CULTIVATORS FOR DRY-FARMING 315 
season. Potatoes grown on dry-farms should be 
cultivated throughout the season, and as the potato 
industry grows in the dry-farm territory there will be 
a greater demand for suitable cultivators. The cul- 
tivators to be used on dry-farms are all of the riding 
kind. They should be so arranged that the horse 
walking between two rows carries a cultivator that 
straddles several rows of plants and cultivates the soil 
between. Disks, shovels, or spring teeth may be used 
on cultivators. There is a great variety on the mar- 
ket, and each farmer will have to choose such as meet 
most definitely his needs. 
The various forms of harrows and cultivators are of 
the greatest importance in the development of dry- 
farming. Unless a proper mulch can be kept over the 
soil during the fallow season, and as far as possible 
during the growing season, first-class crops cannot be 
fully expected. 
The roller is occasionally used in dry-farming, es- 
pecially in the uplands of the Columbia Basin. It is 
a somewhat dangerous implement to use where water 
conservation is important, since the packing resulting 
from the roller tends to draw water upward from the 
lower soil layers to be evaporated into the air. Wher- 
ever the roller is used, therefore, it should be followed 
immediately by a harrow. It is valuable chiefly in 
the localities where the soil is very loose and light and 
needs packing around the seeds to permit perfect 
germination. 
