Ordinarily, however, after fall sowing there is no further need of treatment until the following spring. The spring treatment is of considerably more importance, for when the warmth of spring and early summer begins to make itself felt, a crust forms over many kinds of dry-farm soils. This is especially true where the soil is of the distinctively arid kind and poor in organic matter. Such a crust should be broken early in order to give the young plants a chance to develop freely. This may be accomplished, as above stated, by the use of a disk, corrugated roller, or ordinary smoothing harrow.
When the young grain is well under way, it may be found to be too thick. If so, the crop may be thinned by going over the field with a good irontooth harrow with the teeth so set as to tear out a portion of the plants. This treatment may enable the remaining plants to mature with the limited amount of moisture in the soil. Paradoxically, if the crop seems to be too thin in the spring, harrowing may also be of service. In such a case the teeth should be slanted backwards and the harrowing done simply for the purpose of stirring the soil without injury to the plant, to conserve the moisture stored in the soil and to accelerate the formation of nitrates.—The conserved moisture and added fertility will strengthen the growth and diminish the water requirements of the plants, and thus yield a larger crop. The iron-tooth harrow is a very useful implement on the dry-farm when the crops are young. After the plants are up so high that the harrow cannot be used on them no special care need be given them, unless indeed they are cultivated crops like corn or potatoes which, of course, as explained in previous chapters, should receive continual cultivation.
Harvesting
The methods of harvesting crops on dry-farms are practically those for farms in humid districts. The one great exception may be the use of the header on the grain farms of the dry-farm sections. The header has now become well-nigh general in its use. Instead of cutting and binding the grain, as in the old method, the heads are simply cut off and piled in large stacks which later are threshed. The high straw which remains is plowed under in the fall and helps to supply the soil with organic matter. The maintenance of dry-farms for over a generation without the addition of manures has been made possible by the organic matter added to the soil in the decay of the high vigorous straw remaining after the header. In fact, the changes occurring in the soil in connection with the decaying of the header stubble appear to have actually increased the available fertility. Hundreds of Utah dry wheat farms during the last ten or twelve years have increased in fertility, or at least in productive power, due undoubtedly to the introduction of the header system of harvesting. This system of harvesting also makes the practice of fallowing much more effective, for it helps maintain the organic matter which is drawn upon by the fallow seasons. The header should be used wherever practicable. The fear has been expressed that the high header straw plowed under will make the soil so loose as to render proper sowing difficult and also, because of the easy circulation of air in the upper soil layers, cause a large loss of soil-moisture. This fear has been found to be groundless, for wherever the header straw has been plowed under; especially in connection with fallowing, the soil has been benefited.
Rapidity and economy in harvesting are vital factors in dry-farming, and new devices are constantly being offered to expedite the work. Of recent years the combined harvester and thresher has come into general use. It is a large header combined with an ordinary threshing machine. The grain is headed and threshed in one operation and the sacks dropped along the path of the machine. The straw is scattered over the field where it belongs.
All in all, the question of sowing, care of crop, and harvesting may be answered by the methods that have been so well developed in countries of abundant rainfall, except as new methods may be required to offset the deficiency in the rainfall which is the determining condition of dry-farming.
CHAPTER XII
CROPS FOR DRY-FARMING
The work of the dry-farmer is only half done when the soil has been properly prepared, by deep plowing, cultivation, fallowing, for the planting of the crop. The choice of the crop, its proper seeding, and its correct care and harvesting are as important as rational soil treatment in the successful pursuit of dry-farming. It is true that in general the kinds of crops ordinarily cultivated in humid regions are grown also on arid lands, but varieties especially adapted to the prevailing dry-farm conditions must be used if any certainty of harvest is desired. Plants possess a marvelous power of adaptation to environment, and this power becomes stronger as successive generations of plants are grown under the given conditions. Thus, plants which have been grown for long periods of time in countries of abundant rainfall and characteristic humid climate and soil yield well under such conditions, but usually suffer and die or at best yield scantily if planted in hot rainless countries with deep soils. Yet, such plants, if grown year after year under arid conditions, become accustomed to warmth and dryness and in time will yield perhaps nearly as well or it may be better in their new surroundings. The dry-farmer who looks for large harvests must use every care to secure varieties of crops that through generations of breeding have become adapted to the conditions prevailing on his farm. Home-grown seeds, if grown properly, are therefore of the highest value. In fact, in the districts where dry-farming has been practiced longest the best yielding varieties are, with very few exceptions, those that have been grown for many successive years on the same lands. The comparative newness of the attempts to produce profitable crops in the present dry-farming territory and the consequent absence of home-grown seed has rendered it wise to explore other regions of the world, with similar climatic conditions, but long inhabited, for suitable crop varieties. The United States Department of Agriculture has accomplished much good work in this direction. The breeding of new varieties by scientific methods is also important, though really valuable results cannot be expected for many years to come. When results do come from breeding experiments, they will probably be of the greatest value to the dry-farmer. Meanwhile, it must be acknowledged that at the present, our knowledge of dry-farm crops is extremely limited. Every year will probably bring new additions to the list and great improvements of the crops and varieties now recommended. The progressive dry-farmer should therefore keep in close touch with state and government workers concerning the best varieties to use.
Moreover, while the various sections of the dry-farming territory are alike in receiving a small amount of rainfall, they are widely different in other conditions affecting plant growth, such as soils, winds, average temperature, and character and severity of the winters. Until trials have been made in all these varying localities, it is not safe to make unqualified recommendations of any crop or crop variety. At the present we can only say that for dry-farm purposes we must have plants that will produce the maximum quantity of dry matter with the minimum quantity of water; and that their periods of growth must be the shortest possible. However, enough work has been done to establish some general rules for the guidance of the dry-farmer in the selection of crops. Undoubtedly, we have as yet had only a glimpse of the vast crop possibilities of the dry-farming territory in the United States, as well as in other countries.