**Anish Subedi, Dorcas Franklin \*, Miguel Cabrera, Amanda McPherson and Subash Dahal**

Department of Crop and Soil Sciences, University of Georgia, Athens, GA 30602, USA; anish.subedi@uga.edu (A.S.); mcabrera@uga.edu (M.C.); amanda.mcpherson@uga.edu (A.M.); subash.dahal@uga.edu (S.D.)

**\*** Correspondence: dfrankln@uga.edu

Received: 11 September 2020; Accepted: 13 November 2020; Published: 16 November 2020

**Abstract:** A study of phosphorus accumulation and mobility was conducted in eight pastures in the Georgia piedmont, USA. We compared two potential grazing treatments: strategic-grazing (STR) and continuous-grazing-with-hay-distribution (CHD) from 2015 (Baseline) to 2018 (Post-Treatment) for (1) distribution of Mehlich-1 Phosphorus (M1P) in soil and (2) dissolved reactive phosphorus (DRP) and total Kjeldahl phosphorus (TKP) in runoff water. STR included rotational grazing, excluding erosion vulnerable areas, and cattle-lure management using movable equipment (hay-rings, shades, and waterers). After three years of treatment, M1P had significantly accrued 6- and 5-fold in the 0–5 cm soil layer and by 2- and 1.6-fold in the 5–10 cm layer for CHD and STR, respectively, compared to Baseline M1P. In STR exclusions, M1P also increased to 10 cm depth post-treatment compared to Baseline. During Post-Treatment, TKP runoff concentrations were 21% and 29% lower, for CHD and STR, respectively, in 2018 compared to 2015. Hot Spot Analysis, a spatial clustering tool that utilizes Getis-Ord Gi\* statistic, revealed no change in Post-Treatment CHD pastures, while hotspots in STR pastures had moved from low-lying to high-lying areas. Exclusion vegetation retained P and reduced bulk density facilitating vertical transportation of P deeper into the soil, ergo, soil P was less vulnerable to export in runoff, retained in the soil for forage utilization and reduced export of P to aquatic systems

**Keywords:** soil P; vertical and horizontal P distribution; runoff water; exclusions; strategic grazing
