1921.] PUBLIC DOCUMENT — No. 31. 27 a 



vegetation experiments conducted by the fertilizer control 

 section. 



The fertilizer section has also analyzed 281 different sub- 

 stances sent in by farmers and by the various departments of 

 the Experiment Station. In case of the large ninnber of soil 

 samples which have been examined, the tests made have been 

 largely confined to a determination of the lime absorption 

 capacity of the soils and their content of organic matter. It 

 might be said with reference to the testing of the great variety 

 of fertilizer by-products that an effort has been made, as in 

 the past, to give reliable information in each case as to the best 

 method of utilizing said by-products. 



Vegetation Tests. — The following experiments were planned 

 in the fertilizer section, but the details of growing the crops 

 have been left, in all cases, to the Agricultural Department. 



A pot experiment comprising 60 pots, with millet as a crop, 

 was conducted to study the availability of the water insoluble 

 organic nitrogen in certain commercial fertilizers found in the 

 1916 fertilizer inspection work. Many of these samples were 

 considered of suspicious quality so far as their organic nitrogen 

 source was concerned. The purpose of the experiment was to 

 make further studies of the results of laboratory methods as 

 compared with those obtained in vegetation tests. This work 

 was planned several years ago, but due to a scarcity of coal 

 it has not been possible to operate the greenhouse during the 

 winter months, and this season presented the first opportunity 

 for making the test. 



An experiment comprising 12 pots, with oats as the crop, was 

 conducted to show the residual effect of peat mixtures with and 

 without commercial bacteria. This was a continuation of a 

 pot experiment begun in 1919. 



Another experiment was carried out, using 23 pots with 

 tomatoes as the crop, to compare the effect of bacterized peat 

 with peat which contained no commercial bacteria. This was 

 to parallel work conducted in the field with tomatoes and 

 potatoes during the seasons of 1919 and 1920. 



The tile experiment with apatite and barium sulfide, begun 

 in 1919, was continued this season, with oats followed by buck- 

 wheat as the crop. This experiment comprises 46 tile. 



