Effet des sites et des traitements sylvicoles sur la croissance, l'allocation en biomasse et l'utilisation de l'azote de semis de quatre espèces feuillues en plantations dans le sud-ouest du Québec

1993 ◽  
Vol 23 (2) ◽  
pp. 199-209 ◽  
Author(s):  
Alain Cogliastro ◽  
Daniel Gagnon ◽  
André Bouchard
Keyword(s):  
Weed Control ◽  
Leaf Biomass ◽  
Red Oak ◽  
Total Biomass ◽  
White Ash ◽  
Herbicide Treatment ◽  
Agricultural Potential ◽  
Bur Oak ◽  
Successful Establishment ◽  
Glacial Tills

To identify conditions leading to the successful establishment of hardwoods in plantations, several parameters related to growth, biomass allocation, and nitrogen nutrition were analyzed in relation with variations in soil resources, among four plantation sites, and different weed control treatments. White ash (Fraxinusamericana L.), butternut (Juglanscinerea L.), bur oak (Quercusmacrocarpa Michx.), and red oak (Quercusrubra L.) seedlings were planted in 1988 on four sites typical of glacial tills, littoral sands, and marine clays found in southwestern Quebec. Weed control treatments consisted in the use of a low persistence herbicide (glyphosate) and that of an organic mulch composed of chipped hardwood branches. A control treatment was included in the design. Weed control was best with the herbicide, resulting in an increase in soil temperature, water content, and nitrate concentration. Seedlings from the herbicide treatment reached a greater height and their leaf biomass was 25% that of the total biomass, and twice as much that of the control. Their root biomass accounted for 35% as compared to 50% for the control. The total amount of leaf nitrogen was 10 times greater in the herbicide treatment. Mortality rates were highest for white ash, bur oak, and butternut on sites where water availability was lowest, as well as in the absence of weed control. Red oak mortality was lowest on the littoral sand site. Mortality was the same with either weed control treatments although clearly lower than that of the control. The relative growth rate and net assimilation rate, as well as nitrogen use efficiency, were lower on the marine clay site, a high agricultural potential site. Because of a reduction of weed competition in the herbicide treatment, white ash had similar height growth on all sites, whereas bur oak, butternut, and red oak, in particular, grew best on nonexposed sites with light-textured soils. Successful establishment of hardwood seedlings depends strongly on the control of competing herbaceous weeds during the first years of growth in plantation. In southwestern Quebec, on glacial tills where topography increases water supply through seepage, wind-sheltered sites show a high potential for valuable hardwood reforestation. Such sites have a low agricultural potential because of their very high stonyness.

Chemical weed control in potatoes

1966 ◽  
Vol 67 (2) ◽  
pp. 239-242
Author(s):  
Maurice Eddowes
Keyword(s):  
Weed Control ◽  
Soil Type ◽  
Effective Control ◽  
Herbicide Treatment ◽  
Weed Flora ◽  
Annual Weeds

Dinoseb and TCA were successfully used to control weeds in potatoes by Robertson (1960), and Wood, Sutherland & Stephens (1960). Since then many investigations have been carried out on the use of newer herbicides including the bipyridils, triazines and substituted ureas. The results of a number of these studies, presented at the Seventh British Weed Control Conference (1964), suggested that herbicides might give effective control of annual weeds in potatoes under a range of British conditions. Yields of marketable ware following herbicide treatment were similar, in general, to those obtained following standard post-planting cultivations, but occasionally the yields after herbicide treatment were either as much as 20% higher or lower than the controls. The performance of the herbicides was related mainly to weed flora, soil type and amount and distribution of rainfall.

Effects of nitrogen deposition on nitrate leaching from forests of the northeastern United States will change with tree species composition

2017 ◽  
Vol 47 (8) ◽  
pp. 997-1009 ◽  
Author(s):  
Katherine F. Crowley ◽  
Gary M. Lovett
Keyword(s):  
United States ◽  
Species Composition ◽  
Nitrate Leaching ◽  
Tree Species ◽  
N Deposition ◽  
Red Oak ◽  
Northeastern United States ◽  
Tree Species Composition ◽  
White Ash ◽  
Species Change

As tree species composition in forests of the northeastern United States changes due to invasive forest pests, climate change, or other stressors, the extent to which forests will retain or release N from atmospheric deposition remains uncertain. We used a species-specific, dynamic forest ecosystem model (Spe-CN) to investigate how nitrate (NO3–) leaching may vary among stands dominated by different species, receiving varied atmospheric N inputs, or undergoing species change due to an invasive forest pest (emerald ash borer; EAB). In model simulations, NO3– leaching varied widely among stands dominated by 12 northeastern North American tree species. Nitrate leaching increased with N deposition or forest age, generally with greater magnitude for deciduous (except red oak) than coniferous species. Species with lowest baseline leaching rates (e.g., red spruce, eastern hemlock, red oak) showed threshold responses to N deposition. EAB effects on leaching depended on the species replacing white ash: after 100 years, predicted leaching increased 73% if sugar maple replaced ash but decreased 55% if red oak replaced ash. This analysis suggests that the effects of tree species change on NO3– leaching over time may be large and variable and should be incorporated into predictions of effects of N deposition on leaching from forested landscapes.

HERBICIDES FOR FORAGE CORN NO-TILL SEEDED INTO CEREAL STUBBLE

1983 ◽  
Vol 63 (1) ◽  
pp. 235-241 ◽  
Author(s):  
J. A. IVANY ◽  
J. R. ENMAN
Keyword(s):  
Zea Mays ◽  
Weed Control ◽  
Prince Edward Island ◽  
Zea Mays L ◽  
Crop Yields ◽  
Taraxacum Officinale ◽  
Plant Population ◽  
No Till ◽  
Herbicide Treatment ◽  
Forage Yields

Forage corn (Zea mays L.) was grown successfully in Prince Edward Island by no-till planting the corn into standing cereal stubble 15–20 cm tall using a Buffalo no-till seeder. Planting with the slot-type shoe in a preliminary experiment in 1978 gave better forage yields than planting with a slice-type shoe mainly because of better plant population achieved. Subsequent experiments in 1979–1981 using the slot-type shoe to no-till plant corn in cereal stubble gave good forage yields when adequate weed control was provided with herbicide treatment. Best control of quackgrass (Agropyron repens L. Beauv.) and dandelion (Taraxacum officinale Weber) and crop yields was achieved with glyphosate + atrazine (1.5 + 2.5 kg a.i./ha) or amitrole + atrazine (3.4 + 2.5 kg a.i./ha) applied preemergence after seeding corn and before corn emergence. Control of quack grass and dandelion with glyphosate or amitrole used alone ranged from 71–80%, but paraquat alone did not provide any weed control. Addition of atrazine to paraquat, glyphosate, or amitrole gave improved control of quackgrass and dandelion and higher forage corn yields. Addition of 2.5 kg a.i./ha atrazine gave better results than use of 1.0 kg a.i./ha of atrazine.Key words: Forage corn, no-till seeding, glyphosate, atrazine, aminotriazole, paraquat

scholarly journals The significance of biomass allocation to population growth of the invasive species Ambrosia artemisiifolia and Ambrosia trifida with different densities

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Wenxuan Zhao ◽  
Tong Liu ◽  
Yan Liu ◽  
Hanyue Wang ◽  
Ruili Wang ◽  
...  
Keyword(s):  
Cluster Formation ◽  
Ambrosia Artemisiifolia ◽  
High Density ◽  
High Population ◽  
Leaf Biomass ◽  
Total Biomass ◽  
Low Density ◽  
Population Densities ◽  
Ambrosia Trifida ◽  
Short Period

Abstract Background Ambrosia artemisiifolia and Ambrosia trifida are globally distributed harmful and invasive weeds. High density clusters play an important role in their invasion. For these two species, the early settled populations are distributed at low densities, but they can rapidly achieve high population densities in a short period of time. However, their response to intraspecific competition to improve the fitness for rapid growth and maintenance of high population densities remains unclear. Therefore, to determine how these species form and maintain high population densities, individual biomass allocations patterns between different population densities (low and high), and plasticity during seedling, vegetative, breeding and mature stages were compared. In 2019, we harvested seeds at different population densities and compared them, and in 2020, we compared the number of regenerated plants across the two population densities. Results Most biomass was invested in the stems of both species. Ambrosia trifida had the highest stem biomass distribution, of up to 78%, and the phenotypic plasticity of the stem was the highest. Path analysis demonstrated that at low-density, total biomass was the biggest contributor to seed production, but stem and leaf biomass was the biggest contributors to high-density populations. The number of seeds produced per plant was high in low-density populations, while the seed number per unit area was huge in high-density populations. In the second year, the number of low-density populations increased significantly. A. artemisiifolia and A. trifida accounted for 75.6% and 68.4% of the mature populations, respectively. Conclusions High input to the stem is an important means to regulate the growth of the two species to cope with different densities. These two species can ensure reproductive success and produce appropriate seed numbers. Therefore, they can maintain a stable population over time and quickly form cluster advantages. In the management, early detection of both species and prevention of successful reproduction by chemical and mechanical means are necessary to stop cluster formation and spread.

Weed Control in Established Alfalfa(Medicago sativa)

Weed Science ◽  
1978 ◽  
Vol 26 (1) ◽  
pp. 37-40 ◽  
Author(s):  
L. R. Robison ◽  
C. F. Williams ◽  
W. D. Laws
Keyword(s):  
Medicago Sativa ◽  
Weed Control ◽  
Control Plot ◽  
Herbicide Treatment ◽  
Second Year ◽  
Carry Over ◽  
Harvest Year ◽  
Low Rate

Several soil-applied and two foliar herbicides were evaluated for weed control in established alfalfa(Medicago sativaL.) in two experiments for two consecutive years. Most of the soil-applied herbicides effectively controlled weeds in the first harvest year following application; however, there was little carry-over into succeeding years. Except for the low rate of secbumeton [N-ethyl-6-methoxy-N′ (1-methylpropyl)-1,3,5-triazine-2,4-diamine] in the first alfalfa cutting of 1973, no herbicide treatment significantly increased alfalfa yields over the control plot. In fact, some herbicides caused injury to alfalfa at high rates of application, as did reapplication a second year at the original rate of application.

Effect of Tillage Systems on the Efficacy and Phytotoxicity of Imazaquin and Imazethapyr in Soybean (Glycine max)

Weed Science ◽  
1989 ◽  
Vol 37 (2) ◽  
pp. 233-238 ◽  
Author(s):  
J. Anthony Mills ◽  
William W. Witt
Keyword(s):  
Glycine Max ◽  
Weed Control ◽  
Field Experiments ◽  
Conventional Tillage ◽  
No Tillage ◽  
Tillage Systems ◽  
Adequate Control ◽  
No Till ◽  
Herbicide Treatment ◽  
Giant Foxtail

Field experiments were conducted to evaluate the interactions of tillage systems with imazaquin and imazethapyr on weed control and soybean injury and yield. Control of jimsonweed, common cocklebur, ivyleaf morningglory, velvetleaf, and giant foxtail from imazaquin and imazethapyr in conventional tillage was generally equal to or greater than control in no-tillage. However, under limited rainfall, weed control in no-tillage was generally equal to or greater than control in conventional tillage. Reductions in soybean heights due to herbicide treatment were evident in both tillage systems in 1985 and 1986 but not in. Soybean yields were reduced in 1985 from imazaquin at 140, 210, and 250 g/ha and imazethapyr at 105 and 140 g/ha. Yields were not reduced in 1986 and. Imazaquin and imazethapyr appear to provide adequate control of jimsonweed, common cocklebur, ivyleaf morningglory, velvetleaf, and giant foxtail in conventional and no-till systems.

Reduced Rates of Herbicides Following Hilling Controlled Weeds in Conventional and Reduced Tillage Potato (Solanum tuberosum) Production

1996 ◽  
Vol 10 (2) ◽  
pp. 311-316 ◽  
Author(s):  
Robin R. Bellinder ◽  
Russell W. Wallace ◽  
Erik D. Wilkins
Keyword(s):  
Solanum Tuberosum ◽  
Weed Control ◽  
Conventional Tillage ◽  
Reduced Tillage ◽  
Split Application ◽  
Tillage Systems ◽  
Herbicide Treatment

Time of hilling (4, 5, or 6 weeks after planting; WAP) and 0.5x, 1x, and split (0.5x + 0.5x) rates of metolachlor + metribuzin were evaluated in conventional tillage (CT) and rye-stubble, reduced tillage (RT) potato plots. Weed populations 4 to 10 WAP were generally higher in CT than in RT. Weed control was excellent in both tillage systems when 1x rates of metolachlor + metribuzin were applied delayed preemergence, or in a split application where 0.5x was applied delayed PRE and hilled 6 WAP, and followed with a second application of 0.5x metolachlor + metribuzin 7 days after hilling (DAH). Weed control with 0.5x rates of metolachlor + metribuzin applied 7 DAH, when hilled 4 and 5 WAP, was equivalent to the lx and split-rate treatments. Weed control was reduced only when hilling was delayed to 6 WAP and 0.5x of metolachlor + metribuzin applied 7 DAH. Total yields were not influenced by tillage, hilling, or herbicide treatment, however, larger numbers of green and small-sized tubers reduced marketable yields in RT.

scholarly journals The Effect of Different Weed Management Strategies on the Growth and Yield of Direct-Seeded Dry Rice (Oryza sativa)

2016 ◽  
Vol 34 (1) ◽  
pp. 57-64 ◽  
Author(s):  
S. MUHAMMAD ◽  
I. MUHAMMAD ◽  
A. SAJID ◽  
L. MUHAMMAD ◽  
A. MAQSHOOF ◽  
...  
Keyword(s):  
Weed Control ◽  
Crop Yield ◽  
Weed Management ◽  
Management Strategies ◽  
Control Measures ◽  
Growth And Yield ◽  
Primary Concern ◽  
Herbicide Treatment ◽  
Direct Seeded ◽  
Hand Weeding

Weed management is a primary concern in direct seeded rice (DSR) cropping because weed growth becomes a major constraint on crop yield. A two year field study was set up to evaluate the effect of various weed control measures on crop growth, grain yield and grain quality of DSR. The experiment involved five different weed control measures: hand weeding, hoeing, inter-row tine cultivation, inter-row spike hoeing and herbicide treatment (Nominee 100 SC). The extent of weed control (compared to a non-weeded control) ranged from 50-95%. The highest crop yield was obtained using hand weeding. Hand weeding, tine cultivation and herbicide treatment raised the number of fertile rice tillers formed per unit area and the thousand grain weight. Tine cultivation provided an effective and economical level of weed control in the DSR crop.

Influences of light intensity on weed-induced stresses of tree seedlings

1990 ◽  
Vol 20 (5) ◽  
pp. 503-507 ◽  
Author(s):  
T. E. Kolb ◽  
T. W. Bowersox ◽  
L. H. McCormick
Keyword(s):  
Soil Moisture ◽  
Light Intensity ◽  
Tree Species ◽  
Red Oak ◽  
Tree Seedlings ◽  
Northern Red Oak ◽  
White Pine ◽  
White Ash ◽  
Reduced Height ◽  
Four Levels

Growth of northern red oak (Quercusrubra L.), white ash (Fraxinusamericana L.), and white pine (Pinusstrobus L.) seedlings was evaluated for 2 years after germination in 12 environments that consisted of four levels of herbaceous interference (fern, fern free, grass, grass free) crossed with three levels of light intensity (100, 45, and 20% full sun), at two clear-cuts in central Pennsylvania. Grass and fern interference reduced soil moisture content and reduced height or diameter growth of all species. Shading ameliorated soil moisture, reduced herbaceous growth, generally reduced growth of all tree species in interference-free environments, and had no effect on growth of any tree species in fern and grass environments. Reduction in growth due to herbaceous interference was lower for northern red oak and white pine than for white ash, while shading had similar effects on growth of all species. Results suggest that stresses induced by shading alone have little short-term effect on the establishment of these species under conditions of heavy herbaceous interference.

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