224 



<tl:le to draw all of the nitrogen that may be needed out of 

 the air by means of cover crops. 



In so far as phosphoric acid is concerned, I believe that 

 i>ecause of the slo^v circulation of phosphoric acid in the 

 ;&;oil, that it would be profitable to use material containing 

 Teadily available phosphoric acid in the growing of fruit. 

 Now as to the amount, that would depend entirely of course 

 oil the age of trees and the set of fruit and climatic condi- 

 tions and various other things. 



As to potash, there is a great deal of interest just at 

 present in potash because it is not accessible to us in any 

 considerable quantity nor at any reasonable price. If the 

 land is light enough and if the crops are large enough, surely 

 the lighter soils would justify the use of potash in the grow- 

 ing of peaches, apples and pears. It will depend largely in 

 my opinion, on the soil. I believe if the soil is heavy enough, 

 it may be found that the use of potash would not give re- 

 turns that Avould warrant the use of potash fertilizers. It 

 !■! a soil question to a great extent, and a question of those 

 other factors which I discussed, factors of vegetable matter, 

 or lime and of tillage, which of course are bound to vary 

 from one orchard to another, but if the soil is thin, or if the 

 amount of vegetable matter is low, even in the heavier land, 

 the use of potash salts might be justifiable and profitable, 

 but just now we are confronted by the problem of placing 

 a larger supply of |)otash at the disposal of the trees as well 

 iiS of other crops. 



We have thought a great deal about ways and means of 

 making more readily available the potash supplies in the 

 si;il itself, because, after all^ most of our heavy soils are 

 exceedingly well provided with potash. There is hardly 

 any danger of exhausting them, surely not in the case of 

 I'j'uit trees. But the problem is how to make a sufficiently 

 large amount of potash available within the growing season 

 to supply the maximum needs of the crop? You will find 

 that there is a difference of opinion among soil specialists, 

 as to how that might be best accomplislied under existing 



