24 THE ESSENTIALS OF AGRICULTURE 



For example, when the farmers of humid regions have moved 

 into regions of limited rainfall, their difficulties have been greatly 

 increased because they have taken with them the crops and 

 methods used in humid climates. On the other hand, when 

 some Russian immigrants brought wheat which had been grown 

 for centuries in a comparatively dry climate to a region in the 

 United States where the rainfall was limited, the result was that 

 wheat farming prospered beyond the hopes even of the first 

 settlers. The development of a corn suited to the climate of the 

 North changed corn-growing from uncertainty to certainty. In 

 China and Africa the sorghums are plants which are capable of 

 withstanding long droughts. These have been introduced into 

 regions of limited rainfall in the United States, with the result 

 that large stretches of fertile soil which otherwise would have 

 been suitable only for grazing have been made into successful 

 farms. 



24. Where plants get their food. The young plant lives on 

 the food already stored in the seed, tuber, or other part planted, 

 until it has developed a system of feeding roots, and until its 

 leaves have been unfolded in the air and light. The plant is 

 then usually able to live on the soil and air entirely, but it stands 

 a much better chance of making a satisfactory development if 

 the part planted contains a sufficient reserve of food to help 

 sustain the plant while it is young. This is especially important 

 when the weather or soil conditions are not ideal for the nourish- 

 ment of the tender plant. It is interesting to know that beans, 

 for example, may be grown to the flowering stage without nutri- 

 tive salts from the ground, the plant depending entirely on the 

 stored-up food in the thick, fleshy seed leaves. This is one rea- 

 son why corn, which contains an abundance of food and which 

 germinates vigorously, is chosen for seed, and why the piece of 

 potato which is planted is of larger size than is required to sup- 

 port the plant until its leaves reach the surface. Besides the food 

 which is obtained from the parent, the growing plant makes 

 food from materials which it secures from the soil through its 

 roots and from the air through its leaves. 



