BUREAU OF SOILS. 491 



One of the striking things in intensive agriculture has been the 

 experience that hinds long under irrigation change in character and 

 become more like humid soils than soils of the arid regions. While 

 it is reasonable to suppose that virgin soils, particularly under irriga- 

 tion, should be of great and of lasting fertility, it is an actual fact 

 that after a lapse of comparatively a few years' occupation the need 

 of fertilizers is felt, and the largest applications of fertilizers are 

 now being made to keep up the productivity of the irrigated soils of 

 the dry regions of the West. An appropriation should be requested 

 to study specifically the changes in the irrigated h'uds of the West 

 in order to furnish a basis for the intelligent use of fertilizers or 

 other efficient means of maintaining the productivity of the soils 

 under such artificial conditions. 



In the physical laboratory an increase should be made for research 

 investigations in soil physics, with particular reference to aeration, 

 heat, and moisture relations, subjects which have long been under 

 investigation by the bureau and in which a great advance in knowl- 

 edge is now taking place. 



An appropriation should be made for soil management investiga- 

 tions, including particularly practical methods of controlling the 

 physical condition of the soil through tillage. Tillage is one of the 

 three methods for the control of soil productivity, the other two being 

 rotation of crops and fertilization, and it is considered very im- 

 portant thatthe laboratory extend its operations to include practical 

 methods of soil control through tillage. This it would be entirely 

 practicable to do if funds were available. 



In the fertilizer laboratory an increase is needed for the investiga- 

 tion of natural and artificial sources of supply of fertilizer material. 

 During the past fiscal year an emergency appropriation of $2,500 was 

 available after the 4th of March, and during the present fiscal year 

 $10,000 was available for this work. Sufficient information has been 

 accumulated to justify the belief that by the first of December a 

 special report can be prepared showing that it Is not unreasonable to 

 expect that available sources of potash and of nitrate of soda can be 

 found in this country and that our phosphate supply can be more 

 economically used than at present. 



An appropriation should be made for the purpose of investigating 

 the method of handling and manufacturing fertilizer material and 

 farm manures to realize the greatest possible benefit to the farmer. 

 The fertilizer manufacturers themselves realize the importance and 

 necessity for this work, particularly in view of the present knowledge 

 of fertilizer use which is being developed by the Bureau of Soils. 

 Changes take place in the manufacture and storage of fertilizers that 

 cause inexplicable results in the crop. The idea of reversion of 

 phosphates, the change in the composition of mixed fertilizer ma- 

 terial on standing, the preparation and availability of waste products 

 in the preparation of fertilizer ^oods all require investigations and a 

 thorough understanding to maintain the grade of goods that will 

 insure reasonably uniform success when applied to the soil. The 

 importance of this work in itself, as well as the magnitude of the 

 commercial fertilizer business and the willingness and desire of 

 the manufacturers to understand these matters, all combine to justify 

 the appropriation requested. 



