Nitrogen fertilization management in common bean and castor bean intercropping systems

The objective of this work was to evaluate the nutrition and agronomic characteristics of common bean and castor bean under intercropping subject of nitrogen fertilization in top dressing. A randomized block design in a 2×2×4 + 4 factorial scheme was used, and there were three replicates. The treatments consisted of two common bean cultivars (Pontal and Pérola), which were intercropped with two castor bean cultivars (Energia and Paraguaçu), and combined with four nitrogen treatments (0, 50, 100 and 200 kg ha-1). Four additional treatments involved bean and castor bean cultivars at a single dosage of 40 kg ha-1 nitrogen. The nitrogen, potassium, calcium, magnesium and sulfur contents in castor bean intercropped with common bean leaves were influenced by nitrogen treatments. For common bean applied as top dressing, the maximum grain yields were 1,122 and 1,024 kg ha-1 for cultivars (cvs.) Pontal and Pérola, respectively, with a dose of 100 kg ha-1 nitrogen. Similar results were observed for castor bean, for whom 100 kg ha-1nitrogen provided the largest number of bunches and number of berries per bunch and the highest grain yield. The maximum values observed were 38 and 27 bunches per plant, 27.6 and 35.4 berries per bunch and 1,474 and 1,286 kg ha-1 grain yield for cvs. Paraguaçu and Energia, respectively.