1122 EXPERIMENT STATION EECORD. 



(sodium acetate or glycerin) greatly increased the rapidity of deuitriflcatiou. 

 Denitrification was also favored by the addition of starch, straw, rape calie, 

 compost, etc. With well rotted rape calce and compost, however, reduction was 

 much less than with the fresh materials. 



The bacterial nature of the denitrificatiou was confirmed by adding pure 

 cultures of Bacterium denitrificans and B. nitrovonun to sterilized soils, and 

 thus securing active denitrification. 



The formation of nitrites went on very slowly in dry soils when only nitrate 

 was added, but when organic matter (starch, rape cake, etc.) was added the 

 rate of reduction was greatly increased. 



Pot experiments on paddy and upland rice soils with nitrate alone or in 

 combination with other fertilizing materials gave results confirming those ob- 

 tained in the laboratory experiments and indicated that nitrate applied to paddy 

 soils is reduced to some extent first to nitrite, then to ammonia and elementary 

 nitrogen. The loss (largely as free nitrogen) from this source is increased by 

 applying with the nitrate such fertilizers as fresh oil cake, straw, compost, 

 etc., which supply organic matter which is easily assimilated by denitrifying 

 bacteria. It therefore appears that nitrate of soda is not well suited to applica- 

 tion as a fertilizer on itaddy soils, and particularly in connection with other 

 organic fertilizers. If such fertilizers must be employed they should be used 

 only in well rotted condition. 



On soil sickness, I. Pouget and D. Chouchak {Conipt. Rend. Acad. Sci. 

 [Paris], l^o (,1901), Xo. 2It, pp. 1200-1203; abs. in Rev. Sci. [Paris], 5. ser., 8 

 (1007), A'o, 25, p. 196; Rev. Gen. Agron., n. ser., 3 (1908), ^'o. 1, pp. 1, 2; Chem. 

 ZentbL, 1908, 1, Ao. 7, p. 667). —^Observations on uncultivated soils and on those 

 on which alfalfa had been grown are reported, the results indicating that the 

 alfalfa plants excreted a toxic principle which, gradually accumulating in the 

 soil, injuriously affects the growth of plants. These conclusions are drawn from 

 studies of the effect of calcined and uncalcined aqueous extract of the alfalfa 

 soil, the exact nature and proiierties of the toxic i)riuciples not being determined. 



Results of experiments on the application of fertilizers and of a study of 

 crop rotations, P. Buurin (Rcsultaini Opuitov po Prcmyencniyii Udobrenii i 

 Izurliniiini Hyevooborotov. St. Petersburg, 1901, pp. 188, illus.; rev. in Zhtir. 

 Opiiitn. Agron. [Russ. Jour. Expt. Landw.], S {1901), No. 4, pp. /,33-/f35).— 

 This report gives the results of experiments conducted during the last 12 to 

 15 years on the experiment field of the Institute of Agriculture and Forestry 

 at Xovo-Alexandria. 



Under the local climatic and soil conditions green manuring, particularly 

 with lupines, gave good results. The lupines were preferable under these 

 conditions to vetches, being less exacting in their demands on the soil and in 

 their moisture requirements. They also produced a larger mass of green 

 matter. In fact, fall fertilizing with lupines on fallow gave more organic 

 matter and nitrogen than the cereals could utilize completely. In some cases 

 the leguminous plants gave as good i-esults on cereals when grown for seed 

 or hay and only the stubble plowed under as when the whole plant was so 

 used. The author therefore rec-onmiends fall green manuring, especially for 

 the more exacting crops, e. g., corn, root crops, fruits, and oil plants. Freedom 

 of the field from weeds is essential to the success in green manuring, especially 

 with lupines. Since the repeated use of green manures alone results in the 

 exhaustion of the mineral constituents of the soil, mineral fertilizers, especially 

 those supplying phosphoric acid and potash, should be used with the green 

 manures. Whether phosphoric acid or potash will give the best results de- 

 pends upon the nature of the plants grown. 



