This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1910 edition. Excerpt: ...rock, it might be stated that the Experiment Station at Auburn has, during the past few years, carried out under its supervision more than one hundred cooperative soil and crop tests in a great many different localities in the State with a view to determining the comparative efficiency of raw phosphate and acid phosphate for fertilizing purposes. These tests have been carried out upon quite a variety of soils, and upon most soils the Raw Phosphate Has Failed To Give Anything LIKE AS GOOD RESULTS AS THE ACID PHOSPHATE. "In the case of acid phosphate, the ready solubility of most of the phosphoric acid contained therein promotes its rapid and thorough distribution through the top layer of the soil, and hence the plant food is so well disseminated that it is brought within easy reach of the root system of the plant, whereas in the case of the crude insoluble phosphate the diffusion and distribution of the phosphoric acid is necessarily slow, and much of the phosphate is left unutilized at the end of the season in which it is applied. "For the above reasons It Is Deemed Inadvisable To Employ The Crude Phosphate to any great extent upon any given soil until comparative tests of the crude rock and acid phosphate have been made upon that soil, and, even under these conditions, it will probably be found necessary to use much larger amounts of phosphate rock than are ordinarily employed to secure a satisfactory return from its application." While the experience of the German Experiment Stations, combined with a majority in this country, show emphatically that raw rock phosphate has little or no fertilizing value, in addition the method of applying followed by users of this material in this country is Most Extravagant And Wasteful. The method ... Это и многое другое вы найдете в книге Soil fertility and permanent agriculture (Cyril George Hopkins)