EFFECT OF AMMONIUM SULPHATE UPON PLANTS IN 
NUTRIENT SOLUTIONS SUPPLIED WITH FERRIC 
PHOSPHATE AND FERROUS SULPHATE AS SOURCES 
OF IRON 
By Linus H. Jones and John W. Shive 
New Jersey Agricultural Experiment Station 
INTRODUCTION 
The experimental work reported in this paper grew out of a study 
of ammonium sulphate [(NH 4 ) 2 S 0 4 ] as a possible source of nitrogen for 
wheat and soybean plants in nutrient solutions. The status of the 
problem regarding the direct utilization of ammonium salts by agricul¬ 
tural plants is still in a very unsatisfactory condition. While experi¬ 
mental evidence favors the idea that ammonium salts are good sources 
of nitrogen for the higher plants, it also indicates that plants differ in 
their ability to utilize ammonium salts. Some plants appear to require 
the ammonium ion as well as the nitrate ion for growth at certain stages 
of their development. In some recent work Espino (5) 1 has shown that 
the rice plant during the early stages requires the ammonium ion for 
normal growth. From a review of the more important contributions 
to the literature on the mineral requirements of the rice plant, this 
author summarizes by saying: 
There is good reason to suppose that: (i) This plant requires the same chemical 
elements as do other higher plants. (2) The young plants are not suited to deriving 
their nitrogen from nitrates but thrive very well when ammonium sulphate (or possibly 
other ammonium salts, such as cholride, nitrate, etc.) is supplied. (3) Older plants 
are able to derive their nitrogen supply from nitrates, but may be able to thrive with¬ 
out the nitrate ion when the ammonium ion is supplied at a proper rate. 
He calls attention to the fact, however, that— 
none of these points is at all well established in a quantative way. 
The more recent work of Trelease and Paulino (19) and that of Trelease 
(20) is of interest in this connection. The results of their studies of the 
rice plant in soil cultures indicate that ammonium nitrogen is much more 
effective than nitrate nitrogen in increasing the yields of this plant. The 
yields obtained per unit of molecular nitrogen were highest when the 
nitrogen was applied to the cultures in the form of ammonium sulphate; 
they were lower when supplied as ammonium nitrate, and still lower 
when supplied in the form of calcium nitrate [Ca(N 0 3 ) 2 ] or sodium nitrate 
(NaNOg). 
A review of the literature on the general subject of the utilization of 
ammonium as a source of nitrogen for the higher plants can not here be 
1 Reference is made by number (italic) to “ literature cited,” p. 727-728. 
Vol. XXI, No. 10 
Aug. 15, 1 g21 
Key No. N. J-8 
Journal of Agricultural Research, 
Washington, D. C. 
zn 
(701) 
