MANURES. 247 



it is desirable that it should be. In either case the manure should 

 be spread broadcast over the whole surface, and not applied 

 directly to the hill or furrow, for the reason that phosphoric acid 

 is most necessary in the development of the seed of the plant, 

 and generally during the latter stages of its growth, at a time 

 when the roots are supposed to occupy every part of the soil, and 

 when many of them, at least, would have passed beyond the 

 narrow limits of the hill or furrow. 



The application of phosphoric acid is not most profitable when 

 made most strictly in accordance with the generally accepted scien- 

 tific theories concerning its use by plants ; for it is shown by long 

 experience that it is not so active a manure for wheat as ammonia 

 is, although wheat contains, in the ashes of its seed, about 50 per 

 cent, of phosphoric acid ; and that it is a most valuable stimulant 

 for turnips, although the ashes of these contain only about 7 per 

 cent. Possibly the reason for this apparent discrepancy between 

 theory and practice is to be found in the fact that during the early 

 stages of growth, when the plant is acquiring its ability to make 

 use of the materials already contained in the soil, the phosphoric 

 acid is more necessary to the turnip than to the wheat ; whereas, 

 the wheat, by the time it requires a considerable proportion of 

 phosphoric acid, is in a condition to take up an amount which 

 could not be made use of by the young turnip plant. 



We often hear farmers make a distinction between manures 

 which act quickly, and those which are lasting ; and in ordinary 

 practice, the preference is almost invariably given to the "lasting" 

 manure. This idea is not founded, in my opinion, upon reason ; 

 for it may be stated, as a general principle, that manures are last- 

 ing only in proportion as they are "lazy." For example: 

 Twenty dollars' worth of whole bones, spread upon an acre of 

 land, would not produce a very marked efFect upon the crop im- 

 mediately following the application ; while twenty dollars' worth 

 of fine bone-dust would probably produce an excellent, and an 

 equal value of a good superphosphate — a capital result. On the 

 other hand, the effect of the whole bones would be perceptible on 



