CEREAL CULTIVATION WESTERN AREA 387 



then harrowed and afterward kept clean during the 

 summer, the same as summer tillage. About December 1, 

 it is again plowed 5 inches deep and sown with barley or 

 wheat (Blanchard, 1910, pp. 15-17). 



412. The crops adapted for greeriTmanuring in this area 

 are rye and vetch previously mentioned, field peas, sweet 

 clover, Tangier peas, and perhaps in some places horse 

 beans. 



The field pea is found to be a very valuable crop on its 

 own account under dry-farming in eastern Oregon, in addi- 

 tion to its value as a green-manure crop preceding a cereal. 

 At Moro, Oregon, the best variety yielded an average of 

 19.3 bushels an acre in a 3-years trial, worth at that time 

 $35 in the regular market. This value is obtained in the 

 place of nothing from summer tillage and even the roots 

 plowed under benefit the following cereal crop and there 

 is the use of the fodder besides, and the possible residual 

 effect upon the soil (Stephens, 1915, p. 38). 



An interesting example of the benefit to wheat of pre- 

 ceding intertilled crops, one of which is a legume, is 

 given by Cardon (1915, pp. 39-43). Experiments at 

 the Nephi, Utah, substation, covering 5 years, resulted 

 in an average yield of wheat following peas of 14.39 

 bushels an acre, while wheat following summer tillage 

 averaged 12.89 bushels an acre, or 1.5 bushels less. Wheat 

 after potatoes and wheat after corn made still better 

 yields. The pea crop was harvested, so the value of that 

 crop above ground was obtained, in addition to the per- 

 manent benefit to the soil of the remaining portions of 

 the plants turned under. 



413. Rotation of crops. There is no doubt that the 

 general adoption on the farms in the Western area of rota- 

 tions, including primarily a green-manure and a culti- 



