224 EXPERIMENT STATION EECOBD. 



Some biochemical investigations of Hawaiian soils, with special reference 

 to fertilizing with molasses, S. S. Peck (Hawaiian Sugar Planters' Sta., Agr. 

 and Chem. Bui. 3.'^, jjp. 39, pi. 1). — Ammouification, nitriflcation, denitrification, 

 and nitrogen fixation were studied with three samples of cane soil by (1) in- 

 oculating nutrient solutions with small amounts of the soil, or (2) observing 

 the progress of nitrogen transformation in the soils themselves. 



The relative effect of varying amounts of dextrose and molasses (the latter 

 containing 42 per cent of sucrose and 11.9 per cent of invert sugar) was tested 

 in these experiments. 



The results, although not entirely conclusive on all points under investiga- 

 tion, showed that " molasses applied at intervals on land on which cane is 

 growing and fertilizer had been applied will work harm by destroying nitrates 

 already applied or by preventing the formation of nitrates from other sources 

 of nitrogen supplied in the fertilizer. Molasses applied "to land lying fallow 

 or at an interval of several weeks prior to the planting of the crop may produce 

 beneficial results by providing a stimulus to the nitrogen-fixing bacteria of the 

 soil and thereby adding a store of nitrogen to the soil in a form which can be 

 made readily available to the crop at a later date by the other organisms in 

 the soil." 



The organisms transforming nitrogen were found in considerable numbers 

 down to a depth of 4 ft., but were most abundant near the sui^face except in 

 the case of the nitrogen-fixing organisms, which were apparently equally active 

 at all depths examined. "^%^' 



In comparative tests of gypsum, calcium carbonate, sodium nitrate, potas- 

 sium sulphate, carbon bisulphid, dextrose, molasses, and superphosphate, " the 

 addition of lime, as carbonate, sulphate, or phosphate, stimulated ammonifica- 

 tion. Nitrate of soda and carbon bisulphid depressed the process. Dextrose 

 had a slightly beneficial effect, but was considerably surpassed in this respect 

 by molasses. The addition of this material and that of potassium sulphate 

 produced equally favorable results. No relation can be discerned between the 

 number of organisms and the degree of ammouification, confirming Lipman and 

 Brown's results [E. S. R., 23, p. 621] referring to the effect of dextrose in 

 increasing the absolute numbers of organisms in a soil, but not the relative 

 ammonifj'ing power. . . . The most eflicieut hindrance to denitrification was 

 rendered by carbon bisulphid." 



As regards nitrification, calcium carbonate exerted the most favorable action. 

 Carbon bisulphid stimulated nitrification to a slight extent. The soils to which 

 the sugars were added showed the maximum power of fixing nitrogen. The 

 least effect was observed in the case of acid phosphate, and this is attributed 

 to a checking of the activity of Azotobacter by the acidity resulting from the 

 use of the superphosphate. The nitrogen-fixing organisms were not entirely 

 destroyed by carbon bisulphid, and later, under favorable conditions of moisture 

 and temperature, exceeded in numbers those in untreated soil. Both nitrifying 

 and nitrogen-fixing bacteria were killed by an exposure of 10 minutes to a 

 temperature of 85° C. In all of the soils examined there were present num- 

 bers of various forms of Protozoa, but these were entirely destroyed by 

 pasteurization. 



A bibliography is appended. 



Whitney's new theory of soil fertility, P. Keische (Erndhr. Pflanze, 6 

 {1910), No. J,, pp. 37, 38; abs. in Chem. Ztg., 3', {1910), No. 1,1, Repert., p. 

 162). — This article presents data reported by Mitscherlich to show that fer- 

 tilizing materially affects the composition of the soil solution. 



Fertilizers, J. Fritsch {Les Engrais. Paris, 1909, vols. 1, pp. 239, flgs. 10; 

 2, pp. 255, flgs. 15; rev. in Rev. G4n. Chim., 13 {1910), No. S, p. 154).— This is 



