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Three approaches for estimation critical period in onion crop .
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Abstract: Onion crop suffer strongly from weed competition. An estimation of the critical period of weed control is very important for planning weed control strategies. For this purpose two field experiments were carried out at Sids Station during 2002 / 2003 and 2003 / 2004 winter seasons in transplanted onion. Every experiment included 16 treatments of weed removal and weed competition which eight of them weed-free period at 2, 4, 6, 8, 10, 12, 14 and 16 weeks from onion transplanting and eight treatments of weed competition at 4, 6, 8, 10, 12, 14, 16 weeks from onion transplanting and weed competition treatment for all season. Results of the effect of the treatments on weeds and onion crop were used to estimate critical period of weed competition to onion using three approches which were: regression models, classical biological and economic approach. Results showed that the maximum yield losses of onion due to weed onion competition in the whole season were 87.7 and 88.7 percentage from weed free plots due to weed infestation by 26.3 and 26.8 ton / feddan in 2002/2003 and 2003/2004 seasons, respectively. The relationship between onion yield and marketable yield and weed free and weed competition periods were linear, quadratic and logistic functions. To maintain 95% of maximum onion yield the maximum time allowed to let weeds grow after crop transplanting is 1.2 weeks. The same level could be achived if the crop kept free from weeds from its transplanting at least 13.4 to 14.3 weeks. With the use of classical biological approach results show that early weed competition period was 4 weeks and late competition period was 13 weeks allowed to maximum yield. With applying economic approach results exerted that early economic threshold was 3 weeks and late economic threshold was 13 weeks. From the previous analyses we can recommend that the critical period of onion weed competition the between 4 and 13 weeks and weed control strategies should be used to prevent weed competition in this period to maintain maximum onion yield.
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| Publication year |
2005
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| Pages |
pp. 474-489
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| Availability location |
المعمل المركزى لبحوث الحشائش
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| Availability number |
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| Organization Name |
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| City |
القاهرة
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| serial title |
Egypt, J., Appl. Sci
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| ISSN |
1110-1571
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| Author(s) from ARC |
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| Agris Categories |
Weeds and weed control
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AGROVOC
TERMS |
Allium cepa.
Plant competition.
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| Proposed Agrovoc |
critical period;approaches;
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| Publication Type |
Journal
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