Variations in chemical properties and enzyme activities of soil irrigated with low quality stream water

The present study was undertaken in an effort to evaluate the effects of irrigation with low quality water from the Niluefer stream (Bursa, Turkey) on selected chemical and biochemical characteristics of soil. For this purpose, an incubation study was carried out for 12 months, during which time low quality stream water was applied to soil pots in order to keep the soil moisture at 70% of the field capacity. The results of the study indicated that EC sub(2)5c values of the stream water added soil were significantly higher than those of the control. The addition of stream water also markedly increased the total nitrogen and phosphorus content. On the other hand, the stream water had an inhibitory effect on soil urease, dehydro-genase, alkaline phosphatase and b-glucosidase. The average enzyme activity values calculated at the end of the one-year incubation period showed that addition of Niliifer stream water to soil inhibited various enzyme activities by 8 to 30%, with maximum inhibition (30%) being observed for dehydrogenase activity.