Bibliography 



U.S. Department of Agriculture Soil Conservacion Service 

 in cooperation with Montana Agriculture Experiment Sta- 

 tion. 1 985. Soil Survey ofRosebud County Areaand Part of 

 Big Horn County, Montana. Lewis A. Daniels and others. 

 Unpublished. 



U.S. Bureau of Reclamation, 1982. Reclamation Instruc- 

 tions: Irrigauon. 



,\nderson, Arial, January 18, 1990. Land Classification 

 Specifications for Irrigation Suitability. Unpublished 

 memo, 8pp. RWRCC, Helena, Montana. 



Glossary 



Alluvium 



Arable land 



Material such as sand, silt, or clay depos- 

 ited on land by streams. 



In this document, land that could provide 

 enough income to warrant consideration 

 for irrigation development 



Land classes I through 3 are arable, class 6 

 is nonarable. Classes 4 and 5 are lands 

 limited to rare or unique situations requir- 

 ing special studies and are not used in this 

 analysis. 



Available water The capacity of soils to hold water avail- 

 capacity able for use by most plants. Commonly 

 [available defined as the difference between the 

 moisture amount of soil water at field moisture 

 capacity] capacity and the amount at wilting point 



and commonly expressed as inches of 



water per inch of soil. 



Field moisture capacity - the percentage of 

 water remaining in the soil two or three 

 days after having been saturated. 



Wilting point - the moisture content of 

 soil, on an oven dry basis, at which a plant 

 (specifically sunflower) wilts so much that 

 it does not recover when placed in a hu- 

 mid dark chamber. 



Bedrock The solid rock that underlies the soil and 



other unconsolidated matenaJ or that is 

 exposed at the surface. 



Channery Thin flat fragments of limestone, sand- 



stone or schist up to 6 inches in diameter 



Clay A soil textural class containing more than 



40 percent clay, less than 45 percent sand 

 and less than 40 percent silt 



Colluvium Soil, rock fragments, or both, moved by 



creep, slide, or local wash and deposited at 

 the bases of steep slopes. 



Complex soil Twoor more kinds of soil occurring in such 

 an intricate pattern diat they cannot be 

 shown separately on a soil map. 



Depth to rock The distance from soil surface to bedrock. 



Eolian Material transported by wind. Includes 



earth materials ranging from dunesands to 

 silty loess deposits and volcanic ash. 



Flooding The temporary covering of soil with water 



from overflowing streams or runoff fi"om 

 adjacent slopes. Average frequency and 

 probable dates of occurrence are estimated. 

 Frequency is expressed as rare, occasional, 

 or frequent. Rare means chat it floods less 

 than once in ten years; occasional chat it 

 floods once in two to ten years; and fre- 

 quent that it floods once every two years. 

 Probable dates are expressed in months; 

 May and June, for example, means that 

 flooding can occur during this time. 



Flood plain A nearly level alluvial plain that borders a 



stream and is subject to flooding unless 

 artificially proteaed. 



Irrigable land Arable laridunderaspecific plan for which 

 a water supply is or can be made available, 

 and which is provided with, or planned to 

 be provided with, irrigation, drainage, 

 flood protection, and other facilities as nec- 

 essary for sustained irrigation. (Bureau of 

 Reclamation) 



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