30 AGRICULTURAL EXPERIMEXT STATION. 



The present method of treating rock phosphates to make its 

 phosphoric acid available quadruples the cost of the phosphoric 

 acid to the consumer. 



The field for investigation in the direction of reducing this cost, 

 by the means of less expensive methods of preparation, is a 

 promising one. 



The successful experiments in the use of the "Thomas Slag" as 

 a source of phosphoric acid certainly gives encouragement to work 

 in this direction. That some plants can obtain nourishment from 

 sources that are not available to other plants seems to be well 

 established. 



Investigations as to what plants are especially well adapted for 

 extracting phosphoric acid and potash from their most insoluble 

 compounds should be prosecuted vigorously. 



It does not seem improbable that facts might be brought to light 

 from such investigations that would be of great use in devising 

 systems of crop rotation in which gTound phosphatic rock and 

 feldspar might be made the chief source of phosphoric acid and 

 potash. The researches of Dr. Atwater on the atmosphere as a 

 source of nitrogen to plants were followed by results which warrant 

 a further investigation of the subject. If there is any class of 

 plants which will gather any considerable quantity of nitrogen from 

 the atmosphere during their growth, they should be made to con- 

 tribute to the supply of nitrogenous manures. 



The number of lines of investigation in feeding plants which may 

 possibly lead to valuable practical results is great, but the most 

 important are those which have for their object cheaper fertilizers 

 for the farmers. 



Box Experiments with Fertilizers. 



The station has commenced experiments which we hope will aid 

 in solving some of the problems concerning fertilizers, alluded to 

 above. 



In 1887, boxes three feet square and one foot high, without 

 bottoms, were procured and set in the earth in the open field. In 

 the spring of 1888 three boxes were filled with loam that had been 

 piled up in a heap and shoveled over many times in order to make 

 it as uniform as possible. One set of these boxes was left without 

 the application of fertilizing material of any kind. The remaining 



