Question

What are different types of soil structures which can occur in nature briely describe them?

Answer 1

Soil structure is defined by the way individual particles of sand, silt, and clay are assembled. Single particles when assembled appear as larger particles. These are called aggregates . Aggregation of soil particles can occur in different patterns, resulting in different soil structures.

Answer 2

Answer:

Granular. Roughly spherical, like grape nuts. Usually 1-10 mm in diamteter. Most common in A horizons, where plant roots, microorgan isms, and sticky products of organic matter decomposition bind soil grains into granular aggregates.

Platy. Flat peds that lie horizontally in the soil. Platy structure can be found in A, B, and C horizons. It commonly occurs in an A horizon as the result of compaction.

Blocky. Roughly cube shaped with more or

less flat surfaces. If edges and corners remain sharp, we call it angular blocky. If they are rounded, we call it subangular blocky. Sizes commonly range from 5-50 mm across. Blocky structures are typical of B horizons, especially those with a high clay content. They form by repeated expansion and contraction of clay minerals.

Prismatic. Larger, vertically elongated blocks, often with five sides. Sizes are commonly 10-100 mm across. Prismatic structures com monly occur in fragipans.

Columnar. The units are similar to prisms and

are bounded by flat or slightly rounded verti cal faces. The tops of columns, in contrast to those of prisms, are very distinct and normally rounded.

Massive. Compact, coherent soil not sepa rated into peds of any kind. Massive structures in clayey soils usually have very small pores, slow permeability, and poor aeration.

Single grain. In some very sandy soils, every grain acts independently, and there is no binding agent to hold the grains together into peds. Permeability is rapid, but fertility and water holding capacity are low.