Weed Control in Lowbush Blueberries in Eastern Canada

. 2000. Herbicidal weed control and crop-year NPK fertilization improves lowbush blueberry (Vaccinium angustifolium Ait.) production. Can. J. Plant Sci. 80: [351][352][353][354][355][356][357][358][359][360][361]. Past research has shown that fertilizer applied in the vegetative year can increase yield, but not always. Fertilizer applied in the crop year without weed control also has been shown to increase yield. The present study, conducted on a natural lowbush blueberry stand for 8 yr, compared the effects of factorial combinations of two rates each of N (0, 60), P (0, 26), and K (0, 50 kg ha -1 ) applied either in the vegetative or crop year, with or without weed control. Greatest production was obtained with weed control, which increased ripe fruit yield by 247% over that from plots without weed control. Nitrogen alone or P and K with N also increased yield, but only when applied in the crop year to weed-controlled plots. Phosphorous or K alone was of little benefit. Nitrogen increased ripe fruit yield from 3910 (unfertilized plots with weed control) to 4440 kg ha -1 and in combination with P and K to 5520 kg ha -1 . Yield increases from weed control and N were due to increased berry weight and hastened maturity, but weed control also increased total berry number. The increase by P and K was due to an increase in total and ripe berry numbers. Nitrogen applied in the vegetative year, although producing more flower buds m -2 than when applied in the crop year, gave lower yields. Fruit abortion, due to insufficient nutrients in the crop year, particularly N, is suspected to be the reason for the reduced yield. La recherche a montré que la fumure du bleuet nain dans l'année de croissance végétative peut à l'occasion accroître le rendement. La fumure dans l'année de frutification, sans maîtrise des mauvaises herbes, a également démontré des effets positifs sur le rendement. Dans nos travaux, réalisés pendant 8 ans sur un peuplement naturel de bleuets nains, nous avons comparé les effets de combinaisons factorielles de deux doses chacun des trois éléments N (0 et 60), P (0 et 26) et K (0 et 50 kg ha -1 ), apportés soit dans l'année végéta-tive soit dans l'année de production, avec ou sans désherbage chimique. C'est le désherbage chimique qui a donnait lieu à la production la plus forte, accroissant le rendement en fruits mûrs de 247 % par rapport aux parcelles non désherbées. L'azote, seul ou avec P et K, causait également des hausses de rendement, mais seulement lorsqu'il était utilisé l'année de récolte dans les parcelles désherbées. Employés seuls, le phosphore ou le potassium n'apportaient que peu d'avantages. La fumure N faisait monter le rendement en fruits mûrs de 3910 (parcelles non fertilisées avec désherbage) à 4440 kg ha -1 et, complétée par P et K, à 5520 kg ha -1 . Les augmentations de rendement résultant du désherbage et de la fumure N étaient dues à l'accroissement du poids du fruit et à l'accélération de la maturité, le désherbage produisant en plus une augmentation du nombre total de fruits. Les g...

Section: Herbicidal Weed Controlsupporting

confidence: 76%

Herbicidal weed control and crop-year NPK fertilization improves lowbush blueberry (Vaccinium angustifolium Ait.) production

Penney¹,

McRae²

2000

“…Many studies were initiated to test the impact of several herbicides on weed control and blueberry productivity (Hoelper and Yarborough 1985;Jensen 1986;Yarborough et al 1986). Broadcast, preemergence applications of hexazinone became accepted as the most effective herbicide to control a broad range of weeds in blueberry fields (Jensen 1985). Hexazinone controls most herbaceous weeds without causing significant damage to blueberry plants (Yarborough and Ismail 1985).…”

Section: Mots Clésmentioning

confidence: 99%

“…Hexazinone controls most herbaceous weeds without causing significant damage to blueberry plants (Yarborough and Ismail 1985). Spot applications of 2,4-D or glyphosate complements the hexazinone treatment and provides control of shrubs and trees (Jensen 1985;Yarborough 1985a). Blueberry productivity increases significantly when herbicides are applied.…”

Section: Mots Clésmentioning

confidence: 99%

“…Some weed species such as Apocynum androsaemifolium Ait., Cornus canadensis L., Hypericum perforatum L., and Pyrus melanocarpa (Michx.) Willd., are tolerant to the hexazinone use (Jensen 1985;Yarborough et al 1986;Yarborough and Bhowmik 1989). The reduction in weed cover has not immediately translated into a proportional increase in blueberry cover and many areas have become bare.…”

Section: Mots Clésmentioning

confidence: 99%

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Weed survey of lowbush blueberry fields in Saguenay–Lac-Saint-Jean, Québec, following eight years of herbicide application

Lapointe¹,

Rochefort²

2001

Lapointe, L. and Rochefort, L. 2001. Weed survey of lowbush blueberry fields in Saguenay-Lac-Saint-Jean, Québec, following eight years of herbicide application. Can. J. Plant Sci. 81: 471-478. A weed survey was conducted in 1995 and 1996 in eight lowbush blueberry (Vaccinium angustifolium Ait.) producer sites of the Saguenay-Lac-Saint-Jean region to measure the impact of repeated herbicide applications on weed frequency and percent cover. A previous survey (1981)(1982)(1983), done in the same area before the widespread use of herbicides by the producers, had shown an impact of weed abundance on blueberry productivity. Weed frequency decreased from 1981-1983 to 1995-1996. Some species have apparently disappeared and all showed a reduction in abundance, suggesting that tolerance to herbicides or shifts to herbicide tolerant species has not occurred in this region. Weed cover decreased from over 65% to 10% in surveyed blueberry producer sites, and their presence no longer affects blueberry productivity. However, herbicide use is associated with an increase in percent bare ground, which now accounts for an average of 38% of lot surfaces. Blueberry plants do not seem to be able to quickly colonise bare weeded sites. In plots weeded manually, blueberry shoots did not increase in cover after 2 yr. Herbicide applications are still needed to maintain the weed populations at low levels, but we now have to stimulate the colonisation of bare patches by blueberry plants.

“…Trevett (1961) The recent widespread use of the soilapplied herbicide hexazinone has resulted in control ofmany woody species (Jensen 1986 (Nir 1982 For personal use only. (Table 1).…”

mentioning

confidence: 99%

Control of Speckled Alder in Lowbush Blueberry With Selective Fall Herbicide Treatments

Jensen¹,

North²

1987

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