Food for between the date of its application and the time it can be 

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

 4* 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 100 per cent., making 

 the matter of selection of material exceedingly important. 



In the third place, because Nitrogen, in this immedi- 

 ately available form, is so readily soluble, and so completely 

 carried in the soil water, there is danger of its loss by leach- 

 ing that is, while there is no question as to the usefulness of 

 this form of Nitrogen i. e., Nitrate so far as its absorp- 

 tion 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 applica- 

 tions are not properly adjusted, there may be an abnormal 

 and inferior development of plant, because of too large a use 

 of Nitrogen, or, as it forms no fixed compounds in the soil, 

 there may be a loss from leaching into the drains when ap- 

 plied previous to the growth of the plant or in too large quan- 

 tities at the wrong time. 



In the fourth place, it should receive careful attention, 

 because its right use as a Nitrate its most available form- 

 permits, not only an economical utilization by the plant, but 

 a control of its growth; it may be used in such a way as to 

 change the natural tendency, and thus improve it for specific 

 uses; thus, in addition to the increase in yield which it may 

 cause, it enhances the market value of the plant. 



As already pointed out, the mineral cle- 

 ric Acid ments potash and phosphoric acid are 

 relatively cheap as compared with Nitro- 

 gen. In the case of potash, the availability 

 Nitrogen. Q f ^ different forms in which it is usually 



obtained is not a matter of great importance, since all forms 

 are soluble in water, distribute freely in the soil and are 



