الفهرس 
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Abstract
This study was conducted during 2016/17 and2017/18 on Balady mandarin trees . This study consisted of the following twelve treatments Unweeded control, Devo, Devo followed by Round up, Dinimic, Dinimic followed by select super, Roundup, Roundup twice, life line, Goal twice, mulching for two months with (white or black plastic sheets) and hand hoening twice. The scope of this study was evaluating the efficacy of some single or combinations of pre- emergence and post emergence herbicides, manual hoeing as conventional method techniques and plastic mulch as new alternative technique on weeds, and their effects on growth, yield and it components as compared with unweeded check in Balady mandarin orchards.. Controlling weeds by using different herbicides manual hoeing and mulching with white and black polyethylene sheets had a material effect on controlling the weeds and improving yield and both physical and chemical of the fruits compared with unweeded control. Mulching especially with plastic sheet and Devo followed by Roundup Roundup twice considerably surpassed the other treatments in controlling the total annual + perennial weed species by percentage 96.8 ، 94.9 and 90%in 1st season and 95.3 ,92.7 ,92.5 and 90.9% 2nd season up till 90 days from application as compared with unweeded check respectively,and promoting productivity of the trees Increased vegetative growth aspects such as length and thickness of shoot, leaf area and number of leaves /shoot in the spring growth cycle relative to unweeded treatment (control) .The highest mandarin fruit yield per feddan (12.3 & 12.1 tons) was recorded when the weeds were controlled by mulching weeds with black plastic as compared with hand Hoeing is the most widely used method (5.5 &5.3, )While the yield per feedan fell to (4.0 & 2.4) when the weeds ware left without treatment during both seasons when we left the grass without treatment all the investigated methods was noticeably
very effective in improving both physical and chemical characteristics of the fruits in terms of increasing fruit weight and dimensions( highest and diameter), T.S.S %, total and reducing sugars%, vitamin C and decreasing fruit peel weight% and thickness and total acidity% relative to the control. The best chemical treatment was the application of Devo followed by Round up, followed by using Round up twice The best results with regard to fruit quality were obtained due eliminations weeds by mulching with black plastic.
For weed species susceptibility to weed control treatments depending data on reduction of fresh weight (g/m2). In general rusults showed that all weed species namely Dinebra Retroflexa Vahl, Echinochloa colonum L.and Brachiaria reptans, L as narrow leaf weeds weed are susceptible (s) all weed control treatment s in both season excepted Dinimac were tolerant(t) to it , Portulaca oleracea,L , Trianthema portulacastrum,L and Euphorbia geniculata ,Ortega as broad weed are susceptible (s) to all weed control treatment s in both seasons .Meanwhile , Cynodon dactylon L, Convolvulus arvensis,L and Cyperus rotundus as perennial weeds are tolerant to Devo (t) , Dinamic, Dinamic followed by select Super . , It is suggeste Economical study for the promised treatment was calculated d to use mulching by black plastic sheets or Devo followed by Roundup, or Roundup twice as mandarin trees grown under middle Egypt conditions.Net profit of one feddan previous promised treatment (mulching with plastic sheets) for over the control treatment reached 37825 LE and 43250 LE during both seasons, respectively.