6 GROWTH OF WHEAT SEEDLINGS. 



EXPERIMENTS WITH NUTRIENT SOLUTIONS AND DISTILLED 

 WATER CULTURES. 



DESCRIPTION OF SOLUTIONS AND METHOD OF SOWING. 



The following experiments were carried on in nutrient solutions 

 and in distilled water cultures, eliminating the disturbing factors 

 due to the presence of soil grains. For the most part wheat was used 

 on account of the ease in handling the young seedlings. The seed, 

 which was furnished by the Pennsylvania experiment station, was 

 washed with warm water for about six hours and then sprinkled on 

 perforated aluminum disks about 12 inches in diameter. These disks 

 were floated, by means of glass tubes, in shallow pans which held 

 about 3 liters of water. In this way approximately 1,000 seeds were 

 used in each pan. The preliminary washing removed all of the 

 readily soluble salts, the actual amounts so removed, as has been 

 shown by the authors in previous experiments 1 of this kind, being 

 quite large. The distilled water was prepared especially for this 

 purpose and a small amount of carbon black was placed in each pan. 



After some preliminary work a set of 13 pans was started, as fol- 

 lows: 



Solution 1. Distilled water. 



Solution 2. Distilled water + 0.5 gram of calcium carbonate. 



Solution 3. 150 parts per million of sodium nitrate. 



Solution 4. 150 parts per million of sodium nitrate + 0.5 gram of calcium 

 carbonate. 



Solution 5. 150 parts per million of potassium chlorid. 



Solution 6. 150 parts per million of potassium chlorid + 0.5 gram of calcium 

 carbonate. 



Solution 7. 150 parts per million of potassium sulphate. 



Solution 8. 150 parts per million of potassium sulphate + 0.5 gram of calcium 

 carbonate. 



Solution 9. 10 parts per million of hydrochloric acid. 



Solution 10. 10 parts per million of hydrochloric acid + 0.5 gram of calcium 

 carbonate. 



Solution 11. 10 parts per million of sulphuric acid. 



Solution 12. 10 parts per million of sulphuric acid + 0.5 gram of calcium 

 carbonate. 



Solution 13. 150 parts per million of sodium nitrate + 75 parts per million 

 of potassium sulphate. 



FIRST CROP OF SEEDLINGS. 



These cultures were started January 24 and grown until February 

 2. The plants were then harvested, representative samples were 

 selected and photographed, and the others were dried, weighed, and 

 prepared for analysis. The photographs are shown in Plates I 

 and II, the controls being the same in each case. The solutions were 



iU. S. Dept. Agr., Bureau of Chemistry Bui. 138. 



