Sod Grass 



A grass that forms a Sod, e.g., Kentucky bluegrass. 



Softwood 



The wood of a coniferous tree, e.g., pine, in contrast to 

 Hardwood (q. v.). 



Soil 



The aggregate of weathered minerals and decaying 

 organic material that covers the earth in a thin layer in which 

 plants grow. 



Soil Creep 



The very slow movement of surface soil down a slope. 



Soil Erosion 



The loosening and movement of particles of soil from 

 the surface of the land by wind or flowing water, including 

 Accelerated erosion and Normal erosion, cf. Gully erosion, 

 Rill erosion, Sheet erosion, Splash erosion. 



Soil Horizon 



A layer of soil with characteristics resulting from soil- 

 building processes. See A, B, C horizons, Podzolization. 



Soiling 



The feeding of livestock with mowed, fresh forage such 

 as bromegrass or legumes, in contrast to their grazing on a 

 pasture. 



Soil Productivity 



The capacity of a soil to produce plant growth because 

 of its chemical, physical, and biological properties. 



Soil Profile 



A vertical section of the soil from the surface through 

 all its horizons into the parent material, cf. Soil horizon. 



Soil Reaction 



The acidity or alkalinity of the soil usually expressed 

 as pH (q. v.). 



318 



