Il6 MAINE AGRICULTURAL EXPERIMENT STATION. I914. 



and is supposed to be quickly and completely available to the 

 plant. 



4. Active water insoluble organic nitrogen. The nitrogen 

 in this column is that portion of the organic nitrogen which is 

 insoluble in water but is converted into ammonia by the action 

 of the permanganate of potash solution. This is probably quite 

 readily available to plants. 



5. Inactive organic nitrogen. This is the portion of the 

 organic nitrogen that is not converted into ammonia by the 

 action of the permanganate solution. It is probably only slowly 

 available to plants. 



6. Available or active nitrogen. In this column is given the 

 sum of the percentages found in the first four columns, viz : 

 nitrate nitrogen, ammonia nitrogen, water soluble organic nitro- 

 gen and active water insoluble organic nitrogen. 



7. Total nitrogen found. 



8. Total nitrogen guaranteed. 



Phosphoric Acid. Under the head of "phosphoric acid" are 

 given the usual columns with the exception that inverted and 

 insoluble phosphoric acids are this year omitted. If it is de- 

 sired to know what the insoluble phosphoric acid is it may be 

 found by substracting the available from the total as given in 

 the table. If it is desired to know what the reverted phos- 

 phoric acid is for a given sample this may be found by sub- 

 tracting the soluble phosphoric acid from the available. 



Potash. No change is made in the arrangem.ent of the potash 

 results. The potash found and that guaranteed by the manu- 

 facturer are given. 



THE MEANING OF THE RESULTS 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 of 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 



