Nov. 8, 191S Relation of Sulphur Compounds to Plant Nutrition 245 



finer parts of the root system from the soil. Such objection would not 

 apply to the sand cultures, which therefore gave conclusive evidence of the 

 stimulating effect of calcium sulphate upon the root development of rape. 

 The benefit to the tops from this salt was much less pronounced, but 

 nevertheless definite. As in most other cases, the elemental sulphur 

 was detrimental to the plants, presumably because of toxic action. 

 There seems to be no doubt that the rape plant has specific need for 

 sulphur, which should be met by including sulphates in its fertilizer 

 treatment. 



GRAMINEAE 



Barley {Hordeum vulgare). — One crop was grown upon a set of soils 

 which had already produced one crop of peas with fertilizer treatment 

 and a second crop without fertilizer. The barley crop was not fertilized, 

 as the pea crops had been light. The variety planted was New Zealand 

 Chevalier. In Table VII are given the average air-dried weights of the 

 yields from duplicate boxes. 



Table XVII. — Average zveights {in grams) of air-dried barley crop 



Weight. 



Relative 



yields 

 when con- 

 trol= 100. 



Relative 



yields 

 when con- 

 trol=ioo. 



1. Control 



2. Complete fertilizer 



3. Complete fertilizer+sodium sulphate . 



4. Complete fertilizer+calciura sulphate. 



5. Sodium sulphate only 



6. Calcium sulphate only • 



7. Sulphur only 



36. 5 

 59- o 

 67. o 

 62. 5 

 43-5 

 38.5 

 39- o 



100 

 162 

 184 



119 

 106 



9-5 

 10.5 

 14- 5 

 15.0 

 14.0 

 17. o 

 13-5 



153 

 158 

 147 

 179 



142 



The Hmited data available are insufficient for the deduction of definite 

 conclusions concerning the effects of the sulphur supply upon the growth 

 of the barley crop. They indicate, however, that sulphur and the sul- 

 phates here applied had little influence upon the production of straw in 

 this crop either when added to a complete-fertilizer ration or when applied 

 alone. Conditions were decidedly different in the case of the grain. 

 While the production of straw seems to have been limited, this amount 

 of straw produced 40 to 80 per cent more grain in the crops receiving 

 sulphur and sulphates alone than in the control crops. Likewise, the 

 crops receiving sulphates in addition to a complete-fertilizer ration pro- 

 duced about 40 per cent more grain than those receiving only the com- 

 plete ration (PI. XXII, fig. 2). 



O.^TS {Avena saliva). — This crop was grown upon a set of soils which 

 had borne two unsatisfactory barley crops, the first of which had been 

 fertilized. The oat crop was not fertiHzed. Wisconsin Wonder was 



