Factors Determining Soil Characteristics and Types: An Overview, Slides of Earth Sciences

Download Factors Determining Soil Characteristics and Types: An Overview and more Slides Earth Sciences in PDF only on Docsity! 14.4 What factors determine soil characteristics? Fig 14.16 Rainforest Soil Distribution Docsity.com 14.5 What are the types of soils? Grassland soils – Such as in U.S. Midwest form in sub-arid regions – Not strongly leached, so very fertile – Thick dark A horizon, light B horizon Docsity.com Soil types relate to different soil-forming factors in different locations. Forest soils generally contain less organic matter and have more clay-rich B horizons than grassland soils. Desert soils have the least organics and low-clay B horizons. Arid soils often enriched in calcite. Rainforest soils are strongly weathered and have low fertility due to massive dissolution of minerals and organics. Highly weathered tropical soils may have economically valuable bauxite. Immature soils, with poorly developed horizons, form where there has been insufficient time for weathering. Most immature soils are on unstable landscapes or areas too cold for weathering reactions to be effective. 14.5 What are the types of soils? Docsity.com @! all of the calcium in the soil originated by weathering of the basalt, then a 100m thickness of Can we explain calcite-rich soil? Original thickness basalt Id have ibe of basalt implied completely by the analyses. weathered away, Calcite-rich soil eet Current thickness ® Problem 2: |f the calcium is from weathering 100 m of basalt, then there should be a large volume of less-soluble elements left behind in the soll in addition to the calcium. @ Problem 1: Top of basalt is not very weathered and has: a vesicular, rubbly appearance as the top of a lava flow should look, i Less-soluble elements measured in the soil: No evidence that 100 m of weathering occurred. Less-soluble elements No evidence that 100 m of weathering occurred. Copyright © 2006 Pearson Prentice Hall, Inc. expected from weathering 100 m of basalt, Dogs gy19220 14.6 How do we know ... that soils include atmospheric additions? The issue – desert soils seem to have more calcite than they should – If so, how does it get there? A hypothesis: Is Ca delivered in dust and rainfall? Windblown dust may originate from many miles away and rain is obviously from far away. Can such a thought be tested … most certainly. Docsity.com