The determination of cellulose in soil

Abstract

INTRODUCTORY. DURING the course of an investigation into the decomposition of green manures in soil it was necessary to determine the amount of cellulose that underwent changes at the different stages of fermentation. Charpentier [1920] has shown that when cellulose, in the form of filter-paper, is mixed with soil it can be recovered quantitatively by extraction with Schweitzer's reagent, an observation later confirmed by Barthel and Bengtsson [1924]. This method, however, cannot be applied directly to soils mixed with plant materials, as the plant tissues contain, amongst other constituents, hemicelluloses and lignin which interfere with the extraction of cellulose with Schweitzer's reagent. The hemicelluloses are to a certain extent soluble in Schweitzer's reagent and are precipitated with alcohol. Lignin on the other hand acts as a barrier to the complete dissolution of cellulose in Schweitzer's reagent.Waksman and Tenney [1927] suggested treating the material with a 5 % solution of NaOH for 30 minutes at 15 lbs. pressure in order to remove the hemicelluloses and lignin before extracting the cellulose with Schweitzer's reagent. Solutions of sodium hydroxide of strength greater than 1-2 % are known to attack cellulose, so that any treatment in which the plant material is exposed to the action of alkali of more than 1-2 % strength at high temperatures is bound to give a low yield of cellulose. Bengtsson [1924] proposed treating the soil mixed with plant materials with a solution of sodium bisulphite in hydrochloric acid at a temperature of 100°for 72 hours and then extracting cellulose with Schweitzer's reagent. Apart from the fact that the sulphite process of separating cellulose gives lower yields than the Cross and Bevan method, the period of digestion required for the preliminary treatment of the material makes the process too long.With a view to the elimination of these disadvantages an attempt was made to find a suitable method for the estimation of cellulose in plant materials mixed with soil. I This paper is an abridged form of part of a thesis approved for the degree of Ph.D. in the University of London.

Spectrophotometric methods for lignin and cellulose in forest soils as predictors for humic substances

“…Currently, one of the most acknowledged methods to measure humic and fulvic acids in soils is based on alkaline extraction (Lehmann & Kleber, ), with either titration methods based on potassium dichromate oxidation (Curcio et al, ) or HF–HCl treatment as suggested by the International Humic Substances Society (Botero et al ., ). Lignin is typically evaluated in soil by alkaline CuO oxidation (Thevenot et al, ), whereas cellulose, together with other polysaccharides, is measured by various colorimetric methods (Aziz et al ., ) or gravimetric semi‐quantitative methods based on Schweitzer's reagent extraction (Daji, ).…”