Effect of mechanical tillage treatments intensity on weed infestation and yield of quinoa (Chenopodium quinoa Willd.)

Abstract

The absence of registered herbicides for quinoa cultivation poses a significant challenge in achieving effective weed control through alternative methods. Field experiments, in two growing seasons (2021 and 2022) using different intensities of weed control treatments in quinoa were carried out at the Swojczyce Research and Teaching Station of the Wroclaw University of Environmental and Life Sciences. Three varieties of quinoa: Titicaca, Vikinga, and Zeno were sown at 50 cm inter-row spacing. Weeding treatments with a weeder were performed at BBCH (Biologische Bundesanstalt, Bundessortenamt und CHemische Industrie) phases 13, 17, and 50, with the choice of 1, 2, or 3 treatments. In the variant with 3 weed control treatments, all weeds in the rows were removed at the end of June after the last treatment and evaluation of weed infestation. The varieties responded similarly to the weeding treatments, and the differences in the parameters determined resulted from morphological characteristics. Three inter-row weeding treatments reduced weed count by 70.5% and weed weight by 56.4%. As a result of the increased intensity of weeding treatments, the weed structure changed, and the proportion of common lambsquarters (Chenopodium album L.) increased while that of other dicotyledonous species decreased. Mechanical treatment also had a positive effect on the morphological features of quinoa plants and seed yield. Compared to the control, it increased by 35.8%. The study showed the strong competitiveness of common lambsquarters against quinoa. The biomass of a single quinoa plant and the weight of a single panicle were negatively correlated with the biomass of common lambsquarters. The practical application of inter-row weeding on soils with common lambsquarters in the seed bank may not have the expected economic effect.