Wednesday, February 1, 2012

Mowing the Prairie

This isn't worth taking any pictures of but today was so nice out I decided to mow my little meadow today. The overgrown grass and plant stems were so thick it had been creating a dense mat hiding the bare ground. I was surprised how many times I had to empty the lawn mower. 

The two schools of thought here are to remove organic matter or to keep it.

Removing the grass and added plant stems is always advisable over the winter. But when mowing we're given the option of letting the organic matter chop up and lay on the ground as a mulch. This doesn't remove the organic matter but does aid in soil building (which is not needed for most prairie plants). This favors plants who's seeds might be tasty for birds and rodents. The organic matter hides them so they can germinate freely. However, this also encourages the existing plant community to come back and shade things out.

Removing organic matter entails controlled burns, and bagged mowing. The exposure to bare earth encourages germination to species that normally do so with more sun light. These tend to be plants with seeds the size of grains of sand or there abouts. Burning has the same effect but favors species that like the ashy (sulfur?) added into the soil. This burns off seed coats to some plants while destroying the seeds to others.

A sort of third option with removing organic matter would be grazing but I'm not a farm. This is normally done during the growing season. For a fascinating take on the benefits of grazing and the manure, I turn you to the Prairie Ecologist. Apparently the added fertilizer creates a noticeable healthier and greener plants. This encourages the grazing animal (in this case a Bison) to favor that plant when grazing for most of the year. To me, this could explain why deer favor certain plants in one's garden and overlook others, that is all things being equal with "deer resistance."

Not mowing at all eventually leads to shrubs and trees taking over.

So you see there are ways to encourage and sway a plant community over time. The trouble is everything you do will effect 1 to 3 years down the road.