Urease and dehydrogenase activity of alkali and reclaimed soils

Abstract

Alkali soils have low amounts of organic carbon and nitrogen and low levels of urease and dehyrogenase activity. There is a marked improvement in these properties after reclamation by chemical or biological methods. After 12 years, greatest accumulation of organic matter and enzymes was found in soils with a tree cover, followed by those with a grass cover, and it was least in soils reclaimed by application of a chemical amendment (gypsum) followed by cropping. The enzymatic activities were correlated positively with organic carbon and Kjeldahl nitrogen and negatively with pH and CaCO2. Organic carbon accounted for most of the variation in enzymatic activities.