122 BOARD OF AGRICULTURE. [Pub. Doc. 



material is such as to make it much less desirable for mix- 

 tures, although it can be mixed readily with potash salts 

 and nitrate of soda. It is also very heavy, and not so easily 

 distributed as the other phosphates. 



Where it can be obtained at reasonable prices, its use is 

 strongly recommended, being far superior to the ground 

 phosphate rock, either of the nodular or apatite form. It is 

 especially useful for acid soils, for soils rich in vegetable 

 matter and for sandy and clay soils deficient in lime. Its 

 value from the standpoint of availability, of course, is 

 measured to a large extent by its fineness of division. 



Plants nmst have and all soils must be provided with a 

 suitable proportion of food, soluble, available, digestible, if 

 the crops are to acquire enough food to make profitable crops. 

 One advantage possessed by those insoluble materials, in the 

 opinion of some, is that they prevent the soil from being 

 exhausted ; this is true, but there are many soils which have 

 enough phosphates in them to gTow maximum crops for a 

 hundred years which will not grow a decent crop if not 

 properly managed, and the further addition of substances of 

 this sort will not cause " two blades to grow where one grew 

 before." 



It does seem, therefore, that, with this knowledge of phos- 

 phates, the farmer should be able to utilize the various ma- 

 terials at his command in such a way as to derive the greatest 

 benefit in yield or crop, as well as in returns per unit of cost. 

 That is, not only to be paid for the material and its appli- 

 cation, but to give such an increase in crop as will give him 

 a profit, while at the same time to have left in his soil at 

 the end of a year more of the mineral elements that he had 

 when he started. This is the crucial test of a good farmer, 

 — one who not only grows large but profitable crops, — and 

 after he has grown them his soil is left in better condition 

 than when he started. 



Farmers also know that another element of great im- 

 portance on many soils is potash ; and farmers from the 

 earliest times have recognized the value of wood ashes, whose 

 chief usefulness depends upon the potash that they contain. 



