Welcome to Acta Prataculturae Sinica ! Today is

Acta Prataculturae Sinica ›› 2026, Vol. 35 ›› Issue (4): 124-134.DOI: 10.11686/cyxb2025228

Previous Articles    

Effects of barnyardgrass on rice growth and yield traits, and determination of its economic control threshold

Ju-feng FAN1,2(), Lang PAN1, De-jun PENG1, Ya-jun PENG2,4, Si-fu LI2,4, Cheng-yin NONG1,2, Jian-hao DU3, Xiang-ying LIU1, Guo-lan MA1,2,4()   

  1. 1.College of Plant Protection,Hunan Agricultural University,Changsha 410128,China
    2.Institute of Plant Protection,Hunan Academy of Agricultural Sciences,Changsha 410125,China
    3.Shaoxing Shangyu Xinyinbang Biochemical Co. ,Ltd,Shangyu 312369,China
    4.Hunan Provincial Key Laboratory for Biology and Control of Weeds,Changsha 410125,China
  • Received:2025-06-09 Revised:2025-08-15 Online:2026-04-20 Published:2026-02-07
  • Contact: Guo-lan MA

Abstract:

This research aimed to clarify the quantitative relationship between barnyardgrass (Echinochloa crus-gallidensity and Oryza sativa growth and yield loss, and establish an economic threshold model for its control. Pot and field experiments were conducted to systematically evaluate the competition effects of 0-25 plants·m-2 barnyardgrass on rice growth traits (plant height, tiller number) and yield components (effective panicles number, filled grains number, 1000-grain weight) in both direct-seeded and machine-transplanted rice systems. Regression models were used to analyze the barnyardgrass density-rice yield loss relationship, and a control threshold model was constructed based on crop parameters. Pot trials showed that at ≥7 plants·barrel-1, rice plant height and tiller number were suppressed by 25.15% and 80.82%, respectively, exhibiting significant density-dependent stress. Field data indicated that 25 plants·m-2 barnyardgrass reduced rice height by 15.27% in direct-seeded rice and 24.07% in machine-transplanted rice, and reducing effective panicles number by 70%-80%, filled grains number by 45.55% and 52.80%, respectively, and 1000-grain weight by 3.46% and 3.86%, resulting in 86.44% and 89.40% yield loss in seeded and machine-transplanted rice, respectively. Regression model analysis indicated a quadratic relationship for direct-seeded rice (y=1.0870 x2+1.1526 x-4.0842, R2=0.969) and a linear response in machine-transplanted rice (y=11.6774 x-15.1928, R2=0.948). After calibration, the economic thresholds for weed control were determined to be 2.55 (direct-seeding) and 1.63 plants·m-2 (machine-transplanting). Barnyardgrass reduces rice yield primarily by inhibiting tillering (>42% reduction rate) and subsequently affecting panicle development (>70% reduction in effective panicle number). The dynamic threshold models established in this study provide a basis for the precise control of barnyardgrass under different rice cultivation modes. These results reveal differential responses of direct-seeded and machine-transplanted rice to varying barnyardgrass density stresses. This information holds significant practical value for constructing precision weed management systems.

Key words: barnyardgrass density, rice, direct-seeded and mechane-transplanted, yield, economic threshold