J30 MAiNi; AGRICUI.TURAL e;xpe;rime;nt station. 1912. 



The Meaning 01? the Rksuets Found for Nitrogen. 



In order to obtain an idea of the value of the organic nitro- 

 gen in any given brand from the figures given in the table, it 

 is necessary to compare the columns of active insoluble and 

 inactive insoluble nitrogen, and also take into consideration 

 the amount of soluble organic nitrogen. That is, the organic 

 nitrogen is valuable in proportion as the percentage o± the 

 •active is greater than the inactive, and the amount of water 

 soluble is large or small. A fertilizer showing more than twice 

 as much active as inactive insoluble nitrogen would be rated as 

 high grade. Also in one carrying a quite large percentage of 

 water soluble and small amounts of active and inactive water 

 insoluble the nitrogen would be likewise rated as high grade. 

 One showing a small amount of water soluble and a larger 

 amount of inactive than active would be classed as a poor grade 

 if organic nitrogen. The percentage of inactive as compared 

 with the total organic is the measure of the value of the organic 

 nitrogen in the goods. With a fair amount of organic nitrogen 

 soluble in water, a large per cent of active and a small amount 

 ■of inactive, the organic nitrogen is considered good. If but a 

 =;mall amount is soluble in water and less active than inactive 

 is found the organic nitrogen would be considered low grade. 



The column headed "available nitrogen" is somewhat ana- 

 logous to the available phosphoric acid column which has been 

 used for years. It cannot, however, be railed upon without 

 reference to the other results reported in the table. While as a 

 general rule the nearer the figures in the available column ap- 

 proach to the figures in the total nitrogen column the better the 

 grade of nitrogen in the goods this must be construed in con- 

 nection with the other preceding figures. The mineral nitrogen 

 is all available and consequently must be taken into considera- 

 tion in estimating the availability of the organic nitrogen. This 

 may be illustrated as follows: If a fertilizer contains 3.50 per 

 ■cent total nitrogen and the percentage in the available column 

 is 3 per cent or more the nitrogen would be considered high 

 grade, particularly if the nitrogen is largely organic, i. e., con- 

 tains only a small per cent of mineral nitrogen. If, however, 

 a fertilizer of the above nitrogen content carried over 2 per 

 cent of its nitrogen as mineral, an availability of only 3 per 

 cent would show the organic nitrogen to be of a poorer quality. 



