Inter- and Intra-specific Competition of Potato with Four Common Weed Species and Their Impact on Tuber Yield

Abstract Weeds compete with crops including potato and cause a huge yield and quality reduction. This competition varies according to weed type and their infestation level. The objective of this study was to explore the inter- and intra-specific competition of potato and four of its major weeds, i.e., Amaranthus retroflexus , Chenopodium album , Salsola kali , and Solanum nigrum , under varying densities. The weeds and potato plants were grown in pots by maintaining weed densities of 0, 2, 4, and 6 weed plants, together with the potato plant densities of 0, 1, 2, and 3, with all possible interactions and a control (only weed or potato plants). The results showed that with an increase in the density of A. retroflexus , potato height and yield started decreasing, and there was a 9–49% tuber yield reduction due to A. retroflexus interference depending on its density. The A. retroflexus height and biomass were positively influenced under low inter-specific competition with potato compared to when grown alone (intra-specific competition). The maximum C. album height and biomass were observed under low intra-specific (only 2 C. album plants) and inter-specific competition conditions (2 C. album × 1 potato). There was a 9–48% reduction in tuber yield when potato was exposed to competition from different densities of C. album . The height and biomass of S. kali were significantly higher under low inter- and intra-specific competition. Tuber yield loss due to S. kali interference was 32–63% under inter-specific competition conditions. The highest height and dry weight of S. nigrum were recorded under low competition/densities (2 S. nigrum × 1 potato). Yield loss under inter-specific competition of potato with S. nigrum was 22–43% depending on the densities of S. nigrum . In general, the weeds performed well under low competition and caused a decrease in tuber yield, showing their ability to compete at inter-specific competition conditions. The results of this study could be helpful in providing insights into the competition of potato with their common weeds, enabling a focus on the management of the most competitive ones.