Seletividade de herbicidas para a canola PFB-2.

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Water deficit and plant recovery affect interaction between soybean and slender amaranth.

Biotic and abiotic factors such as competition with weeds and water deficit may cause significant losses to soybean productivity. This study aimed at evaluating the effect of water deficit and plant recovery in the interaction between soybean (Glycine max) and slender amaranth (Amaranthus viridis) by using growth variables. A replacement series experiment was performed and treatments were arranged in a factorial scheme; they were composed of two water regimes (field capacity and water deficit (50% of field capacity)) and different soybean and slender amaranth proportions (100:0, 50:50 and 0:100%). Water regimes were applied 20 days after plant transplant. Height, leaf area and shoot dry matter were evaluated in soybean and slender amaranth under field capacity and water deficit, returning to normal irrigation conditions to evaluate the water recovery. Soybean exhibited competitiveness which was equivalent to the slender amaranth, independent of the water regime. Water deficit negatively influenced height, leaf area and shoot dry matter of soybean and slender amaranth. There was a reduction in leaf area and shoot dry matter of soybean after plant recovery caused by the irrigation deficit period. Key words: Amaranthus viridis; competition; Glycine max; replacement series; water stres