2010-03-04 / Community News

Rainwater Retention on Rangelands

Rainfall is likely the most limiting factor for livestock production on Texas rangelands. While other factors like soil texture, pH, insects, and disease can significantly impact productivity, without rainfall forage production is a moot point. For livestock producers, learning how to garner the most production from every drop of rain equates to greater forage production, especially in times of moderate to severe drought. Greater grass forage production for grazing livestock means less pressure is exerted on other sources of nutrition, particularly browse, or woody species, upon which many wildlife species are dependent for food and cover. For livestock producers, maintaining a dependable forage base can prevent sell offs in times of drought, leading to stability in livestock stocking rates. Greater stability in stocking rates as a result of responsible grazing management, means a more reliable income stream throughout good times and bad, and can lead to lower input costs, particularly the high costs of supplemental feeding, the greatest input cost in most livestock operations. A stable and dependable forage base can also significantly lower the second highest input cost for most operations, animal health management. Livestock with greater forage availability will maintain better body condition and will be less susceptible to some of the ailments that face animals on nutritionally deficient ranges.

In years of above normal precipitation, even mediocre ranchers can appear as if they are doing a pretty good job of managing their forage base, but at the first signs of drought it becomes very clear which ranchers are truly managing their land and those that are simply mining it for

all its worth. Besides providing insulation from sell offs in times of drought, managing forage utilization and rangeland cover can extend the benefits of rainfall received. Research has shown that infiltration rates on rangeland generally increase as herbaceous cover increases. Vegetative cover (grass and weeds) slows water movement across the soil surface, allowing more time for water to infiltrate before flowing off the land into drainages and waterways. Herbaceous cover not only increases infiltration, but also serves as nature’s best filter to remove pollutants and heavy metals and prevent them from entering watercourses. Herbaceous cover can also help to reduce evaporation after low intensity rainfall events by shading the soil and lowering the soil temperature, and by reducing the ability of wind to evaporate rainfall from the soil surface.

Woody plants are important components in the lifestyle of many wildlife species, and serve as a source of cover and cooling shade for livestock Some woody plants namely mesquite, huisache, saltcedar, and red- and blueberry juniper are notorious for consuming large amounts of ground moisture, thus reducing

the amount of moisture available to other more usable plants like grasses and forbs. Brush canopy coverage, like that of the aforementioned plants, is also responsible for

intercepting and evaporating

40% or more of the rainfall received on rangelands. Removing undesirable brush canopy coverage usually results in an increase in rainwater infiltration which equates to more moisture available for use by forage species and for deep percolation into the groundwater supply. For the sake of the future in Texas, range managers are key to helping conserve water quantity and enhancing water quality.

So, what is the take home message? Proper range management increases rainfall infiltration which means greater soil moisture and increased vegetation growth for livestock and wildlife, while conserving water supplies and enhancing water quality.

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

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