Manejo de plantas daninhas em sistema consorciado e monocultivo de feijão e mamona

Abstract

The intercropping of crops is common in Brazil, especially in family farming. The actual advantage of this technique compared to monoculture farming becomes more evident when the cultures involved differences between present demands on the resources, either in quality, quantity and timing of demand. Thus, the cultivation of castor, indicated by the federal government of Brazil as the first choice for the production of biodiesel related projects, and used mainly in intercropping with short cycle crops such as common bean, the main protein source in population with less purchasing power, can set good option for farmers. However, satisfactory crop yields will be achieved only concerned with knowledge of the limiting factors such as weed competition and the correct way of management. This important issue that motivated the proposition of this project. The objective of this work was to investigate the influence of the weed community on agronomic characteristics of common bean and castor cultivars an intercropping and monoculture, at conditions edaphoclimatic of State Goiás, Brazil, of region the “Cerrado”. We used a randomized complete block design in a factorial 3 x 2 x 2 + 10, with four replications. The treatments consisted of three common bean cultivars with different growth (Pérola = type II/III; Pontal = type III; Estilo = type I), two cultivars of castor differentiated sized (Guarani = medium size and Paraguaçu = high size), combined with two types of weed management: weeded manually (without weed infestation throughout the cycle of cultivars) and not weeded area (with weed infestation throughout the cycle of cultivars) intercropping, more treatments in monoculture crop area, and the three bean cultivars over the two castor cultivars with weeding and no weeding. In the plots weeded three weedings were carried out over the cycle, spaced every 15 days until complete closure of the crop. We evaluated the weed infestation, the coverage rate, the agronomic characteristics and castor and Equivalence Area Index – EAI. It follows that: The predominant species of weeds in quantitative terms in the “Cerrado” region were: Brachiaria decumbens, Tridax procumbens, Alternanthera tenella and Chamaesyce hirta. The presence of weeds in crops of common bean and castor was intercropped or monocultures harmful in any time of the cycle, regardless of the species, the size and the amount of weeds present. The presence of weeds during the crop cycle promoted a decrease of yield of 32% and 67% of common bean and castor under intercropping respectively. The common bean cultivars Pontal, Pérola and Estilo and of castor Guarani and Paraguaçu showed potential for the cultivation of crops involved in intercropping system. The use of common bean intercropping with castor under management of invasive community, demonstrated effectiveness in relation to the cultivation of these crops alone, independent of genetic material. The use of intercropping system resulted in obtaining yields of castor and the order of 1.328 kg ha-1 and 1.827 kg ha-1 respectively for areas kept free of weed competition, regardless of the cultivars.