198 DRY-FARMING 
It is undoubtedly true that the thorough tillage 
involved’in dry-farming exposes to the action of the 
elements the organic matter of the soil and thereby 
favors rapid oxidation. Jor that reason the different 
ways in which organic matter may be supplied regu- 
larly to dry-farms are pointed out in Chapter XIV. 
It may also be observed that the header harvesting 
system employed over a large part of the dry-farm 
territory leaves the large header stubble to be plowed 
under, and it is probable that under such methods 
more organic matter is added to the soil during the 
year of cropping than is lost during the year of fallow- 
ing. It may, moreover, be observed that thorough 
tillage of a crop like corn or potatoes tends to cause a 
loss of the organic matter of the soil to a degree nearly 
as large as is the case when a fallow field is well cul- 
tivated. The thorough stirring of the soil under an 
arid or semiarid climate, which is an essential feature 
of dry-farming, will always result in a decrease in 
organic matter. It matters little whether the soil is 
fallow or in crop during the process of cultivation, so 
far as the result is concerned. 
A serious matter connected with fallowing in the 
Great Plains area is the blowing of the loose well- 
tilled soil of the fallow fields, which results from the 
heavy winds that blow so steadily over a large part of 
the western slope of the Mississippi Valley. This is 
largely avoided when crops are grown on the land, 
even when it is well tilled. 
