RELATION OF THE MOLECULAR PROPORTIONS IN THE 
NUTRIENT SOLUTION TO THE GROWTH OF WHEAT 1 
By M. C. Sewell 
Associate Professor of Soils, Department of Agronomy, Kansas Agricultural 
Experiment Station 
INTRODUCTION 
The investigation herein reported was made to determine the comparative 
effects of three salts in varying proportions upon the growth of wheat in sepa¬ 
rate stages, namely, the seedling phase, the vegetative phase, and the fruiting 
phase. The salts used were potassium di-hydrogen phosphate, calcium nitrate, 
and magnesium sulphate. The problem was attempted with the expectation 
that possibly the data obtained would give some knowledge on which to base 
fertilizer practice pertaining to the wheat crop. 
The results seem to show an interesting relation between the nitrogen and 
phosphorus potassium salts in the growth response. With a high molecular 
proportion of nitrogen, a maximum grain yield was obtained with a low molec¬ 
ular proportion of the phosphorus potassium salt. With a low molecular pro¬ 
portion of nitrogen, equally high grain yields were obtained only with a high 
proportion of the phosphorus potassium salt. 
EXPERIMENTAL DATA 
Wheat, first germinated in a nutrient solution, was grown in quartz sand, five 
plants to a culture. The containers were cylindrical half-gallon jars, glazed 
within and without, and holding 2,500 gm. of dry sand. After the seedlings were 
planted the jars were sealed with a wax preparation, and a paraffined paper cone 
was inserted as a supply orifice for adding water and the nutrient solutions. 
Surplus solution was removed by suction through a glass tube, plugged with 
glass wool at the lower end, which extended to the bottom of the jars. Measure¬ 
ments were made of transpiration losses, old solution removed, and new added 
every three and one-half days. During the fruiting phase distilled water was 
added daily between the three and one-half day periods. 
The salts were used in 21 partial volume molecular* proportions, all having a 
calculated osmotic value of approximately 1 atmosphere at 25° C. but differing 
(by increments of 1.8) in salt proportion. 
The seedling phase consisted of a period of five weeks, the vegetative phase a 
period from the end of the seedling phase until the first appearance of flowering, 
and the reproductive phase extended from the vegetative phase until the 
maturity of the five best cultures of the group. 
1 Accepted for publication Dec. 15, 1923. Department contribution No. 150. The investigation re¬ 
ported in this paper was conducted in cooperation with the special committee on salt lejuirements of 
representative agricultural plants, National Research Council, Division of Biology and Agriculture. 
Dr. H. H. King, Department of Chemistry, Kansas Station, assisted in the experiment during the seed¬ 
ling phase of growth. 
Journal of Agricultural Research, 
Washington, D. C. 
(387) 
Vol. XXVIII, No. 4 
Apr. 26, 1924 
Key No. Kans.-41 
