Soil quality: a new index based on microbiological and biochemical parameters

Abstract. The objective of this investigation was to evaluate some chemical, physical, biological and biochemical parameters and to determine a minimum data set to establish a soil quality index. Four different forms of management (native forest soil, soil deforested in 1982 and 1983 and under natural pasture for the last 8-10 years, soil deforested 26 years ago and under no-tillage for 6 years, and soil deforested 40 years ago and under conventional tillage) were established in an experimental site located in Entre Rios Province, Argentina in a Vertic Argiudoll soil. Soils sampled from the different treatments were monitored for their organic C, total N and extractable P contents and for aggregate stability, respiration C, dehydrogenase, urease, protease, acid phosphomonoesterase, β-glucosidase and arysulphatase activities. Different contents of organic C and total N between cultivated treatments and the forest soil indicated the extractive effect of cultivation and agricultural practices during different periods of time. Organic C presented significant correlations with most of the others properties. Among the various polynomial expressions that could be formulated, one (organic C=-0.4008 arylsulphatase+0.4153 dehydrogenase+0.4033 acid phosphomonoesterase+0.4916 β-glucosidase) had a R² value which did not differ from that of the complete model.