EFFECT OF MAIZE-SOYBEAN INTERCROPPING AND HAND WEEDING ON WEED CONTROL

Abstract

     The aim of our study was to investigate interactive effects of maize-soybean intercropping and hand weeding on the growth of weeds. The field experiments were laid out in a split-plot design with three replications. The main plots were three weeding regimes: No-weeding (NW), hand-weeding once at 3-4 leaf stage of maize (HW1) and handweeding twice at 3-4 leaf and 8-9 leaf stages of maize (HW2). The sub-plots were different intercropping patterns: Mo (sole maize), M1 (maize + 1 soybean row in the inter-row of maize), M2 (maize + soybean grown in the same row with maize) in spring-summer season. In winter season, M2 was replaced by M3 (maize + 2 soybean rows in the inter-row of maize). Weed density and biomass were determined within three random quadrats (0.25 m²) per plot at three growing stages of maize: 3-4 leaf stage (S1), 8-9 leaf stage (S2) and 13-14 leaf stage (S3). The results showed that the intercropping and hand weeding sharply suppressed weed growth. In the experiments, goosegrass (Eleusine indica) was the most prevalent weed with a higher density and a dry matter; however, its growth was strongly reduced by maize-soybean intercropping and hand weeding. Double hand-weeding significantly reduced weed density and biomass compared with single hand weeding. Even though intercropping positively suppressed weed growth, the study confirmed the importance of hand weeding in weed control efficiency. Our results suggested that under cultivation condition without herbicide usage, maize-soybean intercropping should be combined with 2 hand-weeding.