CHAPTER III.

THE IRRIGATION PROBLEM IN KANSAS.

Address delivered at annual meeting, American Society of Agricultural Engineers, Lincoln, Neb., June 18, 1924, by GEO. S. KNAPP.

The irrigation problem in Kansas differs strikingly from that in many of the other states where irrigation is a recognized institution. This is largely because of differences in climate and water supply.

Throughout the Western states, where very little can be raised without irrigation, there are millions of acres of good fertile land. This land for the most part is valueless without water, but the supply of water is inadequate to ever irrigate more than a small portion of it. Because of this the value of a tract of land depends largely on the water available, and the water right for an acre of land is usually worth considerably more than the land itself. With this condition, the production per unit of water is frequently more important than the yield per acre.

Sound public policy in the Western states requires that the largest possible production be secured with the water used, and we find that the activities of these states have wisely been directed toward securing greater economy in the use of water in order that more acres of land may be brought under cultivation. Laws enacted by the Western states have been of a regulatory nature, designed to control and supervise the use of water. Agricultural colleges and experiment stations have carried on multitudinous experiments, the purpose of which is to teach greater economy in the use of water and thus secure a higher "duty of water"-a term almost never heard in connection with Kansas irrigation.

In contrast to this, Kansas is to-day exercising little or no regulatory control over the use of water. Laws on the statute books for that purpose are for the most part inoperative, because they do not deal with present-day conditions, and what influence the state is having with regard to irrigation is directed toward encouraging the greater use of water.

Differences in climate and water supply are largely responsible for these conditions. There is no part of the state of Kansas where crops cannot be grown without irrigation. Rainfall varies from about sixteen inches at the western end of the state to more than forty inches in the southeast corner. In the western counties such crops as kafir, milo, wheat and other small grains are grown without irrigation, but do not yield as well without irrigation as where irrigated, and in dry years may be almost a failure. In the central and eastern portions all crops common to the humid states are grown. Frequently the yield is as great as in the humid states. On other years a drought in July and August may seriously damage a crop which had promise of a satisfactory yield, although the rainfall may be but a few inches below normal. In the western portion irrigation will result in increased yields every year, and in the eastern part, where water is available, the application of but a few inches of water at a critical period will often save a crop from serious injury by drought.

Very little surface water is available for irrigation in Kansas. In the Garden City district there are a number of canals taking water from the Arkansas river, but they are using the entire available supply, and new development

must depend almost wholly on ground water. There is hardly a place in western Kansas where a sufficient supply of ground water cannot be found, but the depth to water on the uplands is too great for economical irrigation. For that reason new development is confined to the valley lands of the state, of which there are about five million acres. In the valleys this water is found in beds of waterlaid sand and gravel subsequently covered with alluvial deposits of soil. The depth to water in such valleys varies from eight to twenty feet. This water is recovered by pumping, and the pumping heads range from fifteen to forty feet.

As far as is known, this water supply is adequate for the irrigation of all land under which it is found, and there appears to be no reason to regulate or restrict its use. In some localities there are pumping plants on almost every farm. These plants have capacities ranging in size from two to as much as eight cubic feet per second. Many of them have been in operation more than ten years. During the irrigation season when many of the plants have been in operation almost continuously the water table has been lowered from two to four feet by pumping, but in no year has the water supply been exhausted to the point where the water plane has not recovered its normal elevation long before the next irrigation season. There has in this period been no decrease in the available supply.

In that type of pumping plant in most common use, a horizontal centrifugal pump is set in a pit just above the water plane. The pump is driven either by an electric motor or an internal-combustion engine. In a few instances farm tractors are used. The well system consists of a number of wells, usually placed in a straight line and spaced 40 feet apart. In the construction of the wells, open pits about five feet in diameter are dug down to the water and walled up with cement blocks or concrete. A perforated well casing 16 inches in diameter is then sunk through the entire water-bearing stratum by the use of a sand bucket. Where the water-bearing material is 25 or 30 feet thick and is composed of fairly coarse sand and gravel, about 250 gallons per minute can be expected from each well.

The cost of a pumping plant will of course vary with local conditions of water supply, but as a rule a plant large enough to irrigate 160 acres of land, i. e.. having a capacity of 3 or 4 cubic feet per second, can be put in for $2,000. This would be a construction charge of $12.50 per acre-a cost which is remarkably low when compared with the cost of irrigation enterprises in the West. very few of which can be built for less than $50 to $100 an acre. The cost of pumping will range from $1.50 to $2.25 an acre-foot with electric energy at 4 cents per kilowatt hour. Where more than an acre-foot per acre is used the cost of pumping would probably exceed the annual maintenance and operating charges on a gravity project, but if the difference between the construction cost of the pumping plant and the gravity project were invested at six per cent, the income would more than cover the cost of pumping and the owner of the pumping plant would still obtain cheaper water than the farmer under the gravity project.

The pumping-plant irrigation project is entirely an individual enterprise. It is optional with the farmer whether or not he will install a pumping plant on his farm, and if he does install one he has no one to consult but himself regarding the use of water. The questions he is interested in are, first, Will the increased yields obtained through its use justify him in making the neces

sary investment? and second, If he does install it, what is the proper amount of water to apply?

It is easily seen that where the supply of water is, for practical purposes, unlimited, and where the farmer can obtain water whenever he wants it, but does not need to pay for more than he actually uses, the question resolves itself into, not necessarily what amount of water will produce the maximum yield per unit of water, but what amount of water will make the largest net return when all items affecting the cost of production are taken into consideration.

For a number of years experiments in the use of water have been carried on at the Garden City Experiment Station, a branch of the Kansas State Agricultural College. The results of some of this work are reported in a recent publication.1 In order to make a comparison of the relative profit or loss between dry-land and irrigation farming, and to determine the economy of the use of various amounts of water, four of the crops used in these experiments-milo, kafir, wheat and barley-are considered here. The yields and amounts of water are shown in Table 1.

LAND AND LABOR COSTS.

To arrive at the cost of growing the crop, the investment in unirrigated land is assumed to be $60 an acre, and an annual charge of 8 per cent on that amount, or $4.80 an acre, is made to cover interest and taxes.

A basic charge is made of $2 per day for a man and $1 a day for a horse. This may be above or below the prevailing price in any particular locality, but it undoubtedly will afford a profitable market to the farmer for his labor. The time required for men and teams to cover a given acreage in each of the several farm operations obviously varies with soils and other conditions. The average shown in Table 2 has been determined by the United States Department of Agriculture2 from the actual experience of a large number of men over a wide range of conditions for many years. Table 2 also shows the cost per acre for each operation, based upon what is considered an average day's work. Table 3 shows the average number of field operations involved in the production of the crops reported on in this paper. These operations charged at the price per acre shown in Table 2 comprise the tillage and harvesting charges made in Table 5.

These charges are fixed charges for each acre, and do not vary greatly with the yield per acre, except possibly the charges for twine and shocking, which are so small that they cannot materially affect the relative cost of producing the various crops.

Seed is charged for at the same price per bushel that is given the various crops in Table 4. Milo and kafir were planted at the rate of six pounds per acre, and wheat and barley sown at the rate of three pecks per acre.

Binder wear and repair is calculated at 15 cents per acre, but no allowance is made for wear or depreciation on the other farm machinery.

A charge of 10 cents per bushel is made for threshing all crops. This is believed sufficient to cover the cost of taking the grain from the shock and putting the threshed grain in the bin.

1. Knapp, Geo. S. Relation of Crop Yields to Quantity of Irrigation Water in Southwestern Kansas. Bulletin 228, Kansas Agricultural Experiment Station; 1922.

2. Chilcott, E. C., Cole, J. S., and Burr, W. W. Spring Wheat in the Great Plains Area. Bulletin No. 214, U. S. Department of Agriculture; May 1915.

IRRIGATION COSTS.

In the case of the irrigated land there is added to the dry-land investment of $60 an acre a charge of $2,500 for the irrigation pumping plant. Assuming that this plant will serve 160 acres of land, the additional investment for the irrigation plant is $15.63 per acre. Interest and taxes on this additional investment at 8 per cent makes an annual charge of $1.25 per acre. The annual depreciation is assumed to be 5 per cent. This amounts to a total of $125 per year and constitutes an annual charge of $0.78 per acre on the irrigated farm.

The charge for interest, taxes and depreciation on the pumping plant, amounting to $2.03 per acre, is considered an annual charge on each acre of land included in the irrigation project, irrespective of the amount of water applied. These items are affected but little by the amount of time the

TABLE 2. Average cost per acre of farm operations involved in production of crops.