Impact of Plant Density and Leaves Defoliation of Sunflower Intercropped with Sugar Beet on The Productivity of Both Crops and Competitive Relationships تأثير الکثافة النباتية وتوريق دوار الشمس المحمل على بنجر السکر على إنتاجية کلا المحصولين والعلاقات التنافسية

Abstract

At Sakha Agricultural Research Station, two field experiments were conducted during 2018/2019 and 2019/2020 seasons to study the effect of sunflower densities (12.5, 25.0 and 37.5 % from the recommended) and defoliation (25.0, 37.5 and 50.0 % leaves) of sunflower intercropped with sugar beet on productivity and quality of both crops and economic evaluation. The productivity of sugar beet root yield t/fed. reached 83.69 and 83.07% compared to pure stand in both seasons, respectively. Simultaneously, increase defoliation of sunflower leaves increased all studied characters of sugar beet in both seasons. Sugar beet yields i.e. root, top and sugar yield t/fed were significantly affected by the interaction between plant density and leaves defoliation ratio in both seasons. Plant height, seed yield kg/fed. and oil yield kg/fed. of sunflower were increased by increasing sunflower plant densities from (12.5 to 37.5) in both seasons. All studied characters of sunflower were not significantly affected by increasing defoliation except, 100-seed weight and seed yield/plant in both seasons. Stem and head diameter, seed yield/plant and seed oil % were significantly affected by the interaction between plant density and defoliation ratio in both seasons. The treatment of intercropping sunflower with the highest density and 50% defoliation gave the highest values for land equivalent ratio (LER), total and return incomes in both seasons. It could be concluded that sunflower intercropped with sugar beet at (37.5%) and 50% sunflower leaves defoliation gave the highest LER, total income and economic return for sugar beet and sunflower were obtained when .