Influência da densidade de digitaria insularis nas características agronômicas de phaseolus vulgaris cv. IPR Tuiuiú

Abstract

The common bean (Phaseolus vulgaris) is one of the most important crops for Brazil and several other countries. The common bean is a plant belonging to the family fabaceae, corresponding to the most cultivated species of the genus Phaseolus. The bean cycle is considered short when compared to other cultivated plants, varying between cultivars from 60 to 110 days, being widely used in crop rotation systems. One of the major limitations to the productive potential of this species is the interference of weeds, which can lead to reductions of 15 to 97% of the yield, depending on the cultivar, sowing time, composition and density of weeds. The decrease in yield is a reflection of the limitation of bean crop growth and development by competition for light, nutrients and water and allelopathic interactions, which also considerably increase the operational costs of harvesting, drying and processing the beans. The Digitaria insularis corresponds to a species that has been raising concern in farmers, aggravated by the occurrence of herbicide resistant biotypes. It belongs to the Poaceae family, being one of about 300 species of the genus Digitaria distributed in different regions of the world. It is a perennial, herbaceous, erect, erect, rhizomatous species with striated stems, 50 to 100 cm high, native to tropical and subtropical regions of America. In this context, the objective of this work was to evaluate the interference of different densities of D. insularis in common bean cv. IPR Tuiuiú in no-tillage. The experiment was conducted in the Mid-west Meso-region of the State of Paraná, in the city of Laranjeiras do Sul. The design was a randomized complete block (DBC) with 7 treatments (0, 1, 2, 3, 5, 8 and 12 plants of D. insularis m-²) and 4 replicates, each experimental unit consisting of a plot of 4 m2 cultivated with beans and different densities of D. insularis. The seeds of D. insularis were seeded in trays and later placed in a floating system, and transplanted to the plots when they reached adequate size. The variables analyzed were: yield per hectare, leaf chlorophyll content, plant height, stem diameter, dry shoot mass, root dry mass, total dry mass, one thousand grain yield and leaf area. It was concluded that the Digitaria insularis influenced negatively bean crops in all evaluated variables, except a thousand grain weight, causing losses in bean crop yield of up to 74%.