Dry-Farming : A System of Agriculture for Countries under a Low Rainfall

by John Andreas Widtsoe

The scarcity of water

For the development of a well-rounded commonwealth in an arid region it is, of course, indispensable that irrigation be practiced, for dry-farming of itself will find it difficult to build up populous cities and to supply the great variety of crops demanded by the modern family. In fact, one of the great problems before those engaged in the development of dry-farming at present is the development of homesteads in the dry-farms. A homestead is possible only where there is a sufficient amount of free water available for household and stock purposes. In the portion of the dry-farm territory where the rainfall approximates twenty inches, this problem is not so very difficult, since ground water may be reached easily. In the drier portions, however, where the rainfall is between ten and fifteen inches, the problem is much more important. The conditions that bring the district under the dry-farm designation imply a scarcity of water. On few dry-farms is water available for the needs of the household and the barns. In the Rocky Mountain states numerous dry-farms have been developed from seven to fifteen miles from the nearest source of water, and the main expense of developing these farms has been the hauling of water to the farms to supply the needs of the men and beasts at work on them. Naturally, it is impossible to establish homesteads on the dry-farms unless at least a small supply of water is available; and dry-farming will never he what it might be unless happy homes can be established upon the farms in the arid regions that grow crops without irrigation. To make a dry-farm homestead possible enough water must be available, first of all, to supply the culinary needs of the household. This of itself is not large and, as will be shown hereafter, may in most cases be obtained. However, in order that the family may possess proper comforts, there should be around the homestead trees, and shrubs, and grasses, and the family garden. To secure these things a certain amount of irrigation water is required. It may be added that dry-farms on which such homesteads are found as a result of the existence of a small supply of irrigation water are much more valuable, in case of sale, than equally good farms without the possibility of maintaining homesteads. Moreover, the distinct value of irrigation in producing a large acre yield makes it desirable for the farmer to use all the water at his disposal for irrigation purposes. No available water should be allowed to flow away unused.

Available surface water

The sources of water for dry-farms fall readily into classes: surface waters and subterranean waters. The surface waters, wherever they may be obtained, are generally the most profitable. The simplest method of obtaining water in an irrigated region is from some irrigation canal. In certain districts of the intermountain region where the dry farms lie above the irrigation canals and the irrigated lands below, it is comparatively easy for the farmers to secure a small but sufficient amount of water from the canal by the use of some pumping device that will force the water through the pipes to the homestead. The dry-farm area that may be so supplied by irrigation canals is, however, very limited and is not to be considered seriously in connection with the problem.

A much more important method, especially in the mountainous districts, is the utilization of the springs that occur in great numbers over the whole dry-farm territory. Sometimes these springs are very small indeed, and often, after development by tunneling into the side of the hill, yield only a trifling flow. Yet, when this water is piped to the homestead and allowed to accumulate in small reservoirs or cisterns, it may be amply sufficient for the needs of the family and the live stock, besides having a surplus for the maintenance of the lawn, the shade trees, and the family garden. Many dry-farmers in the intermountain country have piped water seven or eight miles from small springs that were considered practically worthless and thereby have formed the foundations for small village communities.

Of perhaps equal importance with the utilization of the naturally occurring springs is the proper conservation of the flood waters. As has been stated before, arid conditions allow a very large loss of the natural precipitation as run-off. The numerous gullies that characterize so many parts of the dry-farm territory are evidences of the number and vigor of the flood waters. The construction of small reservoirs in proper places for the purpose of catching the flood waters will usually enable the farmer to supply himself with all the water needed for the homestead. Such reservoirs may already be found in great numbers scattered over the whole western America. As dry-farming increases their numbers will also increase.

When neither canals, nor springs, nor flood waters are available for the supply of water, it is yet possible to obtain a limited supply by so arranging the roof gutters on the farm buildings that all the water that falls on the roofs is conducted through the spouts into carefully protected cisterns or reservoirs. A house thirty by thirty feet, the roof of which is so constructed that all that water that falls upon it is carried into a cistern will yield annually under a a rainfall of fifteen inches a maximum amount of water equivalent to about 8800 gallons. Allowing for the unavoidable waste due to evaporation, this will yield enough to supply a household and some live stock with the necessary water. In extreme cases this has been found to be a very satisfactory practice, though it is the one to be resorted to only in case no other method is available.

It is indispensable that some reservoir be provided to hold the surface water that may be obtained until the time it may be needed. The water coming constantly from a spring in summer should be applied to crops only at certain definite seasons of the year. The flood waters usually come at a time when plant growth is not active and irrigation is not needed.

The rainfall also in many districts comes most largely at seasons of no or little plant growth. Reservoirs must, therefore, be provided for the storing of the water until the periods when it is demanded by crops. Cement-lined cisterns are quite common, and in many places cement reservoirs have been found profitable. In other places the occurrence of impervious clay has made possible the establishment and construction of cheap reservoirs. The skillful and permanent construction of reservoirs is a very important subject. Reservoir building should be undertaken only after a careful study of the prevailing conditions and under the advice of the state or government officials having such work in charge. In general, the first cost of small reservoirs is usually somewhat high, but in view of their permanent service and the value of the water to the dry-farm they pay a very handsome interest on the investment. It is always a mistake for the dry-farmer to postpone the construction of a reservoir for the storing of the small quantities of water that he may possess, in order to save a little money. Perhaps the greatest objection to the use of the reservoirs is not their relatively high cost, but the fact that since they are usually small and the water shallow, too large a proportion of the water, even under favorable conditions, is lost by evaporation. It is ordinarily assumed that one half of the water stored in small reservoirs throughout the year is lost by direct evaporation.

Available subterranean water