|Riassunto in Inglese:|
Management of crop residues, crop rotation and soil tillage are important agronomic practices that can conserve or greatly influence the soil fertility in term of content of soil organic carbon and crop productivity. In order to determine long-term dynamics of such practices, long-term field researches have been established in Southern Italy by the Research unit for cropping systems in dry environments of the Agricultural Research Council. At the experimental farm in the Northern part of Apulia Region, three long-term trials are currently being carried out on clay-loam soil since 1977, 1989 and 1990. A series of treatments on the effects of burning or incorporation of crop residues, soil tillage and crop rotations based on winter durum wheat have been compared. At the experimental farm of CRA-SCA in the central part of Apulia, since 1976 almond plants have been submitted to different treatments consisting of weed management based on chemical weeding, weed mulching, weed incorporation through minimum and conventional tillage. In general the incorporation of straw and stubble showed slight increments in organic soil matter respect to burning. The best results for soil organic carbon and soil quality were obtained when residual incorporation included a treatment with additional mineral nitrogen. The tillage method did not influence the organic carbon, total nitrogen and available phosphorous contents of the soil, nor did crop rotations. In the almond trial, no-tillage with green mulching determined a general increase of TOC with respect to other treatments.