Compaction and erosion: effects on soil ecology and soil quality.

Abstract

AbstractSoil degradation is a severe global problem. It has notable adverse economic and ecological impacts on local, regional, national and global scales. Important soil degradative (degradation) processes with severe adverse impacts are soil compaction and soil erosion among others. Decline in inherent soil quality can occur because of compaction and erosion, through adverse effects on many physical chemical and biological properties of the soil. This chapter focuses on physical and biological or ecological effects of soil compaction and erosion. As agriculture becomes more and more mechanized concerns for compaction of both the surface soil layer and the subsoil continue to increase. Soil compaction alters basic soil properties such as pore volume and pore size distribution, macropore continuity and soil strength. These properties have a large influence on elongation of plant roots and on movement of water, air and heat in soils. Soil erosion is considered to be the major cause of soil degradation. One-sixth of the world's soils have already been degraded by water and wind erosion. In Europe, soil degradation due to erosion is probably the most important environmental problem caused by conventional agriculture. Soil erosion reduces land productivity, degrades soil functions and challenges agricultural sustainability. Soil erosion on agricultural land is affected by different management practices and varies with landscape position and land use. Erosion can play an important role in the sequestration or release of carbon, nitrogen and phosphorus. The nutrient enrichment or eutrophication in surface waters is most commonly related to erosion from agricultural soils; in some regions this may be the most important reason to protect soil resources. Erosion leads to depletion of plant-available water and a reduction in water use efficiency. Climate change together with changes in land use, farming practice and population pressure on the land is thought to constitute a threat of increased erosion. Maintaining and improving soil quality require the protection of soil resources from degradation; this issue is discussed with particular emphasis on soil erosion, the most widespread and deleterious among the degradation processes. The most important possibilities to reduce compaction by heavy machinery are outlined briefly. Integrated soil conservation measures at the farm and catchment level have also been developed successfully and they have proved to be the most reliable options to limit soil erosion.