22 AGRICULTURE. [CH. 



only that portion of the soil which is capable 

 of being dissolved by rain-water which is 

 available as food. It is of jio_42ractical advantage 

 to a growing plant, that the soil should contain food 

 which will not be ready for use until the next year, or 

 the next century. The life and growth of the plant is 

 determined by the supplies which are then ready 

 for use, or corning into use. 



37. It has therefore been necessary to distinguish 

 the inorganic matter according to its soluble condition. 

 Those portions of the soil which are ready 

 for use, or in other words, can be dissolved in rain- 

 water, are known as the active^mgredients of the 

 soil; whilst those which areribt ready for 

 use, because they are not soluble in rain-water, 

 are termed dormant or sleeping. The distinction 

 between the two conditions is exceedingly simple; 

 but the influence resulting therefrom is of the greatest 

 importance. An analysis of a soil which represents 

 the total composition of a soil, is of little or no prac- 

 tical value, unless it distinguishes between 

 that which can be used by the crop, and 

 that which cannot. The fanner wants to know 

 what ingredients the land contains, which will be of 

 service for the crop he is going to sow, and if an 

 analysis leads him to rely upon all the substances in 

 the soil being ready for his use, he will be deceived. 

 For all practical purposes, a chemical analysis must, in 

 the first place, separate the dormant matter of the 

 soil from that which is active, and must thus inform 

 the farmer what there is in the soil which he can 

 make use of. Without this distinction being drawn, 

 the chemical analysis of soils may be of scientific 

 interest ; but it will be calculated to mislead those 

 who fail to distinguish between that which can be 

 used, and that which cannot be used, or, in other 

 words, between the active and dormant con- 

 stituents of the soil. 



