Investigating the Efficiency of Different Cover Crops on Weed Populations and Yield and Yield Components of Soybean (Glycine max L.)

IntroductionPlanting cover crops, along with effective management practices, offers a sustainable alternative to conventional weed control methods. Beyond weed suppression, cover crops contribute positively by increasing organic matter, improving soil structure, enhancing water retention capacity, controlling soil-borne diseases, reducing soil erosion, and ultimately boosting crop yields. Materials and MethodsTo investigate the effect of winter cover crops on weed populations and the yield and yield components of soybean (Glycine max L.) in Golestan province, a field experiment was conducted from 2016 to 2018. The experiment employed a three-replicated split-plot design within a randomized complete block design at the Gorgan University of Agricultural Sciences and Natural Resources. Seven types of cover crops, triticale (Triticosecale witmackx), common oat (Avena sativa L.) , alfalfa (Medicago scutellata L.), canola (Brassica napus L.), sainfoin (Onobrychis sativa L.), perko (Brassica napus L.var. sensolata), and no cover crop (control), were tested under two weed management conditions (with weeding and without weeding). Each plot measured 6 × 3 meters, and crops were manually sprayed 30 days after planting. Parameters measured included plant height, leaf area, and dry weight of cover crops. Results and DiscussionAccording to the results, the best cover plants varied in their effectiveness in several key areas. Perco and field oats were the most effective in achieving a high leaf area index, whereas triticale had the shortest time to reach the maximum leaf area index. Canola and triticale exhibited the highest amount of dry matter accumulation and the shortest time required to reach 50% of the maximum dry matter accumulation. However, across the two years of the experiment, sainfoin proved to be the weakest cover plant in terms of both leaf area index and dry matter accumulation. In terms of soybean yield, the no-weeding treatment led to a decrease of 24% in the first year and 16% in the second year when compared to the average yield of cover crops. The impact of cover plants on soybean performance was significant in the first year. Cover plants significantly influenced the average number of pods per plant, the number of seeds per pod, the weight of 100 seeds, and overall yield. However, in the second year, while the average number of pods per plant and the weight of 100 seeds did not show statistically significant differences, the influence of cover plants on yield and other metrics was still evident. In general, the study suggests that triticale and field oats can be suitable pre-sowing options for soybean planting. These cover plants help reduce the weed population and either increase or stabilize soybean yield without the need for additional fertilizer inputs. This conclusion highlights the potential of triticale and field oats to enhance sustainable agricultural practices by improving yield and managing weeds effectively. The findings underscore the importance of selecting appropriate cover plants to optimize crop performance and minimize the need for chemical inputs. By choosing the right cover plants, farmers can improve their crop yield and manage weed populations more effectively, contributing to a more sustainable agricultural system. Triticale and field oats, in particular, show promise in achieving these goals, offering a viable strategy for enhancing soybean production and ensuring environmental sustainability. In conclusion, the research emphasizes the significance of cover plant selection in agricultural practices. Triticale and field oats have demonstrated their potential as effective cover crops, capable of boosting soybean yield and managing weeds without the reliance on fertilizers. This study provides valuable insights for farmers aiming to adopt more sustainable and productive farming practices. ConclusionThis study highlights the potential of cover crops in sustainable agriculture to effectively reduce the weed seed bank and prevent declines in crop yield over the long term. Among the cover crops evaluated, triticale and common oat are recommended pre-planting options for soybean cultivation, especially when complemented with effective weed management practices.