1917] EUKAL ENGINEERING. 887 



to three weeks. When the soil was not watered before planting the best 

 yields of cotton were obtained with one irrigation before blooming and with 

 three during flowering. 



The apparatus used for distribution of irrigation water at the Karayaz ex- 

 periment station is described, and a large amount of statistical and other data 

 on climate, crop yields, and methods and amounts of irrigation are also 

 included. 



Spray irrigation, M. B. Williams {U. S. Dept. Agr. Bui. 405 (1911), pp. 40, 

 figs. 19).—" The object of this bulletin is to familiarize the farmer with condi- 

 tions under which spray irrigation may be undertaken profitably, suggest 

 possible water supplies, and illustrate typical pumping machinery and dis- 

 tribution systems so as to aid the prospective irrigator in determining whether 

 spray irrigation should have a place in his farm operations. It is also intended 

 to present information necessary in working out an intelligent design and in- 

 stallation of a spray system." 



With reference to economic conditions justifying spray irrigation it is stated 

 that, assuming a cost of $250 per acre on a stationary plant for a small acreage, 

 the farmer should be able to increase his annual returns from each acre some- 

 what more than $51. Adequate markets, labor, and fertilizer facilities are 

 other essentials for successful spray irrigation, as well as good roads and 

 equipment for quick hauling of perishable truck and berry crops. 



With reference to farm conditions adapted to spray irrigation, it is stated 

 that " spray irrigation can be practiced to advantage on both light and heavy 

 soils. By this method it is possible to apply evenly to sandy soils the small 

 quantities of water which such soils will retain, without the loss of water 

 by percolation which might occur with other methods. It is possible also 

 to apply to heavy clay soils the small quantities of water required to soften 

 such soils when they have baked after rains and to apply water no faster 

 than the soil can absorb it, thus preventing loss by surface run-off. Lands 

 to be irrigated should be drained as completely as possible of excess moisture. 

 Many tile-drained fields are the most responsive to crops under spray irriga- 

 tion. Spray irrigation is practically independent of the topography of the 

 field and can be applied to land too rolling or rough for surface methods. It 

 is, therefore, adaptable to the irrigation of sidehills on which soils tend to 

 wash or erode. . . . 



" For spray irrigation sufiicient water to cover the land to a depth of 1 in. 

 per week for humid regions and 1^ in. per week for arid regions is believed 

 to be a safe estimate for designing purposes. A spray plant should be large 

 enough to supply these amounts of water in a reasonable length of time. This 

 is accomplished generally by installing the system to spray from one-fifth to 

 one-half of the total acreage at one time, depending somewhat upon the type 

 of distribution used and the available water supply. . . . 



" Three types of spray irrigation construction have been adopted more or 

 less widely for field irrigation — (1) hose and movable nozzle or movable lines 

 fed from an imderground pipe system and hydrant, (2) circular nozzles fed 

 from an underground pipe system, and (3) overhead spray lines fed from an 

 underground main feed pipe. . . . The hose and portable nozzle system of spray 

 irrigation is the oldest and least efiicient of spray methods. It is impo.ssible 

 to get an even application over the entire field or under one position of the 

 nozzle. The constant attendance necessary and the liability of over or under 

 irrigation makes the cost of operation high and the results dependent upon 

 the skill of the laborer. The greatest field for this type of irrigation seems 

 98133°— No. 9—17 7 



