One of the great difficulties in dry-farming concerns itself with the prevention of the growth of weeds or volunteer crops.  As has been explained in previous chapters, weeds require as much water for their growth as wheat or other useful crops.  During the fallow season, the farmer is likely to be overtaken by the weeds and lose much of the value of the fallow by losing soil-moisture through the growth of weeds.  Under the most favorable conditions weeds are difficult to handle.  The disk harrow itself is not effective.  The smoothing harrow is of less value.  There is at the present time great need for some implement that will effectively destroy young weeds and prevent their further growth.  Attempts are being made to invent such implements, but up to the present without great success.  Hogenson reports the finding of an implement on a western dry-farm constructed by the farmer himself which for a number of years has shown itself of high efficiency in keeping the dry-farm free from weeds.  Several improved modifications of this implement have been made and tried out on the famous dry-farm district at Nephi, Utah, and with the greatest success.  Hunter reports a similar implement in common use on the dry-farms of the Columbia Basin.  Spring tooth harrows are also used in a small way on the dry-farms.

They have no special advantage over the smoothing harrow or the disk harrow, except in places where the attempt is made to cultivate the soil between the rows of wheat.  The curved knife tooth harrow is scareely ever used on dry-farms.  It has some value as a pulverizer, but does not seem to have any real advantage over the ordinary disk harrow.

Cultivators for stirring the land on which crops are growing are not used extensively on dry-farms.  Usually the spring tooth harrow is employed for this work.  In dry-farm sections, where corn is grown, the cultivator is frequently used throughout the 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 cultivators 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 market, 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 respected.

The roller is occasionally used in dry-farming, especially 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.  Wherever 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.