1922] WOOD ARD— SOIL FERTILITY 89 



sulphur containing substances were added to the non-sulphur 

 containing nitrogenous fertilizers, they produced yields equal to 

 those from ammonium sulphate. 



Shedd (63) grew soy beans, oats, alfalfa, and wheat in pots 

 containing Kentucky soils. Eight different soils were used, and 

 flowers of sulphur added at the rate of 100 and 200 pounds per 

 acre. Both controls and sulphur treated pots received tricalcium 

 phosphate, potassium nitrate, and calcium carbonate. There were 

 some increases but also some decreases. 



Eaton (19) grew sweet corn in pots containing sand. He 

 compared the effect of gypsum, flowers of sulphur, and sodium 

 sulphate. The controls as well as the different sulphur treatments 

 were watered with a nutrient solution which contained no sulphur. 

 Gypsum increased the yield, while flowers of sulphur and sodium 

 sulphate gave increases for the smaller applications and decreases 

 for the larger appUcations. 



DuLEY (17) reported a darker green in sweet clover and corn 

 when fertilized with gypsum or sulphur. More nodules were also 

 produced on the roots. 



PiTZ (57) grew clover in agar-agar containing dipotassium 

 phosphate with and without calcium sulphate. Greater length of 

 roots was obtained with the calcium sulphate. Clover was also 

 grown in Miami silt loam with and without calcium sulphate. 

 The calcium sulphate increased the root length. 



Hart and Tottingham (29) found a decided increase in develop- 

 ment of beans, red clover, and peas when fertilized with either 

 calcium sulphate or sodium sulphate. In beans and peas the 

 increase was in the seed, in clover it was in the hay and roots. 

 Sulphates increased the yields of both tops and roots in radishes. 

 The yield of rape tops was increased by both calcium and sodium 

 sulphates. Barley was not affected by the sulphates, and oats to 

 only a slight extent. 



Olson (54) conducted field experiments with alfalfa at the 

 Washington Agricultural Experiment Station and obtained in- 

 creased yields from the use of acid phosphate and gypsum, but 

 not from other forms of phosphorus. Two hundred pounds of 

 gypsum per acre increased the yields of alfalfa from 100 to 500 

 per cent. 



