ENV100Y5 Lecture Notes - Lecture 25: Soil Retrogression And Degradation, Land Degradation, Overgrazing

• School: UTM
• Department: Environment
• Course: ENV100Y5
• Professor: Barbara Murch

Document Summary

Soil erosion: transport and deposition (someplace else) of sediment, natural process; often accelerated by human activities, problem when it occurs faster than new soil is formed (leaving faster than it is coming in) 5-7 million hectares of productive cropland lost annually to accelerated erosion and soil degradation. Soil degradation has many causes: soil degradation results from deforestation, agriculture, overgrazing, chemical contamination, etc, over the past 50 years, soil degradation has reduced global grain production by. Grazing practices can contribute to soil degradation. On the other hand improves/ preserves soil: holistic management: simulating the behaviour of natural herds actually. Irrigation boosts productivity but can cause long-term problems and soil degradation: groundwater depletion, waterlogging, salinization = buildup of salts in surface soil layers, salinization inhibits production on 20% of all irrigated cropland, costing more than billion/year. Increase fungal pathogens: alters root morphology (surface, not deep roots, can cause salinity problems, subsidence (downward shift of surface)