Received: 05-11-2022 / Accepted: 27-01-2023
This study was conducted to evaluate the effects of hand weeding and planting density on weed and growthand yield of the rice variety Huong Thuan 8 cultivated by organic method. The experimentwas arrangd in a split-plot design with three replications. Hand weeding was the main factor with 3 levels: no weeding (L0), hand weeding once at 20 days after transplanting (L1), hand weeding twice at 20 and 40 days after transplanting (L2), and regular weeding every 20 days until heading as weed-free check(L3); the sub-factor consisted of three plant densitytreatmentsas 30 hill/m2 (M1), 40 hill/m2 (M2) and 50 hill/m2 M3). The results showed that the increase in hand weeding combined with planting density reduced weed density, and weed dry mass, which led to an increase inweed control efficiency. Furthermore, there were significantdifferences in the growth traits (plant height, tiller number), the physiological traits (leaf area index, dry matter), yield components and grain yield when the number of hand weeding time increased from L0 to L2 and plant density increased from M1 to M3. However, there was no significant difference in the yieldbetween L2 and L3as well as between M2 and M3. The highest grain yield (4.34-4.47 ton/ha) was found at L2M2, L2M3, L3M2 andL3M3.