United States Department of Agriculture^ 



BUREAU OF CHEMISTRY. 



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\ 1'LAX FOK COOPERATING IN TIIK STUDY OF AYAILAISLK 

 PLANT FOOD. 



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At the San Francisco meeting of the American Association of 

 Agricultural Colleges and Experiment Stations in isw), a committee 

 on cooperative work between stations and the Department was 

 appointed. 



The report of this committee was most favorable, especially with 

 reference to the desire for cooperation on the part of station workers. 

 Among the suggestions from the committee is the following : 



"A fourth type of cooperation is seen in those investigations which 

 require the combined work of many stations, for example, an attempt 

 to obtain definite information on the changes produced in plants by 

 environment, and the value of this factor in the study of the vary- 

 ing effects of soil and climate in some single crop. Such experiments 

 call for the work of many stations at the same time. It is manifest 

 that the uniformity and efficiency of the work would require that 

 such cooperation be arranged and supervised by some central organi- 

 zation; and it is equally manifest that the Department is best pre- 

 pared to undertake the task." 



In accordance with this suggestion, the Bureau of Chemistry 

 two years ago arranged for cooperative experiments as to the effect 

 of environment on the chemical composition of plants, and it now 

 desires to arrange a cooperative study of the methods for determin- 

 ing available plant food in soils, not only between the stations and 

 tin- Department of Agriculture, but between the stations themselves 

 and farmers who will be interested in the work. 



The intention is to arrange a systematic plot study, in which the 

 sr.MJing of the plots, sampling of the soil, harvesting of the crop, and 

 tin- chemical study of the soil will be the same in every detail, and 

 will be carried out by each of the stations taking part in the work, 

 there being a distribution of the material and results obtained from 

 rarli station among all stations taking part. From the analysis of 

 the crop will be determined the ability of the soil to supply plant 

 food, while upon the soil sample, taken previous to planting, efforts 

 will be made to secure chemically, as near as possible, the result 

 obtained by the crops. 



As a basis for analytical work, a method for the estimation of avail- 

 able P 3 O 5 and K>O is proposed by this Bureau. Detailed instruction 



