Soil Micro Nutrients in Beef Cattle Back Grounding Site On Karst Landscape.

Beef production in the US comes mainly from grain-fed beef cattle raised in feedlots. Beef cattle back grounding that represent an intermediate tier in the U.S. commercial beef production system grows weaned calves from cow-calf enterprises to weights and conditions ready for feedlot finishing. Beef cattle back grounding in feedlots adopts confined feeding and raise weaned calves under intensive management. Back grounding feedlots concentrate animals, feed materials, and manure on small land areas; thus these sites typically can contain high levels of soil nutrients .Our preliminary study on this site revealed that higher soil organic matter, NH₄-N, NO₃-N, and STP concentrations were associated with the feeder and nearby grazing area than any other site locations. We also investigated soil micro nutrient levels across this feed lot landscape. We found significantly higher levels of Fe (639.2  mg kg^-1) and Zn (35.6  mg kg^-1) in the feeder area than offsite locations. The Fe and Zn levels were nearly three times higher than the levels of offsite sinkhole locations. But the Cu level in the feeder area (3.1  mg kg^-1) was similar to the grazing and offsite sinkhole areas.