Soil quality under the energetic crop giant reed (Arundo donax L.), cropping sequence and natural grassland

The objective of this study was to determine, on the same pedological, topographic and climatic conditions, the effect of a continuous giant reed cropping (GR), a cropping sequence (CS) as well as of untilled native grassland (NG) on some soil quality characteristics. Between the examined parameters, total soil organic carbon (TOC), light fraction carbon (LFC), dissolved organic carbon (DOC) cumulative mineralized carbon (Cm), microbial biomass carbon (MBC), basal respiration, metabolic quotient (qCO2), potentially mineralizable carbon (C0), dehydrogenase (DHA), catalase (CA) and ß-glucosidase (GL) activities, as well as fluorescein diacetate hydrolysis (FDA), biological index of fertility (BIF) and initial potential rate of carbon mineralization (C0•k), were higher in the continuos giant reed cropping than in the cropping sequence. The C mineralization rate (k) was lower in GR than in CS, while the metabilc potential (MP) was similar in the two sites. For what concerns the difference between GR and NG, this last usually considered as a reference or base line in evaluating attributes of soil quality, GR showed higher values for TOC, LFC, DOC and catalase activity. TOC and catalase, also for their analytical semplicity, may be suggested as the most suitable soil biochemical indicators for differentiating the effects of different crop management systems