14 BULLETIN 1435, U. S. DEPARTMENT OF AGRICULTURE 
The important items of cost in the care of a young grove are labor 
and fertilizer. Spray material is a relatively small item for young 
trees. 
In computing these costs no charge is made for the use of land, 
buildings, and machinery. Man labor is charged at 30 cents and 
horse labor at 20 cents an hour. 
It will be seen from Table 9, that the cost of labor and the cost 
of materials increase with the age of the trees. The total labor cost 
ranged from an average of about $16 per acre for the 1-year-old trees 
to $22 per acre for the 5-year-old trees. The fertilizer applications 
ranged from 247 pounds per acre to 921 pounds per acre. 
Table 8 shows the average number of hours of man and horse 
labor per acre in each of the age groups for trees from 1 to 5 years 
old. Plowing and harrowing are the more important tillage opera- 
tions from the standpoint of amount of labor required. The tree 
rows are cultivated throughout the year (fig. 3). Comparatively 
few groves were disked and less than one-third of the total were, 
mowed as will be seen from Table 10. Table 8 further shows that 
there was comparatively little variation in the number of hours of 
labor used for tillage operations as the age of the trees increased. 
The hours of labor for hoeing and pruning gradually increased as 
the trees got older. This is also true for labor in spraying and 
fertilizing. 
Fic. 3.—It is the usual practice with young groves to keep the strip of ground on which the trees 
are set cultivated clean throughout the year. The wide strips between the tree rows are plowed 
once a year. The weeds turned under add much needed humus to the soil 
The total hours of man labor per acre for all the operations average 
31.5 hours for the l-year-old trees to 46.4 hours for the 5-year-old 
trees. Hours of horse labor for the same groups range from 32.7 to 
40.2. 
There is considerable variation in the number of times an operation 
is performed. For example, some groves are sprayed once, others 
are sprayed two or more times. Table 10 shows the number of groves 
on which certain operations were performed and the number of times 
the operation was done. The column headed ‘“‘Plowing”’ shows that 
6 of the 148 farms were not plowed, 47 were plowed once, 12 three 
times, and 7 were plowed more than three times. Disking has not 
become general in citrus groves. Only 22 of the 148 groves were 
disked. The operation of harrowing is rather generally performed. 
Only 8 of the 148 groves were not harrowed. Less than one-third of 
