FERTILIZERS. 647 



manure, of 522 lbs. of nitrogen residnul in the soil. The relative increase was 

 only about four-fifths as great when lime was ai)i)lie(l with the mamn-e. In the case 

 of land receiving complete mineral fertilizers containing, during the period under 

 discussion, GR-i ll)s. of nitrogen, the relative increase was only about 260 ll)s. of 

 nitrogen. . . . 



"The experiments of this station show little difference in the proportions between 

 the nitrogen and organic matter on the several manured plats, excei)t that lime has 

 shown a tendency to cause a more rapid loss of the organic matter than of the nitro- 

 gen of the manure it accompanies. Where no manure is used, the residual carbon 

 is relatively greater than the residual nitrogen, as compared with the fertilized lands. 

 . . . The use of mineral fertilizers, with and without nitrogen, was attended by an 

 increase of carbon relative to nitrogen ; this was more pronounced where yard manure 

 was applied." 



The maintenance of soil fertility under the renting- system, H. Bode 

 ilTaJ/iUrhr., Frmlrirhs-Unir. Halle, 1902, pp. 64). 



Limestones, W. Freak (Pennmjlmma Sta. Rpt. 1901, pp. 187-191). — Anah^ses of 

 42 samples are rcpoi'ted. 



Nitrogen-fixing- bacteria, J. G. Lipman {Pop. Scl. Mo., 62 {1902), No. 2, pp. 

 137-144). — This is a popular discussion on the source of nitrogen as plant food, nitri- 

 fication and denitrification in soils, and the fixation of free nitrogen l)y root tubercles 

 and by soil bacteria independent of leguminous plants. There are, according to the 

 author, about 6 forms of bacteria capable of fixing atmospheric nitrogen known at 

 present, and there is little doubt that others will be found before long. 



FERTILIZERS. 



Report on experiments with phosphatic fertilizers on winter grain during 



1900-1901, (). Keitmair {Berlrld ilhcr d'lr vt'it Winterlialmfrnclit in) Tfnhste 1900 

 eingeleitetcn uml 1901 zum Ahschluss gehrachten PJio.^plutt-Dungumjx-VerstieJie. Vienna: 

 Landwirischtftru'hchemischen Versnchsiaiion, 1902, pp. 100, map 1). — This is an account 

 of a continuation of previous experiments (E. S. R., 12, p. 8:^9) in which the action 

 of phosphoric acid in general and of different kinds of phosphates are discussed and 

 74 cooiaerative field experiments on rye and wheat in different parts of the Austrian 

 Empire, but principally (about one-half) in German Bohemia, are reported. The 

 Ijhosphatic fertilizers were very effective on winter rye, but much lesS so on winter 

 wheat. Superphos])hate was the most effective form of phosphoric acid used, but 

 Thomas slag was but slightly less effective and was more economical. The Algerian 

 and Belgian phosijhates were about equally effective, and in cheapness and effective- 

 ness not very inferior to superphosphate and Thomas slag. The proportion of the 

 phosphoric acid applied taken up by the crop was in no case as high as 10 per cent 

 (with superphosphates 8.2 per cent, with Thomas slag and crude phosphates about 

 7 per cent). An application of 60 kg. per hectare (53.53 lbs. per acre) of phosphoric 

 acid was abundant for rye and probably excessive in case of the more readily avail- 

 able forms, such as superphosphate and Thomas slag. 



Do phosphatic and potassic fertilizers exert a direct influence upon culti- 

 vated plants? C. LuMiA {SUiz. Spir. A(/r. Ital, 35 {1902), pp. 525-549; abs. in Chem. 

 Centbl, 1902, IT, No. 21, p. 133S). — The author concludes from his investigations and 

 observations that the mineral constituents of fertilizers exert a direct and favorable 

 action on the micro-organisms of the soil, but have only an indirect effect on plants 

 by furnishing conditions favorable to organisms which supply them with nitrogen 

 compounds. 



The returns from top-dressing with potash salts, Bacrmann {Deut. Landw. 

 Ftesse, 29 {1902), No. 97,p>p- 785, 786). — Exv:)eriments with kainit on barley, oats. 



