Effects of planting patterns and seed coating treatments on insect community diversity and yield in wheat fields

To clarify the effects of different agricultural cultivation and management practices on insect diversity and wheat yield in winter wheat fields, this study employed a split-plot field design with main plots consisting of irrigated and rain-fed fields, and subplots consisting of tebuconazole-imidacloprid seed dressing treatment and no seed dressing treatment. The impacts of winter wheat planting patterns and seed dressing treatment on insect diversity and wheat yield were systematically evaluated. Results showed that throughout the entire growing season, compared to rain-fed fields, pest abundance in irrigated fields decreased by 8.55%, while non-pest abundance increased by 21.68%. During the heading stage, seed dressing treatment significantly reduced pest subcommunity abundance and dominance index by 190.5 individuals and 0.12 units, respectively, while significantly increased diversity and evenness indices by 0.27 and 0.16, respectively, compared to the non-seed dressing treatment. During the grain-filling stage, compared to rain-fed fields, pest subcommunity abundance in irrigated fields significantly decreased by 31.97 individuals, while non-pest subcommunity diversity and evenness significantly increased by 0.12 and 0.08 units, respectively, and dominance significantly decreased by 0.08 units. In terms of theoretical yield, seed dressing treatment significantly increased yield by 1.16 t/ha compared to non-seed dressing treatment under rain-fed conditions, while under irrigated conditions, seed dressing treatment showed slightly higher yield than non-seed dressing treatment. Overall, irrigation treatment significantly increased non-pest abundance but did not affect pest abundance throughout the entire growing season. In seed-dressing fields, pest abundance during the heading stage was lower than in non-seed-dressed fields, and in irrigated fields, pest abundance during the grain-filling stage was lower than in rain-fed fields. Seed dressing treatment significantly improved yield compared to non-seed dressing treatment under rain-fed conditions. It is recommended that seed dressing treatment be adopted in rain-fed fields, while non-seed dressing treatment be used in irrigated fields, with pest control strategies adjusted according to pest development characteristics at different growth stages. These findings provide a feasible pathway for promoting sustainable agricultural development and ensuring ecological environment safety.