68 Maine Agricultural Experiment Station. 1919. 



ate ar.d sulphate for growing crops. The law calls for the total 

 water soluble potash and that is what is given in the table. 



How Can the User of Fertilizers be Protected by the 



Law? 



During the past 20 years there has been such a decided 

 economic change that fertilizer manufacturing has been prac- 

 tically revolutionized. Less than a generation ago fertilizers 

 were practically all made by the use of a few standard materi- 

 als such as nitrate of soda, sulphate of ammonia, dried blood, 

 dissolved bone black, and muriate or sulphate of potash. When 

 a manufacturer put out a definite formula it practically always, 

 year after year, carried the same constituents in practically the 

 same proportions. Furthermore these goods were shipped into 

 large storehouses in Maine and it was possible for the inspector 

 to go to these storehouses and draw a sample from packages 

 out of a lot of a 100 to 500 tons of each brand. Because of the 

 rather comparatively uniformity of manufacture and the sam- 

 ples taken from such large shipments the occasional random 

 sample fairly represented the goods which were given to the 

 consumer. 



For many years the chief change made was in the source 

 of phosphoric acid which is- largely now from acid treated phos- 

 phatic rock. The acid phosphate thus resulting is chemically 

 identical with dissolved bone black, and the substitution made 

 no difference. 



But gradually there was a great change in the organic nitro- 

 gen situation. Dried blood became altogether too valuable for 

 feeding purposes to be used as a fertilizer. It was replaced 

 with high grade tankage which in turn came to be used more 

 and more as a feeding stuff until only low grade tankage con- 

 taining a large amount of bone was available. The economic 

 situation led to the saving and the using of materials of inferior 

 quality which would not have been tolerated in earlier years. 

 This, however, has been partly overcome by a wet process of 

 treatment where under the action of sulphuric acid many of 

 these low grade ammoniates which are of low activity and 

 availability are rendered active and available. Also after the 

 beginning of the war potash salts which had been obtained 



