[Effect of rotting corn straw on the development of bacteria of the Azotobacter group]

The effects of the addition of ground maize straw, nitrogen compounds, ground lucern and water to soils incubated at 30 degrees C in Erlenmeyer flasks, on Azotobacter chroococcum growth have been studied. The results showed that the highest number of Azotobacter in soils treated with different percentage of ground maize straw without addition of nitrogen compounds and with water at 100% field capacity appeared as soon as the 5th day, reaching a maximun on the 20th day when the following numbers of bacteria were observed: control, 1,5 times 20(6); straw 1% 30 times 10(6), 2%, 33 times 10(6) and 4%, 77 times 10(6) per gram of air dried soil. This enables us to assume that the anaerobic decomposition of straw (cellulose and hemicellulose principally) in nature leads to the indirect utilization of its energy for a high asymbiotic microbiogical soil fixation of atmospheric nitrogen.