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



239 



different set of the same type of soil, but which had produced two crops 

 of rape (both fertilized) and three crops of radishes, the last radish crop 

 having been fertilized. The soils were Umed for this crop. The yields 

 of air-dried crops are given in Table I. 



T.VBLE I.- — Average weights (in grams) of air-dried bean crops 



The relative yields of seed showed irregular results from the appli- 

 cation of the sulphates. When added to the usual complete-fertilizer 

 ration, sodium sulphate depressed growth, while calcium sulphate 

 slightly favored it. When applied alone, both salts gave results decidedly 

 better than the control untreated soils. In this case the soluble sodium 

 sulphate gave better results than the comparatively insoluble calcium 

 sulphate. It seems possible that the superior results from the sodium 

 sulphate applied alone as compared with its effect when added to the 

 complete-fertilizer treatment may have been due to an unfavorable 

 excessive accumulation of soluble salts in the latter case which might 

 not occur when it was added alone. 



The relative yields of straw from this crop showed no significant 

 effects which might be due to the added sulphates. Sulphur alone was 

 decidedly injurious to the beans. The effect is more noticeable in the 

 case of the grain than with the straw. This might be expected to obtain, 

 since the plants already weakened in general vitality would probably 

 be depressed in the power of reproduction. This was more probably 

 due to sulphites and other toxic oxidation products of the sulphur than 

 to the sulphur itself. It could not be due merely to the acidity of the 

 soil produced by oxidation of the sulphur, for it occurred with crop D, 

 which was limed. 



Clover (Trifolimn pratense). — The variety grown was Medium Red. 

 Crop A was grown on fresh fertilized and limed soil. Crop B followed 

 crop A on the same soil without fertilizer treatment, but with the addi- 

 tion of fresh soil in boxes 13 and 14, to which calcium carbonate and 

 elemental sulphur were applied. Crop C was grown on completely 



