28 BULLETIN 815, U. S. DEPARTMENT OF AGRICULTURE. 
Further study of the seasonal variations in production from the 
east and west sections of the investigational plat is afforded by 
Table X, m which the total production at each picking period, 
including the fruits of the Cull grade, is expressed in terms of field 
picking boxes. It is interesting to study this table in the light of 
the data presented in Tables V and IX, showing the picking dates 
and the sizes of the picking rings used for fruit of the Green grade 
throughout the period durmg which these records were obtained. 
Such study will show the reasons for the variations stated in Table X, 
which at first appear to be incorrect. For example, during the 
first three years there is recorded a very heavy increase in yield from 
December to January, notwithstanding that Table V shows that the 
intervals between those pickings were less than 30 days. In 1916-17 
there was a decrease in production at that period, although the inter- 
val between the pickings was 33 days. The explanation is found in 
Tabie IX in the use of a ring of a smaller size for the January picking 
during the first three seasons and the use of a larger sized ring in 
January, 1917. 
TaBLeE X.—Total fruit yields of the lemon trees of the Lisbon variety in the investiga- 
tional performance-record plat for each month during the 4-year period from July, 1913, 
to June, 1917, inclusive. 
[The yields are expressed in terms of the number of field boxes offruit. Records on 14 of thetreesin the 
west section of the plat were begun in July, 1914. Eleven of thesetrees were cfthe Bull strain.] 
. Number of field boxes offruit produced. 
| 
Month. East section of plat, 106 trees. West section of plat, 15 trees. 
| 1913-14 1914-15 | 1915-16 1916-17 1914-15 1915-16 | 1916-17 
———E—————————— eae es | 
hkyes oo ee F 613 43h 184 594 2 63 4 
INUEUS Geena ee 323 123 733 12 oto eceeee 3k S 
September.....-- 11 153 66 11% 62 3 2 
Ociobers—-F ee 46 483 26 27 36 23 14 
INGVem DCE 322 see eo Be 472 22 21 1gk 93 253 
December.......- 60 79 574 53 20 243 294 
JANUARY oe ees ese 200 179 1052 453 48 36 164 
Rebruatrysee 409 2064 113 192 28 274 343 
Marchese sie 204 246 1133 235 39 28 
PATE Ae eee ne Sal sae See ee ee | sae ee Ue! Pan a eae oe > BY Bol es eee eee 
IM ya nee oe ee 186 479 1172 Bi! 7 el Peers ee serene LAS See oe ee 
ae oe eee 70 | 237 i 573 35 103 351 
Total... ..- 1,279 | 1,5043 | 1,108: | 1,10 2538 | 195 | 190 
Heaviest -...---.- | February .-| March....-. April......| March.....| January. . jJ anuary-. J February. 
TOU RES eee eee | September} August....| November| September} July..-....- October... 7 August. 
Similarly, Table X shows a decrease in yield from February to 
March, 1914, with a picking interval of 36 days, and practically no 
change in the production for that period in 1916, with a picking inter- 
val of 30 days, while there was an increase in the crops for that month 
in 1915 and 1917, with picking intervals of 21 and 33 days, respec- 
tively. Table IX shows that a change was made in March, 1914, and 
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