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Managing the Mobile Composting Unit

Updated: Jan 8, 2021

We have reached the point in the fall season when not even the hardiest of grasses are growing. The ground has the beginning crust of winter frost that stays hard most days and the ponds have begun to freeze over in earnest.

Cows in a winter hay field.
The herd take a break from manicuring the hay field.

In the past, my dad always pushed the cattle to graze for as long as possible, often into January and perhaps even February before he would begin giving the cattle bales of hay. The reason for this was two fold. First, baled hay costs money, even if you baled it yourself. Fuel, equipment and your own time factor into the cost and the bare minimum calculation puts a bale at $15 to produce. Grass left over in the hay fields during winter, however, is essentially free. The cows do all the work of harvesting and processing for you. They even leave compact piles of composted fertilizer scattered about in the process.

The second reason to hold off on feeding bale hay is that if the winter season turns severe, or there is a general shortage of hay, the price for it can skyrocket from the usual $50-60 per bale to $120-140 per bale. That can turn surplus bales into a cash crop in a hot minute.

Looking at hay as a cash crop, however, has long term implications. Every bale that is sold off the farm is made up of plants that sent down roots to absorb nutrients from the soil. Carbon, phosphorus, potassium and nitrogen (along with many other micronutrients) are all packed into the stems and leaves of the hay. Selling it to someone else sends all that soil fertility to their farm (or feedlot) where their cows process it into compost for them. It is forever gone from our farm and land, weakening the soil and depleting the natural microbiome in the process.

So, what to do?

Well, I'm glad you asked.

Cattle gather around hay rolled out on the ground.
The cows noshing newly unrolled hay.

The first thing I am doing differently from my dad is that I am already bale feeding my cows. Not a lot, mind you, I still want the cows to utilize as much of the free grass on the ground as possible. But I also want them to compost the hay's nutrients where I need them to on my fields. Since cows have a rather laissez faire attitude to their bathroom habits, I use the hay to encourage targeted deposits.

How that works is that I take my hay bales - grown on the best, most fertile soils on the farm - and unroll them on my poorer soils. The cows, looking for an easy snack, gravitate to the hay. But cows, being the slobs they are, stand around peeing and pooping on the hay as they eat it, trampling the nutrients and organic matter back into the soil. By the time spring rolls around, the areas where I fed the cattle will be lush with newly invigorated growth, richer soils and a more diverse set of microorganisms.

How's that for science?

In the spring, these lines where I rolled out hay will be bright green with jump started grass.

To make the best use of this process, I am trying to find someone who has more cows than they have grass and hay. If I can bring extra cows onto our farm, I can use my surplus hay to both make money and support the fertility of its soil - all I have to do is pay attention to where the land needs a boost and unroll bales for hungry cattle in that spot. The cow owner gets the benefit of lower priced but excellent hay and someone to manage his cows. I on the other hand, get mobile composting units to position around the farm as I see fit. A win-win proposition if I can just find the right cattle owner.

So there it is, the grand plan for all of you to see. Let me know if you have an extra 25-30 cows looking for tasty, tasty hay and a place to process it.

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Dec 09, 2020

Gotta pass these nuggets of wisdom on to a few of my biology teacher friends. Great to see you actualizing the theory!


Dec 05, 2020

I love the innovation. Wish I had some hungry cows to send your way.

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