388 



B. 72; Bu. of Soils Cir. 7; Fla. E. S. B. 43; Fla. E. S. B. 87; Bu. of 

 Soils Cir. 21 ; Bu. of Soils Cir. 19 ; Univ. Idaho B. 9 ; Univ. Idaho 

 B. 28; Univ. Idaho B. 49; Univ. 111. B. 150; Univ. 111. B. 108; Univ. 

 111. B. 99; Univ. 111. B. 123; Iowa Col. B. 82; Iowa Col. B. 94; Ky. 

 Ag. Col. B. 126; Univ. Minn. B. 65; Miss. E. S. B. 132; Miss. E. S. 

 B. 58; Miss. E. S. B. 66; Univ. Mo. Bs. 3, 83, 92, 86, 84 88, 93; 

 Bu. of Soils Cir. 3; Cornell Univ. B. 119; Nev. E. S. B. 39; Bu. of 

 Soils Cir. 20; N. Dak. E. S. B. 24; 0. E. S. B. 150; R. I. E. S. B. 

 121; R. I. E. S. B. 139; Univ. Tenn. B. 3; Univ. Tenn. B. 78; Tex. 

 E. S. B. 43; Tex. E. S. B. 100; Tex. E. S. B. 125; Tex. E. S. B. 99; 

 Utah Ag. Col. B. 52; Wash. E. S. B. 85; Wash. E. S. B. 34; Kept. 

 No. 7, Wyo. E. S. ; Univ. of Cal. Cir. 18 Bu. of Soils; R. I. E. S. B. 

 131; R. I. E. S. B. 120; R. I. Ag. Sta. B. 109; R. I. Ag. Sta. B. 

 131; Rept. Sec. of Nova Scotia, 1909; Bu. of Soils B. 25; Bu. of 

 Soils B. 22. 



FERTILIZATION AND FERTILIZERS. 



THE GREAT AGRICULTURAL PROBLEM. 



Preserving Productivity. The foundation of the material 

 wealth of this nation and its position among the nations of the world 

 is the productive capacity of its soils, and, under favorable climatic 

 conditions, there are three principal methods of controlling this pro- 

 ductive capacity. These are (1) cultivation, including drainage and 

 irrigation; (2) rotation of crops, and (3) fertilization. Of these, 

 cultivation and rotation are in the hands of the farmer himself. 

 Fertilizing materials, however, have, to a very large extent, to be 

 gathered for him from different parts of the world and manipulated 

 to some extent before they are ready to be applied to the lands. It is 

 generally believed that simple fertilizers, such as muriate of potash, 

 nitrate of soda, or plain superphosphates, when used alone are neither 

 as safe nor as efficient as when used in combination, and as they can 

 usually be mixed more thoroughly by machinery and more cheaply 

 in large quantities, the practice has grown of buying them ready 

 mixed from dealers or manufacturers. 



The character of the materials which can profitably be used in 

 these mixtures and the proportion in which the valuable constituents 

 should be contained for the best results for different soils and crops 

 have been a perplexing problem for the manufacturer as well as for 

 the farmer, and have been the subject of much investigation by ex- 

 periment stations for the past half century. 



As a result of the investigations of the experiment stations, we 

 have a fair number of fertilizer materials^which can be obtained at 

 prices justifying their application to soils to which they give a mod- 

 erate increase in crop production! 'On account, fainofver, of their un- 

 certain action, due largely to seasonal differences and changing soil 

 conditions, and of lack of knowledge as to just how they act on the 

 soil or on the plant, we still have little exact knowledge of the kind 

 of material adapted to different soils or crops or the proportions in 

 which the several ingredients should be combined. 



