18 
BULLETIN 188, U. S. DEPARTMENT OF AGRICULTURE. 
was the same as in the other experiments, so that the average distance 
between the plants before thinning was slightly over 2 inches. Owing 
to the smallness of the area the yields were not measured, and as 
there were only two rows in each plat in the center of the field it is 
probable that the behavior of the plants in this test was influenced 
to some extent by adjoining rows. Table IX gives the total number 
of plants considered and the average number of mature heads and 
branches per plant. 
Table IX. — Heads and branches ofmilo plants, showing the effect of thinning at various 
dates at the San Antonio Experiment Farm in 1914. 
Number of 
plants. 
Number per plant. 
Date thinned. 
Mature 
heads. 
Branches. 
Mav 12 
58 
1.2R 
0.43 
May 2.5 
84 ! ■ . 1.19 
73 1 1.13 
70 
.23 
1.00 
1.30 
While the difference between the first and last thinning is not 
great, there is a fairly consistent variation. There is a gradual 
decrease in the number of mature heads from the first to the last 
thinning date, but the reverse is the case with the number of branches, 
as they increase as the date of thinning is delayed. This is to be 
expected, for, as has been shown in previous tables, the 12-inch 
spacing between plants is so wide that they will send out either 
tillers or branches to offset it. Where thinning is delayed long 
enough to allow the plants to become of sufficient size to largely pre- 
vent tillering, as was the case with the June thinnings, branches will 
be produced if the conditions during the later part of the season are 
sufficiently favorable. 
While, as already intimated, too much importance should not be 
given to the data in this table, the results are in accord with the pre- 
vious experience of the writer and indicate that the time of thinning 
is not of great importance if it is done early enough to avoid injury to 
the adjoining plants. If the thinning is done when the plants are 
very small, there may be produced a considerable number of tillers, 
a very small percentage of which will not develop, owing to crowding 
later in the season. This is shown where counts were made early in 
the season and at ripening time (Table V, p. 10). In the field plant- 
ings on the experiment farm during the last two years it was found 
to be unnecessary to do much thinning. In 1913 the time consumed 
in thinning the field plantings was not greater than was necessary 
to thin corn, where the plants were thinned to 2 feet apart in the 
row. No thinning was necessary in 1914. In both years the rows 
were 4 feet apart and about 5 pounds of seed to the acre were planted. 
