الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
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Abstract
This experiments was carried out during 2021&2022 and 2023 seasons at Sids Horticultural Research Station (28° 54’25.7” N 30°56.59.8” E), Beni-Suef Governorate, Horticultural Research Institute, Agricultural Research Center, Egypt to evaluate the efficacy of some weed control methods on weeds and Flame seedless grapevine productivity with monitoring chemically herbicidal residues berries at harvest.
One hundred and four healthy vines 10- years old approximately homogeneous shape, size, and productivity were selected and allocated for this study. Vines trained to cane pruning under Spanish Parron system. Vines were spaced at 2×3 meters apart. In which weeds were naturally infested with weeds.
The treatments were as follow:
The experiment included the following thirteen weed control treatments arranged as follows:
T1: Unweeded check (control).
T2: Hand hoeing twice at 20 and 40 days after the first irrigation.
T3: Hand hoeing third at 20 & 40 and 60 days after the first irrigation.
T4: Roundup 48 % WSC (glyphosate-isopropyl ammonium) at 2.5 L/fed. applied at 30 days from the first irrigation.
T5: Roundup 48 % WSC at 2.5 L/fed. applied as post – emergence twice at 30 and 60 days from the first irrigation.
T6: Starane 20 % EC (Fluroxypyr) at 0.2 L/fed followed by Roundup 48% WSC at 2.5 L/fed. applied as post- emergence at 21 and 30 days from the first irrigation, respectively.
T7: Goal 4F 48 % SC (Oxyflurofen) at 1L./fed. applied as post- emergence at 30 days from the first irrigation.
T8: Goal 4F 48 % SC at 1L./fed. applied as post- emergence twice at 30 and 60 days from the first irrigation.
T9: Black polyethylene mulch by plastic sheets thickness100micron covering soil surface with up to 60 days from the first irrigation. .
T10: Green polyethylene mulch by plastic sheets thickness 100micron covering soil surface with up to 60 days from the first irrigation.
T11: Organic Mulches with rice straw (Oryza sativa L) mulch at 10 ton/fed.by 25 kg/plot covering (20 cm high from soil surface) up to 60 days after the first irrigation.
T12: Legume cover crop (Egyption clover, Triflium alexandrium).
T13: Legume cover crop ( cow pea (Vigna unguiculata)).
All the experimental trees received the regular horticultural practices that carried out in vineyard except those dealing with the present treatment.
The obtained results during three studied seasons could be summarized under the following main items.
1. Effect of weed control treatments on weeds at 120 day from application
Weed survey in experimental fields showed weed species predominate in three seasons were red-rooted pigweed (Amaranthus retroflexus L.), mexican fire plant spurge (Euphorbia geniculata, Ortega), black jack (Bidens pilosa L.), common cocklebur (Xanthium strumarium L.), lamb’s quarters (Chenopodium album L.), prickly sida (Sida alba L.) and nalta jute, jews mallow (Corchorus olitorius L.); as annual broad-leaved weeds, and jungle rice (Echinochloa colonum L. Link), signal grass (Brachiaria repans L.), green bristlea grass, green foxtail (Setaria viridis L.) as annual grassy weeds and were marvel grass (Dichanthium annulatum L.) and bermuda grass (Cynodon dactylon L.) as perennial weeds which were the most important weeds of flame seedless vineyards
Black polyethylene mulch, rice straw mulch, Roundup twice, hand hoeing third and Starane + Roundup gave the highest controlling percentage of total annual weeds which reduced fresh weight by 97.5, 97.4, 96.9, 93.2 and 91.8% comparing with the weedy check, respectively. While, green polyethylene mulch treatment gave lower controlling percentage of annual grassy weeds which reduced fresh weight by 68.8%.
The highest controlling percentage of perennial grassy weeds achieved with Roundup twice, black polyethylene mulch, rice straw mulch, hand hoeing third, Roundup and Starane + Roundup by 99.0, 97.3, 96.8, 92.7, 91.9 and 90.0% comparing with the weedy check, respectively.
Black polyethylene mulch, Roundup twice, rice straw mulch, hand hoeing third, and Starane + Roundup gave the highest controlling percentage of total annual and perennial weeds which reduced fresh weight by 97.4, 97.4, 97.3, 97.3, 93.1 and 91.4% comparing with the weedy check, respectively. While, Goal 4F and green polyethylene mulch treatments which gave lower controlling percentage of total annual and perennial weeds which reduced fresh weight by 77.7 and 63.5 % comparing with the weedy check, respectively.
2. Effect of weed treatments on vegetative growth characteristics.
All weed control treatments were significantly enhanced shoot length, number of leaves/ shoot, leaf area (cm2), wood ripening coefficient, weight of pruning wood (kg/vine) and cane thickness (cm). The best treatments in this respect was mulching with black polyethylene and rice straw, Roundup twice and hoeing third.
3. Effect of weed control treatments on leaf pigments
The superior treatments were mulching with black polyethylene and rice straw, Roundup twice, hoeing third Starane+ Roundup and Egyptian clover in chlorophyll a chlorophyll b, total chlorophyll and total carotenoids
4. Effect of weed control treatments on yield.
All treatments significantly increased the yield (kg/vine) and the yield(ton/fed), where the percentage of increase ranged from. (34.28 to 126.13%) for yield (kg/vine) and yield (ton/fed) compared with unweeded check
The black polyethylene and rice straw mulching treatments showed significant superiority over all weed control treatments in yield ( kg/vine), and yield (ton/fed.). Roundup twice, Starin+Roundup treatments outperformed all other chemical treatments and hoeing third times outperformed hoeing twice, and finally Egyptian clover outperformed cowpea as a cover crop. The lowest weed competition index was recorded in mulch with black polyethylene followed by rice straw mulch followed by hoeing third, roundup twice and Egyptian clover.
5. Effect of weed control treatments on cluster characteristics
Black polyethylene, rice Straw achieved the highest weight of cluster, by increment percentage (126.1 and124.1%), respectively, without significant between them. followed by hoeing Third, Roundup twice, Egyptian clover and Starane+ Roundup without significant between them while least weight of cluster recorded with un weeded check.
The highest values of cluster berries and cluster length were recorded with rice straw, roundup twice, black polyethylene and hoeing third, respectively. On the other side, the least values of cluster berries and cluster length were recorded with un weeded check. While, the least values of cluster compactness (5.59, 5.73 and 5.78) recorded due to use black polyethylene mulch and rice straw mulch, Roundup twice without significant between them compered to un weeded check.
6. Effect of weed control treatments on berries physical and chemical properties.
6-1- Physical characteristics
Applying the weed control significantly increased berry weight as compared with the un weeded control. The maximum values of berry weight were produced by black polyethylene mulch, rice straw mulch, Egyptian clover, Starane L. + Roundup and hoeing third without significant differences between them, respectively, followed by roundup twice Meanwhile the lowest values obtained from the weedy check, respectively.
The higher berry size was observed under mulching with black polyethylene and rice straw, followed by Starane + Roundup and Egyptian clover by followed by Roundup twice and hoeing third by compared to the un weeded check which produced the minimum values respectively.
6-2-Chemical characteristics
All weed control treatments under study were significant in improving these traits
The best TSS % was obtained from black polyethylene mulch followed by rice straw mulch, roundup twice, Egyptian clover and hoeing third.
*Reducing sugar % of grape berries were increased by all weed control treatments, the superior treatments were mulching with black polyethylene, rice straw, Roundup twice, Egyptian clover and hoeing third.
*All treatments decreased acidity content in berries than the un weeded check ones. The highest acidity percentage content were found in grape berries of un weeded check while grape berries with black polyethylene mulch, rice straw mulch roundup twice and hoeing third contained the lowest values in this respect without significant differences between them, respectively.
Weed control treatments significantly increased TSS/acidity compared to unweeded check. The highest values were achieved with black polyethylene, rice straw mulch, Roundup twice and hoeng third, Egyptian clover, while the least value recorded with un weeded check.
* The highest values of anthocyanins was recorded due to use rice straw mulch followed by black polyethylene mulch and Roundup twice. On other hand the un weeded chick was recorded the lowest value of anthocyanin.
6-Herbicides residues in grape berries
Herbicide residues, which determined by HPLC in grape berries at harvest were below than the maximum residue allowable level
7- Economic feasibility study
Economic evaluation, showed that yield is a profitable enterprise for grapevine growers by using Egyptian clover, black polyethylene mulch, rice straw mulch, followed hand hoeing third that recommended as good and clean alternatives for weed control in vinyardes. Egyptian clover treatment achieve the highest economic return although black polyethylene and rice straw mulching treatments gave high relative yield than Egyptian clover treatment because the gross income from the Egyptian clover treatment includes the income from grapes, plus additional income from clover, and additional black polyethylene treatment was the higher total cost from all treatments. Also, roundup twice and Starane + Roundup treatments which can be recommended as good for weed control in vineyards.
Conclusions
The results show that some safe economic alternatives to mechanical weed control by hand hoeing third or mulching the soil with synthetic material i.e black polyethylene, as well as, organic material i.e. rice straw or Egyptian clover (berseem) as a cover crop for weed control during the grapevine crop life to produce good yield and can be used fairly in organic farming conditions in Egypt. Also chemically by herbicides i.e. Roundup twice at 2.5 L and Starane at 0.2 L + Roundup at 2.5 L for weed control with the herbicidal residues were lower than their maximum residual level (MRL).