114 MAINE AGRICULTURAL EXPERIMENT STATION. I913. 



oratory as a check upon the results that may be expected in 

 the field. 



EXPI,ANATI0N OF THE TaBLES. 



Under the head of "Nitrogen" in the tables are found eight 

 columns of figures under the following headings : 



1. The nitrogen from nitrates. In this column is given the 

 percentage of nitrogen present as nitrate. Nitrate nitrogen is 

 wholly and quickly available. 



2. Nitrogen from ammonia salts. In this column is given 

 the nitrogen from ammonium salts, chiefly sulphate. Ammonia 

 nitrogen while not usually as quickly available to the growing 

 plant as nitrate nitrogen is completely available. 



3. Water soluble organic nitrogen. This is the soluble ni- 

 trogen from organic materials, such as dried blood, dried fish 

 or meat, tankage, cottonseed meal, etc. It dissolves in water 

 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 organc 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 excepton that inverted and 

 in'soluHe phosphoric acidsi are this year omitted. If it is 

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

 found by subtracting the available from the total as given in 

 the table If it as desired to know what the reverted pho^s- 

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

 tracting the soluble phosphoric acid from the available. 



