Effect of organic manure and tillage depths on sunflower (Helianthus annuus L.) production

One of the factors affecting the productivity of sunflower is poor management of soil service operations such as tillage depth. As choosing the depth of tillage helps in increasing the growth of the root system, which is reflected in the plant vegetative growth. Although the addition of animal manure can increase the activities of microorganisms in the soil and the soil contents of available nutrients, the effects on sunflowers were not tested under dry land conditions of Basrah province. Field experiment was carried out during the 2020 growing season, at two locations, to determine the effect of three tillage depths (10, 20 and 30 cm) and four organic manure levels (M0 = without manure, M1 = 6 t ha⁻¹, M2 = 8 t ha⁻¹, M3 = 10 t ha⁻¹) on sunflower performance, seed yield and selected soil properties. Results showed that, the maximum vegetative parameters, yield component and yield were recorded at 30 and 20 cm tillage depth treatments at the both growing locations without significant differences between them compared to 10 cm tillage depth. Number of seeds head⁻¹ was not influenced by tillage depth treatments over the two locations. Tillage depth of 30 cm significantly improved seed yield as compared to 10 cm tillage depth. The maximum seed yield recorded by 30 cm tillage depth. The application of organic manure had a significant effect on sunflower seed yield, biomass yield, head diameter, 500 seed weight, seeds head⁻¹, leaf area, leaves plant⁻¹, plant height and stem girth at the both growing locations.