Increased Growth ofNicotiana glutinosaas Partially Related to Accumulation of Ammonium-Nitrogen in Soil Fumigated with Methyl Bromide

Abstract

Biological and chemical changes were measured in soil fumigated for various periods with methyl bromide (27,000 .mu.l/l air) in a moving airstream. Height of N. glutinosa plants grown in fumigated soil increased as the period of fumigation increased above 16 h. Increased growth was correlated with elimination of a coenocytic fungus from the roots of plants grown in soil fumigated for longer than 4 h and with elimination of microorganisms other than recognized fungal pathogens. Increased growth was correlated with an increase in inorganic N (primarily ammonium) in soil fumigated for 16 h or longer. Concentrations of various plant nutrients were determined in tissues of 35 day old N. glutinosa plants grown in fumigated soil. Only N was closely correlated with increased growth, although high concentrations of Cu, Mn, Zn and P in plants grown in soil fumigated for 128 h may have accounted for some increased growth.