Phosphorus (P) is reported as total P as a percentage of DM. The method is a modification of the standard Kjeldahl procedure. Digestions are conducted at FESL and analyses of digestate are done with the Technicon Autoanalyzer at the Ruminant Nutrition Lab., Animal Science.

Suggested text statement: “For phosphorus analysis, samples were digested using a modification of the aluminum block digestion procedure of Gallaher et al. (1975). Sample weight was 0.25 g, catalyst used was 1.5 g of 9:1 K2SO4:CuSO4, and digestion was conducted for at least 4h at 375°C using 6 ml of H2SO4 and 2 ml H2O2. Phosphorus in the digestate was determined by semiautomated colorimetry (Hambleton, 1977).”


Gallaher, R. N., C. O. Weldon and J. G. Futral. 1975. An aluminum block digester for plant and soil analysis. Soil Sci. Soc. Amer. Proc. 39:803-806.

Hambleton, L. G. 1977. Semiautomated method for simultaneous determination of phosphorus, calcium and crude protein in animal feeds. J.A.O.A.C. 60:845-852.