GEOG-120 Lecture Notes - Lecture 28: Cation-Exchange Capacity, Soil Retrogression And Degradation, Erosion
22 Dec 2020
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Document Summary
Materials move through soils and plants gain many of the nutrients through a set of processes called ion exchange in which positive charged particles and negatively charged particles are exchanged between the soil and the soil solution. Cation exchange capacity is a measure of a soil"s ability to hold cations, preventing them from leaching away, being useful for plants. As soil ph becomes lower, cation exchange capacity diminishes, nutrients leach away, and soil instead may supply plants with harmful aluminum ions. Soil is a crucial part of the nitrogen cycle: Motionless nitrogen gas from the atmosphere must be xed; which happens when air in the top layer of soil comes in contact with various specialized nitrogen- xing bacteria. Ammonium ions are rst converted into nitrite ions then into nitrate ions. Plants can take up nitrate ions as nutrients through their roots. Occurs when bacteria convert nitrates in soil or water into gaseous forms of nitrogen.
