Soil Structure 



The arrangement of particles in the soil, e.g., single 

 grain, granular, columnar. 



Soil Texture 



The relative proportions of the various sizes of mineral 

 particles (gravel, sand, silt, clay) in the soil. cf. Silt. 



Soil Type 



An area of soil which is relatively uniform in profile 

 characteristics and in texture of the surface soil, a sub- 

 division of a soil series, e.g., Cecil sandy loam and Cecil clay 

 loam are soil types in the Cecil series. 



Solar Constant 



The energy received from the sun above the upper limit 

 of the atmosphere, equal to 1.94 gram-calories per minute 

 per square centimeter. 



Solarizafion 



The inhibiting effect of extremely high light intensities 

 on Photosynthesis. 



Solifluction 



The flow of saturated soil upon an impermeable layer 

 or on frozen ground, especially under conditions of alternate 

 freezing and thawing. 



Solonchalk 



A type of soil that has a high concentration of soluble 

 salts in relation to other soils, usually light-colored, "white 

 alkali." cf. Saline soil. 



Solonetz 



A type of soil in which the surface horizons of varying 

 friability are underlain by dark-colored, hard soil which is 

 usually highly alkaline and columnar in structure, "black 

 alkali." cf. Alkali soil, Solonchalk. 



319 



