Effects of sunflower residue management options on productivity and profitability of succeeding rice under different crop establishment methods

Context: Sunflower is a potential summer crop for diversifying the rice-fallow system in eastern India. However, the phenolics present in the plant extract can inhibit the growth of subsequent crops. This allelopathic effect could be affected by rice establishment methods having various degrees of soil disturbance and different planting materials. In the present era of climate-conscious agriculture, technologies like residue retention/incorporation and conservation tillage are being popularized. Therefore, it is essential to assess the effects of sunflower residue incorporation on succeeding rice crop under different crop establishment methods.Objective: The present study was conducted to assess the effect of sunflower residue management options on succeeding rice crop productivity and profitability under different crop establishment methods.Methods: The experiment was laid out in split-plot design with three sunflower residue management options in the main plots, viz., no sunflower crop, removal, and incorporation of sunflower residue in main plots and three rice establishment methods in sub-plots, viz., transplanting, dry-direct and wet-direct seeding of rice. Results: The incorporation of sunflower residues reduced the germination of rice seeds by 21.5% in dry-direct seeded rice, which was avoided in wet-direct seeded and transplanted rice having pre-germinated seeds and seedlings, respectively. The weed dry weight in sunflower residue incorporated plot was 28.3% lower as compared to the plot with no preceding sunflower crop. The positive interactive effects of sunflower residue incorporation and transplanting of rice led to better weed suppression, higher crop growth and improved soil nutrient availability, resulting in the highest rice productivity and profitability. In contrast, sunflower residue incorporation and dry-direct seeding interacted negatively, resulting in the lowest rice productivity and profitability. Conclusions: Transplanting could be the best establishment for the rice crop to harness the benefits of incorporating preceding sunflower crop residue. Including sunflower as a summer crop in the rice-based cropping system and incorporating the generated residues in soil could potentially enhance the productivity and profitability of transplanted rice and, therefore, become a viable option for crop intensification in eastern India. Significance: The study identified the suitable establishment method for the succeeding rice crop in sunflower residue removed/incorporated soil. The results could be used to intensify the rice-based cropping system and develop climate-smart agriculture practices in eastern India and similar agroecological regions around the globe.