534 



Journal of Agricultural Research 



Vol. V, No. II 



Table \'III. — Percentage composition of ash of samples in Table VII 



Constituent. 



Sample 



No. 285. 



Sample 

 No. 852. 



Sample 

 No. 900. 



Ratio 

 between 

 minimum 

 and maxi- 

 mum. 



Silica (SiOa) 



Ferric and aluminic oxids (Fe203+ 



AI2O3) 



Calcium oxid (CaO) 



Magnesium oxid (MgO) 



Sodium oxid (NaoO) 



Potassium oxid (KjO) 



Phosphorus pentoxid (P2O5) 



Sulphur trioxid (SO3) 



Carbon dic::id , not determined 



Total. 



1.405 



• 540 

 .490 

 . 900 



• 500 

 .380 

 . 090 

 •590 



•387 

 36. 070 



7-594 

 2. 742 

 19. 617 



.3- 059 

 2. 742 



j6. 895 



73. 020 



0-339 



. 261 

 41. 628 

 6.364 

 3-234 

 13. 146 

 3.860 

 5.008 



0.485 



• 143 

 33- 432 

 5.828 

 1.483 

 23- 787 

 4-349 

 3-562 



73- 840 



73- 069 



39 



As Stated before, Nos. 285, 812, and 852 were collected from the same 

 branch, whereas No. 900 was taken an equal distance from the root on 

 another branch, as the former was so greatly weakened that no sap 

 exuded from it at the proper time, although new growth came on it later, 

 showing that it was not dead. If a comparison now be made of Nos. 285, 

 812, and 852, it will be found that there has been a marked reduction in 

 practically all of the mineral substances in the sap in the two succeeding 

 years compared with the first, and, moreover, this was very sharp in 

 some constituents in the second and, in others, in the third year. Fur- 

 thermore, it will be noticed that among those which show a decided 

 decrease in the second year are potassium and phosphorus, both of which 

 are included among the chief essential plant-food elements. 



According to the different analyses of the sap, potassium is among 

 the high mineral constituents, and as this element has shown the largest 

 loss, this may account for the weakened condition of the branch. 



The ratios of calcium oxid to magnesium oxid and of potassium oxid 

 to sodium oxid in the various samples of Table VII are as given in Table 

 IX. 



Table IX. — Comparison of ratios of calcium oxid to magnesium oxid and potassium oxid 

 to sodium oxid in sap of wild grape from the same point on the vine at the beginning of 

 the sap flow during four successive years 



285 



812 



852 



900 



