MICROBIOLOGICAL ACTIVITIES IN THE SOIL OF AN UPLAND BOG IN EASTERN NORTH CAROLINA

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Abstract
Nitrification does not occur in the soil of this upland grass-sedge bog under natural conditions. It may be initiated by liming and drainage, as determined by pot experiments, but only after an interval of 6-10 weeks. No leguminous plants are found growing on the bog, yet the soil contains 0.24% total N. Its source may be to some extent atmospheric N fixed by non-symbiotic organisms. Azotobacter sp. are not present on account of soil acidity and anaerobic conditions. Bacillus amylobacter was found in several soil samples. Addition of enough lime to neutralize the acidity results in a great increase in numbers of bacteria, but does not appreciably change numbers of fungi. Liming markedly increases the rate of CO2 production by the soil microorganisms. When the soil is saturated with, or contains too little, water, the rate of CO2 production is reduced in comparison with soil at optimum moisture concentration. The soil has a wide CO2 ratio (13.6:1) which tends to retard decomposition of the soil organic matter. When the soil is neutralized with lime and allowed to become quite dry, actinomyces become very numerous, giving the soil a whitish appearance. Cellulose added to the soil in the form of filter paper is very slowly decomposed on account of the lack of available N.

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