Experimental Error in Crop Tests 
79 
as they started, so as to prevent variability in the number of 
stalks per pot. Thus uniform conditions were provided thru- 
out all pots except the one or two variable factors under obser- 
vation. The pots were located in trenches within a cornfield, 
with their tops level with the field. They were filled with 
fertile surface soil from the Experiment Station Farm. The 
manure which was used in half of the pots during 1914 and 
1915, as designated, was well-rotted sheep manure, and was 
thoroly mixed with the upper ten inches of soil. 
Table 38 — Suinmary of data showing the effect of the size of 
pot upon grcwlh of corn. Rogue's Yellow Dent corn 
(19U) 
Size of 
pot 
Moisture-free 
contents 
No. of 
pots 
averaged 
Dry matter 
Total 
leaf- 
area 
per plant 
Height 
of plant 
Soil 
Manure 
Ear 
Total 
Inches 
Pounds 
Pounds 
Grams 
Grams 
Sq. in. 
Inches 
12x12 .... 
32.5 
4 
10 
98 
705 
76 
12x12 
32.5 
1.75 
4 
82 
269 
1167 
102 
12x24 
85 
4 
63 
206 
1165 
100 
12x24 
85 
1.75 
4 
186 
402 
1353 
106 
16x24. . . . 
150 
4 
108 
316 
1343 
110 
16x24 ... 
150 
1.75 
4 
270 
535 
1369 
112 
16x36 ... 
239 
3 
242 
442 
1193 
116 
16x36 . . 
239 
1.75 
8 
287 
558 
1322 
114 
21x36. . . . 
583 
4 
299 
628 
1308 
112 
21x36. . . 
583 
1.75 
4 
341 
708 
1405 
114 
30x36 . . 
956 
3 
405 
728 
1269 
108 
30x36 ... 
956 
1.75 
4 
416 
781 
1287 
114 
Table 39 — Shoiving in per cent the effect of increasing the 
size of pot. The results in the different sizes without 
moMure are here expressed in per cent of the results in 
the smallest size without manure. Rogue's Yelloiv Dent 
corn (191J^)'^ 
Wt. of soil Dry matter Total 
Size of pot (moisture- leaf-area 
free) Ear Total per plant 
Inches Pounds Per cent Per cent Per cent Per cent 
12x12 32.5 100.0 100.0 100.0 100.0 
12x24 85.0 632.5 211.0 165.2 131.3 
16x24 150.0 1082.3 324.1 190.6 144.7 
16x36 239.0 2417.0 453.6 169.3 153.0 
21x36 583.0 2990.0 643.8 185.6 147.4 
30x36 956.0 4046.7 747.0 180.0 142.1 
*Data calculated from Table .38. 
