Potatoes are also generally planted by machinery. Wherever seeding machinery has been constructed based upon the principles of dry-farming, it is a very advantageous adjunct to the dry-farm. Harvesting The immense areas of dry-farms are harvested almost wholly by the most modern machinery. For grain, the harvester is used almost exclusively in the districts where the header cannot be used, but wherever conditions permit, the header is and should be used. It has been explained in previous chapters how valuable the tall header stubble is when plowed under as a means of maintaining the fertility of the soil. Besides, there is an ease in handling the header which is not known with the harvester. There are times when the header leads to some waste as, for instance, when the wheat is very low and heads are missed as the machine passes over the ground. In many sections of the dry-farm territory the climatic conditions are such that the wheat cures perfectly while still standing. In such places the combined harvester and thresher is used. The header cuts off the heads of the grain, which are passed up into the thresher, and bags filled with threshed grain are dropped along the path of the machine, while the straw is scattered over the ground. Wherever such a machine can be used, it has been found to be economical and satisfactory. Of recent years corn stalks have been used to better advantage than in the past, for not far from one half of the feeding value of the corn crop is in the stalks, which up to a few years ago were very largely wasted. Corn harvesters are likewise on the market and are quite generally used. It was manifestly impossible on large places to harvest corn by hand and large corn harvesters have, therefore, been made for this purpose. Steam and other motive power