LEGUMES AND GRASSES 



In 1931, Chilcott (10) stated that 

 the use of biennial and perennial 

 hay and forage crops in rotations 

 was not of major importance in the 

 Great Plains. The conservation 

 and utilization of scanty rainfall 

 was of such predominant impor- 

 tance as to relegate the use of bien- 

 nial hay and forage crops in 

 rotations to a minor role. 



In 1938, Mathews and Cole (52) 

 discussed dryfarming problems in 

 the Great Plains and Intermountain 

 dryland areas. They stated: 



Maintenance or increase of the organic- 

 matter content of the soil through the 

 application of manures or green manures 

 will not pay for the cost where crops are 

 grown for grain. Stover yields may be 

 increased enough to justify the added 

 expense. 



The inclusion of sod crops in short 

 rotations has not been a success. Estab- 

 lishing a stand of grasses is often too 

 expensive unless it is to be left for more 

 than 2 or 3 years. Further, while the 

 long-time effect of a grass sod may be 

 good, its effect on the crop immediately 

 following is generally bad, because it 

 leaves the soil exceedingly dry. 



In 1939, CoJe and Mathews (12) 

 reported a study on subsoil mois- 

 ture conditions under semiarid con- 

 ditions at Havre, Mont., Mandan, 

 N. Dak., North Platte, Nebr., and 

 Hays and Colb}^ Kans. This 

 study showed that the depth to 



which water penetrated depended 

 on the quantity and type of pre- 

 cipitation and the character of the 

 soil. As a general rule, the annual 

 cycle of water charge and discharge 

 was confined to that part of the 

 zone where roots developed freely 

 and no water reached the under- 

 lying substrate. Occasionally, the 

 entire root zone filled with water, 

 and a small quantity of water pene- 

 trated beyond reach of plant roots. 



In 1944, Jacks (38) discussed the 

 effects of grass on soil. He stated 

 that the most striking effects are 

 related to the physical properties of 

 the soil. Perennial grass, grown in 

 a semiarid temperate climate, was 

 the most efficient producer of gran- 

 ular soil structure. In more arid 

 climates, where grasses grow with 

 difficulty, or in more humid cli- 

 mates, which exert a disintegrating 

 effect on soil structure, granulation 

 was less highly developed. Re- 

 gardless of climate, perennial 

 grasses were found to be more effec- 

 tive than any other kind of 

 vegetation. 



Jacks reported that the full 

 effects that grass had on soil were 

 achieved in 2 years in moist tem- 

 perate climates and in 4 years in 

 dry temperate climates. Hoots are 



Legend for problem areas in soil conserva- 



D14 



tion (81) shown in figure 1. 





Great Plains: 



D15 



Dl 



Black Glaciated Plains, Eastern 







Dakotas 



D16 



D2 



Dark Brown Glaciated Plains, 







Central Dakotas 



D17 



D3 



Badlands of North Dakota 



D18 



D4 



Residual Plains, West Dakotas 





D5 



Badlands of Montana 



D19 



D6 



Thinly Glaciated Plains and 







Scablands 



D20 



D7 



Triangle Area of Montana 





D8 



Western Montana Foothills and 



D21 





Benches 



D22 



D9 



Central Montana Shale Hills and 

 Plains 



D23 



D10 



Powder- Yellowstone Residual 

 Plains 



D24 



Dll 



Pierre Shale Plains 



Rocky 



D12 



Nebraska Sand Hills 



E2 



D13 



Northern Brown Plains 





Nebraska-Kansas Dissected Loess 

 Hills and Tablelands 



Central Nebraska-Kansas Loess 

 Plains 



Central Kansas Shale — Sand- 

 stone Hills and Loess Plains 



Breaks of the High Plains 



Great Bend Sandy Plains, Ar- 

 kansas River 



Arkansas River Loessial Out- 

 wash Plains 



Plains of Upper Arkansas and 

 Purgatoire Rivers 



Cimarron — Canadian Breaks 



Southern High Plains 



Red Plains of Kansas, Oklahoma, 

 and Texas 



Red Prairies of Kansas, Okla- 

 homa, and Texas 

 Mountains: 



Outlying mountains of Montana 

 and Black Hills of South Dakota 



