Assessment of the biological activity of soils in the subtropical zone of Azerbaijan

The enzymatic activity; the microbial population; and the intensities of the nitrification, ammonification, CO₂emission, and cellulose decomposition were studied in gray-brown, meadow-sierozemic, meadow-forest alluvial, and yellow (zheltozem) gley soils in the subtropical zone of Azerbaijan under natural vegetation, crop rotation systems with vegetables, and permanent vegetable crops. On this basis, the biological diagnostics of these soils were suggested and the soil ecological health was evaluated. It was shown that properly chosen crop rotation systems on irrigated lands make it possible to preserve the fertility of the meadow-forest alluvial and zheltozem-gley soils and to improve the fertility of the gray-brown and meadow-sierozemic soils.