By MYRON MERZ
NRCS District Conservationist
In the real estate world you hear the words, “Location, location, location,” stressing that location has a direct relationship to the value of a property. When we look at rangelands we might say the most important thing to have would be “cover, cover, cover.”
What we mean by this is if we keep a grass cover and mulch on our rangeland more of the precious rainfall we receive will soak into the ground rather than running off, as it does on bare ground.
A healthy grass cover and mulch allow rainfall to soak into the ground like a sponge, which increases the quantity of water available to plants, protects the soil from erosion and allows water to filter naturally through the soil. This, in turn, helps out ground water quality and allows springs and streams to flow as mother nature intended. Additionally, this grass cover acts as insulation from the extremely hot summer months and as freeze protection in the winter months.
If we have bare ground and don’t have this protective “armor” layer, we have a situation where very little of the rain soaks into the ground. This leads to decreased production, less water getting into the soil profile, more sediment and pollutants in streams, soil temperatures that increase evaporation, increased soil erosion and desert-like conditions.
On bare ground or overgrazed rangeland, about 75 percent of rainfall runs off and doesn’t get into the soil profile. The portion that does go in the ground does not help with deep moisture and most of it stays within the top three inches of soil. Adding to this is evaporation in the warmer months, so the total amount of rainfall that makes it into the soil profile is very low in this situation.
It takes about 500 pounds of water to grow a pound of grass. If we can get this water to soak in, rather than run off, it will go toward growing more grass.
Historically Texas rangelands were covered with a blanket of grass and very little water from rainfall was wasted. This was the period of time before fences, when the buffalo roamed. There were periodic wildfires that would keep brush in check and nature was in perfect balance.
As early settlers moved in with large herds of cattle, they thought there was an unlimited supply of grass and didn’t believe in “wasting” grass. Eventually the better, tall grasses were repeatedly overgrazed to the point the majority were grazed out and less-desirable grasses took over. As fences were constructed and wildfires stopped on the plains, the situation gradually grew worse and most rangelands in Texas were in bad shape.
Getting the land back the way it needs to be is no easy task today, as we have frequent droughts, brush encroachment and land is split up into smaller units. We can’t control the amount of rainfall we get in a year and when we want it.
However, we can make the most efficient use of the rain we do get.
Instead of allowing our rainfall to be lost by runoff or evaporation, the only way to make efficient use of rainfall is by leaving a protective armor on the soil by leaving a grass/mulch cover and by grazing or harvesting about half or less of the forage that is produced in a year.
Another reason to leave half of the forage produced is because grass plants need some of the nutrients that are stored in the leaves for their own growth. On grass plants that are continually overgrazed, the root system of the better grasses will gradually decrease to the point that the plants will decrease and eventually die out.
So remember “cover, cover, cover” when we are trying to store as much of the limited amount of rain we receive.
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