Denitrification: enzyme content and activity in desert soils

TitleDenitrification: enzyme content and activity in desert soils
Publication TypeJournal Article
Year of Publication1990
AuthorsPeterjohn WT
JournalSoil Biology and Biochemistry
Date Published1990
Accession NumberJRN00120
Call Number00461
Keywordsarticle, articles, denitrification, enzyme content, journal, journals, soil carbon, soil nitrogen, soil, denitrifying enzymes

The content of denitrifying enzymes in upland desert soil was strongly associated with indices of N and C availability. Combinations of several predictors could explain 71% of the variance in enzyme content in Chihuahuan desert soils and 87% of the variance in soils from various deserts in the southwestern U.S.A. A significant fraction of the enzyme content in wet desert soil is derived form a persistent pool of enzymes capable of tolerating extended periods of desiccation. The synthesis of new denitrifying enzymes appears to involve a complex interaction between available C, N, and soil moisture. The activity of denitrifying enzymes in desert soil was optimal at a pH of 7.0 and a temperature of 40 C. The Q10 for denitrification was 1.74, and the activation energy was bout 41 kJ mol-1. In addition, enzyme activity in freshly wet soil was not limited by NO-3 availability, and only slightly limited by the availability of C. Thus, wet desert soil appears to provide optimal conditions for several variables that can influence denitrification.