Study of Charasteristics of Inorganic Pyrophosphatase Activity in Marshland, South of Iraq


Marsh land (south of Iraq) is of great interest at present time, therefore studying some of microbial properties, including enzyme activities, can be useful as indicator of soil quality of this area. Hence, this study was carried out to compare inorganic pyrophosphatase (EC 3. 6. 1. 1) activity in this soil with their counterparts of other soils of south Iraq (Al–Zubair and Abul–Khsib soils). Results indicated that inorganic pyrophosphatase activity at all substrate concentrations in marsh land soil was higher than those of Al–Zubair soil, but lower than those of Abul–Khasib soil. Expressed as PO4-3 – P released per gram soil per 5 hrs, the average Vmax values were 21.93, 37.23, and 33.33 while average Km values were 19.82, 18.26 and 29.77 for Al–Zubair, Abul–Khasib and marsh land soils, respectively. The results also revealed that the threshold of salinity negative effect on inorganic pyrophosphatase activity varies according to initial E.C. of soils (6 and 12 dS.m-1 for Abul–Khasib andmarsh land soils, respectively).