NITROGEN-FERTILIZATION OF SUGARCANE IN AN INTERCROPPING SYSTEM WITH MAIZE AND POTATO IN THE HUMID TROPICAL CLIMATE OF MAURITIUS

The competition for fertilizer nitrogen between sugarcane and a compan ion crop (maize or potato) grown between the sugarcane rows was studie d using nitrogen-15 labelled nitrogen in three field experiments in Ma uritius. The effect of the timing of nitrogen application on nitrogen recovery by sugarcane was also investigated. Not more than 15 kg ha(-1 ) of the 120 kg ha(-1) nitrogen applied to the sugarcane was taken up by the companion crop but this was compensated for by the uptake of 8 kg ha(-1) nitrogen applied to maize or potato. The present recommendat ions for nitrogen fertilization of pure stand sugarcane were found to be applicable to sugarcane intercropped with non leguminous food crops . Though fertilizer nitrogen uptake by sugarcane was increased by dela ying nitrogen application until after the harvest of the maize and pot ato, this was not accompanied by an increase in sugarcane yields.