We have determined five enzymatic activities (actual and potential dehydrogenase, catalase, acid and alkaline phosphatase) and one nonenzymatic catalytic activity (H2O2 splitting in autoclaved samples) in the 0–10–, 10–20– and 20–30–cm layers of a brown luvic soil submitted to a complex irrigation and crop rotation (2– and 3–crop rotations) experiment. Each activity in both non-irrigated and irrigated soil under wheat and maize crops was significantly higher in the intermediate layer than in the upper, respectively deeper layers. Non-irrigation – in comparison with irrigation – resulted in significantly higher soil phosphatase activities in the 0–10–, 10–20– and 20–30–cm layers, whereas dehydrogenase and catalase activities were significantly higher in irrigated soil. The soil under wheat or maize was more enzyme-active in the 3– than in the 2–crop rotation and in the monoculture. In the monoculture and in the 2–crop rotation, higher enzymatic activities were registered under wheat than under maize. In the 3–crop rotation, higher enzymatic activities were recorded maize under wheat. The enzymatic indicators of soil quality decreased depending on the nature of crops and kind of irrigation in the following order: maize ( 3–crop rotation ) > wheat ( 3–crop rotation) > wheat ( 2–crop rotation ) > maize ( 2–crop rotation ) > wheat ( monoculture ) > maize ( monoculture ).
Genetic perturbation enhances functional heterogeneity in alkaline phosphatase
