الفهرس 
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Abstract
The aim of this study was to try to find alternative solutions to use these waste instead of burning them, and then the allelopathic properties of these waste were searched to be used in the field of weed control or reducing its density in economic crops as an alternative to chemical pesticides. Laboratory experiments Laboratory experiments were carried out to evaluate the allelopathic effect of shoot and root sorghum plant extracts on the germination and growth of wheat and some weeds that grow with it, such as narrow-leaved weeds such as (Phalaris minor and Avena fatua) and broad-leaved weeds such as (Coronopus sqmatus ,Malva parviflora ,Lepidium sativum ,Beta vulgaris, Rumex dentatus, Ammi visnaga and Silybum marianum).These seeds were collected from the Gimmeiza Research Center affiliated to the weed Research Central Laboratory,ARC, Giza, Egypt. The experiment was conducted during the two planting seasons 2020/2021- 2021/2022. Sorghum samples were collected and washed with plain water, then with distilled water, and then separated into two parts, the vegetative part and the other the root system, then the samples were dried on room temperature, these samples were ground and turned into a powder to be used in the experiment and to make the necessary analyzes. The extract was prepared by dissolving 2 grams of powder in 200 ml of distilled water and shaking at frequent intervals. The extract was filtered using filter paper and the filter paper was washed with 5 ml of distilled water, then the extract reached a fixed volume by adding distilled water and reaching a volume of 200 ml. This extract was made from different concentrations (0-10-20-30- 40-50-60-70- 80-90-100%) which equal from 1 to 100 mg from dry material (ml) from distilled water by diluting the original extract. Each concentration had six replicates and each plate contained constant number of seeds. Readings were taken for the number of developing seeds and followed up every day, recording the growth rates for a period of twenty days. Wheat grains and weed seeds were soaked for two hours in a extract before transplanting into dishes. At frequent intervals, the filter paper is sprayed with distilled water to avoid drying. After twenty days, when we did not notice any increase in the growth rates, the experiment was terminated, and the wheat samples were separated into a vegetative group and a root group. The lengths and weights of each stem and root were taken, then the samples were dried in the oven, ground and used as a powder in the necessary analyzes for allelopathic compounds as secondary metabolites as saponins, phenolics and flavonoids. Field experiement Two field experiments were conducted during the growing seasons 2020/2021 and 2021/2022 to study the allelopathic effect of sorghum plant residue (roots, stems, roots + stems in addition to the weed killer Atlantis treatment and the control, without any treatments) under the influence of different rates of nitrogen fertilizers (60, 75, 90). kg of nitrogen per feddan) on the growth and germination of the wheat crop and the growth of weeds associated with it. The most important results are summarized in the following: The dominant weed species in wheat fields Nine types of weeds were counted, including eight broadleaved species, which are - (Coronopus sqmatus, ,Malva parviflora ,Lepidium sativum ,Beta vulgaris, Rumex dentatus, , Ammi visnaga, , Silybum marianum) And only two types of weed grasses are Avena fatua and Phalaris minor. Density of weeds Mixing the roots and stems of the sorghum plant each individually or the roots and stems together with the soil and using the herbicide Atlantis led to a clear decrease in the number of grassy or broadleaf weeds or the number of total annual weeds /m2 after 70 days of sowing compared to the control treatment (without adding sorghum or herbicide) in both growing seasons, where the effect of the whole plant treatment (roots and stems) was the best biological treatment in terms of reducing the percentage of broad-leaved and narrowleaved weeds together by percentage of 55% compared to the control, so the sorghum residue had an inhibitory effect on weeds other vital transactions. Fresh and dry weights of weeds: The use of roots, stems, (roots + stems) of the sorghum plant and the herbicide Atlantis resulted in a significant decrease in the fresh and dry weight of grassy, broadleaf and annual weeds in both growing seasons. The effect of adding (roots + stems) of the sorghum plant was similar to the effect of the herbicide on the fresh and dry weight of the total annual weeds in both growing seasons.Total annuals without significant differences between 75 and 95 kg nitrogen per feddan in both growing seasons. characteristics of the wheat crop and its components: Dry matter accumulation and distribution The addition of sorghum plant residue (roots, stems, roots + stems) and the use of the herbicide Atlantis resulted in a significant increase in the dry weight of wheat plants compared to the control treatment at 70 and 100 days of sowing in both growing seasons, without significant between them which they gave the highest dry weight of wheat plants / m 2 at 70 and 100 days of sowing in both growing seasons. Increasing the nitrogen fertilizer rate increased the dry weight of wheat plants at a rate of 90 kg nitrogen per feddan. The effect of the interaction between sorghum plant residues and the nitrogen rate was significant on the dry weight of wheat in both growing seasons. The residues of sorghum plants and the rate of nitrogen or the interaction between them did not affect the ratio of dry matter distribution to parts of wheat plants (leaves, stems, ears) in both growing seasons. Adding sorghum roots to the soil led to an increase in the dry matter compared to the control, and an increase in the nitrogen level from 60 to 90 kg led to an increase in the dry matter. Plant height Mixing the soil with the roots of the sorghum plant alone led to obtaining the highest height of wheat plants compared to wheat plants growing in the control plots. As for the effect of the herbicide Atlantis, it led to the height of the plants compared to both the biological treatments and the control. It was noted that the height of the plants increased significantly with the increase in the rate of nitrogen fertilizer, and the interaction did not affect between sorghum plant residues and nitrogen levels significantly on the height of wheat plants The number of spikes The results showed that the number of wheat spikes/m2 increased by adding sorghum plant residue compared to the control treatment in both growing seasons, where the treatments containing the whole plant (roots + stems) gave the highest number of spikes in both growing seasons. Also, the use of nitrogen fertilizer at a rate of 90 kg nitrogen / fed to obtain the highest number of spikes compared to the rate of nitrogen fertilizer 60 kg nitrogen /fed the results also showed that the effect of the interaction between sorghum plant residue and nitrogen fertilizer rates was significant in the number of spikes / m2 in both planting seasons. The length of the spike The length of the spike did not differ significantly in wheat plants .The residues of sorghum plants (roots, stems, stems + roots) or herbicide, but the previous treatments led to a significant increase in the length of the spike compared to the control treatment in both planting seasons. A significant increase in the length of the spike in both planting seasons, and the best rate was at 90 kg. The interaction did not show a significant effect on the length of the spike. Number of spikelets / spike The treatments of sorghum plants affected significantly on the number of spikelets / spike of wheat. The number of spikelets/spike increased by the roots of the sorghum plant compared to the control treatment. The number of grains/ spike Wheat plants grown in the experimental plots ( roots only or roots + stems) of sorghum plants were added gave higher grains / spike compared to plants grown in the control treatments. Weight of 1000 grains Mixing the soil with roots + shoots of sorghum plants led to the best increase in the weight of 100 grains compared to the control. However, all the biological treatments of sorghum were better than the treatment of the herbicide Atlantis in both seasons. This indicates the importance of sorghum residues as a biological herbicide and as stimulator for productivity of wheat. The nitrogen fertilizer treatments affected the weight of 1000 grains by increasing the nitrogen fertilizer from 60 to 90 kg nitrogen/ feddan, as the weight of 1000 grains increased by increasing the nitrogen fertilizer. Also, the interaction between sorghum plant residues and nitrogen fertilizer rates significantly affected the weight of 1000 grains in both growing seasons. Straw cyield Sorghum plant residues had a significant effect on straw yield/feddan in both growing seasons. The sorghum plant treatment (roots + stems) gave the highest straw yield/feddan compared to the control treatment in both seasons. Also, increasing the rate of nitrogen fertilizer increased straw yield/feddan and had the best effect. At an average of 90 kg nitrogen/feddan in both seasons, the interaction also did not significantly affect straw yield/feddan in both planting seasons. Crop grains yield / feddan Roots, (roots + stems) treatments of sorghum plants and Atlantis herbicide gave the highest grain yield/fed compared to the control treatment, and the highest percentage of yield was when adding sorghum roots to the soil, in both growing seasons. The interaction between sorghum plant residues and nitrogen fertilizer levels significantly affected the grain yield/ feddan. The addition of nitrogen fertilizer at a rate of 90 kg nitrogen/ feddan to treating the roots of sorghum plants resulted in obtaining the highest grain yield/ feddan in both growing seasons. Chemical analysis of plant samples Fresh wheat plant samples were used for photosynthetic pigments analysis. Other wheat plant samples were used for carbohydrates, proteins, proline and alkaloids. Concolusion - Using sorghum plant residues as biological treatments to control the density of weeds associated to wheat plants - The use of stems and roots of sorghum reduces the percentage of germination of some weeds, such as (Malva parviflora, Lepidium sativum, Coronopus sqmatus , ,Beta vulgaris, Rumex dentatus, , Ammi visnaga, , Silybum marianum). - The use of sorghum shoots only reduces the percentage of germination of Phalaris ana Avena fatua. - Using the shoots and roots of sorghum gave the highest percentage of the weight of 1000 grains. - The use of sorghum roots alone led to obtaining the highest height of wheat plants and obtaining the highest percentage of the number of spikes - Using sorghum plant residue helps to increase wheat yield, productivity. from the previous results, it may be conducted that sorghum plants is a potential allelopathic crop and it has more suppressive effects on weeds than wheat .Also, data indicated that in corporation of sorghum roots with 75 kg N/fed, could be recommended for optimum grain yield. Finally, the herbicidal activity of the tested sorghum extracts was higher against the germination and growth of weeds associated to wheat crop which suggest the ability to use these sorghum plant extracts as alternative to herbicides in controlling weeds in the future.