ATMOSPHERIC-XITROGEN FERTILIZERS. 
19 
AMMONIUM NITRATE, SODIUM NITRATE, AND CYANAMID. — SECTION I. 
Results with cotton. — This set of experiments was practically a 
duplication of the work of 1919 except that where cyanamid and 
acid phosphate were used the materials were applied separately. 
The yields for the two years, given in Table 8, show a slight dif- 
ference in favor of sodium nitrate over ammonium nitrate. How- 
ever, it is felt that the soil variations were great enough to account 
for most, if not all, of the differences. Both the sodium-nitrate and 
cyanamid series were more favorably located in this respect than the 
SECT/ON 1. 
S£CT/OMtt 
Fig. 1.— Diagram of field No. 1 located at Muscle Shoals, Ala., showing plat arrangements and treatments 
for the season of 1921. The soil type is Clarksville loam. Three rows per plat without buffer row. Size 
of plats, one-fortieth of an acre. The index figures refer to the number ofpounds of NH3, P 2 5 , and K 2 
used per acre. Ac. P.= Acid phosphate; B. Slag = duplex basic slag; K= potassium sulphate; Am. S. 
= ammonium sulphate; S. N. = sodium nitrate; Am. X. = ammonium nitrate; Ca. N. = calcium nitrate; 
M. S. (CI.) = mixed salt made from potassium chlorid and ammonium nitrate; M. S. (SO*) = mixed salt 
made from potassium sulphate and ammonium nitrate. 
ammonium-nitrate series. Plate III, Figure 2, illustrates the relative 
cotton yields with the different rates of application of ammonium 
nitrate. 
Cyanamid was not as satisfactory a fertilizer as the other two 
materials, but the results were mucK better than those obtained the 
first year on the same plats using cyanamid in mixture with acid 
phosphate. At the smaller rates of application the differences for 
the two years were less noticeable, but at the equivalent of 80 pounds 
of ammonia per acre the material failed to give quite as good results 
as sodium nitrate. The difference was not great, however, as shown 
by Plate IV, Figure 1. The retarding effect of heavy applications 
at the beginning of the season was a handicap from which the plants 
were never able to recover completely. 
