Gas in soil

Conrad R, Erkel C, Liesack W. Rice cluster I methanogens, an important group of Archaea producing greenhouse gas in soil. Curr. Opin. Biotech. 2006 17 262-267. 

Fig. 13.4 shows the rapidity with which nitrates can be reduced to nitrogen gas in soil maintained under completely anaerobic conditions. In these experiments, conducted by Jones (1951), 5 mg N in the form of potassium nitrate was added to an air-dry Codorus loam together with 0.5% sucrose and optimum moisture. It will be noted that nearly 50% of the nitrate was reduced to nitrogen gas within 2 days and about 80% within 3 days. If moist soil had been used rather than air-dry soil the rate would undoubtedly have been even more rapid. In similar experiments, where sucrose was omitted, the rate of nitrogen evolution was not appreciably different from that shown in Fig.13.4. The soil itself contained sufficient available energy material for a near-maximum rate of denitrification.

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