THE INFLUENCE OF AVAILABLE NITROGEN ON THE FERMENTATION OF CELLULOSE IN THE SOIL

Abstract

The rate of cellulose destruction in the soil increased as the available N increased. A maximum rate was obtained when the ratio of N to cellusose was 135; N in excess of this had no influence and accumulated as NO3. With lower amounts of N the cellulose fermenters reduced the NO3 as rapidly as formed. The amount of cellulose fermented per mgm. of N was largest with small amounts of N. Ammonification took place in the presence of cellulose, and ammonium N could satisfy the N requirements of the cellulose fermenters. In soils high in carbohydrate poor plant growth is due to lack of NO3 and not to inhibition by carbohydrates. Availability of protein N was directly proportional to its rate of ammonification. Amino-acid N was as good as ammonium N.