As we experience droughts, we are reminded that forage production on our pastures is not a guarantee and that we should manage our livestock enterprises in such a manner that when drought strikes we are prepared so we can minimize the damage to our forage base as much as possible during. Now we can readily evaluate the health of our pastures as we move to spring in the current drought.
Yes, rainfall is very important, but the productivity of our pastures is directly related to how rainfall is actually captured to replace soil moisture. The last few weeks have given us hope that it still can rain in South Texas. The amount of rainfall that moves into the soil profile is affected by the type and density of vegetative cover, intensity of the rainfall event, amount of moisture in the soil before the rain event, the capacity of the soil to hold water, and land slope.
While you cannot change some of these factors, management of your pasture will help determine the condition of the soil and vegetation that can make a difference in capturing rainfall. So, evaluating your pasture conditions and then adjusting management decisions could help protect forage and soil resources.
Evaluation of your pastures should include monitoring both current and changes over time to determine if damage to the soil, water, and plant communities is occurring. The first indicator of pasture health is vegetative cover—both the amount and species composition. Good vegetative cover, with little bare ground, slows the movement of water across the land and lessens the impact of raindrops on the soil surface.
The greater the raindrop impact and the faster the water moves, the more soil will be dislodged and carried away. The slower the movement of water, the more time there is for it to soak into the soil.
The second indicator of the health of your pasture is the soil surface. Large areas of bare ground, pedestal plants, litter dams, rills and gullies are signs that rainfall is running off the land rather than infiltrating the soil.
Another danger sign is stream bank erosion, which often occurs when riparian vegetation (the vegetation along rivers and streams) is inadequate to stabilize the bank against flowing water. Riparian vegetation is important for maintaining natural stream channels. Closely checking stream bank stability and riparian zone vegetation can help you recognize a problem with the land upstream.
So as we survey our pastures this spring, look for signs of increasing bare ground, reduced litter, changing plant species, and stream bank erosion. All of these signs indicate that rainfall is not being effectively captured and perhaps you should consider altering your management plan, like reducing stocking rates, before the next drought or storm degrades your property.