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Soil structure: Platy soil structure

L: In place platy structure.

R: Intact plates removed from matrix.

 

www.flickr.com/photos/jakelley/53410253540/in/dateposted-...

 

Soil Peds are aggregates of soil particles form as a result of pedogenic processes; this natural organization of particles forms discrete units separated by pores or voids. The term is generally used for macroscopic (visible; i.e., greater than 1 mm in size) structural units when observing soils in the field. Soil peds should be described when the soil is dry or slightly moist, as they can be difficult to distinguish when wet.

 

Platy soil structure is characterized by peds that are flat and platelike. They are generally oriented horizontally. A special form, lenticular platy structure, is recognized for plates that are thickest in the middle and thin toward the edges. Platy structure is usually found in subsurface soils that have been subject to leaching or compaction by animals or machinery. The plates can be separated with little effort by prying the horizontal layers with a pen knife. Platy structure tends to impede the downward movement of water and plant roots through the soil.

 

There are five major classes of macrostructure seen in soils: platy, prismatic, columnar, granular, and blocky. There are also structureless conditions. Some soils have simple structure, each unit being an entity without component smaller units. Others have compound structure, in which large units are composed of smaller units separated by persistent planes of weakness.

 

For more information about describing and sampling soils, visit:

www.nrcs.usda.gov/resources/guides-and-instructions/field...

or Chapter 3 of the Soil Survey manual:

www.nrcs.usda.gov/sites/default/files/2022-09/The-Soil-Su...

 

For additional information on "How to Use the Field Book for Describing and Sampling Soils" (video reference), visit:

www.youtube.com/watch?v=e_hQaXV7MpM

 

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Uploaded on February 10, 2010
Taken on August 5, 2006