Abstract:

In order to clarify the current situation of weeds in soybean （Glycine max）-maize （Zea mays） banded compound planting pattern fields in Sichuan Province， the occurrence of the weeds was investigated from 2023 to 2024 in 29 towns of 13 cities in Sichuan Province using an inverted W-shaped nine-point sampling method， and the relative abundance of weeds in each region was calculated to determine the dominant species. This was followed by analysis of community characteristics using the Berger-Parker index， Margalef index， Shannon-Wiener index， Simpson index， and Sorensen similarity coefficient to assess community structural similarities. soybean-maize In 2024， The highest dominance index of weeds was found in the southwestern Sichuan region， with a Berger-Parker index of 5.84， while the Simpson index， Shannon-Wiener index and Pielou index were lower than those for weeds in other regions， and where the dominant weeds were Digitaria sanguinalis， Alternanthera philoxeroides， Commelina communis and Persicaria runcinata with relative dominance values of 25.92， 18.11， 13.48 and 10.00， respectively. The second-highest weed dominance was found in the eastern Sichuan region where Echinochloa crus-galli， D. sanguinalis and A. philoxeroides were the dominant weeds， with relative dominance values of 35.65， 11.82 and 11.76， respectively. The Simpson index， Shannon Wiener index， and Pielou index in the western Sichuan region were higher than those in other regions， and the dominant weeds in this region were D. sanguinalis， Arthraxon hispidus， E. crus-galli and A. philoxeroides， with relative dominance values of 33.46， 33.41， 7.61 and 6.68， respectively. The dominant weeds in the central Sichuan region were D. sanguinalis， A. hispidus， Calystegia hederacea and Cyperus rotundus， with relative dominance values of 36.16， 14.20， 7.95 and 7.11， respectively. The Sorensen similarity coefficient analysis revealed significant structural differences in weed communities among different regions， with similarity indices ranging between 0.5 and 0.6. From this analysis， D. sanguinalis， A. hispidus， A. philoxeroides and E. crus-galli emerge across different regions of Sichuan as the dominant weed species in soybean-maize fields sown with a banded compound planting pattern. The findings provide a theoretical basis for the scientific selection of targeted control agents and optimization of weed management strategies.

Key words: weed community characteristics, species diversity, relative dominance, Berger-Parker index, soybean-corn banded compound planting