Comparing Continuous and Tactical Grazing Systems for Improved Soil Health and Cleaner Water in the Better Grazing Project.

Beef cattle production is a major component of agriculture in the southeastern United States. Traditionally, cattle are grazed in a continuous system which has shown several detrimental effects, including nutrient runoff and poor pasture condition. Grazing systems which have the ability to retain and recycle carbon and phosphorus for plant use are necessary in the development of a sustainable agriculture system. By making management practices more effective and cost efficient, they are more likely to be adopted on a widespread basis. Tactical grazing, a strategic rotational grazing system involves: excluding areas vulnerable to nutrient loss from continuous grazing, short-term flash grazing, and cattle luring techniques to distribute nutrients throughout the pasture. Two treatments, continuous grazing and tactical grazing will be studied. Soil analysis will include combustible carbon, permanganate carbon, and soil test phosphorus at each vulnerable area before, during, and after treatment. In addition to laboratory testing methods, visible and near-infrared reflectance spectroscopy (VNIR) will be used to develop real-time estimates of these nutrients throughout the pasture and create a soil nutrient calibration library to enhance rapid nutrient measurement of soils. Previous research determined that field samples can be used to predict total C, organic C, and inorganic C, and P with less reliability using Vis-NIR spectra. VNIR scans from a portable ASD Vis/NIR AgriSpec (ASD Inc, Boulder, CO) unit will be taken from the field moist soil samples and used to create a calibration curve for carbon and phosphorus. We hypothesize that the tactical grazing system techniques will improve overall pasture soil health and that highly correlated calibration curves can be created for in situ measurement of carbon and phosphorus in order to provide a rapid method of nutrient determination for assessing better grazing systems.