HUMID AND DRY-FARM SOILS 



63 



10 



i CLAY or'; 



'TILL OR 

 t GRAVEL I 



.-:."■. '^t-.-ti . °. ';'•■■• 

 ?.•^^■•:'=^„'^^ 



m 







ARID 

 SOIL 







ARID SOIL 

 FAULTY 



MASS iS 



Fig. 18. Difference in structure between humid and arid soU. The third 

 section, though arid, is questionable for dry-farming. The gravel 

 streaks break the continuity of the soil mass. (Adapted from Hil- 

 gard.) 



