40 BULLETIN 462, U. S. DEPARTMENT OF AGRICULTURE. 



raphy of the grove is flat to gently rolling, the highest elevation 

 being not more than 10 or 12 feet above sea level. The surface soil is 

 light and sandy in some parts and a good quality of low hammock in 

 others, the latter type being very light and porous. The soil is shal- 

 low over all the grove, there being a substratum of rock or hardpan 

 under nearly the entire grove. The depth of this substratum varies, 

 averaging about 20 inches beneath the surface. On account of the 

 low character of the ground the trees are grown on ridges to prevent 

 flooding out during periods of excessive rains. 



Notwithstanding the low-tying topography and the frequent need 

 of drainage due to excessive rainfall, there often is a very serious 

 need for irrigation. This is caused mainly by the long periods of 

 drought, but is partly due, also, to the extreme shallowness of the 

 soil, since the moisture absorbed by the trees can not be replenished 

 from below on account of the layer of impervious rock. 



The water supply for the irrigation of this grove is obtained from 

 two 6-inch artesian wells. Each well is about 600 feet in depth, 

 and when allowed to flow freely will supply about 400 gallons per 

 minute, exerting a pressure of 7 pounds per square inch when capped. 

 Several patches of garden vegetables scattered through the grove' 

 are watered by the wells at their natural pressure. "When it is 

 necessary to irrigate the grove this pressure is supplemented by a 

 2-stage horizontal pump having a capacity of TOO gallons per minute 

 and operated by a 50-horsepower gasoline engine. 



The distribution system consists of about 33 miles of iron pipe, 

 varying from 1 inch to 6 inches. A 6-inch main delivers the water 

 to laterals varying in size from 4 inches at the main to 1^ inches at 

 the ends. The laterals, which run parallel to each other, are placed 

 along every fourth row of trees, the tree rows being 25 feet apart. 

 One-inch pipe uprights are connected to the laterals at intervals of 

 100 feet. The hydrants are placed under trees and stand about 2 

 feet above the ground on the 1-inch pipe uprights. 



In connection with this system there are 50 pieces of 1-inch 

 garden hose, each about 50 feet long, and 50 movable sprinklers, 

 each sprinkler being attached to about 6 feet of 1-inch pipe. This 

 pipe is sharpened at one end and has the nozzle at the other, with 

 a hose connection about 1 foot from the bottom. When in use the 

 sharpened end of the pipe is pushed into the ground and the appa- 

 ratus is connected by hose to a convenient hydrant. The pipe thus 

 stands upright, delivering a spray of water through the nozzle, and, 

 in this position, may be left temporarily while other pipes are being 

 set up. 



Fifty of these nozzles are in operation when irrigation is in full 

 force. Each nozzle is placed in the center of the square formed by 

 four trees, the spray watering one side of each tree when in a single 



