Effects of green and nitrogen fertilization on the yield and yield components of irrigated winter beans

The contribution of plant residues to the soil is an essential requirement for the success of no-tillage systems, especially in areas with a tropical climate where the organic material decomposition rate is high. The type of straw present on the soil surface can influence the culture implanted subsequently, mainly with regard to the availability of nitrogen (N). The objective of this study was to investigate the effect of cultural remains of maize (exclusive or intercropped with cover crops) on the development and productivity of the common bean grown in succession and fertilized with different N doses. The experimental design was a randomized block arranged in a factorial scheme (5 × 4), with four replications. The treatments consisted of combinations of cultural remains of exclusive maize, maize + Crotalaria spectabilis, maize + Cajanus cajan, maize + Canavalia ensiformis, and maize + Urochloa ruziziensis cultivated previously and of four N rates (0, 40, 80, and 120 kg ha-1) applied to bean crops. The plots consisted of seven lines of 7.5 m length with 0.45 m spacing between the lines. The evaluated parameters were: dry matter of the plant cover, dry matter of the aerial part (beans), production components, weight of 100 grains, and grain yield. The intercropping of maize and cover crops promoted an increase in dry matter over the soil, compared to the exclusive maize crop. There was an increase in the dry matter of bean plants with the increase in N rates in the two years of cultivation; regarding productivity, there was an increment only in the first year of cultivation. The maize consortium with cover plants provided adequate soil cover, but did not influence the productivity of beans cultivated in succession in the two years of cultivation.