204 DRY-FARMING 
The precariousness of dry-farming must be done 
away with. The year of drouth must be expected 
every year. Only as certainty of crop yield is as- 
sured will dry-farming rise to a respected place by the 
side of other branches of agriculture. To attain such 
certainty and respect clean summer fallowing every 
second, third, or fourth year, according to the average 
rainfall, is probably indispensable; and future in- 
vestigations, long enough continued, will doubtless 
confirm this prediction. Undoubtedly, a rotation of 
crops, including hoed crops, will find an important 
place in dry-farming, but probably not to the com- 
plete exclusion of the clean summer fallow. 
Jethro Tull, two hundred years ago, discovered 
that thorough tillage of the soil gave crops that in 
some cases could not be produced by the addition of 
manure, and he came to the erroneous conclusion that 
‘tillage is manure.” In recent days we have learned 
the value of tillage in conserving moisture and in 
enabling plants to reach maturity with the least 
amount of water, and we may be tempted to believe 
that ‘‘tillage is moisture.” This, like Tull’s state- 
ment, is a fallacy and must be avoided. Tillage can 
take the place of moisture only to a limited degree. 
Water is the essential consideration in dry-farming, 
else there would be no dry-farming. 
