A few thoughts on diversity

If you graze livestock in a pasture and if you pay attention to the behavior of the animals and the consequences of your animals' behaviors, then you will gain insights into how "diversity" happens.

Something as simple as where a cow pees becomes a story. The urine contains water, salt, ammoniacal nitrogen and potassium and a well-hydrated Bossie can easily drench four-square-feet of sward.

The bacteria in the soil convert the ammoniacal nitrogen to nitrates. Depending on the soil temperatures and amount of clay (cation exchange base to the soil scientists) some or much of the ammonium may be lost before it can be converted.

The nitrogen causes the grass to turn deep, dark green and grow like the dickens. The growth is mirrored below the soil and the roots drive deep. If you see a green, growing patch of grass during a drought, there is a pretty good chance you are looking at ground-zero for a urine dump.

The grass also engages in something called "luxury consumption" of the potassium. That is where the grass absorbs and stores more potassium than it needs for its immediate use. Never-the-less, the blast of nitrogen is used up before the potassium is. The cows will in time eat the deep, green grass and move on with the nitrogen (protein at this point) and some of the potassium.

After the flush of grass comes a resurgence of the clover or other legumes. Legumes are unique in that they can "fix" atmospheric nitrogen with the help of specialied soil bacteria. The legume that is most resistant to grazing is white clover. However, it is shallow rooted and not aggressive at scrounging for water, potassium or phosphorous. If there are any small clover plants smouldering within the patch of pasture drenched with urine, they explode in growth AFTER the grass growth depletes the nitrogen.

If there aren't any small clover plants, then some of the hard-seed in the soil's latent seed bank will germinate and exploit the newly created clovarian utopia. That is not to say that the urine causes the seeds to germinate. Rather, seeds are always germinating, a few percent a year. Most die. A few win the lottery.

Picture from New Zealand. Can you SEE where the urine patches are/were?

Because of clover's miraculous ability to fix nitrogen and because of its very high palatability to grazing animals, much of the "management" part of Management Intensive Grazing involves fiddling with how you handle your animals such that an average of 10%-to-50% of the surface area of your pasture is clover. Why the huge range? Because different areas have different potential.

If you rotate your animals through your pastures you will have urine patches of various vintages. Some will be new. Some will be dominated by grass growing like a house-afire. Others will be dominated by white clover. And, over time, the cows will graze the clover (they LOVE clover) and the windfall of potassium will eventually be redistributed to new urine patches and the old urine patch will revert back to baseline.

But That's Not All, Folks...

The simple fact of watching people carry luggage out to a vehicle and the slamming of automobile doors creates an irresistable need in me to visit the restroom. It is from growing up in a large family. "TRY!!!!"

Grazing animals are similar. There are just some things that make them pee and/or poop.

A grazing animal defecates and urinates when it stands up. Just like birds poop and pee as they launch from power wires or from a roosting tree. They de-balast. 

Consequently there is a net migration of nutrients to the tops of hills where the breeze surpresses biting insects. There is a net migration of nutrients to shady spots where cows can ruminate, discuss the farmer's fashion sense and talk politics.

Grazing animals urinate when they drink water or shortly thereafter.

Weirdly, cows urinate when their feet get wet. That has the unfortunate consequence of depositing nutrients in your farm pond or the crick that runs through the pasture.

Grazing animals are hardwired to be herd animals. In a totally open and otherwise featureless pasture they will invariably "loaf" next to the scrapped out tractor or pile of tires that almost, sort-of look like a sleeping cow if you tilt your head and squint real hard. 

This is actually a good thing.

Since cows tend to concentrate nutrients over the decades, certain portions of your pasture will become depleted of nutrients. You will start to see thin, thready grasses like poverty grass (Panicum virgitum) and other indicator species.

The problem with nutrient migration and luxury consumption is that areas that are oversupplied with certain nutrients...say four times the needed amount...don't produce four times as much forage. The overall, net production of the pasture falls.

The obvious solution is to move your stock watering tanks to those depleted areas and let the critters move the nutrients back.

Or, if the stock tanks are immobile, just move a few barrels where you want them to congregate. In the winter you can spread some spoiled hay on the ground and the critters will lounge on it...peeing and pooping as they stand up.

Or you can create a windbreak with your round bales and they will usually bed down behind that windbreak/faux-cowz. One guy I know does not own a tractor. When he buys the round bales he has them spaced out a bit and fences them off in a ladder-like fashion. He feeds by turning off the electric fence and moving the divider wire. Easy-peasy. And he has the vendor put the bales where the pasture is the poorest.