AGR 2320 Lecture Notes - Lecture 14: Bulk Density, Porosity, Clay Minerals
12 Oct 2016
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Agr 2320 lecture 14 porosity and bulk density. Clay has a lot more pore space: pore space is around and inside the aggregates, has lower bulk density. As soil particle size increases, bulk density becomes greater b/c less total pore space. Sand is easy to till b/c doesn"t aggregate like clay does. Get reduction in organic matter after yrs of cultivation. Reduction in organic matter makes the soil lose some stability. Lower bulk density in wet clay soil vs dry clay soil: b/c clay soil puffs out and there is a larger volume. Affects clay and some loam soils: not sandy soils. Different types of clay have different swelling potentials. Kaolimite: minimal swelling, no space between repeating layers of clay. Smectite: large swelling potential, very common in canada, has a lot of space between sheets of clay that attracts water. Pore size distribution varies with texture and structure: clay has more micropores than sands, sands have more macropores than clays.
