CHARACTERISTICS OF SOILS 



TABLE I 



The plant secures its carbon as carbon dioxide, which is 

 a gas, from the air through its leaves. 



All other foods the plant secures from the soil through 

 its roots. (Fig. 1.) 



4. Temperature and food preparation. The wise 

 farmer begins the preparation of a field some time, if 

 possible, before he expects to plant the crop. He has 

 learned that with a reasonable period given to such prepa- 

 ration, the crop responds more quickly after planting, 

 grows better and yields better, than if the period of prep- 

 aration is shortened. One of the reasons for this better 

 behavior of the crop is that the period of preparation makes 

 it possible, under normal conditions, to develop and store 

 in the soil an abundant supply of available plant-food 

 prior to the time of planting. Plants resemble animals 

 in some of their food demands. They need a proper 

 supply of food in the earlier days of their existence. 

 Like animals, they are likely to show, during the remainder 



