Location: Soil Plant Nutrient Research (SPNR)
Project Number: 3012-11000-011-05
Start Date: Sep 01, 2012
End Date: Sep 30, 2015
Grazing practices and stocking density will be compared at the USDA-ARS Central Plains Experimental Range (CPER). Traditional Grazing Management (TGM) practice consists of season-long (mid-May to early October) grazing in pastures at moderate stocking rates. With TGM, grazing animals (cattle) are in the same pasture all season at low stocking densities (20 yearling-steers per 320 acre pasture). A novel Adaptive Grazing Management (AGM) practice will be initiated in 2013 where grazing will still occur from mid-May to early October at moderate stocking rates, but grazing animals (cattle) will rotate among 10 different pastures. This will enable shorter grazing periods (weeks) rather than season-long, and much higher stocking densities (200 yearling steers per 320 acre pastures, or ten-fold increase over the TGM practice). Livestock manure distribution will be quantified following grazing periods in each pasture using belt transects extending from pasture corners to centers of pastures to determine if the AGM practice results in more even distribution of manure (associated with the higher stocking densities). Fifty individual manure pats will be permanently marked and GPS coordinates obtained on each of 10 pairs of pastures comparing TGM and AGM grazing practices to determine if the grazing practices influence the longevity of manure pats. Soil samples will be taken at selected manure pat locations three times over each of 2 years to determine rates of nutrient cycling, and greenhouse gas emissions will be determined on additional selected manure locations.