259 
IX.—Quantités totales de matiéres nutritives enlevées par 
hectare et par an en adoptant les moyennes de A. 
Hallet. 
Résultat total; 239°376 kilos d’azote; 334°890 kilos 
d’acide phosphorique; 44°728 kilos de potasse; et 
506°868 kilos de chaux. 
[ TRANSLATION. | 
CONTRIBUTION TO THE PROBLEM OF THE PLANT-FOOD 
REQUIREMENTS OF THE OIL PALM. 
The problem of the plant-food requirements of Elaeis 
guineensis is of great importance in view of the movement for 
utilizing rational agricultural methods of exploitation for this 
tree, as well as for many other tropical products hitherto 
exploited only in the forest state. 
This problem is at present very difficult to solve, because its 
terms are not yet exactly defined. On the one hand, a single 
complete analysis, that of Zeller, has been carried out in regard 
to the materials taken up by the oil palm, but certain useful 
points are still left in doubt; on the other hand, the observa- 
tions and partial analyses of various authors are extremely 
divergent, and unfortunately indications which might elucidate 
these divergencies are wanting. 
However, with the assistance of the existing bibliography, I 
have drawn up the following nine tables on a uniform basis. 
I.—Composition (per cent.) of the parts of an oil palm 
in the principal nutritive constituents: nitrogen, 
phosphoric acid, potash, lime. 
Il.—Weight and average number of the different parts 
of an oil palm (figures referring in general to the 
common variety). 
II1].—Quantities of nutritive materials taken up by an oil 
palm expressed in kilograms of nitrogen, phos- 
phoric acid, potash and lime). 
TV.—Quantities of nutritive materials taken up, at the rate 
of 125 trees per hectare. 
V.—Quantities of nutritive materials to be returned to 
the soil per year per hectare on account of ihe 
material permanently fixed by the plants in addition 
to all the waste and residues of the plantations and 
crops. 
Total result: 18°166 kilos of nitrogen; 16°785 
