INFLUENCE OF SPACING ON PRODUCTIVITY OF CORN. O 
sippi'and Texas the varieties were planted in drills; in those at the 
Arlington Experiment Farm the plantings were in hills. 
The corn was planted more thickly than required, and when the 
plants were 6 to 8 inches tall they were thinned to the spacing desired. 
The spacings were controlled in the drill plantings by varying the 
distance between individual plants in the row. whereas in the hill 
plantings the hills were uniformly spaced and the stand was controlled 
by thinning to the desired number of plants per hill. 
The experimental plats at Clarksdale were on fertile "delta" land 
of uniform appearance that had been cropped to cotton in the 
preceding years. The rows were 3.S9 feet apart and 211 feet Ions: 
in 1917. and 3.49 feet apart and 104 feet long in 1918. At Waco the 
plat was on uniform sandy soil, characteristic of the Brazos River 
valley, cropped the previous year to cotton. The plants were grown 
in rows 3.15 feet apart and 100 feet long. At San Antonio the plats 
were on black upland of uniform appearance during the entire three 
years of the experiment. The corn occupied land on which cotton 
had been grown the preceding year. The plants were grown in rows 
4.1 feet apart and 132 feet long in each of the three experiments. 
At the Arlington Experiment Farm in 1917 and 1918 the plats 
were on upland of uniform appearance. The plat used in 1917 had 
been in sod the previous year, and the plat used in 1918 had been 
cropped to soy beans the preceding year. The plats used in 1919 
and 1920 were on uniform reclaimed river land on which corn had 
been grown in the preceding years. The plants were grown in hills 
3.3 feet apart in each direction. 
DESCRIPTION OF THE VARIETIES. 
The single-ear type was represented by four varieties and the 
prolific type by three varieties. These varieties are listed and 
described as follows : 
SINGLE-EAR VARIETIES. 
U. S. Selection 120. white dent, ears 7$ to 9h inches long, kernels broad, indentation 
smooth to slightly rough. 12 to 14 rows. 60 to 65 days from germination to flowering. 
Singleton, strawberry dent, ears S to 10 inches long, kernels longer than broad, 
indentation slightly rough. 16 to 20 rows, 65 to 70 days from germination to flowering. 
Wilson, yellow dent, ears S^ to 11 inches long, kernels longer than broad, indentation 
smooth to roueh, 18 to 22 rows. 55 to 65 days from germination to flowering. 
Delaware White-Cap, white-capped yellow dent, ears 8 to 10 inches long, kernels 
longer than broad, indentation slightly rough, IS to 24 rows, 60 to 70 days from ger- 
mination to flowering. 
PROLIFIC VARIETIES. 
Cocke Prolific, white dent, ears slender, 7 to Sh inches long, indentation smooth. L0 
to 14 rows, 65 to 75 days from germination to flowering. 
Arlington Prolific, white dent, ears slender. ~h to S inches long, indentation smooth, 
12 to 16 rows, 65 to 70 days from germination to flowering. 
Biggs Seven-Ear, white dent, ears slender. 7 to 8^ inches long, indentation smooth, 
10 to 14 rows, 60 to 70 days from germination to flowering. 
RESULTS OF THE EXPERIMENTS. 
Data from the experiments conducted at Clarksdale. Miss., in 
1917 and 1918 are shown in Table 1. The prolific outyielded the 
single-ear type at every spacing. Using the results obtained at the 
closest spacing in each experiment as bases for calculating the rela- 
tive gains made as the spacing increased, there is a total of seven 
comparisons between the two varieties. In these, the single-ear type 
35697—23 2 
