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2010-07-29 digital edition

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2010-07-29 / General Stories

Effects of Grazing on Rangeland

In rural Texas, cattle are a way of life. But, is it a healthy life for YOUR rangeland? Think back to the last drive you had down a rural highway, how much tall grass prairie did you see? Many properties in rural Texas are victims of overgrazing by livestock. We must begin to focus on quality land management rather than solely on livestock production so that we may promote diversity in the range and create better land stewardship. We can start by understanding how our rangeland becomes stressed and overgrazed.

Plants contain several growing points. Grasses for example have a main growth point in the crown of the plant, also called the plant base. As the grass begins to develop, this point will continue to develop and eventually produce a seed head. Grasses also have a secondary growth point at each joint (or node) at the base of each leaf blade. These produce leaf, sheath and stem growth.

Plants can only produce leaves at an intact growing point. The closer the growing point is to the ground the more successful the plant will be at producing a seed head because it is more protected from being eaten. Destruction of the plant by grazing when its growing points are elevated reduces new leaf production thereby decreasing the plants ability to produce food and tolerate grazing. Excessive grazing also prevents the production of seed heads and new seedlings.

Unfortunately, plants are not created equal. Timing and the elevation of growth points on grasses, forbs (weeds), and browse (woody shrubs and trees) vary greatly. For example, little bluestem has a growing point close to the ground until the seed head is ready to emerge (moderate grazing resistance), whereas yellow indiangrass has a growing point that elevates above ground level soon after growth begins (low grazing resistance). Forbs contain growing points close to the ground in the early growing season and woody browse species house growing points that are elevated above ground making them much more accessible to browsing animals.

Many of the improved pastures seen in cattle operations are comprised of bermuda grass, which contain stolons (aboveground) and rhizomes (below ground). This allows the plant to recover faster than a native plant that is overgrazed because that growing point is lower to the ground making it more inaccessible to animals.

In order to effectively manage your rangeland you must first know what plants comprise your rangeland. Then, based on the growing point and grazing resistance of those plants you can begin to define a proper stocking rate. The amount and quality of forage available as well as seasonal patterns must also be considered when defining your stocking rate. Remember, you must also consider the wildlife population when defining a stocking rate because they utilize the range as well.

Overstocking your rangeland will lead to overgrazing which will decrease your plant productivity because you have increased pressure on the plants. If these plants are unable to stay productive you have less seed produced and fewer seedlings of desirable plants. This allows less palatable plants to invade thereby decreasing the quality of your rangeland.

Whether you’re an avid cattleperson or a wildlife enthusiast, the plants on your range feed the animals in your area and decrease soil erosion. Proper management and good land stewardship should be the main goal so that we may continue to conserve our soil and plant resources.

If you would like to contact your local biologist, see our website at; http://www.tpwd.state.tx.us/ wildlifebiologist.

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