Sulfofication in Soils

Sulfur has long been known to be one of the essential plant food constituents. It has always been believed, however, that there was sufficient present in all soils for optimum crop production. This assumption has been very largely based on Wolff’s analyses of the ash of various crops which showed the presence of very small amounts of sulfur. Several investigators have found a considerable loss of sulfur upon ignition of plants for ash determinations, and recently Hart and Peterson, of Wisconsin, pointed out definitely the inaccuracy of determining the total sulfur of plant tissues by examinations of the ash. They analyzed numerous feeding stuffs for total sulfur, using the Osborn method, and compared their results with the earlier analyses of Wolff. This comparison showed quite conclusively that a large proportion of the sulfur in crops is lost upon ignition. It is evident, therefore, that considerably larger amounts of sulfur are removed from soils by common farm crops than has been supposed.