Purpose This study addressed the severe weed infestation and the great difficulty of weed control in next generation dryland rice (NGDR) fields, with the aim of developing a safe, efficient, and sustainable weed management mode, thereby providing a theoretical basis and technical support for green weed control.
Methods Based on the main weed populations and their occurrence patterns in NGDR fields, key techniques including herbicide formulation ratio, optimal application timing, and application methods were optimized. Field trails of three weeding modes with a total of 16 herbicide combinations, preemergence killing and sealing+postemergence removing and sealing (mode A), postemergence removing and sealing+postemergence killing and removing (mode B), and postemergence removing and sealing (mode C) were set up. Through systemic field efficacy tests, the weed control effect, rice safety and yield, herbicide reduction, and herbicide residual in soil and rice kernel were comprehensively analyzed, and then screened efficient and sustainable weed control models and herbicide combinations for weeds in NGDR fields.
Results Among the three modes, 11 herbicide combinations could efficiently control dominant grassy and broad leaf weed with control efficacy ranging from 80.0% to 96.6%. Mode A exhibited the best control efficacy, with weed control consistently maintaining a rate of over 81.6%, and it was suitable for areas with sufficient rainfall during the sowing period and fields with good soil moisture conditions. Mode B and mode C also demonstrated excellent weed control efficacy ranging from 72.2% to 87.4%, and they were suitable for areas with relatively low rainfall during the sowing period and fields with insufficient soil moisture. Furthermore, mode C was not limited by soil moisture conditions, and compared with mode A, it reduced the applications by 1-2 times, with the amount reduction of active ingredient used by 64.7%.
Conclusion The combinations of bensulfuron-methyl+pretilachlor and MCPA·bentazon+metamifop·cyhalofop-butyl+pentafluoride·pretilachlor in the mode A show properties of wide weed-controlling spectrum, high weed control efficiency, safety, and yield preservation. In mode B, the combinations of penoxsulam+pretilachlor and propanil+MCPA·bentazone can control weeds at all growth stages while ensuring safe and stable rice yields. For mode C, herbicide combination cyhalofop-butyl·fluroxypyr-meptyl+pretilachlor+fluroxypyr offers comprehensive advantages, including high weed control efficacy, reduction of herbicide usage, and yield preservation. Mode C is ecological friendliness to farmland ecosystems and demonstrates outstanding application value, making it a preferred technical mode for the green and efficient control of weeds in the NGDR fields.
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