FERTILIZERS. 933 



preventing loss from this source. " The two sovereign remedies against washing on 

 the farm are, first, a dense, well-matted sward, which should be kept in good condi- 

 tion by frequent top-dressing; or if this fails, a prompt restoration of laud rendered 

 unproductive to a forest condition." 



Soil improvement, R. L. Bennett (Arkansas Sta. llpt. 1897, pp. 70-00, fig. 1). — 

 Reprinted from Bulletin 46 of the station (E. S. R., 9, p. 634). 



The bacteria of the soil, -with special reference to soil inoculation, R. S. Mac- 

 Dougall (Train. Bot. Soc. Edinburgh, 21 189"/ , pp. 25-40). 



The Cunrau estate and the Rimpau system of marsh culture, 1 ". Sverdrup 

 {Tidsslr. NorsTce Landbr., 4 {1807), pp. 400-426). 



FERTILIZERS. 



Denitrification and farmyard manure, K. Warington (Jour. Roy. 

 Agr. Sue. England, 3. ser., 8 [1897), pt. IV. pp. 577-607). — The author 

 takes exceptions; to the conclusions of German investigators (E. S. B., 

 8, pp. 761, 873) regarding denitrification as due to the action of manure 

 in the soil. He maintains that the denitrifying organisms present in 

 manure, straw, litter, etc., are derived originally from atmospheric 

 dust. Of the conditions necessary to their activity "the supply of 

 organic matter is by far the most important." Figures from Wagner's 

 and Maercker's experiments are quoted to show that the variations in 

 the extent of denitrification in different cases may be explained by 

 variations in the amounts of assimilable organic matter supplied in the 

 manures. 1 Attention is called to the fact, already noted by Deherain 

 (E. S. IJ.. 8, p. 870), that the amount of manure used in these experi- 

 ments was far in excess of that ordinarily applied in practice and the 

 results obtained, therefore, furnish "no proof that the same actions 

 will occur to the same extent in ordinary arable farming." This state- 

 ment is borne out by the results of the Eothamsted field experiments 

 with manure, which are quoted and discussed. 



"One fact which conies into great prominence in the German experiments is that 

 ordinary farmyard manure is valueless as food for plants until it is nitrified; this is 

 surely the only conclusion we can draw from the want of action of the manure when 

 applied in large quantities in the pot experiments. In the light of these results the 

 economy of large dressings of farmyard manure becomes very questionable." 



On the substitution of soda for, and its value in connection 

 with, potash, II. J. Wheeler and Gr. M. Tucker (Rhode Island Sta. 

 Rpt. 1890, pp. 221-241, pis. i, dgms. 10). — This is a continuation of inves- 

 tigations carried on since 1894 (E. S. R., 8, p. 579). During the first 

 2 years of the experiment 2 classes of plants were selected: (1) Those 

 which had given indications that they might be benefited by soda and 

 (2) those which it was thought would not be benefited by it. 



•' [In 1890, however, it was decided to] conduct the experiments in such a way as 

 to exhaust the assimilable potash from the soil as rapidly as possible in order that 

 any differences which might be attributable to the use of soda might become more 

 strikingly manifest. In order to accomplish this it was planned to grow, if possi- 



1 See also Stutzer, Dent. Landw. l'resse, 24 (1897), p. 665 (E. S. R., 9, p. 635). 



