SOILS FERTILIZERS. 523 



country, with twenty times as many people to the square mile and just as many 

 animals as are found in the United States, is able to secure its food supply. 



"Japan is now supporting a population in her four main islands of more 

 than 48,500,000 people and more than 2,600,000 horses and cattle, nearly all of 

 them laboring animals and all on only 21,321 square miles of cultivated land. 

 This is at the rate of 2,277 people and 125 horses and cattle to each square mile 

 of cultivated laud." 



It is shown that this result is brought about by the careful saving and use of 

 every bit of fertilizing material, the use of green manure, and great care in the 

 prepai'ation and handling of the soil. Much of the fertilizing material is used 

 In the form of composts. Tlie methods of composting used in Japan are 

 described as well as a type of house employed for the storage and protection 

 of the compost and the composition of samples of the composts, green manures, 

 and ashes used. 



Dry farming' in China, F. H. King (Rural New Yorker, 69 (IVIO), No. 

 4031, pp. 101, 102, figs. 2). — The methods which have been developed after long 

 years' experience in China are briefly described, i)articularly the method of 

 utilizing manures of various kinds in composts which are practically niter 

 beds. 



The importance of suitable combinations of fertilizing constituents for 

 plants, O. Lemmermann (Illus. Landic. /Jg., 29 {1909), No. 98, pp. 903, 90^).— 

 Referring to a previous communication by Clausen (E. S. R., 22, p. 322) the 

 author cites the work of various investigators as indicating that it is of great 

 importance in plant production to secure an optimal relation between the 

 various constituents of plant food, not only generally but for individual plants. 



Work of the chemical laboratory, B. Welbel {Ohodtchniiil Otehet Ploty. 

 tieUk. Khoz. Opuitn. titani::!!, I'f (1908), pp. 9-'t-l-'i3, 181-190, pis. 3, figs. 1).— 

 In continuation of previous work along similar lines (E. S. R., 20, p. 717) in- 

 vestigations were made during 1908 on the influence of manure and fertilizers, 

 as well as green manure, upon the fertility of the soil. 



Influence of fertilizers and manure. — In view of the fact that previous ex- 

 periments had shown that the application of manure on fallow in a 4-year 

 rotation sensibly and profitably increased the yield of the following crops, and 

 that the manuring increased the proportion of nitrates in the soil as w^ell as 

 the amount of nitrogen assimilated by the crops, further experiments were 

 undertaken to study the relation of the manuring to the assimilable phosphoric 

 acid of the soil. In pot experiments it was found that the yields were better 

 in a rotation with manure than in one without manure, but that the efl:ect 

 of the manure disappeared after 3 years. The manuring increased both the 

 assimilable nitrogen and the assimilable phosphoric acid. In 3 years about 65 

 per cent of the nitrogen and nearly all of the phosphoric acid applied in the 

 fertilizers were assimilated. The addition of manure ashes favored nitrifica- 

 tion and furnished a good source of assimilable phosphoric acid. The use of 

 sterilized manure reduced nitrification and such manure was but slightly 

 superior to manure ashes as a source of assimilable phosphoric acid. The 

 nitrogen of the manure was assimilated to a much less extent than the phos- 

 phoric acid. 



The results indicate that manure exerts a beneficial effect through its min- 

 eral constituents and biological properties, but an unfavorable effect, particu- 

 lary on nitrification, through its dead organic constituents. The results of the 

 pot experiments were confirmed in the main by those of field experiments, and 

 the general conclusion is drawn that the effect of manure in increasing yields is 

 due to the presence of nitrogen and phosphoric acid which is readily assimi- 



35128— No. 6—10 3 



