











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 
typical 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 newly 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 
== SO 
