ably quick use of the constituent when appHed in organic ^^'^^ ^^^ 



materials, it is necessary, first, to select those likely to change _^^ 



rapidly, and second, to depend upon favorable weather con- "5 

 ditions — i.e.y warm and moist — in order that a rapid change 

 into soluble and available forms can take place, and thus 

 permit the plant to obtain its nitrogenous food — that is, it is 

 possible, in the use of these forms, which must undergo a 

 change, to get very meagre returns, though an amount is 

 applied largely exceeding that necessary for the crop, either 

 because the Nitrogen may have been in such combination 

 as to strongly resist decay, or the season may have been such 

 as to render the change, in even high-grade materials, so slow 

 as to prevent the plant from obtaining a sufficient amount to 

 meet its demands. The second, or ammonia, form of Nitro- 

 gen is immediately soluble, and is readily distributed in the 

 soil by means of the soil water; it is then fixed until changed 

 into the Nitrate {orm, which takes place rapidly under average 

 seasonal conditions, though an appreciable time must inter- 

 vene between the date of its application and the time it can 

 be used. In the case of the third form, the Nitrate, no condi- 

 tions modify its availability; it is readily soluble, and imme- 

 diately distributes itself by means of the soil water every- 

 where in the soil, and as it comes in contact with the roots 

 of the plants is at once absorbed by them, and continues to 

 be absorbed until used up, or so long as there is sufficient 

 moisture in the soil to cause activity in the plant itself. The 

 availability of the Nitrogen in the various materials may, 

 therefore, range from practically nil to lOO per cent., making 

 the matter of selection of material exceedingly important. 



In the third place, because Nitrogen, in this immediately 

 available form, is so readily soluble and so completely carried 

 in the soil water, there is danger of its loss by leaching — that 

 is, while there is no question as to the usefulness of this form 

 of Nitrogen — i.e.. Nitrate — so far as its absorption by the 

 plant is concerned, the best results are not always obtained 

 from its use, because advantage is not taken of its peculiar and 

 valuable characteristics; it is completely soluble in the soil 

 water and distributes itself readily everywhere in the soil, 

 and wherever it comes in contact with the feeding rootlets 

 it is bound to be taken up, hence, when the applications are 

 not properly adjusted, there may be an abnormal and inferior 

 development of plant, because of too large a use of Nitrogen, 



