FERTILIZING 



in round figures, of ioo pounds each of wood and leaves and 

 700 pounds of fruit, with 35 trees to the acre. 



Fruit 



Total 



Annual weights 

 Nitrogen . . . 

 Phosphoric acid 

 Potash .... 

 Lime .... 

 Magnesia . . . 

 Iron 



35°° 



11 -3 

 3-6 

 6.6 



29.1 



44 

 •5 



3500 

 25.6 



5-3 

 15-9 

 29.5 



8.9 



24500 

 16.2 

 6.4 

 41.5 

 3- 

 3-4 



3'Soo 

 53-i 

 15-3 



64. 



61.6 



16.7 



It is evident that important amounts of plant food are annually 

 removed from the soil by an apple orchard, and that unless ade- 

 quate returns are made, plant food will become a limiting factor 

 in any vigorous and productive orchard. 



Functions and effects of minerals. We shall attempt to show the 

 various functions and characteristic effects of the more important 

 of these minerals and of nitrogen in the apple plant. We do not 

 yet have an exact knowledge of all the functions of these elements 

 in the plant. Therefore the following summary is not complete, 

 but the functions given are the commonly accepted ones. 



Nitrogen. This element, with sulphur and phosphorus, serves 

 chiefly in the formation of protein and protoplasm. It therefore 

 occurs largely in the living areas — such as the cambium layers, leaf 

 mesophyll, and growing tips — and in seeds and other food-storage 

 organs. Like phosphorus, it migrates very strongly from the older, 

 more mature, or dying tissues of plants to the living portions and 

 toward the heads or upper portions. Like potash and soda, the 

 assimilated nitrogen is apparently subject to considerable losses as 

 maturity is reached and passed, due to migration and to the action 

 of rain and dew. 



In general, the effect of nitrogen applications is to produce a 

 strong vegetative growth and to retard greatly the maturity and 

 ripening of most plants. 



Phosphorus. This element is an essential constituent of nucleo- 

 proteids and renders their formation possible. It is therefore 

 necessary for cell divisions and for all new growth, and in its 



