SPRAY IRRIGATION. 3 



from one main crop and a possible intercrop. On the other hand, the 

 irrigator of truck who follows intensive culture has a chance of 

 dividing the annual increase among three to six crops. The high cost 

 of spray irrigation eliminates its use on many crops which respond 

 readily to irrigation. It is possible, however, to use cheaper methods 

 of distribution on many of these crops which are grown on land hav- 

 ing an even surface. A combination of spray irrigation and surface 

 methods on the same farm often can be placed under one pumping 

 plant, as illustrated in figure 1, thereby utilizing to the fullest extent 

 the water supply, pumping equipment, and main pipe lines. The 

 tjrpical farm illustrated in figure 1 indicates the use of spray irriga- 

 tion on the more uneven parts where the topography is not adapted 

 to cheaper methods but where the soil and southern slope are desir- 

 able for the growing of early and intensive truck and berry crops 

 that will justify spray irrigation. The main feed pipe is extended to 

 the upper and more even parts of the farm, where cheaper methods 

 of irrigation can be applied to alfalfa, orchard, bush berries, pota- 

 toes, and other crops grown in wide rows for horse cultivation. 



Truckers in the arid sections seem to favor a combination of spray 

 irrigation and surface irrigation on the same field. The spray is 

 used in the preparation of the seed beds, germinating seeds, and start- 

 ing newty set plants. Later the crops are irrigated during the matur- 

 ing and fruiting periods by the surface furrow or check methods. A 

 portable spray equipment often meets these conditions most economi- 

 cally, because it can also be used for the irrigation of hot-bed and 

 cold-frame crops. 



Adequate markets, labor, and fertilizer facilities are other essen- 

 tials for successful spray irrigation. Good roads and equipment for 

 quick hauling of perishable truck and berry crops to a railway or 

 other express service station must be assured unless some valuable 

 annual crop, such as tobacco or onions, which can be cured on the 

 farm, is being grown for deliberate marketing. The express service 

 for irrigated trucking purposes must be able to deliver the products 

 promptly and in a fresh, unwilted state to markets which require a 

 continuous supply of high-grade vegetables. Many of the most suc- 

 cessful users of spray irrigation are operating on small areas for the 

 raising of only such crops as can be consumed by the local trade of 

 a small town or community, thus simplifying the transportation ques- 

 tion greatly. 



Intensive truck or berry growing under irrigation requires a large 

 amount of more or less experienced labor. The irrigator should man- 

 age his farm in a way which will enable him to hire men for long 

 periods and reduce the necessity for employing many laborers for 

 short periods. The moisture-supply control given by spray irrigation 



