122 EXPERIMENT STATION EECOED. 



become more, but apparently less potent. The increased decomposing power of 

 the new flora is associated with its numerical superiority over old flora. 



" The rates of decomposition and of bacterial increase in the toluened soil 

 were found to be adversely affected by the addition of the original untreated 

 soil. The original soil therefore contains some factor which linuts bacterial 

 action. 



" Chemical hypothesis having been found unsatisfactory the factor is shown 

 to be biological. Large organisms (protozoa) were found in the untreated, but 

 not in the partially sterilized soils, at least two of which are known to destroy 

 b.Mcteria. 



" These large competing and destructive organisms are killed by heat and 

 most of them by toluene, and can then serve as food for bacteria. In both these 

 directions the effect of partial sterilization is beneficial. 



"As the effect of partial sterilization in increasing productiveness is shown 

 on so many soils, and apparently always in the same way, it may be expected 

 that these competing and destructive protozoa are of common occurrence and 

 constitute an important factor in soil fertility. 



" In relation to plant growth partially sterilized soils are peculiar in that 

 they supply not nitrate, but other nitrogen compounds such as ammonia, to the 

 plant. The nitrifying organisms will develop if they get into the toluened soil, 

 but they did not work in the heated soils. With this difference in the course of 

 nitrogen nutrition may be correlated the difference in nitrogen content of the 

 plant and in the character of growth." 



Experiments on the accumulation of green manure nitrogen in light sandy 

 soils, C. VON Seeliiorst (Mitt. Deut. Landw. GcselL, 2-J (1909), No. 33, pp. 512- 

 516). — This is a report of a continuation of experiments with large vegetation 

 tanks (E. S. R, 19. p. 319; 20, p. 316). 



The results reported show that in the case of wheat about the same amounts 

 of nitrogen were removed in the drainage and in the crop, but that this was 

 not true in the case of rye and barley. With barley on soil which had received 

 a late green manuring the greater part of the nitrogen removed from the soil 

 was found in the crop. With rye on soil receiving an early green manuring 

 the greater part was found in the drainage. Larger losses of the nitrogen of 

 the soil were observed in the case of potatoes than with cereals and this is 

 accounted for by the larger proportion of nitrogen removed in the drainage. 

 The amount taken up in the crop was the same with potatoes as with cereals. 



On the relation of native legumes to the soil nitrogen of Nebraska prairies, 

 F. J. Alway and R. M. Pinckney (Jour. Indus, and Engin. Chem., 1 (1909), 

 No. 11, pp. 771, 772). — Analyses are reported which show the distribution of 

 nitrogen in typical Nebraska prairie soils at different depths down to 6 ft., 

 and the probable relation of the nitrogen content of the soil to the natural 

 vegetation, particularly the leguminous plants, is discussed. 



It was found that the nitrogen in one of the soils to a depth of 6 in. varied 

 from 0.25 to 0.317, with an average of 0.2S4 per cent, and it is estimated 

 from the data obtained that the soil contained about 10.000 lbs. of nitrogen 

 per acre to a depth of 2 ft. It is estimated that the natural growth of legu- 

 minous plants on this soil furnishes about 10 lbs. per acre of nitrogen annually. 

 The indications are that the nitrogen content of the soil has long since reached 

 an equilibrium. 



Soil nitrogen, J. Wrightson (Agr. Gaz. [London], 70 (1909), No. 1854, P- 

 30). — In this article it is contended that leguminous plants are not the only 

 fixers of atmospheric nitrogen. 



Some effects of nitrogen-fixing bacteria on the growth of nonleguminous 

 plants, W. B. Bottomley (Proc. Roy. Soc. [London], Ser. B, 81 (1909), No. B 



