259 



IX. Quantites totales de matieres nutritives enlevees par 

 hectare et par an en adoptant les moyennes de A. 

 Hallet. 



Resultat total: 239*576 kilos d'azote; 334*890 kilos 

 d'acide phosp'h'orique; 44*728 kilos de potasse; et 

 56*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. 



!. Composition (per cent.) of the parts of an oil palm 

 in the principal nutritive constituents : nitrogen, 

 phosphoric acid, potash, lime. 



II. Weight and average number of the different parts 

 of an oil palm (figures referring in general to the 

 common variety). 



III. Quantities of nutritive materials taken up by an oil 

 palm expressed in kilograms of nitrogen, phos- 

 phoric acid, potash and lime). 



IV. 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 the 

 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 n : tr ^en; 16785 



