EXPERIMENT STATION BULLETINS. 299 



food, and they should not be condemned when they fail to produce re- 

 sults if the real cause of low yields is due to some other condition. 



The "best results from the use of commercial fertilizers will be obtain- 

 ed, only, when all of the conditions affectifig plant growth are as nearly 

 perfect as it is possible to make them. "Fertilizers are foods (not stim- 

 ulants) for healthy soils. They are not medicine for sick land." 



Study your soil conditions and by experimenting determine what 

 forms of plant-food, if any, are required and in what amounts they 

 should be used to produce the most economical results. Only in this 

 way can these questions be definitely answered. 



LICENSED BRANDS. 



Thirty-six manufacturers and fertilizer companies have licensed 303 

 distinct brands for sale in the State during the season of 1915. The 

 brands appearing in the following tables of analyses, and none others, 

 can be legally sold. 



Parties mixing or importing fertilizers for their own use and not for 

 sale are not affected by the restrictions of the law and neither are they 

 protected under it. 



COLLECTION OF SAMPLES. 



The analyses reported in this bulletin were made on samples collected 

 by inspectors sent out from the Experiment Station. The inspectors 

 cover practically all parts of the State where fertilizers are sold, and 

 the samples are drawn from stock in the hands of dealers by means of a 

 specially constructed tube with which a core from the entire length of 

 the bag is secured. In no case is a sample taken from a lot containing 

 less than five bags nor from a bag that has previously been opened. The 

 samples are drawn and sealed in the presence of a witness and shipped 

 to the laboratory for analysis. For the first time, samples were taken 

 of the fall shipments and the analyses reported in this bulletin repre- 

 sent both spring and fall shipped goods. The inspectors failed to find 

 three of the licensed brands on the market and upon investigation it was 

 found that in one of these cases at least, the particular brand was not 

 shipped into the State. 



RESULTS OP INSPECTION. 



(a) Quantity of plant-food. 



A study of the tables of analyses shows that, of the 358 samples 

 analyzed, representing 300 brands, 74 (20.7%) are below guarantee* in 

 one or more constituent. Twenty-one (5.9%) are below guarantee in 

 nitrogen, 19 (5.3%) are below in available phosphoric acid, 5 (1.4%) in 

 total phosphoric acid and 33 (9.2%o) in potash. 



*A shortage of more than 0.10 per cent of nitrogen or mofc than 0.20 per cent available phosphoric acid or potash Ls con" 

 Bidered below guarantee. 



