8:27 pm #79429
Another area of this general discussion I don’t believe I have ever seen adequately addressed is soil compaction. My filelds have had a tractor on them once in the last 35 years for mowing and baling 2 years ago after I got hurt, otherwise all the manure spreading and haying, etc. has been strictly horse powered- not even a pickup truck. I recently took my 3/4ton out across the field to pick up something and I could feel the divets every where the truck drove. My understanding is that 90% of compaction takes place on the 1st pass. Another factor I wonder about is the vibration from the motor as the wheels are rolling over the ground. Vibration is used to settle concrete and many other things. In my experience there is a negative economic impact from the extra compaction caused by the use of tractors on land when animal power could just a easily do the job. I can feel the difference every time I walk across my fields (and the fields of others). JayMay 5, 2013 at 11:23 pm #79430
Just a side note on compaction.. When I was out west a few years ago, they were flooding their land on water shares. This would settle and need broken up every few years. The way I saw them doing this was with a very large one bottom plow,pulled by a large track machine. This was plowing to about 4ft.. Big clods were breaking off as they came up. 100% compaction. This plow was pulled with a cable that steam was coming off in the cool morning air. They work all their land with tractors and have a huge problem with this when they add the water effect over years. So compaction is a problem for everyone to deal with in one form or the other.May 6, 2013 at 6:28 am #79431
Compaction is also a problem because we plant so many annuals and not enough perennials which send down deep roots to help brake up some compaction.May 6, 2013 at 9:17 am #79439
To clear up any confusion (I’ve read this paper front-to-back at least 10 times):
This paper doesn’t compare the energy efficiency of horses and tractors. Rather, its an insanely detailed account of all of the inputs (converted to energy) on a model mixed-power low-input farm in the midwest, put together by the land institute. To give you an idea of the level of detail: if someone went to town to buy a bolt, they charged for the energy to make the bolt and the energy to get to town (the gasoline, and the depreciation on the truck.)
Originally, they hoped to use the horses very extensively, but (probably due to teamster staffing challenges) the horses were only used about 115 hours/yr. Because of this, they used a lot of (tractor) energy to grow the horse feed, making the horses less energy efficient than the tractors.
Because the highly underutilized horses were a drag on the farm’s labor/energy efficiency, they used their database to simulate what the farm’s productivity would have been if all of the work had been done by tractors.
I’m sure that the study’s authors would totally disagree with the conclusion that it shows anything about the relative energy efficiency of horses and tractors in general, just that on that farm, which couldn’t use horses nearly as much as they planned, having horses made them less energy efficient.May 6, 2013 at 12:14 pm #79444
While it is an interesting study, It’s definitely not a good comparison of horses and tractors at all. To do that properly you would have to compare two completely separate but similar operations, one with only horses, the other only tractors. Even then it would be hard to totally compare, because the types of operations where horses are most efficient are different than operations where tractors reach their peak efficiency. And it’s not only about efficiency, it’s about the big picture of the effects ( or lack thereof) on the environment and local farm system. Of course if you only use horses two hours a week and use the tractors to help grow their feed you would come up with results like this. I would also guess, as suggested in a previous post, that teamster experience was a big factor. I’m not quite as familiar with farming as I am logging, but I do know that the difference in efficient use of time between a beginner and an old hand can be quite large.
So, interesting study, but not very realistic conclusions as far as comparing horse and tractor efficiencies.May 6, 2013 at 9:28 pm #79449
It seems an underlying thing to have an understanding of what is meant by “efficiency”. Is it just human hours spent which seems to be the most commonly used one or? or? or….? I guess that’s what we often debate here which is very good. JayMay 7, 2013 at 12:32 am #79450
Here is an article I have posted before on the same subject, it is from Ireland.
Attachments:You must be logged in to view attached files.May 7, 2013 at 1:29 pm #79456
As I mentioned, one unjust comparison or measure really involves the “work done per unit of time”. That’s how we ended up in the modern ag version of an arms race in the first place. “If I can farm faster then I can farm more ground” and we’re off and running with 80 ft cultivators, 400HP tractors and complaining that our old corn planter tumbles seed when we operate at field speeds of 6 mph or greater ….. and, until very recently, still getting close to the same price for products as we did 30 yrs back.
Don’t get me wrong, I think draft-animal power is the way to go. The paper I posted was just another opportunity to look at somebody’s attempt to quantify efficiency of farming with animals. complete with its flaws (the paper not the horses). But what I like, as Jay points out, it puts something out there for us to look at, think about and reflect on what we do.
Reading an article and seeing its misconceptions and shortcomings can often clarify our own positions for doing what we do.May 7, 2013 at 3:50 pm #79463
Yes it was definitely an interesting read, and I agree that seeing it’s shortcomings can help us clarify our own positions.
To address the efficiency question/point. Efficiency is strictly a ratio, of input to output. You can use any values you want to: human hours or horse hours, or you could address other issues such as the inherent inefficiencies of the tractor as a power source, like the fact that with, for example, a 50 HP tractor, you only end up with actually maybe in the 6-10 HP range at the drawbar. There are many other values you can put into the efficiency ratio, all very interesting studies.May 8, 2013 at 11:11 am #79479
The one problem I have with using time in efficiency calculations is that I feel it’s one thing I truly own and, as such, I don’t like my choice of how to use it to be considered a debit.
My point is – if I milked 4 cows this morning, what differene does it make whether I did it in 45 minutes or 1hr and 45 minutes? I still milked 4 cows. The rub comes when we convert the “saved” time into other work … so in that hour I “saved” I may have mucked out 5 stalls. But I would have gotten to those later anyway …. so where does it end? That’s the arms race or just race period.
Please don’t believe for a moment that I’m not a victim of this eas well. I easily fall prey to the “hurry hurry so I can …. hurry hurry”. It’s a battle.
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