40 



EXPERIMENT STATION RECORD. 



It may be determined from this table " that the relative proportions of the different 

 plant-food constituents are approximately the same for these different varieties of 

 fruit tn-cs. This means that under like conditions of soil fertility a mixture of nitro- 

 gen, phosphoric acid, and potash which would meet the requirements of one variety 

 would also meet the needs of the other varieties, so far as the supply of these plant- 

 food constituents is concerned." 



In some years fruit trees hear no fruit. It is, therefore, desirable to know the 

 amounts of food constituents used by different parts of the tree. The following 

 table gives these data: 



Amounts of food constituents used per acre by different parts of a tree. 



The above table is calculated on the basis of 85 apple, 120 peach, 120 pear, 120 

 plum, and 240 quince trees per acre in each instance. An acre of peach trees uses 

 considerably larger quantities of plant food than any of the other varieties of fruit 

 trees. The amounts of the nitrogen and potash required per acre in the case of the 

 different fruit trees are practically the same, while the amount of phosphoric acid 

 used is only about one-fourth as much as of nitrogen or potash. 



"In most commercial fertilizers used on fruit trees the phosphoric acid is present 

 in proportions about 4 times the nitrogen. This is on the assumption that the soil 

 contains more nitrogen relatively than phosphoric acid, which may or may not be 

 true in individual cases. The question may be raised as to whether quantities of 

 phosphoric acid are not frequently applied much in excess of the actual need of a 

 season's crops. . . . 



"In respect to the amounts of plant food used per acre by the fruit of the different 

 varieties of trees, the amounts of nitrogen, phosphoric acid, and potash in the differ- 

 ent fruits are in about the following order: Quinces use the most, and then follow 

 apples, peaches, plums, and pears. 



"Potash is present in the fruit in larger quantities than is any other plant-food 

 constituent: nitrogen comes second, being present to the extent, approximately, of 

 one-half the amount of potash. Then follow, in order, phosphoric acid, magnesia, 

 and lime, all of these being present in much smaller amounts. 



"In the leaves, the plant-food constituents used per acre are greatest in the case 

 of the peach, the apple coining second, and then quince, pear, and plum, 



