Soil degradation and land use

The main aspects of environmental degradation that involve soil (erosion, soil compaction, soil crusting, deterioration of soil structure, flooding, losses of organic matter, salinization, onsite and offsite damages, etc.) result from human activities. Since conventional agricultural production systems have resulted in excessive erosion and soil degradation, change is needed that will control such ruin. Scientific results have clearly shown that agricultural management systems can play an important role in preventing soil degradation provided that appropriate management practices are adopted. Long-term field experiments in different types of soils have shown that alternative tillage systems, such as minimum tillage, ripper subsoiling, etc., improve the soil structural quality. Continuous conventional tillage causes a decrease in soil organic matter content associated with a decrease in aggregate stability, leading, as a consequence, to the formation of surface crusts, with an increase in runoff and erosion risk. In hilly environments, land leveling and scraping are dangers to soil, causing its erosion.. After leveling, slopes being prepared for planting (particularly vineyards) are almost always characterized by the presence of large amounts of jumbled earth materials accumulated by the scraper. In this vulnerable condition, a few summer storms can easily cause soil losses exceeding 500 Mg ha(-1)year(-1). Moreover, land leveling and the resulting soil loss cause drastic alteration of the landscape and loss of the cultural value of the soil. Subsoil compaction is strongly underevaluated, even though the presence of a ploughpan at the lower limit of cultivation is largely widespread in the alluvial soils of the plains cultivated by monoculture. It is responsible for the frequent flooding of such plains when heavy rains concentrate in a short time (rainstorm), since the presence of this ploughpan strongly reduces drainage. Alternative tillage practices, like ripper subsoiling, are able to avoid the formation of this compact layer.