PHOSPHORUS ANALYSIS OF PLANT MATERIAL

Abstract

Although satisfactory methods for the determination of total phosphorus in plant material are available, they are, for the most part, too long and complicated to serve where a great number of comparative tests in studies of phosphorus nutrition of plants are desired. These methods provide for either volumetric or gravimetric determinations. For the former, 2 to 4 gm. of plant material are required; for the latter, 6 to 12 gm. of material are necessary. The amounts of available material are frequently less than these. By means of a colorimetric method used by the author in phosphorus studies, duplicate samples of only 0.25 gm. were found to check quite consistently within the range of 1 or 2 per cent. in routine analyses. This method is similar to the official micro-method in the 1940 edition of "Official and Tentative Methods of Analysis" (2) but is somewhat less time consuming. It is the purpose of this paper to report upon a method for the determination of total phosphorus and the inorganic fraction of phosphorus in plant material. Total phosph