22 
BULLETIN 1180, U. S. DEPARTMENT OF AGRICULTURE. 
relative merits of the three forms of phosphorus, but merely a meas- 
ure of the returns from the nitrogen applied in mixture with the 
phosphorus carriers. The experiments were conducted at the same 
time and in the same manner as those of Section I, previously dis- 
cussed, and the data are therefore comparable. 
Results with cotton. — The yields of cotton for the two years are 
given in Table 10. The increases produced by ammonium sulphate 
were of about the same order as those produced by the two nitrates 
of Section I. Any variations may be attributed largely to factors 
other than the source of nitrogen. The use of cyanamid in mixture 
with either calcined phosphate or basic slag was entirely satisfactory, 
as is shown by Plate VI, Figures 1 and 2, and Plate V, Figure 2. 
While the yields show considerable difference with these two mix- 
tures, the figures are in reality somewhat misleading. The soil of 
series B was very shallow and located on the side of the hill where 
moisture conditions were often the limiting factor to growth. Series 
C was on lower and richer soil. It is felt that the use of cyanamid 
with either of the two basic phosphates or with acid phosphate 
applied separately is satisfactory and where used under exactly the 
same conditions would give about equally good yields. 
Table 10. — Yields per acre of cotton from Section II of field No. 1 in 1920 and 1921. 
Plat. 
Yields of seed cotton (pounds). 
Fertilizer ratio. 
1920 
1921 
Actual. 
Average. 
Increase 
over 
check. 
Actual. 
Average. 
Increase 
over 
check. 
Series A. — Ammonium sulphate: 
0-0-0 
/ 200 
\ 224 
1,080 
1,344 
1,272 
1,792 
1,440 
2,112 
1,868 
2,368 
/ 172 
\ 2.56 
612 
660 
776 
1,144 
1,008 
1,236 
1,348 
1,792 
/ 225 
\ 178 
1,066 
1,104 
1,449 
1,388 
1,520 
1,6.56 
1,618 
1,744 
| 212 
} 1,212 
\ 1, 532 
} 1,776 
} 2, 118 
X 214 
} 636 
\ 960 
} 1, 122 
} 1, 570 
| 202 
} 1,085 
} h 419 
| 1,588 
J 1,681 
f 84 
\ 136 
/ 596 
\ 724 
/ 952 
I 1,144 
J 1,024 
\ 1,168 
/ 1,208 
I 1,712 
/ 44 
\ 116 
/ 324 
\ 300 
/ 428 
\ 648 
f 596 
\ 920 
J 704 
\ 1,028 
/ 200 
\ 276 
/ 708 
\ 744 
/ 1,064 
\ 996 
/ 1, 188 
I 1, H2 
/ 936 
\ 1,260 
} 110 
} 660 
} 1,048 
} 1,246 
| 1,460 
} 80 
} 312 
} 538 
} 758 
} 866 
j- 238 
| 726 
} 1,030 
| 1,150 
} 1,098 
2-8-4 
320 
564 
906 
388 
4-8-4 
586 
8-8-4 
800 
Series B . — Cyanamid (with calcined 
phosphate in 1920; with basic 
slag in 1921): 
0-0-0 
0-8-4 
{ I 
{ I 
1; 
2-8-4 
324 
486 
934 
226 
4-8-4 
446 
8-8-4 
554 
Series C — Cyanamid (with basic 
slag): 
i! 
2-8-4 
334 
503 
596 
304 
4-8-4 
424 
8-8-4 
372 
