Emergência de plantas daninhas em lavouras de feijão e de trigo após o cultivo de espécies de cobertura de solo

Abstract

This study aimed to evaluate Euphorbia heterophylla and Bidens pilosa emergence in common bean- and wheat-producing areas, after cultivation of coverage plants. The experiment was carried out under a no-tillage system in straw, during five years, at Capivara Farm of Embrapa Arroz e Feijão, located in Santo Antônio de Goiás, GO. The local soil is classified as dystrophic Oxisol. The treatments combined seven coverage plants (Brachiaria brizantha - cv. Marandu; Brachiaria brizantha intercroping with corn (Zea mays) - hybrid HT BRS 3150; Cajanus cajan; Pennisetum glaucum - cv. BN-2; Panicum maximum - cv. Mombaça, Sorghum bicolor - cv. BR 304 and Stylosanthes guianensis - cv. Mineirão and two crops cultivated successively in the areas (common bean - cv. Pérola and wheat - Embrapa 42. All coverage plants were cut together by using a straw crusher and left on the ground; 60 days after being cut, the common bean and wheat plants were sowed. The number of plants obtained from Euphorbia heterophylla and Bidens pilosa was counted twice and the plants were separated into three growth stages (less than two leaves, from two to four leaves and more than four leaves). Brachiaria brizantha and Panicum maximum coverages were efficient in reducing weed emergence, mainly E. heterophylla in subsequent cultivation of common bean and wheat. No differences were observed in relation to common bean and wheat crop capacity of reducing E. heterophylla and B. pilosa population.