DOI: 10.36347/sjavs.2022.v09i01.002

Pages: 9-13

The experiment was conducted during 2019/2020 at Wondogenet agricultural research center, Sidama region Ethiopia. It was initiated to find a critical weed competition period for Stevia rebaudiana production as weed management plays a great role in agriculture. The experiment was arranged in a randomized complete block design (RCBD) and consisted of three replication and fourteen treatments. Stevia rebaudiana growth and yield, as well as weed data, were assessed during the experiment and subjected to ANOVA using SAS computer software version 9.3, and differences between means were assessed at 5% probability level. Stevia plant height, branch number, and leaf yield were affected significantly due to treatments effects. Weed-free season treatment showed significantly higher stevia fresh yield (6.1 ton/ha) and dry yield (1.20 ton/ha) which was similar to the significantly higher results of the weedy for fifteen days after transplanting. Variation in the weedy period from fifteen days after transplanting (15DAT) to thirty days after transplanting (30DAT) resulted in 33.27% fresh stevia leaf yield reduction and 44.40% dry stevia leaf yield reduction. Weedy season treatment was used as a check and showed significantly lower stevia leaf yield which was also similar to the results of the weedy period for ninety days after transplanting (90DAT). On the other hand, the weedy period for fifteen days after transplanting (15DAT), the weed-free period for ninety days after transplanting (90DAT), and weed-free season treatments showed similar significantly lower weed density. An increase in the weedy period showed higher weed density and weed biomass results. Therefore, as weeds greatly affect stevia growth and yield, early weeding at 15DAT is important and recommended based on the present finding, however, for comprehensive results the experiment should be repeated over site and year.