Interactive effects of tillage, residue management, and forward speed on seeding quality, establishment, and yield of wheat

Achieving uniform seed placement and maximizing wheat yield require an integrated consideration of key operational factors, including tillage method, crop residue level, and forward speed. Although the individual effects of these factors have been widely investigated, their interactive impacts on drill performance under field conditions remain insufficiently understood. Therefore, this study aimed to evaluate the combined effects of tillage systems, residue coverage, and forward speeds on wheat planting quality and grain yield. A field experiment was conducted at the Research Farm of the University of Agricultural Sciences and Natural Resources of Khuzestan using a split–split plot arrangement within a randomized complete block design (RCBD) with three replications. Treatments consisted of three tillage methods—conventional (moldboard plow + disc), conservation (combined tillage), and conservation (chisel packer)—three residue levels (0%, 40%, and 80%), and three forward speeds (4, 7, and 10 km h −1 ). The results showed that tillage method and residue level significantly affected planting depth uniformity, seed distribution uniformity (p < 0.05), and uncut residue (p < 0.01). In addition, the interaction of tillage, residue level, and forward speed had a significant effect on grain yield (p < 0.01). Combined tillage achieved the highest planting depth uniformity (87.66%) and grain yield (7326 kg ha −1 ). The 40% residue level resulted in superior yield performance compared to 0% and 80% residue levels. Moreover, the lowest forward speed (4 km h −1 ) produced the highest average grain yield (6990 kg ha −1 ). Overall, the findings suggest that optimizing wheat planting performance requires the integrated management of tillage practices, residue retention, and operational speed. Such optimization can enhance seeding precision and improve crop productivity under conservation agriculture systems.