Effects of nitrogen fertilization on yield components in a corn-palisadegrass intercropping system.

Pasture and grain crop intercropping is considered an alternative for increasing biomass production during the winter periods in Brazil for the establishment of no-tillage systems. We studied nitrogen (N) fertilization rates in a corn-palisadegrass intercropping system that would allow both corn and biomass production without a reduction in corn yield. A field trial was carried out in São Desidério, Bahia - Brazil using a complete block experimental design with a 5 x 2 factorial layout with two factors: N rate (control, 50, 100, 150, and 200 kg ha-1 N) and two cropping systems (corn with or without palisadegrass). Both corn and palisadegrass were sown simultaneously with N fertilizer applied at sowing. The measurements included corn biomass, grain yield and N uptake. In addition, palisadegrass biomass was assessed at corn harvest and at three consecutive times during the winter. There was an interaction between N rates and the intercropping system. Grain yield was affected by intercropping when N fertilizer rates were lower than 100 kg ha-1, but above that rate, corn grain yield reached 10,000 kg ha-1 and was similar with or without palisadegrass. Nitrogen fertilizers also positively affected corn N uptake. There was no residual effect of N fertilization on palisadegrass biomass production during the sampling periods. However, the biomass of the palisadegrass increased during the winter period and reached 5,000 kg ha-1 of dry matter by the following season. There was no corn yield reduction when corn was intercropped with palisadegrass using nitrogen rates above 100 kg ha-1. In addition, it is possible to increase biomass production for the establishment of no-tillage systems in Brazil.