June IS, i9:»o Effect of ManureStdphuY Composts on Greensand 255 



(5) When no organic matter was added, the amounts of acidity and 

 soluble sulphates were no greater than might be accounted for by the 

 natural oxidation of the sulphur. 



(6) The addition of small amounts of ferrous and aluminum sulphates 

 failed to stimulate sulphofication. 



(7) Calcium carbonate added to the sulphur-manure-soil compost pro- 

 duced a stimulating effect during the early part of the period but failed to 

 increase the acidity, soluble sulphates, or potassium above the maximum 

 reached by the corresponding compost in which no calcium carbonate 

 was used. 



(8) More water-soluble potassium was formed in the composts con- 

 taining the high-potassium greensand, but a larger percentage of the 

 total potassium present was liberated in the composts containing the 

 low-potassium greensand. 



(9) In the composts containing manure, the total amounts of potas- 

 sium recovered in the water extracts varied from 9.1 per cent to a maxi- 

 mum of 41.3 per cent of the total initial amount present. 



(10) Our results indicate that the composting of greensand, or of soil 

 rich in potassium, with sulphur and manure may prove to be a prac- 

 tical and efficient method for obtaining available potassium from com- 

 paratively insoluble materials. 



LITERATURE CITED 

 (i) Ames, J. W., and Boltz, G. E. 



1919. EFFECT OF SULPHOFICATION AND NITRIFICATION ON POTASSIUM AND OTHER 



SOIL CONSTITUENTS. In Soil Sci., V. 7, no. 3, p. 183-195. References, 



P- 195- 



(2) — — — and Richmond, T. E. 



1918. EFFECT OF SULPHOFICATION AND NITRIFICATION ON ROCK PHOSPHATE. In 



Soil Sci., V. 6, no. 5, p. 351-364. References, p. 364. 



(3) Blair, A. W. 



1916. THE AGRICULTURAL VALUE OF GREENSAND MARL. N. J. Agr. Exp. Sta. 



Circ. 61, 13 p., I fig. 



(4) Brown, P. E., and GwaNN, A. R. 



I917. EFFECT OF SULPHUR AND MANURE ON AV.\ILABILITY OP ROCK PHOSPHATE IN 



SOIL. Iowa Agr. Exp. Sta. Research Bui. 43, p. 369-389, 4 fig. Bibli- 

 ography, p. 389. 

 (s) and Warner, H. W. 



1917. THE PRODUCTION OF AVAILABLE PHOSPHORUS FROM ROCK PHOSPHATE BY 



COMPOSTING WITH SULPHUR AND MANURE. In Soil Sci., V. 4, no. 4, 



p. 269-282, 3 fig. References, p. 282. 



(6) Cook, George H. 



1868. GEOLOGY OP NEW JERSEY . . . xxiv, 899 p., illus., I fold. col. map. 

 Newark, N. J. 



(7) HiLGARD, E. W. 



1906. SOILS, THEIR FORMATION, PROPERTIES, COMPOSITION, AND RELATIONS TO 

 CLIMATE AND PLANT GROWTH IN THE HUMID AND ARID REGIONS. XXVii, 



593 p., illus. New York, London. 

 175344°— 20 2 



