IRRIGATION IN FLORIDA. 59 
size and capacity of the pumping unit. The crop to be raised also 
must be taken into account, as must the methods which will be em- 
ployed in distributing water. If the water supply is adequate and 
a 100-acre grove is to be irrigated it is evident that the plant should 
be of such capacity as to irrigate the whole grove within a reasonable 
time in order to obtain maximum service from the plant. This is 
true R also for the 10-acre grove or the 1-acre truck patch. For the 
irrigation of a grove the surface methods probably would prove 
most satisfactory, and an irrigation equivalent to not less than 
two inches of rain should be figured on. A truck patch should have 
about the same amount for furrow irrigation, and about one-half 
of this if spray methods are employed. Another important factor 
to be considered in determining the necessary capacity of the plant 
is the time the farmer desires to consume in watering the grove. If 
he is willing to irrigate 24 hours a day he can get along on half the 
amount of water needed per minute in a day half as long. But night 
irrigation by surface methods seems to be unpopular in Florida and 
it will be best to figure on a 12-hour irrigation day. The personal 
element also enters into the number of days of irrigation required 
to cover the grove, but it is doubtful if a plant can be considered 
efficient if it will not furnish enough water to cover the grove in 
10 days. This period is a good standard for use in Florida. 
If 2 inches of water is to be applied to a 100-acre grove in 10 days 
of 12 hours each, the problem of figuring the gallons per minute is a 
simple arithmetical one; and this is equally true whether the grove 
contains 52 acres or 7 acres. There are 27,154 gallons in an acre- 
inch. Considering loss in transmitting and other losses while irri- 
gating, it is better and easier to say that it requires 30,000 gallons of 
water to cover 1 acre 1 inch deep, or 60,000 gallons 2 inches deep. 
In the 100-acre grove it is necessary to apply 200 acre-inches, or 
6,000,000 gallons of water. If this is done in 10 days, or 120 hours, 
or 7,200 minutes, a pump having a discharge of VqAa — , or 833 gal- 
lons per minute, will meet requirements. For any other acreage, 
gallons divided by minutes will give the capacity of the pump per 
minute. 
Two acre-inches of water would answer for the furrow-irrigated 
patch if diversified truck crops which did not all need water at the 
same time were grown, but as the truck crops require a more rapid 
irrigation than the grove, owing to earlier injury from drought, it 
is well to double this estimate where such crops are to be watered. 
Irrigation by spray methods brings in other problems which can be 
solved readily, although they are of a different nature from those 
just discussed. For the spray plant it is advisable to figure on a 
