The effect of competition from different weed species on the growth of Betula pendula seedlings

2006 ◽  
Vol 36 (8) ◽  
pp. 1900-1912 ◽  
Author(s):  
Ian Willoughby ◽  
David V Clay ◽  
Fiona L Dixon ◽  
Geoff W Morgan
Keyword(s):  
Lolium Perenne ◽  
Tree Growth ◽  
Betula Pendula ◽  
Percent Cover ◽  
Inhibitory Effects ◽  
Weed Species ◽  
Cirsium Vulgare ◽  
Weed Growth ◽  
Local Plant ◽  
Woodland Regeneration

The identification of less competitive weed species and infestation rates might allow weeding operations to be better targeted, help conserve local plant biodiversity, and facilitate reductions in the amount of herbicide used to achieve woodland regeneration. Therefore, the effect of competition from pure stands of Cirsium vulgare (Savi) Ten., Epilobium ciliatum Raf., Holcus lanatus L., Poa annua L., and Persicaria maculosa Gray on Betula pendula Roth was investigated over 2 years. All weed species reduced tree growth significantly compared with weed-free plots, but there were no significant differences among species. When Lolium perenne L., Rumex obtusifolius L., and Cirsium vulgare were established at four densities in plots containing newly planted B. pendula over a 1-year period, all weed species reduced tree growth, but Lolium perenne was the most competitive. Weed density had no significant effect, indicating that even sparse weed growth can have a major impact on tree performance. None of the treatments affected B. pendula survival. These results confirm the inhibitory effects of a range of weed species on tree growth, but not survival, and the capacity of B. pendula to recover in the second year after planting from an initial check in growth. Percent cover was a good explanatory variable for models developed to describe the effects of weeds on tree growth, and preliminary competition indices for the different species are presented.

Importance of seasonal growth patterns in modelling interactions between radiata pine and some common weed species

2004 ◽  
Vol 34 (1) ◽  
pp. 184-194 ◽  
Author(s):  
Mark O Kimberley ◽  
Brian Richardson
Keyword(s):  
Fourier Series ◽  
Tree Growth ◽  
Tree Height ◽  
Height Growth ◽  
Growth Patterns ◽  
Seasonal Effects ◽  
Weibull Function ◽  
Seasonal Fluctuations ◽  
Weed Species ◽  
Weed Growth

Previously described weed competition models that use competition indices based on weed size relative to tree size (e.g., tree height divided by weed height) require models of weed growth and models of weed-free tree growth. A method is presented to model these using standard sigmoidal growth functions and to incorporate regular seasonal patterns of tree growth using Fourier series approximations. The method is tested against data from a field trial at Rotorua, New Zealand, in which Pinus radiata D. Don was grown both on its own and in competition with several common weed species. Weed and tree height were best modelled by a Weibull function, and tree ground line diameter by a Schumacher function. Seasonal fluctuations in both tree and weed growth were adequately modelled by a single-term Fourier series. All weed species showed very similar, strong seasonal fluctuations in height growth, peaking in February. Seasonal fluctuations in tree height growth, and especially diameter growth, were less marked and peaked earlier, in December. Simulations suggested that it is necessary to account for seasonal effects when modelling competition during the first year of growth, but that seasonal effects have less influence in subsequent years.

scholarly journals Allelopathic Effects of Imperata Cylindrica Aqueous Extract on the Germination of Cucumis Sativus and Lolium Perenne

2020 ◽  
Vol 8 (6) ◽  
pp. 2503-2508
Keyword(s):  
Cucumis Sativus ◽  
Lolium Perenne ◽  
Dry Weight ◽  
Imperata Cylindrica ◽  
Allelopathic Effect ◽  
Aqueous Extracts ◽  
Inhibitory Effects ◽  
Weed Species ◽  
Mechanism Of Inhibition ◽  
Root And Shoot Length

In this study, the allelopathic effect of Imperata cylindrica has been investigated. Aqueous extracts of Imperata cylindrica were tested at concentrations of 31.25, 62.5, and 125 mg/ml to study different parameters on Cucumis sativus and Lolium perenne. Various factors were studied to determine the inhibition and growth of root and shoot length, percentage germination, and fresh and dry weight. Results indicated that the aqeous extract of Imperata cylindrica contain allelochemicals which may contribute to its invasiveness and extreme competitiveness. The results of this study show that Imperata cylindrica contains allelochemical compounds particularly in root and shoot extracts that might be the potential candidates for future investigations for the development of herbicides based on its secondary metabolites and their allelopathic inhibitory effects. Further research is needed to investigate the allelopathic effect of Imperata cylindrical aqueous extracts under field conditions against the associated weed species and elucidation of the mechanism of inhibition involved

scholarly journals Inhibitory Effects of Brassicaceae Cover Crop on Ambrosia artemisiifolia Germination and Early Growth

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 794
Author(s):  
Maja Šćepanović ◽  
Marija Sarić-Krsmanović ◽  
Valentina Šoštarčić ◽  
Ema Brijačak ◽  
Josip Lakić ◽  
...  
Keyword(s):  
Cover Crops ◽  
Syringic Acid ◽  
Early Growth ◽  
Ambrosia Artemisiifolia ◽  
Aqueous Extracts ◽  
Inhibitory Effects ◽  
Weed Growth ◽  
Liquid Chromatography Tandem Mass ◽  
Allelopathic Effects ◽  
Vanilic Acid

Several cover crops (CCs) exert allelopathic effects that suppress weed growth. The aim of the present study was to evaluate the effects of aqueous extracts containing different concentrations [0, 0.5, 1, 2.5, 5, 7.5 and 10% (w/v)] of Brassicaceae CCs (Sinapis alba, Raphanus sativus, Camellina sativa) and of the CCs Fagopyrum esculentum and Guizotia abyssinica on germination and early growth of Ambrosia artemisiifolia L. The allelopathic effects were species and concentration-dependent. C. sativa, for example, caused the greatest potential to inhibit germination, shoot, radicle length and fresh seedling weight, whereas S. alba and R. sativus inhibited germination and early growth of A. artemisiifolia only at concentrations ≥7.5%. In contrast, no inhibition was observed when aqueous extracts of F. escultneum and G. abyssinica were added at any of tested concentration. Liquid chromatography-tandem mass spectrometry detected 15 phenolic compounds in Brassicaceae CCs with the highest content (µg/g) of vanillin (48.8), chlorogenic acid (1057), vanilic acid (79), caffeic acid (102.5) and syringic acid (27.3) in C. sativa. Our results suggest that C. sativa is the most allelopathic CCs and that the fruits of C. sativa are the plant organs richest in allelochemicals.

scholarly journals Temporal expression of the sor1 gene and inhibitory effects of Sorghum bicolor L. Moench on three weed species

2014 ◽  
Vol 28 (3) ◽  
pp. 361-366 ◽  
Author(s):  
Roseane Cavalcanti dos Santos ◽  
Gabriela de Morais Guerra Ferraz ◽  
Manoel Bandeira de Albuquerque ◽  
Liziane Maria de Lima ◽  
Péricles de Albuquerque Melo Filho ◽  
...  
Keyword(s):  
Sorghum Bicolor ◽  
Inhibitory Effects ◽  
Temporal Expression ◽  
Weed Species ◽  
Sorghum Bicolor L

scholarly journals Effects of Three Fertilization Methods on Weed Growth and Herbicide Performance in Soilless Nursery Substrates1

2018 ◽  
Vol 36 (4) ◽  
pp. 133-139
Author(s):  
Cody J. Stewart ◽  
S. Christopher Marble ◽  
Brian E. Jackson ◽  
Brian J. Pearson ◽  
P. Christopher Wilson
Keyword(s):  
Fertilizer Treatment ◽  
Fertility Rates ◽  
Weed Species ◽  
Fertilizer Placement ◽  
Digitaria Sanguinalis ◽  
Fertilizer Rate ◽  
Weed Growth ◽  
Eclipta Prostrata ◽  
Preemergence Herbicides ◽  
Large Crabgrass

Abstract Research objectives were to determine the effect of fertilization method (incorporation, subdress, and topdress) on weed growth and the performance of preemergence herbicides applied to soilless substrates. Nursery containers were filled with a pine bark:peat substrate and fertilized at two different rates [4.4 and 9.5 kg.m−3 (8.9 and 19.2 lb.yd−3)] via topdressing, subdressing, or incorporating. Containers were treated with either dimethenamid-P for spotted spurge (Euphorbia maculata L.), flumioxazin for eclipta (Eclipta prostrata L.) or prodiamine for large crabgrass (Digitaria sanguinalis L.). A control was established for each fertilizer rate/placement and weed species that was not treated. Incorporating or subdressing fertilizer resulted in reduced large crabgrass and spotted spurge growth in non-treated containers. Weeds grew larger at the higher fertility rates in both topdress and incorporated treatments but fertilizer rate did not affect growth of spotted spurge or large crabgrass when fertilizers were subdressed. Herbicides generally provided commercially acceptable weed control regardless of fertilizer treatment, but results varied with species. Results suggest that in the absence of herbicides, topdressing may result in greater weed growth compared with subdressing or incorporating fertilizers; however, fertilizer placement will have less impact on herbicide performance if proper herbicides are chosen and applied correctly. Index words: topdress, subdress, incorporate, large crabgrass, eclipta, spotted spurge, preemergence Chemicals used in this study: Flumioxazin (SureGuard®); 2-[7-fluoro-3,4-dihydro-3-oxo-4-(2-propynyl)-2H-1,4-benzoxazin-6-yl]-4,5,6,7-tetrahydro-1H-isoindole1,3(2H)-dione; Dimethenamid-P (Tower) 2-chloro-N-[(2,4-dimethyl-3-thienyl)-N-(2-methoxy-1-methylethyl)acetamide; Prodiamine (Barricade) 2,4-dinitro-N3, N3-dipropyl-6-(trifluoromethyl)-1,3-benzenediamine (Barricade®) Species used in this study: Large crabgrass (Digitaria sanguinalis L.); Eclipta (Eclipta prostrata L.); Spotted spurge (Euphorbia maculata L.)

Cultivar and Weeding Effects on Weeds and Rice Yields in a Degraded Upland Environment of the Coastal Savanna

2011 ◽  
Vol 25 (3) ◽  
pp. 322-329 ◽  
Author(s):  
Amadou Touré ◽  
Jonne Rodenburg ◽  
Kazuki Saito ◽  
Sylvester Oikeh ◽  
Koichi Futakuchi ◽  
...  
Keyword(s):  
West Africa ◽  
Rice Yield ◽  
Upland Rice ◽  
Biomass Accumulation ◽  
Rice Cultivars ◽  
Weed Species ◽  
Weed Growth ◽  
Weed Suppressive Ability ◽  
Rice Yields ◽  
Growing Conditions

Weeds are a major constraint to rice production in labor-limited, upland rice-based systems in West Africa. The effects of weeding regimes and rice cultivars on weed growth and rice yield were investigated at two upland locations (Abomey-Calavi and Niaouli) in the degraded coastal savanna zone of Benin in 2005 and 2006 with below-average rainfall. Four weeding regimes (hoe weeding at 21 d after sowing [DAS], delayed hoe weeding at 31 DAS, hoe weeding at 21 and 42 DAS, and a no weeding control) were the main plot treatments. Cultivars comprising three interspecific upland rice cultivars (NERICA 1, NERICA 2, and NERICA 7) and the parents (Oryza sativaWAB56-104 andO. glaberrimaCG14) were tested in subplots. The most dominant weed species identified were Jamaican crabgrass,Mariscus, and silver spinach. Rice yield was generally low because of drought stress; none of the experiments had a higher mean yield than 1,400 kg ha−1across cultivars. Across cultivars, the best weeding regimes in terms of weed control and rice yields were single weeding at 31 DAS (W31) and double weeding at 21 and 42 DAS (W21+42). Under these weeding regimes, WAB56-104 out-yielded the three NERICA cultivars. CG14 showed the strongest weed suppressive ability (WSA) in Abomey-Calavi but did not have strong WSA in Niaouli because of lower biomass accumulation. WSA of WAB56-104 was similar to that of the three NERICA cultivars. Single weeding at 31 DAS, together with the use of cultivars with good adaptation to unfavorable rice growing conditions, would increase land and labor productivity of upland rice-based systems in West Africa.

scholarly journals Selective fertilization with phosphite allows unhindered growth of cotton plants expressing the ptxD gene while suppressing weeds

2018 ◽  
Vol 115 (29) ◽  
pp. E6946-E6955 ◽  
Author(s):  
Devendra Pandeya ◽  
Damar L. López-Arredondo ◽  
Madhusudhana R. Janga ◽  
LeAnne M. Campbell ◽  
Priscila Estrella-Hernández ◽  
...  
Keyword(s):  
Transgenic Plants ◽  
Sole Source ◽  
Crop Productivity ◽  
Weed Suppression ◽  
Artificial Substrates ◽  
Effective Alternative ◽  
Gene Gain ◽  
Weed Species ◽  
Weed Growth ◽  
Phosphite Dehydrogenase

Weeds, which have been the bane of agriculture since the beginning of civilization, are managed manually, mechanically, and, more recently, by chemicals. However, chemical control options are rapidly shrinking due to the recent rise in the number of herbicide-resistant weeds in crop fields, with few alternatives on the horizon. Therefore, there is an urgent need for alternative weed suppression systems to sustain crop productivity while reducing our dependence on herbicides and tillage. Such a development will also allay some of the negative perceptions associated with the use of herbicide-resistance genes and heavy dependence on herbicides. Transgenic plants expressing the bacterial phosphite dehydrogenase (ptxD) gene gain an ability to convert phosphite (Phi) into orthophosphate [Pi, the metabolizable form of phosphorus (P)]. Such plants allow for a selective fertilization scheme, based on Phi as the sole source of P for the crop, while offering an effective alternative for suppressing weed growth. Here, we show that, when P is supplied in the form of Phi, ptxD-expressing cotton (Gossypium hirsutum L.) plants outcompete, in both artificial substrates and natural soils from agricultural fields, three different monocot and dicot weed species intentionally introduced in the experiments, as well as weeds naturally present in the tested soils. Importantly, the ptxD/Phi system proved highly efficacious in inhibiting the growth of glyphosate-resistant Palmer amaranth. With over 250 weed species resistant to currently available herbicides, ptxD-transgenic plants fertilized with Phi could provide an effective alternative to suppressing the growth of these weeds while providing adequate nutrition to the crop.

Chemical weed control in young peach trees

1975 ◽  
Vol 15 (75) ◽  
pp. 566
Author(s):  
K Koffmann ◽  
J Kaldor
Keyword(s):  
Tree Growth ◽  
Cynodon Dactylon ◽  
Plantago Lanceolata ◽  
Chenopodium Album ◽  
Residual Effects ◽  
Polygonum Aviculare ◽  
Weed Growth ◽  
Lactuca Serriola ◽  
South Wales ◽  
Peach Trees

The effects of five residual herbicides and two mixtures of herbicides on tree and weed growth were studied in two trials over two consecutive seasons in a young peach orchard at Bathurst, New South Wales. In the first trial, dichlobenil at 4.5 and 9.0 kg ha-1 increased tree growth and suppressed weeds, but the residual effects of the low rate were short; simazine (2.2 kg ha-1), trifluralin (2.2 kg ha-1) and simazine (1 1 kg ha-1) plus trifluralin (1.1 kg ha-1) also reduced weed incidence but did not improve tree growth. In the second trial, terbacil (2.2 kg ha-1) and mixtures of diuron (1.1 kg ha-1) and terbacil at 1.1 or 2.2 kg ha-1 effectively controlled weeds, giving faster tree growth. Terbacil (1.1 kg ha-1) and diuron (1.1 kg ha-1) suppressed broadleaf but not grass weeds. Terbacil (1.1 kg ha-1) improved tree growth only in the second season; diuron (1.1 kg ha-1) did not affect tree growth. None of the peach trees displayed toxic symptoms. The main weeds present in the trial site were: Amaranthus powellii, Chenopodium album, Polygonum aviculare, Lepidium hyssopifolum, Lactuca serriola, Rumex acetosella, Sonchus oleraceus, Plantago lanceolata, Cynodon dactylon, Bromus sp, and Eragrostis sp.

Basis for Interactions of Ethofumesate1and Desmedipham on Sugarbeets and Weeds

Weed Science ◽  
1976 ◽  
Vol 24 (6) ◽  
pp. 619-626 ◽  
Author(s):  
Y. Eshel ◽  
R.L. Zimdahl ◽  
E.E. Schweizer
Keyword(s):  
Beta Vulgaris ◽  
Avena Fatua ◽  
Synergistic Interaction ◽  
Wild Oat ◽  
Weed Species ◽  
Synergistic Interactions ◽  
Wild Mustard ◽  
Weed Growth ◽  
Spray Volume ◽  
Brassica Kaber

A synergistic interaction occurred when sugarbeets (Beta vulgarisL. ‘Mono-Hy Al’) were treated with mixtures of ethofumesate (2-ethoxy-2,3-dihydro-3,3-dimethyl-5-benzofuranyl methanesulphonate) and desmedipham [ethylm-hydroxycarbanilate carbanilate (ester)]. Depending on the stage of weed growth synergistic interactions were also observed on two weed species: wild mustard [Brassica kaber(DC.) L.C. Wheeler ‘pinnatifida’ (Stokes) L.C. Wheeler] and wild oat (Avena fatuaL.). Desmedipham penetrated the foliage more slowly than did ethofumesate. The rate of desmedipham penetration was positively correlated with the concentration of its formulants (solvents and adjuvants) in the spraying emulsion, and to a lesser extent with the formulants of ethofumesate. Increasing the spray volume also increased desmedipham penetration. None of these factors affected penetration by ethofumesate.14C-labeled ethofumesate and desmedipham did not translocate out of treated leaves regardless of the concentration of formulants or active ingredients. These data suggest that the synergistic interaction is mainly due to the increased penetration by desmedipham when applied with ethofumesate.

Breed of ewe effects on the utilisation of pasture maintained at two sward heights

1986 ◽  
Vol 1986 ◽  
pp. 78-78
Author(s):  
J M Doney ◽  
A D M Smith ◽  
D A Sim ◽  
I R White
Keyword(s):  
Body Size ◽  
Lolium Perenne ◽  
Accumulation Rate ◽  
Research Station ◽  
Weed Species ◽  
Sward Height ◽  
Experimental Area ◽  
Electric Fence ◽  
Grazing Area ◽  
The Mean

An experiment was carried out at the Glensaugh research station to investigate the effects of breeds of ewe, differing in mature body size on the utilisation of a long-established reseed maintained at sward heights of 3.5 and S.5 cm until weaning.The experimental area, dominated by Lolium perenne (40%), Poa spp (30%) with other grasses (10%) and weed species (20%), was divided into 12 plots each of 0.7 ha. When the mean sward height reached at least 3.5 cm in every plot (13.5.85) they were each stocked with 9 ewes + 15 lambs from one of 3 ewe genotypes (Border Leicester x Blackface, GF; East Friesland x Blackface, EFX; Cheviot x Shetland, SHX) in two replicates. All lambs were sired by Suffolk rams.Mean sward height, herbage mass and estimated herbage accumulation rate were measured weekly and ewes and lambs were weighed weekly. Sward heights were maintained on each plot by movement of an electric fence to vary the grazing area. The area behind the fence was maintained at an equal sward height by non-experimental ewes and lambs to permit movement in any direction. The lambs were approximately 6 weeks old at the beginning of the trial and were weaned after 13 weeks on the plots.

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