It is Not Really What is Above Ground that Matters!

Southeast Area – It is the time of year when our livestock are not the only ones looking for a little green grass! Most of us are tired of feeding and the livestock are in need of a little more variety in their diet. Regretfully, a majority of the Eastern Plains of Colorado have not received sufficient moisture this winter to cause much optimism for our native ranges. In places where moisture has accumulated – road ditches, behind sagebrush plants, etc. – some cool season grasses are beginning to show a little green.

On average, about 60 percent of a plants biomass is below ground in its root system. It is this root system – that most of us never look at – that determines the health and “recoverability” of the above ground portion. The leaves of plants feed the roots to grow more roots to feed the plant to grow more leaves. As leaves are removed by grazing, or other means, root volume decreases in response to plant nutrient needs. Remove too much leaf material past the mid-point – take half, leave half – the roots of a plant actually stop growing until some new leaf material is produced to supply their food. It is estimated that each year, approximately 30 percent of a plants root system must be replaced to maintain the health of the plant. If leaves are continually removed, root mass will not be replaced and will continue to decrease. As roots become shallower in the soil layer, fewer nutrients are available for plant health.

Not all grasses grow and respond to grazing pressure with the same results, thus the reason for development of monocultures and a decrease in diversity. Animals similar to us, we will eat the steak first and then the other stuff. Eventually, the steak is gone and all we have to eat it the other stuff.

Colorado State University has a fact sheet entitled Grass Growth and Response to Grazing no. 6.108. Also, in the Cattlemen’s Library accessed on the CSU Beef website at: http://csubeef.com/, is another fact sheet entitled Grass Growth and Development Considerations for Grazing Management – CL505.

If you need assistance, please contact your local CSU Extension Office in Baca, Bent, Cheyenne, Crowley, Kiowa, Otero, or Prowers County.