Soil erosion is a major obstacle to the sustainability of all forms of intensive agriculture in hilly and mountain areas, exceeding 30 times the rate of sustainability (tolerable erosion). Erosion is often triggered by inadequate plantation models and inappropriate land management techniques. It has also been proven that climate change may accentuate or accelerate soil degradation processes, especially erosion. Apart from the various hypotheses regarding the causes of these changes, their effects on soil are evident, with the increase of erosion, a consequence of the increasing aggressive climatic conditions.
Recent studies have been designed to assess the effects of future climate change scenarios on soils under different cropping systems and have confirmed the importance of maintaining or increasing the amount of organic matter. The cropping systems that would seem to be more sensitive to climate change are those that have adopted traditional ploughing, responsible for the increase of mineralization. On the basis of these results, soil management will play an increasingly important role among the possible adaptation strategies.
Within the potential operational measures, we would suggest to policy makers the adoption of technical and financial support for all management practices that minimize or eliminate soil tillage (conservation tillage), include crop rotation and the use of catch crops (cover cropping), consider burying crop residues or mulching with plant material (organic mulching), adopt organic fertilization and, more generally, reduce crop intensification and respect the suitability of soils.
An adequate supply of organic matter is crucial to protect soil from erosion, since it can improve structural characteristics. The role of vegetative cover is also crucial as it reduces the beating action of rain that is followed by surface crusting, and delays the onset of surface runoff phenomena. If the directions to be followed in arable lands are those mentioned above, and more generally the principles of Conservation Agriculture, a surface grass cover for tree crops is a viable strategy, particularly in areas where a significant increase in aggressive climatic conditions are expected. The greatest hindrance to its dissemination is the competition for water between herbaceous cover and main crop. Where it is possible to overcome this constraint, such a management system has proved more effective than reduced tillage.
(Marcello Pagliai - Università di Firenze - firstname.lastname@example.org)