Bermudagrass management in the Southern Piedmont USA: VIII. Soil pH and nutrient cations

Forage utilization could affect soil nutrient dynamics and depth distribution, potentially changing long-term productivity and environmental quality. The effect of forage utilization on nutrient cycling might also be altered depending upon the source and quantity of nutrients applied. We evaluated changes in soil pH and extractable-soil nutrient cations during the first 5 yr of bermudagrass [Cynodon dactylon (L.) Pers.] management varying in fertilization (three different sources targeted to supply 200 kg N ha(-1) yr(-1)) and forage utilization (four levels). Chicken (Gallus gallus) broiler litter (5.4 Mg ha(-1) yr(-1)) was a significant source of nutrient cations in addition to N and P and therefore, at the end of 5 yr, resulted in extractable-soil concentrations (0- to 15-cm depth) that were 1.5 +/- 0.1 times greater for K, 1.6 +/- 0.2 times greater for Mn, 4.3 +/- 2.2 times greater for Zn, and 7.5 +/- 0.8 times greater for Cu than under inorganic and clover (Trifolium incarnatum L.) + inorganic fertilization regimes. The increases in extractable-soil K, Zn, Mn, and Cu concentrations with broiler litter, however, were only 13 +/- 42% of nutrients applied. Removal of forage as hay resulted in significant declines in extractable-soil K and Mg under all fertilization regimes and in extractable-soil Ca and Mn with inorganic and clover + inorganic fertilization. Cattle (Bos taurus) grazing resulted in greater nutrient cycling within the paddock domain, and the more diverse and higher quantity of several nutrient cations applied with broiler litter either prevented a decline or contributed to an increase in concentrations with time.