Biochemical properties of a Mediterranean soil as affected by long-term crop management systems

Soil biochemical properties under long-term crop management systems may be useful indicators of soil quality. We measured seven enzyme activities and six calculated biological indices at four adjacent study sites on an andosol in a semiarid area of eastern Sicily. Soils were sampled under natural grassland (NG), orange-grove (OG), winter wheat (WW) and horticultural crop (HC) managed according to local agricultural usage. The enzymes investigated were dehydrogenase, catalase, protease, alkaline phosphatase, β-glucosidase and amylase. The calculated biological indices were hydrolyzing coefficient, enzyme activity number, biological index of fertility, metabolic potential, lability index and C management index. Tilled management systems (WW and HC) were lower in total organic C and N and in all the enzyme activities and biological indices than in untilled management systems (NG and OG). Catalase activity and hydrolyzing coefficient were the most suitable soil biochemical properties for differentiating between the effects of different crop management systems, because of their analytical simplicity and rapidity.