Root extracts of Bracchiaria humidicola andSaccharum spontaneum to increase N use by sugarcane
Retaining the mineral N in the form of NH 4 + in the soil for a lengthy period is desirable for reducing losses. Furthermore, there is evidence that sugarcane prefers NH 4 + -N in place of NO 3 − -N. This study aimed firstly, to evaluate the potential of root extracts of Bracchiaria humidicola and Saccharum spontaneum, in contrast with the DCD (Dicyandiamide) inhibitor, to increase absorption of N by plants fertilized with ammonium sulfate, and secondly, to quantify the emission of N 2 O fluxes
... ion of N 2 O fluxes with the use of this inhibitor. The experiment was developed in a glasshouse in an entirely randomized design where four treatments were applied: AS) ammonium sulfate (control); AS+DCD) ammonium sulfate associated with dicyandiamide; AS+BCH) ammonium sulfate associated with root extracts of Brachiaria humidicola; and AS+SCS) ammonium sulfate associated with root extracts of Saccharum spontaneum. Differences were observed in biomass production in plants 45 and 60 days after fertilization (DAF) and 15 and 60 days in biomass accumulation of roots. The application of AS associated with DCD synthetic inhibitor kept NO 3 − -N values low throughout the evaluation period, while in other treatments the concentration increased right up to the second evaluation 15 DAF. Sugarcane plants did not benefit from the increased presence of ammoniacal N promoted by DCD. The use of DCD reduced the average flux of N 2 O during the evaluation period compared to plants receiving AS treatments only, which was not observed when root extracts of B. humidicola and S. spontaneum were used.