376 



BOARD OF AGRICULTURE. 



* The average composition of ground bones is assumed to be equal to 24 per cent, of phos- 

 phoric acid, besides 3.5 per cent, of nitrogen in animal matter at 30 cents per pound. 



The present low price of phosphoric acid in some of these 

 mineral phosphates deserves the particular attention of those 

 of our farmers who aim at a permanent improvement of their 

 soil resources. These phosphates act, of course, very slowly 

 under ordinary circumstances ; yet in form of a fine powder 

 they pay well, if applied with a due consideration of the causes 

 which favor their solubility. As carbonic acid acts powerfully 

 on the disintegration and final solution of all kinds of phos- 

 phates, it is but reasonable to assume that satisfactory results 

 may be secured by incorporating daily a certain amount of 

 finely-ground phosphates — as South Carolina, Navassa, or 

 Sombrero guano, even apatite, etc. — into barn-yard manure, or 

 by composting them in the earlier part of the year and apply- 

 ing in the fall upon meadows and pasture-lands, or upon soils 

 rich in humus. These phosphates, in their finely-divided 

 condition, are apparently in no less suitable form for assimi- 

 lation than a large proportion of the original phosphoric acid 

 in the cultivated soil at times has been ; they increase the 

 stock of that acid for future crops at a small expense. We 

 are too much inclined to judge the entire agricultural value of 

 a fertilizer merely by the crops we chance to get in the first 

 or second year, and forget too frequently that the condition 

 in which the soil is left after the crops have been removed 

 ought to enter as a very important factor in the final calcula- 

 tion of profit derived from the use of a fertilizer. Numerous 

 experiments of German agriculturists with their native "phos- 

 phorites" leave no doubt regarding the good economy of 



