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Drawbar
08-02-2008, 03:27 PM
Well when I started my CNMP (Comprehensive Nutrient Management Plan) for my start-up sheep operation I doubted I would find anything exciting, but in some ways I found out something very profound. The CNMP is basically a plan to deal with the manure these sheep will produce.

In doing the calculations however it seems I was a bit off in regards to the stocking rate of sheep. As my father, Grandfather and his Grandfather have calculated in years past, we always calculated the stocking rate (or how many sheep, cows, or horses you can have on an acre of land) based on how much grass it grew. In simple terms, how much does one animal eat and how many acres does it take to raise the number of animals you want.

Well it seems in my calculations, my stocking rate here is not dictated by what they eat, its dictated by the manure these sheep produce since its lower than what my land can up-take.

HUH you are probably saying?

Well its like this. I always knew that our high quality pastures here can support 10 sheep per acre for most of the growing season. But what I had not taken into account was, the slope of the ground here (a mild 6%), coupled with some soil compaction, the type of grass we grow, and the amount the soil absorbs can only take up so much manure. That number is 5.8 sheep per acre and not 10.

Now this could really pertain to homesteaders. If you have say 15 sheep on a single acre and are supplementing feed by using bales of hay then you just may be polluting their own place with excess manure.

Its interesting to note that stock piling it is not much better since rain, slope, soil type and whatnot can absorb too much of that concentrated manure and pollute your homestead too.

I am not trying to scare anyone here, but what I am trying to say is, before you figure out what you want for animals, and how many to get, you might want to figure out how much your soil can absorb for manure to figure that number out.

I am not expert, but if anyone is interested in how I came out with the formula I did, I will be glad to share. (My CNMP ended up being 23 pages in length so it pretty detailed.)

walls0stone
08-02-2008, 03:54 PM
This is a very real consept. For those who don't think about all the stuff like, kind of ground, kind of grass. soil type...only what's affordable or what is realy cool.

our ditches and water ways have a large embankment on both sides, reducing the amount of stuff that could get into the water. Now I'd say that if you spent lots of time with your land, you would see some sighns..but that takes time.

DaleK
08-02-2008, 05:50 PM
When we did our version here, we also GPS soil-tested most of the farm on grid maps to get a better baseline than what we were doing before, which was taking 2-3 samples from every field every year.
Saw some neat things, like a spot in the middle of one field where the N, P and K were 20 times higher than anywhere else on the field.
In 1919, the house and barns on that farm burnt when the thrashing machine threw a spark into the straw mow and they never rebuilt.
The ashes combined with the manure around the old barnyard are still keeping the fertility levels that much higher 90 years later.

Drawbar
08-03-2008, 01:41 AM
People asked me why I was doing a CNMP by myself. The answer was simple, so I could learn. Boy did I ever. Just doing the calculations was tough. How much does gravel loam soil absorb for the 13 nutrients needed for plant growth (about 56% incidentally). What does slope have to do with manure retention? (A lot) What about soil compaction and manure retention? (A lot) What about copper and zinc levels and adjusting your manure spreading to prevent a build up of these levels.

Yeah I learned a lot. A really good thing was seeing how much manure the sheep produced, and seeing how much dairy farm manure I could add to get just enough manure to really help the grass grow but not pollute my land in the long term. It took a lot of calculations to see just how much dairy cow manure I needed in regards to the number of sheep.

As I said I learned a lot, but I guess you do that when you do a 23 page research paper :)

bookwormom
08-03-2008, 10:05 AM
very interesting, I don't see when you do all that stuff with all your work and kids etc. I 'd take any manure you do not want. this land here has not seen any if ever. I guess folks do not raise tobacco in your neck of the woods. I don't know if I can follow all your figurings, but sure would like to try.