253 



tional to the mineral elements of nutrition present in the soil in a soluble 

 or available form, and an excess of ammonia will not supply this defi- 

 ciency. The aim should be to apply enough and just those elements that 

 will increase assimilation of mineral constituents. Often the increase of 

 mineral food may prove effectual far beyond the increase of nitrogenous 

 matters, but the effect will depend most closelj^ upon the amount of CO2 

 and solar energy available for use, and the reverse must be remembered, 

 solar energy is limited by the amount of soil materials present. Endeavor 

 also to use salts of those acids which are present in the least quantity in 

 the soil. The effect of the addition of ammonium salts is not what NH3 

 would be, for they contain an acid which acts on the constituents of the 

 soil and renders the earthy phosphates more soluble in water. 



Experiment shows that trees die if the supply of mineral food is ex- 

 hausted, even though they be still supplied wath organic food in abund- 

 ance. It must be remembered that the roots of trees go down deep in the 

 soil and bring to the surface much that would not be available were or- 

 dinary crops grown on the field. 



An experiment made by George Ville will show the effect of fertilizers 

 upon vegetation. The plant taken for the investigation was hemp. The 

 characters of the plant taken into consideration are color, stature, weight : 

 " Seven soils were used. First, intense manure (100 kilos of N); second, 

 complete manure (75 kilos of N); third, manure without nitrogen ; fourth, 

 manure without phosphates ; fifth, manure without potash ; sixth, manure 

 without lime, and, seventh, soil without manure. Plants treated with in- 

 tense manure were of the deepest green, height 1.25 metres, weight 11.22 

 kilos; complete manure, height 1.20 metres, weight 11.15 kilos, color less 

 deep; manure without N, height .61 metres, weight 4.74 kilos, color yel- 

 lowish green ; manure without phosphates, height .97 metres, weight 8.22 

 kilos, color medium green ; manure without potash, height .40 metres, 

 weight 5.22 kilos, color light yellowish green ; manure without lime, height 

 1.15 metres, weight 10.57 kilos, color slightly paler than those without 

 phosphates ; plants in unmanured soil, height .18 metres, weight 2.17 

 kilos, color pale green." 



This experiment gives us a fair knowledge of the eflect of different fertil- 

 izers, and may be of some aid in the selection of those intended to be used 

 on orchard land. 



The object of this investigation has been to place at the disposal of thfe 

 fruit grower some definite knowledge of the drain upon his orchard land 



