1922] WOODARD—SOIL FERTILITY 83 
was reported for the same treatment on other crops. Brooks (9) 
also made a comparison of different phosphate fertilizers. He 
found that acid phosphate and dissolved boneblack, which contain 
sulphur, gave greater increases in crop yields than raw bonemeal 
and rock phosphate, which contain little or no sulphur. A more 
rapid early growth of both tops and roots and earlier maturity 
were observed on the plots receiving the dissolved boneblack and 
acid phosphate than on the plots receiving raw bonemeal and rock 
phosphate. 
The use of flowers of sulphur as a fertilizer was observed to 
have an influence aside from its effect in destroying the fungi which 
cause plant diseases. Mares (50) noticed a much greater vigor 
in vines that had been sulphured than in those which had not. 
He found that the sulphur was oxidized to sulphuric acid in the 
soil, and he thought that the sulphuric acid acted on the insoluble 
compounds containing potassium and made the potassium soluble. 
DEMOLON (16) found that heating the soil prevented the oxida- 
tion, and so he concluded that oxidation was caused by micro- 
organisms. PFreIFFER and BLANCK (56) obtained no “increased 
yields of oats for the use of flowers of sulphur in field experiments. 
FEILITZEN (21) in Europe, and SHERBAKOFF (64) in the United 
States both obtained increased yields of potatoes from the use of 
flowers of sulphur. 
BOULLANGER and DucarDIN (3) found flowers of sulphur in- 
creased ammonification but decreased nitrification. The harmful 
effect on the nitrifying bacteria was probably due to the acidity, 
as Lint (38) found that the oxidation of sulphur in the soil in- 
creased the acidity very much. Frep and Harr (23) report an 
increase in ammonification from the use of gypsum in peptone so- 
lutions, and WariNcTON (73) obtained an increase in nitrification 
when gypsum was applied to solutions of urea. GREAVES, CARTER, 
and GoLpTHoRPE (24) studied the influence of calcium sulphate 
on production of nitrates and found it caused a great increase in 
all concentrations used. The increase was very high for the higher 
concentrations of calcium sulphate. 
Brioux and Guerset (7) found that flowers of sulphur 
increased availability of calcium and potassium in both calcareous 
