10 BULLETIN 1180, U. S. DEPARTMENT OF AGRICULTURE. 
available for the young corn and cotton plants, and continued to 
produce good effects until maturity. The material gave every evi- 
dence of being a satisfactory nitrogen carrier from all standpoints. 
UREPHOS. 
The effect of Urephos on wheat and rye, the only crops which re- 
ceived this material, was not markedly different from that with the 
standard materials. In the case of wheat the growth with Urephos 
was very good, while the growth of rye was somewhat poorer. This 
was undoubtedly due to the marked soil variations. No toxic or 
retarding effects were observed at any time. 
EXPERIMENTAL RESULTS. 
The experimental work of the first year was of a rather miscella- 
neous nature and in general differed considerably from the later work. 
It will therefore be discussed separately. 
EXPERIMENTS OF 1919. 
Two series of fertilizer tests were started in 1919, one with summer 
crops and the other with winter crops. The former included experi- 
ments with cyanamid and ammonium nitrate on corn, cotton, and 
miscellaneous crops on field No. 1. The latter experiments were 
with the same fertilizers on wheat, rye, oats, and grass. A new ferti- 
lizer known as Urephos was also used to a limited extent on wheat 
and rye. These winter crops were grown on field No. 2. 
Field No. 1. 
Three sets of experiments were carried out on this area during the 
first season, using cyanamid and ammonium nitrate in comparison 
with sodium nitrate. They were as follows : (1) Availability experi- 
ments with cotton and corn, (2) time-of-application studies with 
cotton and corn, and (3) availability tests on various types of crops. 
The work was started late in the season and was delayed by wet 
weather. The yields were accordingly diminished, and furthermore 
in some cases frosts came before maturity was reached. 
AMMONIUM NITRATE, SODIUM NITRATE, AND CYANAMID ON COTTON AND CORN. — SEC- 
TION I. 
This experiment was planned to determine the relative values of 
ammonium nitrate and cyanamid at different rates of application as 
compared with sodium nitrate, using the materials in the row at the 
time of seeding, as is commonly done. The yields are given in Table 3. 
It will be observed that ammonium nitrate gave as large increases 
of cotton and corn as did sodium nitrate, any differences being within 
the range of possible experimental error. Thus, the yields agreed 
with the observations previously mentioned. 
The results with cyanamid were poorer than with either of the other 
two fertilizers. This was due almost entirely to the fact that the 
cyanamid was mixed with acid phosphate and allowed to stand for a 
few days before use. Laboratory studies later showed that under 
such conditions a considerable portion of the cyanamid may be 
