Important To Adjust Soil, Control Weeds In Pasture
TRIPLETT
Happy Easter! I had the opportunity to travel down to the Texas coast earlier this month for a few days with my family, and the wildflowers we saw in bloom around Navasota on the way home almost made me forget about how much the gas for the trip cost.
As we passed the farmers along the coast working up their soil for planting, I could not help but think about how much more expensive it will be for farmers everywhere to operate this spring. With that in mind, I wanted to continue this week talking about stretching your soil fertility dollar.
Last week we talked about interpreting your soil test results and ways you can save money by not paying for nutrients that you do not need in the fertilizer blend. We also talked about the impact that low soil pH has on nutrient availability. This week, I want to talk about liming to increase soil pH and the importance of controlling pasture weeds.
Not all liming materials are created the same. There are two components to the equation in determining lime quality, particle size and calcium carbonate equivalence.
When liming a pasture or other agricultural field to correct soil acidity, your goal is to purchase the finest lime that you can find. The size of the individual limestone particles determines how quickly it reacts with the soil to increase pH (or if it will change pH at all). Limestone particles smaller than 0.25 millimeter in diameter are very efficient at neutralizing soil acidity. Particles greater than 2 millimeters (bird hunters think number 9 shot or larger) will not react efficiently with the soil to change pH.
Calcium carbonate equivalence, or the amount of calcium carbonate in the material, can vary based on source. Typical agricultural grade limestone ranges from 85 to 100 percent.
Fineness of the liming material, combined with its calcium carbonate equivalence, produces a measure called effective calcium carbonate equivalence. Soil test recommendations for lime are based upon using a material with an ECCE of 100. Ask your lime dealer for the ECCE of the product. If you are purchasing a material with an ECCE of less than 100, you need to adjust your liming rate accordingly.
Your soil test recommendation will base limestone recommendations upon your soil's pH, the type of soil you have (sand, clay, etc.) and the type of crop you are growing.
Ideally, you would add lime about one month or more prior to the beginning of the growing season for your crop, to give it time to neutralize the acidity prior to your first application of fertilizer, but you may add lime any time of the year if you can get it from your dealer.
While you are comparing fertilizer prices and waiting to make that first application this spring, now would be a good time to go ahead and check out your pasture sprayer and get it ready for the year, too. While a good stand of grass will keep pasture weeds to a minimum, a pasture full of weeds robs your grass of moisture, soil nutrients and, in some cases, sunshine.
One study conducted in the 1990s by Dr. David Bade, former Texas AgriLife Extension Service forage specialist, evaluated the pounds of grass and pounds of weeds grown per acre during two consecutive years under conditions of added fertilizer and no added fertilizer. In all four scenarios where no management was given other than fertilizing the pasture, (in two treatments) more weeds were grown than grass. All eight treatments that included using herbicides to control weeds yielded more grass per acre than weeds. However, only half of the four treatments where mowing was used to control weeds yielded more grass per acre than weeds.
Brian Triplett is the Smith County Extension agent for agriculture and natural resources. He can be reached at 903-590-2980 or via e-mail at b-triplett@tamu.edu or on the Web at http://tceblogs.tamu.edu/mt/smith or http://smith-tx.tamu.edu.
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