SOILS FERTILIZEES. 319 



The treatment of the soil had less effect upon nitrification than the time of 

 year, although the application of straw greatly reduced the nitrifying power of 

 the soil. Heavy applications of calcium carbonate did not appreciably affect 

 nitrification, but the addition of peat increased it to a marked degree. The 

 results with applications of clay to the soil were inconclusive. 



Experiments with potatoes and barley on the soils indicated that the produc- 

 tiveness was in direct i-elation to the nitrifying capacity. Plowing under of 

 straw decidedly decreased the yield. The author suggests that by the applica- 

 tion of straw in the fall nitrification may be retarded and loss of nitrogen 

 reduced and that it may be possible so to regulate the nitrification process as 

 to produce plants low in nitrogen. 



Nitrogen economy of arable soils. — II, T. Pfeiffeb, A. Gttttmann, and F. 

 Thiel (Mitt. Landw. Inst. Breslau, 5 {1910), No. 5, pp. 657-713; abs. in Jour. 

 Chem. Soc. [London], 98 {1910), No. 572, II, pp. 535, 536; Zentbl. Agr. Chem., 

 39 {1910), No. 12, pp. 793-797). — This article reports the results of a large num- 

 ber of pot experiments made to ascertain the amounts of nitrogen fixed by soil 

 in its natural state after fallow, oats, and mustard ; in the same soil sterilized 

 by steam under three atmospheres pressure and by carbon bisulphid; and in 

 soil to which sugar was added. Pots holding 13 kg. (28.66 lbs.) of loam were 

 used. Data for yields and nitrogen in crops and soils are given. 



There were gains of nitrogen in every case. The greatest gain after fallow 

 was in soil treated with carbon bisulphid (1.275 gm. per 13 kg. of soil), the next 

 largest in steamed soil (1.031 gm.), and in the natural soil the gain was 0.901 

 gm. The crop grown on steamed soil contained the highest nitrogen content. 

 Carbon bisulphid had little effect upon the nitrogen content of the crop, but the 

 addition of sugar reduced the amount of nitrogen taken up by the plant, although 

 the soil showed a distinct gain in nitrogen. The total gain in soil and crop 

 was practically the same without sugar as with it. The untreated natural soil 

 showed gains of nitrogen in addition to that taken up by the crops. In sand 

 cultures there was a very slight gain of nitrogen accompanying a luxuriant 

 growth of soil algae. 



The nitrogen problems of dry farming, F. J. Alway (Rpt. Brit. Assoc. Adv. 

 Sci. 1909, p. 710).— ^ee a previous note (E. S. R., 22, p. 221). 



Pineapple culture. — VII, Nitrates in the soil, A. W. Blair and R. N. Wilson 

 {Florida Sta. Bui. lOJf, pp. 31-51, figs. ^). — In connection with the series of 

 studies on pineapple culture (B. S. R., 22, p. 640), the authors investigated 

 the formation and accumulation of niti'ates in a coarse white sand, containing 

 over 99 per cent of insoluble matter, which had been planted to pineapples 

 since 1901 and had received two applications annually of a fertilizer contain- 

 ing 5 per cent of nitrogen at rates of from 2.250 to 4,500 lbs. per acre. The 

 nitrogen of the fertilizer was supplied by dried blood, cotton-seed meal, nitrate 

 of soda, castor pomace, and steamed bone meal. 



Nitrates were determined in 10 sets of samples of the soil, taken usually at 

 intervals of 4 to 6 weeks. There was a decided increase of the nitrates with 

 increase of nitrogenous fertilizers. The nitrates were most abundant at the 

 surface. The amount was small beyond a depth of 1 ft , but increased slightly 

 from the second to the fifth foot. The nitrates were more abundant where the 

 surface soil was protected by a covering of plants and decaying leaves. With 

 heavy rainfall there was a falling off of nitrates, but an increase after the rain 

 subsided although no fertilizer had been applied. 



The highest average amount of nitrates for the whole period was found in 

 the soil to which cotton-seed meal had been applied, the soils receiving dried 

 blood and bone meal being next in order in this respect. 



The humus content of cultivated soil and new land, and its solubility, 

 M. Pankov (Zhur. Opytn. Agron. {Rtiss. Jour. Expt. Landw.), 11 {1910), No. 2, 



