WHAT IS MEANT BY DRY FARMING 13 



soil and so near the surface as to aid more or less the 

 growing crops. In semi-arid areas the precipitation some 

 seasons may be so increased as to render them sub-humid 

 for the time being. In such seasons production may be 

 secured by the ordinary methods of tillage. In other sea- 

 sons it may be so low as to render them for the time 

 being in a sense arid, b.ut both these extremes are ex- 

 ceptional. But since it cannot be known when they will 

 come, the special methods of handling these soils when 

 preparing them for being cropped should never be 

 omitted. 



Sub-humid areas are those in which crops may or- 

 dinarily be grown every year, but wherein some seasons 

 the precipitation is so light that partial failure follows in 

 the absence of special measures to conserve the moisture 

 in the soil, and that which comes to it. The precipitation 

 in sub-humid climates may run from, say, 18 to 27 inches. 

 In these the precipitation may occasionally fall so 

 low as to make them temporarily semi-arid. In other 

 instances it may be so abundant as to carry them tem- 

 porarily into the humid class. The aridity of these may 

 in some instances be such as to make crop production 

 difficult, and in other instances the humidity may be 

 such as to call for drainage to carry away the excess of 

 water from the soil. In cultivating these soils some of 

 the practises followed in cultivating dry areas will ren- 

 der production more sure than it would otherwise be. 

 Sub-humid areas have special adaptation for profitable 

 production, as the precipitation is usually enough to 

 produce a crop with proper tillage and it is seldom enough 

 to destroy it or even to seriously harm it. Nor is it 

 enough to remove very much fertility through leaching. 



Humid climates are those in which the precipitation 

 is such that production is reasonably sure every year 

 from the ordinary processes of tillage. In these the 

 precipitation is not only heavy, but in sympathy there- 



