944 EXPERIMENT STATION RECORD. 



Effect of copper sulphate on the bacteriological and chemical constituents 

 of large bodies of water, W. R. Stokes and J. B. Thomas (Amer. Med., 10 {1905), 

 No. 26, pp. 1075-1078, fig. 1). — The results of a limited number of experiments with 

 copper sulphate on a swimming tank in Baltimore filled from the general water sup- 

 ply of the city are reported, from which "it would seem that in fairly pure water a 

 dilution of 1 to 100,000 can be depended upon greatly to reduce the alg?e and fermen- 

 tative bacteria, and also clear the w r ater by precipitating the matter in suspension. 

 In moderately polluted water the fermentative bacteria are not destroyed." 



SOILS— FERTILIZERS. 



Renovation of worn-out soils, W. J. Spillman ( U. S. Dept. Agr., Farmers' Bui. 

 245, pp. 16). — The principal lessons which this bulletin is intended to enforce are 

 briefly summarized as follows: "To build up and maintain fertility in the soil, feed 

 p, large part of the crops, and return the manure to the land. If manure is not avail- 

 able, plow under crops grown for the purpose. Plow deep ( but do not subsoil). Grow 

 leguminous crops for the nitrogen they add to the soil. 



"Commercial fertilizers and lime may be important means of improving the soil, 

 but the fertilizer requirements of different soils and different crops in different sea- 

 sons are so little understood that we are not yet in a position to make positive recom- 

 mendations that are of general application." 



Present definitions of soil fertility, W. H. Jordan (Agr. of Mass., 1904, pp. 

 121-155). — This paper discusses the various theories of soil fertility, particularly 

 those advanced in Bulletin 22 of the Bureau of Soils of this Department. The 

 author's views with reference to methods of soil management necessary to maintain 

 fertility are summarized as follows: 



" (1) Thorough tillage, with efficient machinery, to be given if possible when the 

 moisture conditions of the soil admit of satisfactory pulverization. 



"(2) Frequent surface tillage at times of scanty rainfall, in order to conserve the 

 supply of soil moisture. 



" (3) A sufficiently rapid rotation of crops to insure good soil texture, to allow the 

 necessary frequency of applying fertilizing material, and as a main result to secure a 

 paying stand of crops. 



"(4) The introduction into the soil at frequent intervals of an amount of organic 

 matter necessary to proper soil texture and water-holding power, either by applica- 

 tion of farm manures, by plowing under soiling crops, or by the rotting of the turf. 



" (5) The scrupulous saving of all the excrement of farm animals, both solid and 

 liquid. 



"(6) The purchase of plant food with due reference to the needs of the farm and 

 to the system of farm management prevailing. 



"(7) The maintenance in the soil of those conditions of drainage and aeration 

 which promote the growth of desirable soil organisms, and the introduction into the 

 soil, when necessary, of such organisms as are essential to the growth of particular 

 plants." 



The analysis of soils, E. A. Mann (Jour. Dept. Agr. West. Aust., 12 (1905), No. 2, 

 pp. 141-144). — The value of soil analysis for determining the fertility of soils, espe- 

 cially Dyer's method of determining availability of soil constituents, is briefly dis- 

 cussed. Studies which have been made indicate that the chemical methods are of 

 value in case of West Australiamsoils. 



Fertility studies on Wooster soil, A. H. Snyder and C. L. Cook (Ohio Sta. Bui. 

 167, pp. 85-119). — An account is given in this bulletin of experiments made by the 

 Bureau of Soils, cooperating with the Ohio Station, " to determine whether the results 

 obtained by its wire-basket and aqueous-extract methods of studying the productive- 

 ness and manurial requirements of soils [E. S. R., 17, p. 227] were in accord with 



