556 EXPERIMENT STATION RECORD. 



"The neutral «)r l)asir phosphatic manures, such as basic slag or basic superphos- 

 phate, are in the insoluble form already, and being comlnned chiefly with calcium, 

 the greater part of the phosphoric ac-id is thus available for plant food; this l)eing 

 especially the case with basic superphosphate, the whole of whose phosphoric acid 

 is soluble in citric acid solution." 



Soil chemistry and bacteriology, J. G. Lipman {New Jersey Stas. Rpt. 1901, pp. 

 21S, 214, pf- 1)- — ^ brief statement of the proposed work of this new department of 

 the station, with a description of a method of securing samples of soil for examina- 

 tion. 



On the classification of soils, K. O. B.I0Klykke {Ber. Norges Landbr. Hoiskoles 

 Virks., 1901-1902, App. pp. 3-38, Jigs. 16). 



FERTILIZERS. 



Handbook of fertilizers, 31. Passox [Handbuch des Dungewesens. Leipzig: M. 

 Heimins Nachfolger, 1902, pp. X + 333). — The history of the use of fertilizers in 

 ancient and modern times is traced ; the composition of the plant and soil with ref- 

 erence to fertilization, methods of improving soils, and the nature and use of natural 

 and artificial manures and fertilizers are discussed; and the methods of applying 

 fertilizers to particular crops are explained. There is also a chapter devoted to the 

 best means at the disposal of the farrier for determining the fertilizer requirements 

 of his soils in which a simple sedimentation method of mechanical analysis, the 

 author's apparatus and method for determining calcium carbonate (E. S. R., 13, p. 

 319) , and a plan for plat experiments are described and the practical application of 

 the results so obtained is briefly explained. 



Phosphates, H. J. Patterson {Pennsijlvania State Dept. Agr. Bui. 94, pyp- 87). — 

 A very full discussion of the source" and forms of phosphoric acid used in agriculture 

 and their methods of preparation and application, based to some extent on compiled 

 information, but largelj^ on the author's investigations carried on at the Maryland 

 Station for several years (E. S. R., 12, p. 930). 



"All of the experiments which have been conducted upon the use of phosphoric 

 acid in agriculture have given results which seem to warrant the general statement 

 that much of the practice now followed in the use of phosphates is not founded upon 

 facts. . . . 



"There is no doubt but that tlie first step in the economical use of phosphates is 

 to imitate nature and endeavor to keep the soil well supplied with organic matter; 

 for it is only by such means that the phosphates contained in the soil naturally and 

 those applied artificially can be fully utilized by the cultivated crops. 



" It is very evident from all the tests cited that some crops, particularly the turnip 

 family, have a greater ability than others to use crude or insoluble phosphates, and 

 these experiments would certainly teach thjrt the aim should be to employ such 

 crops for rendering insoluble phosphates available and by such a practice save much 

 that is now being spent for sulphuric acid and the cost of manufacturing the soluble 

 phosphates. 



"The experiments, in most instances, show that the presence of carbonate of lime 

 is of considerable advantage in increasing the availability of phosphates. 



"Some of the testa show that the iron and alumina phosphates are much more 

 valuable as plant foods than is generally considered; in fact, under some circum- 

 stances they seem to be as soluble and even superior to lime phosphates. 



"In regard to the so-called available phosi^horic acid of commercial fertilizers, the 

 results all j)oint to the fact that there is no difference in it depending upon its source; 

 that is, a pound of available phosphoric acid from a mineral source is just as valuable 

 as a pound from an organic source. . . . 



