Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/19/2004
Publication Date: 9/15/2004
Citation: Franzluebbers, A.J., Stuedemann, J.A., Wilkinson, S.R. 2004. Bermudagrass management in the southern piedmont USA. VIII. Soil ph and nutrient cations. Agronomy Journal. 96:1390-1399. Interpretive Summary: A better understanding of the long-term cycling of nutrients in soil with inorganic versus organic fertilization and with differences in forage utilization would help in the development of sustainable agricultural production systems. We found that broiler litter was a significant source of nutrients that resulted in 53% greater soil potassium, 58% greater manganese, 4.1 times greater zinc, and 7.6 times greater copper concentrations than under inorganic or clover+inorganic fertilization regimes in the surface 15 cm of soil. Removal of forage as hay resulted in significant declines in soil potassium, magnesium, and manganese. At the end of 5 years, nutrient availability in surface soil was greater when pastures were grazed by cattle than when pastures were either hayed or left unharvested. These results suggest that broiler litter supplies a diversity of nutrients and that cattle grazing allows nutrients to recycle efficiently within the paddock.
Technical Abstract: We evaluated changes in soil pH and extractable K, Ca, Mg, Zn, Mn, and Cu during the first 5 years of bermudagrass management varying in fertilization and harvest strategies. Broiler litter was a significant source of nutrient cations in addition to N and P, and therefore at the end of 5 years, resulted in 53% greater soil K, 58% greater Mn, 4.1 times greater Zn, and 7.6 times greater Cu concentrations than under inorganic and clover +inorganic fertilization regimes in the surface 15 cm of soil. The increases in extractable K, Zn, Mn, and Cu concentrations with broiler litter, however, were only 13 +/- 42% of that applied. Removal of forage as hay resulted in significant declines in soil K, Mg, and Mn. At the end of 5 years, soil in the surface 15 cm when unharvested had 16% lower K, Mg, and Cu concentrations than when grazed by cattle. There were no differences in extractable cations between low and high grazing pressures. These results suggest that broiler litter supplies a diversity of nutrients and that cattle grazing allows nutrients to recycle efficiently within the paddock domain.