EXTENSION COURSE IN SOILS. 83 



SOILS ADAPTED TO CEREALS. 



(Ref. No. 7, p. 574.) 



The most important cereals are similar in regard to their root sys- 

 tems, which are much finer than those of crops which are commonly 

 intertilled. They are also similar in that their growth takes place 

 early in the season and thoy are therefore able to take advantage of 

 the moisture which has accumulated during the winter. Hence they 

 may be grown in sections of relatively low rainfall, in which the sum- 

 mer is quite dry. 



Oats (Ref. Nos. 7, pp. 587-589; 10, p. 241).— Oats are especially 

 adapted to a northern climate and have a relatively strong root sys- 

 tem, going 50 per cent deeper than other grains. Varieties have been 

 developed which are adapted to different types of soil. The Klherson 

 or sixty-day oat, for instance, is especially well adapted to marsh 

 land, because of its strong stem which prevents it from lodging on a 

 soil on which crops are naturally very subject to that difficulty. 



Rye (Ref. Nos. 7, pp. 585-587; 10, p. 243). — Rye has been devel- 

 oped chiefly in climates of relatively light rainfall, and this, together 

 with the fact that it is sown in the fall and attains considerable root 

 development then, permitting it to mature quickly the succeeding 

 spring, makes it fairly profitable on sandy soils low in water-holding 

 capacity and in sections of the country having a light rainfall. 



Wheat (Ref. Nos. 7, pp. 581-585; 10, pp. 234-241).— On account of 

 the fact that wheat has been more widely grown for human food and 

 over a much larger part of the earth than other cereals, it has devel- 

 oped the power of adapting itself to a greater variety of conditions 

 than other grains. It grows in countries with very hot climates as 

 well as in almost the coldest climates permitting growth of agricul- 

 tural crops. Some varieties will do well with very high rainfall, 

 while others are adapted to regions of very low rainfall. While it 

 can be grown on many different kinds of sod, wheat is best adapted 

 to relatively close-textured soils, such as silt and clay loams. 



SOILS ADAPTED TO GRASSES AND LEGUMES. 



(Ref. No. 7, pp. 536-573.) 



True grasses, especially those used for pasturage and hay, are char- 

 acterized by very fine root systems. They differ also from most other 

 cultivated plants in that they grow continuously through the entire 

 growing season and therefore require a more uniform distribution of 

 moisture than is essential to crops growing only early in the spring 

 or during the midsummer period. The extremely fine root systems 

 of these plants adapt them especially to clay soils, which they are able 

 to permeate and from which they can extract the large supplies of 

 moisture which these soils are able to hold. 



