OXIDATION OF SULPHUR BY MICROORGANISMS IN 
BLACK ALKALI SOILS ‘ 
By Selman a. Waksman, Clara H. Wark, Jacob Joffe, and Robert h . 
Starkly, Department of Soil Chemistry and Bacteriologyt New Jersey Agricultural 
Experiment Station 
The accumulation of sodium carbonate in the soil (black alkali soil) 
brings about a condition in which the soil practically has to be abandoned 
as far as utilization for the growth of plants is concerned. Irrigation, 
whereby the carbonates are washed out from the soil, brings about a 
temporary and unsatisfactory relief. If the sodium carbonate could be 
converted into sodium sulphate (white alkali), much more satisfactory 
results could be ontained, since, as pointed out recently by Vinson and 
associates (rj),^ white alkali is readily and completely leached out from 
soil, while black alkali resists leaching. The use of sulphuric acid on 
alkali soil has been suggested by C. B. Lipman and Sharp (6); this acid 
was found to exert a favorable influence upon the soil by neutralizing the 
carbonate and improving the physical condition of the soil through 
flocculating the colloids. However, the sudden introduction of large 
quantities of acid into the soil may have an injurious influence upon the 
soil microflora. Elementary sulphur would prove, in this respect, of 
greater benefit, since, not only wpuld the injury to the soil microflora be 
less but the addition of small quantities of sulphur even may stimulate 
bacterial activities. 
J. G. Lipman (7) was the first to suggest the use of sulphur for alkali 
soil, in order that the acid formed from the oxidation of sulphur may 
reduce the alkalinity of the soil and transform the sodium carbonate into 
sodium sulphate. O’Gara (9), when applying sulphur and sulphuric 
acid to soils, observed that there was a reduction of the carbonate and 
an increase in the sulphate content of the soil and a decided increase in the 
crop yield. Hibbard (5) demonstrated that by adding sulphur to alkali 
soil the alkalinity is neutralized, this effect being of great value in the 
reclamation of alkali land. Rudolfs (jo) found on adding elemental 
sulphur, at the rate of 1,000 pounds per acre, that the reaction of the soil 
was reduced from Ph between 9.6 and 9.8 to Ph 9.3; with 2,000 pounds 
per acre, to Ph 9.2; with 3,000, to Ph 8.9; and with 3,500, to Ph 8.2. 
However, if black alkali soil is first leached, the use of 3,000 pounds of 
sulphur per acre will change the reaction of the soil from Ph 9.2 to Ph 7.7. 
Although some of the sulphur may be oxidized in the soil without the 
intervention of life, as pointed out by Kappen and Quensell (5) and 
others, it is primarily as a result of activities of certain microorganisms 
that the rapid oxidation of the elemental sulphur takes place in both 
1 Accepted for publication June 29, 1922. Paper No. 112 of the Journal Series, Department of Soil Chem¬ 
istry and Bacteriology, New Jersey A^icultural Experiment Stations. 
2 Reference is made by munber (italic) to “ Literature cited,” p. 305. 
Journal of Agricultural Research, 
Washington, D. C. 
abq 
’ (297) 
Vol. XXIV. No. 4 
Apr. 28, 1923 
Key No. N. J.“9 
