FERTILIZERS. 891 



"(4) Tho a2;ricultural value of a fertilizer bears no strict relation to the eomiiior- 

 cial value; the one is deteriuined by soil, crop, and climatic conditions, the other by 

 market conditions. 



"(5) The variations in the composition and A-alue ot manuractiired I'ertili/.ers 

 which contain the three essential constituents are due to \'ariations in the character 

 and in the itroi»ortion of the materials nsed. 



"(6) The ton basis alone is not a safe guide in the purchase of these connnercial 

 fertilizers. Low ton prices mean either low content of good forms of plant food or 

 the use of poorer forms. Fertilizers, high grade both in quality and ((uantity of 

 plant food, can not be purchased at a low price per ton. 



"(7) The best fertilizers can not exert their full effect on soils that are too dry or 

 too wet, too compact or too porous. They can furnish but one of tlie conditions of 

 fertility. 



"(8) The kind and amount to use should be determined by the Aalue of the crop 

 grown and its power of acquiring food. 



"(9) Adetinite system or jtlan should be adopted in their use; ' hit or miss ' meth- 

 ods are seldom satisfactory, and frcciueutly very expensiv(\" 



Tile best economy of concentrated fertilizers, 8. W. .Johnson {ConiiecHcitt 

 State Sta. lipt. 1S05, pp. 102-165). — A general discussion of this subject intended 

 simply "to illustrate the fact that tlu) interests of those who buy as well as of those 

 who sell commercial fertilizers can be best promote<l by a knowledge, well ap])lied, 

 of all the factors of crop production.'" 



Observations on the injurious effect of nitrate of soda, A. Sxr tzei: (Dttit. 

 laiidw. Pressc, 23 (ISfMi), \o. W, p. '>92). — Nuuicrous instances arc reported in which 

 cereals (rye and occasionally wheat) were unhealthy on fudds to which nitrate of 

 soda had been applied. It is suggested that there was a deiiciency of water as the 

 season advanced and the soil solution ol' nitrate l)ecamc too concentrated. 



On the microbiology of nitrification processes, S. AVinogradsky {('cnlhl. lUtkt. 

 und Par. AlUj., 2 (ISOO). Xo.s. 1.1, pp. 415-428; 14, pp. 449-45S). 



Concerning nitrate destroying bacteria, A. Stftzer and 1\. Matt. {f'ev11)l. 

 Ilakf. and Par. Allg., 2 (1890), Xo. 15, pp. 473, 474). 



The proper management of stable manure in the stable, in the manure heap, 

 and in the field {Deut. landw. Presse, 23 (1S96), Xo. 89, p. 791). 



The preservation of stable manure, P. Waonrr (Landhote, 17 {189i]), Xo. 27, 

 p. 244). 



Sewage disposal in cities and towns, S. BiRRACiK {Purdue Unirersity Mono- 

 fjraphs, Public Health -SVrie.s, Xo. 5, pp. 16). — This is a popular discussion of the nature 

 and composition of sewage ; of old methods of sewage dis]»osal ; and of modern meth- 

 ods of sewage purification, including liroad irrigation, intermittent filtration, sedi- 

 mentation, subsurface disposal, mechanical filtration, and chemical precipitation. 



Sewage disposal on the farm,- T. Smith ( U. S. Dcpt. Af/r., Farmers' Bui. 43, pp. 20, 

 figs. 8). — A popular treatise intluding the following topics: Disposal of niglit soil, 

 liquid sewage, kitchen and chaml)cr sloi)s, and waste and garbage ; and jjrotection of 

 drinking Avater, including ways of contamination and construction of wells. Without 

 attempting to make any definite suggestions applicable to all conditions it is urged 

 that "the ]»rinciples to be kept in tiie foreground are the disposal of sewage iu the 

 superficial layers of the soil in not too great <|uantity, the disinfection of the stools 

 of the sick with lime before such disposition is made, the digging of wells in places 

 kept permanently in grass and at somt; distance from barnyards, and, above all, their 

 thorough protection from contamination from the surface and from the soil immedi- 

 ately below tlic surface." 



Analyses of commercial fertilizers, M. A. Scovkll, A. M. Pktkr. and 11. E. 

 Curtis (Keniuek}i Sta. lipt. 1895, pp. 59-72; XXt-i-ifi').— Reprints «>f liulletins nc and 

 60 of the station (E. S. R., 7. p. 491; 8, p. 40). 



Composition of commercial fertilizers, II. 1!. McDoNXKr.i, kt at,. {Miinjlaud Sta-, 

 Bui. 40, p2>. 69-121). — This bulletin incdndcs a schedule of trade values of fertilizing 



