72 DRY LAND FARMING 



This is the great lack of volcanic ash soils, and it fur- 

 nishes one explanation of the ease with which they are 

 gullied and carried away by the action of water. The 

 adaptation of these soils to a great variety of produc- 

 tion when sufficently supplied with water is simply mar- 

 velous. 



Gumbo soils. Gumbo soils are soils that are pos- 

 sessed of enough of the elements of alkali (see p. 73) to 

 make them adhesive, and yet these elements are not 

 sufficiently adhesive to make tillage impracticable, al- 

 though it may be and is usually difficult. These soils 

 may contain much clay. They usually do, but they may 

 also contain some sand. They are so adhesive that when 

 dry it is exceedingly difficult to plow them. They turn 

 up in great chunks which it is impossible to pulverize 

 until they are softened by rain, which acts on them 

 much as it does on unslaked lime. If worked when wet 

 they adhere to the implements of tillage to such an ex- 

 tent as to make tillage virtually impracticable. In order 

 to till them, advantage must be taken of -those periods 

 when moisture is present in that degree which makes til- 

 lage practicable, and when it is not present in that degree 

 which will result in the baking of the land after it has 

 been worked. This narrows very considerably the sea- 

 son of the year during which gumbo lands may be suc- 

 cessfully tilled. The highways in areas where gumbo 

 soils prevail are almost impassible in time of wet 

 weather. Owing to the adhesive character of these soils 

 when wet it is almost impossible to drive a vehicle along 

 the highway because of the accumulation of plastic soil 

 which adheres to the wheels. 



Gumbo soils are not generally present in extensive 

 areas in the dry west. They are more commonly met 

 with in river basins and in depressions on the higher 

 lands, oftentimes they are found in spots of more or less 

 size in areas where the soil is easy of tillage. That they 



