.2.. THE ;I;IANDBOOK FOE PRACTICAL FARMERS 



•matter^' ;;Tn gome sections the black color also indicates the pres- 

 ' '-en^e Of ah' abundant supply of lime which is also essential. Next 

 to the black soils the reddish brown lands will usually prove to 

 be highly productive and will command the respect and approval 

 of practical farmers. Yellow lands are usually next in value, 

 while the white and the gray colors are not regarded as indica- 

 tive of naturally fertile soil. In dry arid regions, very white 

 spots usually indicate the presence of harmful amounts of alkali 

 salts. 



The presence of well developed oaks or of hickory and walnut 

 trees are evidence of a naturally fertile soil, while"^ a growth of 

 soft woods such as gum and short-leaved pine indicates a poor 

 soil. On cultivated fields the thrifty appearance of the crop 

 plants or a rank growth of weeds may be taken as a reliable 

 guide as to the fertility of the soil. Soils that are practically 

 useless for general farm crops, however, may be well adapted to 

 the growing of special truck crops for the early market. Light 

 sandy soil is best adapted to the growing of early vegetables, 

 small fruits, potatoes and other similar crops, while the heavier 

 loams are best suited to the growing of corn and other grains. 

 Clay soils are best adapted to the growing of wheat and grass, 

 because of their greater moisture holding capacity. The classi- 

 fication of soils with respect to their adaptability to different 

 crops is based largely upon the size of the rock particles of 

 which the soil is composed and to a lesser degree upon the 

 amount of organic matter present. 



In farm practice soils are spoken of as being heavy or light 

 depending upon whether they are hard or easy to work. Clay 

 soils are difficult to till because of the fineness of the particles 

 and their tendency to stickiness, while coarse grained sandy soils 

 are easily cultivated because of the absence of any large quan- 

 tity of material that is finely divided. All soils, however, are 

 mixtures of different sized particles, the size of the individual 

 particles determining the texture and their arrangement the 

 structure of the soil. Wlien the arrangement of the soil par- 

 ticles, or the structure is such as to be highly favorable to the 

 growth of crops the soil is said to be in good tilth. 



Relation of texture and structure to soil management.— A 

 great majority of soils consist of particles varjdng in size from 

 very fine to coarse, although some have only fine and others 

 only coarse particles. The coarse particles are classed as fine 

 gravel or coarse sand; the next finer groups as medium sand, 

 fine sand, very fine sand; the finest as silt and cla}^ The rela- 



