THE SOIL AS AN ASSET 217 



the paper it is written on so far as telling what 

 that soil will produce at any given time. 



The old school accept this as true because 

 they know that such an examination gives 

 them only the bulk of the minerals present, 

 with no indication of how great a percentage 

 may be "available," as they say. What is 

 "unavailable" to-day may be available to- 

 morrow or next week or next month, accord- 

 ing as a variety of causes operate to liberate 

 the "plant food." 



The new school reject such an analysis on 

 the ground that the mineral content is never 

 in a stable condition. It is constantly being 

 added to, or subtracted from, by profound 

 forces active at all times. They do not bother 

 themselves with the query whether or not the 

 "plant food" is available, as they believe, if the 

 minerals themselves are present, the plant food 

 is available in fixed proportions at all times. 

 Whether or not the plant can make use of 

 them is another matter, determined by the 

 proper functioning of the plant itself, and the 

 soil itself. 



What is of utmost importance, however, is 

 the physical condition of the soil. This affects 

 its immediate cropping qualities. It tells the 



