Intercropping of sugarcane with common bean in no-tillage and different nitrogen rates

摘要

The no-tillage of crop rotation and intercropping are sustainable practices to reduce the impact of sugarcane to produce bioethanol on food safety. The objective of this research was to study the effect of side dressing nitrogen application on dry bean (IAC-Alvorada) grown as intercropped crop with green harvested sugarcane ratoon in no-tillage, named "sweet common bean system". Field experiment was carried out in a commercial area (Oxisol), at Sao Jose Farm (Sertaozinho, Sao Paulo State, Brazil), planted with genotype RB865536, on the 3rd ratoon. Five treatments of side dressing nitrogen rates (0, 40, 80, 120, and 160 kg/ha of N, as Urea) were arranged in a complete randomized block, with 6 replications. Evaluations (dry matter, LAI) were done from30 to 90 days after planting (DAS). A quadratic response was observed for dry biomass and grain yield, with 120 and 80 kg/ha, respectively the best N-rate. LAI increasing with N-rates until the maximum of 5.5 at 75 DAS IAC-Alvorada can be considered responsive (12.8 kg of grains per kg of N) to increasing N-rates.