This work aimed to evaluate competition between soybean (BRS 243 RR) and the weeds Bidens pilosa and Brachiaria brizantha, in soil with simulated compactation. Thus columns of PVC tubes (10 cm of diameter) were made with three rings (superior (5 cm high and 1.2 kg dm-3 density); intermediate (10 cm high and around 1.0 and 1.6 kg dm-3 density) and inferior (10 cm high and 1.2 kg dm-3 density). Five crops, soybean, B. pilosa, B. brizantha, soybean and B. pilosa, and soybean and B. brizantha, were cultivated on the columns in a factorial scheme with the densities, totaling 20 treatments. At 30 days after soybean emergence, height leaf, stem and root dry matter, leaf area and specific leaf area were evaluated. B. brizantha was more competitive than B. pilosa, but the latter had higher radicular exploration capacity in soil with higher compactation level, indicating higher suitability under hydric deficit and nutrient scarcity conditions. Considering soybean competitive capacity over weeds, higher compactation levels favor the culture in relation to B. pilosa.
Bidens pilosa; Brachiaria brizantha; soil density; Glycine max
