Strategic-Rotational Grazing in Beef-Pastures for Improving Sustainability: As Measured By Soil Health, and Forage Productivity.

Continuous improvement of the grazing management system, for a healthy, productive, and more-sustainable beef-pasture, is important to sustain agroecosystems in much of the world. This study compares the “strategic-rotational grazing” with “conventional grazing” in terms of soil health, and forage productivity. In 2015, baseline soil health study, four soil health indicators (potentially mineralizable N, soil respiration, ammonia volatilization and urease) were measured in 10 conventionally managed Southern Piedmont pastures (9.31-21.62 hectares). Soil health indicators were measured in 18% of randomly selected locations of a 50-m grid (“matrix”) of the pastures, and specific areas with high cattle activity (“AOIs”). In June 2016, strategic-rotational grazing was implemented in five pastures and five remained conventional. During the baseline study, the “AOIs” were significantly higher in potentially mineralizable N and urease activity, while soil respiration was significantly higher in the “matrix” (1256.98 mg CO₂/day/m²) as compared to the “AOIs” (1047.58 mg CO₂/day/m²), and no ammonia volatilization was observed in any place. In 2016, higher ammonia volatilization was observed in the “matrix”, especially when the sample point was within 5-m of where portable shade or waters had been. This suggests the usefulness of portable shades and waterers in facilitating distribution of cattle urine and feces across pastures. Where we had severe drought (4 of the 10 pastures), the strategic-rotational pastures required significantly less hay (average of 17 bales), as compared to the conventional pastures (average 45 bales). Additionally, NDVI images created from Sentinel-2 satellite data indicated higher forage biomass in the strategic-rotational pastures, mostly due to the contribution from over-seeded exclusions. While it is still early stage of our research, strategic-rotational grazing practices may rapidly improve soil health and forage productivity in Georgia Southern Piedmont pastures.