Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: 7/18/2002
Publication Date: 11/4/2002
Citation: Sigua, G.C., Williams, M.J., Coleman, S.W. 2002. Soil phosphorus dynamics in subtropical beef cattle pastures under different pasture management. 2002 ASA-CSSA-SSSA Meetings, Indianapolis, IN.
Technical Abstract: Long-term pasture management elsewhere is believed to change soil chemical properties, but little is known about whether pasture management, such as fertilizer application, grazing, or haying can initiate such change in sandy and well-drained subtropical beef pastures. The objective of this study was to investigate the effects of grazing (GZ) and haying (HY) on soil phosphorus (P) dynamics (levels and changes) in subtropical beef cattle pastures with bahiagrass (Paspalum notatum) and rhizoma peanut (Arachis glabrata) with (P) or without (NoP) P fertilization in Brooksville, FL from 1988 to 2000. Remarkable changes in the levels of soil P were noted from 1988 to 2000 in STARS. The average soil P values in 1988 were 96.0 + 40.7 mg/kg and 64.4 + 30.8 mg/kg in 2000. During the past 12 years, soil test values for P in STARS have declined by about 33%. Although levels have declined in all units, rates of soil P depletion in hayed pastures (17.7 + 5.6 kg/ha/yr) were greater than in pastures at LU that were only grazed (5.6 + 1.4 kg/ha/yr). Differences in soil P values among farms with P fertilization may still not be of particular concern environmentally, but are important from a fertility management point of view.