دراسة بعض جوانب الادارة المتكاملة لادغال محصول زهرة الشمس).Helianthus annuus L(وأثرها في النمو والحاصل

Study of Some Aspects of Integrated Managmant of Sunflower Weeds (Helianthus annuus L.) and it's Effect on Growth and Yields

Abstract

A field experiment was conducted in one of the fields of Ibn Al-Bitar Vocational School in Al-Husseiniyah district, part of the Holy Karbala Governorate, in sandy loam soil during the spring growing season of 2023. The aim of the experiment was to study the integrated management of weeds in sunflower crops. The experiment was designed according to a Randomized Complete Block Design (RCBD) with a split-plot arrangement. The main plots included four sunflower varieties (Aflami, Ishaqi 1, Ishaqi 2, and Aqmar), while the subplots comprised weed control treatments (weedy check, herbicide treatment METRICAM 70 WP at a rate of 200 g per donum, application of Eragrostis residues at 2 megagrams per hectare, half dose of METRICAM 70 WP at 100 g per donum combined with Eragrostis residues at 2 megagrams per hectare, Eragrostis extract at 3 ml per liter, and hand weeding).
The sunflower varieties significantly affected most of the studied traits. The variety Ishaqi 1 achieved the lowest average dry weight of weeds, measuring 25.6 g, which corresponded to the highest suppression rate of 57.3%. This variety also recorded the highest averages for plant height, disk diameter, number of seeds per disk, seed yield, harvest index, the shortest number of days to physiological maturity, and the highest oil yield, with values of (198.80 cm, 22.62 cm, 1,774.9 seeds, 7.146 megagrams per hectare, 42.02%, 95.72 days, and 2.402 kg per hectare) for the respective traits. On the other hand, the Ishaqi 2 variety demonstrated superior competitiveness against weeds at both 35 and 70 days after planting, recording the lowest weed densities of 31.9 plants per square meter and 27.3 plants per square meter, respectively, leading to weed control rates of 43.13% and 62.4% for the two periods, respectively. Additionally, Ishaqi 2 exhibited the largest stem diameter of 27.01 cm, the highest chlorophyll content of 45.35 SPAD, and the highest average weight of 300 seeds, reaching 23.72 g.
The weed control methods varied in achieving the highest averages for the studied traits. The treatment of half the dose of METRICAM 70 WP combined with Eragrostis residues achieved the best results in weed density at 35 and 70 days after treatment, the highest control rates for both periods, the lowest weed dry weight, the highest suppression percentage, the highest biological yield, the highest oil content, and the highest oil yield, with averages of (34.8 and 24.7 plants per square meter, 40.22% and 71.8%, 25.3 g, 52.5%, 19.055 megagrams, 36.07%, and 2.504 kg per hectare), respectively. Meanwhile, the hand weeding treatment resulted in the highest total seed yield of 7.792 megagrams per hectare.
The two varieties, Ishaqi 1 and Ishaqi 2, alternated in recording the best averages for the interaction effects of the studied traits. Ishaqi 1 outperformed in combination with all treatments regarding weed dry weight, suppression percentage, plant height, number of leaves, chlorophyll content, days to physiological maturity, disk diameter, and oil yield. In contrast, Ishaqi 2, in combination with all weed control methods except the weedy check and Eragrostis extract treatments, excelled in weed density at 35 and 70 days, weed control percentage at 35 and 70 days, stem diameter, and seed yield.
The best interaction for seed yield was achieved by Ishaqi 2 combined with hand weeding, which did not differ significantly from Ishaqi 1 combined with hand weeding or Ishaqi 1 combined with half the herbicide dose and Eragrostis residues.

We conclude that certain sunflower varieties possess a greater ability to compete with weeds, while Eragrostis residues proved effective in reducing weed density and supporting sunflower growth. Additionally, combining herbicides with Eragrostis residues enhanced weed control efficiency and increased sunflower growth and yield. This suggests the potential use of Eragrostis as a substitute or complement to chemical herbicides in weed management, contributing to better and more sustainable crop growth.