AgriLIFE Extension -Denton County

306 N. Loop 288, Suite 222

Denton, Texas 76209-4887

January 28, 2008

TEST SOIL FERTILITY FOR BETTER PLANT HEALTH

 Contact:  John N. Cooper, County Extension Agent-Horticulture, 940.349.2883

  e-mail: jn-cooper@tamu.edu

          Nutrition is important to the health of every living thing and plants are no exception.  Plants don’t need special vitamins or nutrient formulas but they do require adequate supplies of 13 soil-derived minerals they use to construct all the compounds they need to grow and function properly.

           The inherent fertility of a soil is derived from the minerals in the individual particles of sand, silt and clay.  All soils are simply ground up fragments of mineral rocks which give each soil a certain mineral composition, and certain base fertility.  Some soils, especially sandy soils, are inherently infertile, but the mineral availability of any soil can be enhanced with fertilizers.

          Still, soil mineral content is dynamic.  Minerals are depleted as plants grow, mining the soil for available minerals and locking them inside plant tissues.  Most of the minerals except nitrogen are returned to the soil in compost but compost is often taken from one place and used in another.

          Vegetable gardeners continually remove minerals as they harvest their crops and add minerals as they fertilize and amend their garden soil.  Flower beds are treated much the same, with the same result.  Since these activities significantly change a soil’s mineral status, soil tests are needed to adjust and correct fertility programs.  Depending on the intensity with which you garden, flower and vegetable gardens should be tested every one to three years.  To avoid disease problems, flower and vegetable debris should not be turned back into the soil unless it is composted first.

          Lawns are the most heavily fertilized landscape plants of all.  It is not uncommon to make five or six applications of fertilizer per year on turf.  If you don’t bag your clippings, phosphorus and potassium levels may accumulate to levels which allow you to drop these minerals out of your program and use only nitrogen for a while.  Some soil tests have come back with a recommendation to discontinue phosphorus applications in turf for as many as four years.

          One of the fallacies of fertilizing is that, if a little is good, a lot is better.  Many problems arise from using too much fertilizer.  Besides wasting your money and polluting the environment, excess fertilizers damage plants.  Fertilizers, even organic forms, contain powerful compounds and should be used according to specified rates of application.  If you have not measured the area you are fertilizing and weighed or measured the fertilizer you are using, you can only apply the correct amount by accident.

          If you want to know what fertilizers your soil needs and how much to apply, take time to sample your soil.  The more you crop and amend your soil, the more you fertilize, the harder you work your soil, the more dynamic your mineral availability becomes and the greater is the need to test it.  The Texas A&M Soil Testing Laboratory will test your soil for a nominal fee.  Call the Denton County office of Texas Cooperative Extension at 940-349-2883 and request soil testing information or download the information and forms off the internet at http://soiltesting.tamu.edu.  Winter is an excellent time to sample your soil so act now and beat the spring rush.

ORDER CONSERVATION TREES NOW

          The Denton County Soil and Water Conservation District, USDA Natural Resources Conservation Service, Texas Forest Service, and Texas AgriLife Extension Service have teamed up to make conservation trees available to private landowners at nominal prices.  Through this popular public program over 800 landowners in Denton County have planted over 80,000 trees since 1991.  Trees must be picked up at the North Texas Fairgrounds in Denton on the morning of Friday, February 22, 2008.  Trees are available in one-gallon pots at 7$ each.  Rooted seedlings are $30 for 10 trees.  Bare-root seedlings are $20 for 10 trees.  Place your order by calling the Denton County office of the Natural Resources Conservation Service at 940-383-2691 ext. 3 by February 7.

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The information given herein is for educational purposes only.  Reference to commercial products or trade names is made with understanding that no discrimination is intended and no endorsement by AgriLife Extension is implied.

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Extension programs serve people of all ages regardless of socioeconomic level, race, color, sex, religion, disability or national origin. The Texas A&M University System U. S. Department of Agriculture, and the County Commissioners Courts of Texas Cooperating.