24 
BULLETIX 821, U. S. DEPAETMEXT OF AGRICULTURE.. 
district at SI 90. 04 per acre. The initial expense of tlie heating 
equipment and the cost of maintenance would be much greater at 
the present time (1920) than in 1913. However, the minimum 
temperatures experienced in California lemon sections during the 
last few years show that there is an ever-present danger of frost injury 
to lemon orchards unless they are safeguarded by an efficient system 
of heating. From the data presented in this bulletin and from 
cooperative information secured from lemon growers in different 
sections, it would appear that the installation of an orchard-heating 
equipment would be just^ified not in the saving of one season's crop 
but because of the frequency with which seasons of low tempera- 
tures occur. 
Table XIX. — Initial investment for heating equipment and expense per acre for the 
season of 1912-13 on a ranch of 186 acres at Corona. Calif., on ichich some of the inves- 
tigational heated plats were located. 
Itemization. 
Per 
acre. 
By items. 
Total. 
Initial iavestment: 
Heaters 
S50 17 "1 
Oil tank 
7.07 1 
Pipe for oil distribution system 
17. 49 
\ S83. 12 
Miscellaneous equipment 'and supplie^^ 
7.50 
3.89 
5.17 
12.54 ! 
2.16 ' 
5.00 ; 
57.96 i 
21.09 
Cost of maintenance'and operation for the season of 1912-13: 
6 per cent intere=;t on investment 
25 per cent depreciation on heaters 
Handlin?, prtinrinEf, nnti filling hpater"? (P-<5timatwl) 
103. 92 
Oil consumed T ^. 
Labor in lighting and refilling heaters . 
Grand total (if charged to any one year) 
190. 04 
Table XX. — Total estimated production hy grades from plat 6, an acre of Lishon lemon 
trees, for each picking during the calendar year 1914. 
[The data in this plat Avere computed from the in diyi dual-tree records of ten Lisbon lemon trees. This 
plat was heated during the winter of 1913 and was selected for comparison with plat 8 in an orchard of 
Lisbon lemon trees which was not heated during that period. The data from plat 8 for the calendar 
year I'Jl 1 are shown in Table XXI.) 
Classification. 
Date ofpicMng. 
Jan. 3. 
Feb. 14. 
Mar. 23. 
May 4. 
June 3. 
July 15. 
Number of fruits: 
Green grade 
30,260 
730 
52,120 
7,210 
32, 5S0 
2,210 
22,3S0 
5,090 
8,640 
2,360 
5.930 
Tree-Ripe grade 
1.790 
Total merchantable fruit 
30,990 
59,330 
34,790 
27,470 
11,000 
7,720 
Cull grade 
320 
1, 270 
1,660 
1,290 
340 
960 
Total 
31,310 
60,600 
36, 450 
28,760 
11,340 
8.680 
Weight of fruits: 
Green grade. 
Lbs. 02. 
7,782 8 
174 6 
Lbs. 02. 
14, 098 2 
1,841 14 
Lbs. 02. 
8,999 6 
536 14 
Lbs. 02. 
5,993 12 
1,206 4 
Lbs. 02. 
2,220 
545 
Lbs. 02. 
1,440 
Tree-Ripe erade 
379 6 
Total merchantable fruit 
7,956 14 
15, 940 
9,536 4 
7,200 
2,765 
1,819 6 
Cull grade. . .. 
48 12 
201 4 
267 8 
205 10 
62 8 
158 12 
Total. 
8,005 10 
16,141 4 
9,803 12 
7,405 10 
2,827 8 
1,978 2 
