THE EFFECT OF ACETYLENE ON N-TRANSFORMATIONS IN AN ACID OAK-BEECH SOIL

The effectiveness of acetylene (C2H2) as inhibitor of nitrification wa s studied in relation to the decomposition of C2H2. This was done by e xamining the effects of single and multiple additions of different C2H 2 concentrations (10, 100, 1000 Pa) on mineral N and NO3--N production in samples of the organic (FH) and upper mineral (Ah) layer of an aci d oak-beech forest soil. The decomposition of C2H2 was much faster in Ah samples than in FH samples. A single addition of 10 Pa C2H2 was not sufficient for complete inhibition of nitrification in the Ah samples . Nitrification was blocked completely by all other C2H2 treatments in both FH and Ah samples. Addition of C2H2 decreased net mineral N prod uction in Ah samples but not in FH samples. Addition of carboxymethyl- cellulose and chitin to Ah soil had no affect on the rate of decomposi tion of C2H2. Chitin had a negative effect on net NO3--N production.