Monday, February 15, 2016

What do you do about manure?

Manure is the original fertilizer - and in fact, if you're eating organic food, the chances are very good that it was fertlized with manure.   For commercial farms it's composted and sterile - at least that's the way it's supposed to be.

Manure is actually stuff that I like.  It makes for fertile fields, good crop yields, and since it's produced as a by-product of my livestock operation, it closes the loop for me, too.

That is, I collect the manure, spread it on the fields, harvest the crops, feed it to the animals, and then collect the manure - repeat.

Manure is only really useful when temperatures are above 40 degrees F, however.  That's because below that temperature plants really aren't growing or using manure, and soil microbes and residents - like earthworms - aren't active and breaking down the manure.

So in Washington State, the best-practice for manure is during the times when plants aren't growing it's to collect the manure and keep it under cover until temperatures warm up and plants can use it directly.

Lots of pasture-based operators seem to think that manure on pasture at low temperatures is ok - there's a guy over in vermont who boasts about his pigs spreading manure on the snow.  Here's the quote:

There's a problem with this theory; the manure deposited on snow doesn't break down, and in fact, when the snow melts and runs off, the manure probably just runs into the surface water, especially if the area where it's being deposited has any sort of slope.

For my operation we put the pigs into the barns during the portions of the year when the plants aren't growing.  they're fed hay and feed and produce and other stuff, and I'll scrape the manure and any food that they haven't eaten twice a week or so.  It goes into a pile, and that pile is turned (the top of the pile is rotated to the bottom) twice or three times, about two weeks apart.

The natural heat of composting keeps the breakdown of the manure going, and by spring we have a couple of hundred yards of really nice, black compost.   That's spread on the fields and tilled into the crops, and I've usually spread all of it by late spring.

I've worked on this for years; I've had trememdous problems with mud and conditions, and I worked very hard at keeping the animals warm and dry for years.  Putting the animals in the barn for the winter isn't the milk-carton view of farming, but I believe that it's more comfortable for the animals, and certainly more sustainable for the farmer.

My goal is to keep all of the nutrients on my property at all times, and to keep surface water clean and pristine.  It's part of being a good steward of the land and environment.

1 comment:

Bill Gauch said...

There is a science to it, however, the general summary is...

Manure when it's warm is ok. Manure when it's well below freezing with frozen ground is potentially ok. It's the in-between range where it's really an issue. Manure on frozen ground won't perc. into the soil which is generally bad. However, the manure will freeze solid too and lock the nutrients in place. Most of the precipitation is also frozen, so there's little issue with erosion. If there are adequate riparian buffers in place and a decent crop cover of fast-growing cold-loving crops, the nutrient movement will be minimal. A lot of it depends on scale. It's obviously not great to heavily load your soil during cold temps. However, in his case, it seems he is talking about distributing a relatively small load over a relatively small area.