Control of Grass and Sedge in Allegheny Hardwood Stands with Roundup-Residual Herbicide Tank Mixes

Abstract A small plot experiment was carried out to investigate the effect of forest floor disturbance on establishment of grasses and sedges and to test whether addition of a residual herbicide in tank mix with Roundup could reduce grass and sedge reinvasion. Seven residual herbicides, each at three rates of application, were tested against a Roundup control. Herbicides were Hyvar X (bromacil), Karmex (diuron), Racer (fluorochloridone) (R-40244)), Devrinol (napropamide), Surflan (oryzalin), Oust (sulfometuron methyl), and Sinbar (terbacil). Herbicides were applied on three dates of application at two northwestern Pennsylvania sites. Half of each plot was mechanically disturbed to simulate logging disturbance. Response data were collected for 2 or 3 years after treatment application. Soil disturbance was a significant factor in promoting emergence of grass and sedge; most germination occurred during the growing season immediately following treatment. Little grass or sedge emerged on undisturbed areas. In the second growing season following treatment, plants that did emerge grew to full size. Two of the tank mixes, Roundup plus Hyvar X and Roundup plus Karmex, gave less control of vegetation on the plot at the time of treatment than Roundup alone. Most Round-up-residual herbicide tank mixes reduced emergence and growth of new grass and sedge plants, regardless of application date; however, the amount and duration of control differed among herbicides. Roundup (1 # ai/ac) plus Surflan (2-4 # ai/ac) and Roundup plus Oust (0.09-0.19 # ai/ac) produced the best results reducing grass and sedge ground cover for at least 3 and 2 years, respectively. By use of Roundup-residual herbicide tank mixes and manipulation of cutting techniques, forest land managers can minimize the impact of grass and sedge on the forest regeneration process in Allegheny hardwood stands. North. J. Appl. For. 7:124-129, September 1990.

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The effect of a wide range of fertilizer nitrogen application rates and defoliation intervals on the dry-matter production, seasonal response to nitrogen, persistence and aspects of chemical composition of perennial ryegrass (Lolium perennecv. S.24)

The Journal of Agricultural Science ◽

10.1017/s0021859600037424 ◽

1977 ◽

Vol 88 (3) ◽

pp. 711-721 ◽

Cited By ~ 31

Author(s):

P. W. Bartholomew ◽

D. M. B. Chestnutt

Keyword(s):

Dry Matter ◽

Maximum Yield ◽

Ground Cover ◽

Growing Season ◽

Nitrate Content ◽

Nitrogen Application ◽

Fertilizer Nitrogen ◽

Application Rates ◽

Wide Range ◽

Small Plot

SUMMARYA small-plot experiment was made to assess the influence on dry-matter output from grass of a wide range of fertilizer nitrogen and defoliation interval treatments. There were five defoliation treatments, 22, 28, 45, 75 and 112-day regrowth intervalsroughout the growing season each at six levels of nitrogen application, ranging by 300 kg increments from 0 to 1500 kg/ha/year.There was a marked interaction effect between treatments; a positive dry-matter response was maintained to a higher level of applied nitrogen with more frequent defoliation. In 2 years out of 3 maximum dry-matter yield was produced under a 75·day defoliation interval although the mean yield advantage over a 45-day defoliation system was only 11%. Mean yield of digestible dry matter appeared to reach a maximum under a 45·day defoliation interval at 600 kg N/ha but at the lower levels of N the maximum yield was reached at the longest growth interval.Seasonal response to nitrogen under the 22–day and 28–day defoliation systems measured as the increase in yield resulting from increased N at each cutting date reached its peak in July–August. Application for these short growth periods early and late in the growing season appeared to be a relatively inefficient use of nitrogen.The less frequently the sward was harvested and the higher the nitrogen application the greater was the reduction in ground cover as estimated by eye at the end of the growing season, this reached an estimated 25% reduction under 112·day defoliation at 300 kg N/ha/year.In relation to published figures nitrate content of herbage did not reach dangerous levels until nitrogen application reached levels beyond those at which maximum dry·matter yield was achieved.

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EVALUATION OF REVEGETATION TECHNIQUES FOR ROADSIDE CONSTRUCTION SITES

Journal of Environmental Engineering and Landscape Management ◽

10.3846/16486897.2016.1259166 ◽

2017 ◽

Vol 25 (3) ◽

pp. 305-315 ◽

Cited By ~ 1

Author(s):

George HILVERS ◽

Leslie HOPKINSON ◽

Eric DAVIS

Keyword(s):

Warm Season ◽

Ground Cover ◽

Erosion Control ◽

Growing Season ◽

Construction Sites ◽

Experimental Mixture ◽

Threat Level ◽

Seed Mixture ◽

The Impact ◽

Seed Mixtures

Vegetation is often used to control erosion on right-of-way construction sites, but disturbed conditions provide challenges. This research evaluated the impact of common techniques for preparing seedbeds. The study assessed the use of topsoil, and the use of a hydraulic erosion-control product was compared to straw. Experimental seed mixtures were evaluated to understand how native and non-native seeds performed. The intent was to identify critical practices to use in general seeding and mulching specifications. A plot study was conducted comparing vegetation established during one growing season. Treatments included combinations of seed mixture, topsoil treatment, and mulch types. Three seed mixtures were considered: (1) currently used mixture, (2) a warm-season experimental mixture, and (3) a cool-season experimental mixture. Plots with topsoil and no topsoil were compared, and both straw and hydraulic erosion control products were considered. Ground cover, compaction, and biomass were evaluated. Results suggest that alternative seed mixtures that include native and low-threat-level species can provide adequate cover to meet permitting requirements in the first growing season. The warm-season seed mixture provided less cover than the other two mixtures after eight days, but no differences were determined in ground cover among the three seed mixtures at the end of the growing season. Initial germination was improved with hydraulic mulch, but long-term cover was equivalent between hydraulic and straw mulch. Topsoil application would not be recommended if the soil contains undesirable species, and the use of organic amendment products may be more desirable than topsoil alone; however, specifications need to allow the use of these products.

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The Evaluation of Alternative Fodder Crops under African Highland Conditions

Experimental Agriculture ◽

10.1017/s0014479700016483 ◽

1989 ◽

Vol 25 (1) ◽

pp. 99-107 ◽

Cited By ~ 2

Author(s):

Michael J. Potts ◽

Evariste Biranguza

Keyword(s):

Ground Cover ◽

Growing Season ◽

Maize Yield ◽

Field Observations ◽

Forage Grasses ◽

Direct Sunlight ◽

Fodder Beet ◽

Cropping Season ◽

Fodder Crops ◽

Small Plot

SUMMARYFour forage bassicas, kale, rape, turnips and swede, and fodder beet were evaluated for adaptation to tropical highland conditions using small-plot experiments and field observations. In a short cropping season turnips were best adapted with a mean yield of 22 t ha−1. The crop was quick to establish and gave good ground cover. Kale and swedes were better adapted to a long season and yielded more than perennial forage grasses or maize. Yield was related to the length of growing season, exceeding 100 t ha−1 by about 250 days. Kale and swedes established poorly on soils high in aluminium. Direct sunlight appeared to damage swede roots, causing secondary soft rots. Rape showed no advantage over kale. Fodder beet failed to establish satisfactorily in any of the experiments.

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Ecosystem modeling of methane and carbon dioxide fluxes for boreal forest sites

Canadian Journal of Forest Research ◽

10.1139/x00-164 ◽

2001 ◽

Vol 31 (2) ◽

pp. 208-223 ◽

Cited By ~ 11

Author(s):

Christopher Potter ◽

Jill Bubier ◽

Patrick Crill ◽

Peter Lafleur

Keyword(s):

Carbon Dioxide ◽

Boreal Forest ◽

Land Surface ◽

Net Primary Production ◽

Ground Cover ◽

Methane Flux ◽

Growing Season ◽

Ecosystem Model ◽

Heat Fluxes ◽

Water Levels

Predicted daily fluxes from an ecosystem model for water, carbon dioxide, and methane were compared with 1994 and 1996 Boreal EcosystemAtmosphere Study (BOREAS) field measurements at sites dominated by old black spruce (Picea mariana (Mill.) BSP) (OBS) and boreal fen vegetation near Thompson, Man. Model settings for simulating daily changes in water table depth (WTD) for both sites were designed to match observed water levels, including predictions for two microtopographic positions (hollow and hummock) within the fen study area. Water run-on to the soil profile from neighboring microtopographic units was calibrated on the basis of daily snowmelt and rainfall inputs to reproduce BOREAS site measurements for timing and magnitude of maximum daily WTD for the growing season. Model predictions for daily evapotranspiration rates closely track measured fluxes for stand water loss in patterns consistent with strong controls over latent heat fluxes by soil temperature during nongrowing season months and by variability in relative humidity and air temperature during the growing season. Predicted annual net primary production (NPP) for the OBS site was 158 g C·m2 during 1994 and 135 g C·m2 during 1996, with contributions of 75% from overstory canopy production and 25% from ground cover production. Annual NPP for the wetter fen site was 250 g C·m2 during 1994 and 270 g C·m2 during 1996. Predicted seasonal patterns for soil CO2 fluxes and net ecosystem production of carbon both match daily average estimates at the two sites. Model results for methane flux, which also closely match average measured flux levels of 0.5 mg CH4·m2·day1 for OBS and 2.8 mg CH4·m2·day1 for fen sites, suggest that spruce areas are net annual sinks of about 0.12 g CH4·m2, whereas fen areas generate net annual emissions on the order of 0.30.85 g CH4·m2, depending mainly on seasonal WTD and microtopographic position. Fen hollow areas are predicted to emit almost three times more methane during a given year than fen hummock areas. The validated model is structured for extrapolation to regional simulations of interannual trace gas fluxes over the entire North America boreal forest, with integration of satellite data to characterize properties of the land surface.

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The Impact of Climate Change on the Sugar Content of Grapes and the Sustainability of their Production in the Czech Republic

Sustainability ◽

10.3390/su13010222 ◽

2020 ◽

Vol 13 (1) ◽

pp. 222

Author(s):

Miroslava Navrátilová ◽

Markéta Beranová ◽

Lucie Severová ◽

Karel Šrédl ◽

Roman Svoboda ◽

...

Keyword(s):

Climate Change ◽

Czech Republic ◽

Sugar Content ◽

Growing Season ◽

Vegetation Period ◽

The Czech Republic ◽

Impact Of Climate Change ◽

Secondary Sources ◽

The Impact ◽

Growing Region

The aim of the presented article is to evaluate the impact of climate change on the sugar content of grapes in the Czech Republic during the period 2000–2019 through selected indicators on the basis of available secondary sources. Attention is focused on the developments in both the main wine-growing regions of Moravia and Bohemia. In the field of viticulture and wine-growing, the sugar content of grapes, as a basic parameter for the classification of wines, plays an important role. In the Czech Republic, the average sugar content of grapes has had a constantly growing trend. This trend is evident both in the wine-growing region of Bohemia and in the wine-growing region of Moravia. The impact of climate change, especially the gradual increase of average temperatures in the growing season, cannot be overlooked. It greatly affects, among other things, the sugar content of grapes. Calculations according to the Huglin Index and the Winkler Index were used to determine the relationship between climate and sugar content. These indexes summarize the course of temperatures during the entire vegetation period into a single numerical value. The results show that both indexes describe the effect of air temperature on sugar content in both wine regions of the Czech Republic in a statistically significant way. The Huglin Index shows a higher correlation rate. The Winkler Index proved to be less suitable for both areas. Alternatively, the Winkler Index calculated for a shorter growing season was tested, which showed a higher degree of correlation with sugar content, approaching the significance of the Huglin Index.

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Dynamics of the Degradation of Acetyl-CoA Carboxylase Herbicides in Vegetables

Foods ◽

10.3390/foods10020405 ◽

2021 ◽

Vol 10 (2) ◽

pp. 405

Author(s):

Miroslav Jursík ◽

Kateřina Hamouzová ◽

Jana Hajšlová

Keyword(s):

Linear Models ◽

Growing Season ◽

Field Trials ◽

Baby Food ◽

Vegetable Production ◽

The Czech Republic ◽

Herbicide Residues ◽

Harvest Intervals ◽

Small Plot

(1) Background: Aryloxyphenoxy-propionates and cyclohexanediones are herbicides most widely used in dicot crops worldwide. The main objective of the study was to determine the dynamics of herbicide residues in carrot, lettuce, cauliflower, and onion in order to suggest a low level of residues in harvested vegetables. (2) Methods: Small plot field trials were carried out in four vegetables in the Czech Republic. The samples of vegetables were collected continuously during the growing season. Multiresidue methods for the determination of herbicide residues by LC-MS/MS were used. Non-linear models of degradation of individual herbicides in vegetables were calculated using the exponential decay formula. Action GAP pre-harvest intervals for the 25% and 50% maximum residue limit (MRL) and 10 µg kg−1 limit (baby food) were established for all tested herbicides. (3) Results: The degradation dynamics of fluazifop in carrot, onion, and cauliflower was significantly slower compared to quizalofop and haloxyfop. The highest amount (2796 µg kg−1) of fluazifop residues was detected in cauliflower 11 days after application. No residue of propaquizafop and cycloxydim was detected in any vegetable samples. (4) Conclusions: Aryloxyphenoxy-propionate herbicide (except propaquizafop) could contaminate vegetables easily, especially vegetables with a short growing season. Vegetables treated with fluazifop are not suitable for baby food. Lettuce and cauliflower treated by quizalofop are not suitable for baby food, but in onion and carrot, quizalofop could be used. Propaquizafop and cycloxydim are prospective herbicides for non-residual (baby food) vegetable production.

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Facilitation Effects of Haloxylon salicornicum Shrubs on Associated Understory Annuals, and a Modified “Stress-Gradient” Hypothesis for Droughty Times

Plants ◽

10.3390/plants9121726 ◽

2020 ◽

Vol 9 (12) ◽

pp. 1726

Author(s):

Nasr H. Gomaa ◽

Ahmad K. Hegazy ◽

Arafat Abdel Hamed Abdel Latef

Keyword(s):

Species Richness ◽

Water Availability ◽

Stress Gradient ◽

Growing Season ◽

Annual Species ◽

Negative Effects ◽

Growing Seasons ◽

Dry Seasons ◽

The Impact ◽

Haloxylon Salicornicum

Perennial shrub-annual plant interactions play key roles in desert regions influencing the structure and dynamics of plant communities there. In the present study, carried out in northwestern Saudi Arabia, we examined the effect of Haloxylon salicornicum shrubs on their associated understory annual species across four consecutive growing seasons, along with a record of the seasonal rainfall patterns. We measured density and species richness of all the annual species in permanent quadrats located beneath individual shrubs, as well as in the spaces between shrubs. During wet growing season H. salicornicum shrubs significantly enhanced the density and species richness of sub-canopy species, whereas in the relatively dry seasons they exerted negative effects on the associated species. In all growing seasons, the presence of shrubs was associated with enhanced soil properties, including increased organic carbon content, silt + clay, and levels of nutrients (N, P and K). Shrubs improved soil moisture content beneath their canopies in the wet growing season, while in the dry seasons they had negative effects on water availability. Differences in effects of H. salicornicum on understory plants between growing seasons seem due to the temporal changes in the impact of shrubs on water availability. Our results suggest the facilitative effects of shrubs on sub-canopy annuals in arid ecosystems may switch to negative effects with increasing drought stress. We discuss the study in light of recent refinements of the well-known “stress-gradient hypothesis”.

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Modeling the Impact of Climate Changes on Crop Yield: Irrigated vs. Non-Irrigated Zones in Mississippi

Remote Sensing ◽

10.3390/rs13122249 ◽

2021 ◽

Vol 13 (12) ◽

pp. 2249

Author(s):

Sadia Alam Shammi ◽

Qingmin Meng

Keyword(s):

Climate Change ◽

Crop Yield ◽

Crop Yields ◽

Negative Impact ◽

Positive Impact ◽

Information Criterion ◽

Growing Season ◽

Maximum Temperature ◽

Linear Regression Models ◽

The Impact

Climate change and its impact on agriculture are challenging issues regarding food production and food security. Many researchers have been trying to show the direct and indirect impacts of climate change on agriculture using different methods. In this study, we used linear regression models to assess the impact of climate on crop yield spatially and temporally by managing irrigated and non-irrigated crop fields. The climate data used in this study are Tmax (maximum temperature), Tmean (mean temperature), Tmin (minimum temperature), precipitation, and soybean annual yields, at county scale for Mississippi, USA, from 1980 to 2019. We fit a series of linear models that were evaluated based on statistical measurements of adjusted R-square, Akaike Information Criterion (AIC), and Bayesian Information Criterion (BIC). According to the statistical model evaluation, the 1980–1992 model Y[Tmax,Tmin,Precipitation]92i (BIC = 120.2) for irrigated zones and the 1993–2002 model Y[Tmax,Tmean,Precipitation]02ni (BIC = 1128.9) for non-irrigated zones showed the best fit for the 10-year period of climatic impacts on crop yields. These models showed about 2 to 7% significant negative impact of Tmax increase on the crop yield for irrigated and non-irrigated regions. Besides, the models for different agricultural districts also explained the changes of Tmax, Tmean, Tmin, and precipitation in the irrigated (adjusted R-square: 13–28%) and non-irrigated zones (adjusted R-square: 8–73%). About 2–10% negative impact of Tmax was estimated across different agricultural districts, whereas about −2 to +17% impacts of precipitation were observed for different districts. The modeling of 40-year periods of the whole state of Mississippi estimated a negative impact of Tmax (about 2.7 to 8.34%) but a positive impact of Tmean (+8.9%) on crop yield during the crop growing season, for both irrigated and non-irrigated regions. Overall, we assessed that crop yields were negatively affected (about 2–8%) by the increase of Tmax during the growing season, for both irrigated and non-irrigated zones. Both positive and negative impacts on crop yields were observed for the increases of Tmean, Tmin, and precipitation, respectively, for irrigated and non-irrigated zones. This study showed the pattern and extent of Tmax, Tmean, Tmin, and precipitation and their impacts on soybean yield at local and regional scales. The methods and the models proposed in this study could be helpful to quantify the climate change impacts on crop yields by considering irrigation conditions for different regions and periods.

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Assessing the impact of exceptional inter-annual climatic variability on rates of net ecosystem carbon dioxide exchange at Clara bog.

10.5194/egusphere-egu21-13414 ◽

2021 ◽

Author(s):

Matthew Saunders ◽

Ruchita Ingle ◽

Shane Regan

Keyword(s):

Water Table ◽

Elevated Temperatures ◽

Ecosystem Respiration ◽

Anthropogenic Activities ◽

Climatic Variability ◽

Growing Season ◽

Carbon Dioxide Exchange ◽

Mean Annual Temperature ◽

Monitoring Networks ◽

The Impact

Peatland ecosystems are integral to the mitigation of climate change as they represent significant terrestrial carbon sinks. In Ireland, peatlands cover ~20% of the land area but hold up to 75% of the soil organic carbon stock however many of these ecosystems (~85% of the total area) have been degraded due to anthropogenic activities such as agriculture, forestry and extraction for horticulture or energy. Furthermore, the carbon stocks that remain in these systems are vulnerable to inter-annual variation in climate, such as changes in precipitation and temperature, which can alter the hydrological status of these systems leading to changes in key biogeochemical processes and carbon and greenhouse gas exchange.&#160; During 2018 exceptional drought and heatwave conditions were reported across Northwestern Europe, where reductions in precipitation coupled with elevated temperatures were observed. Exceptional inter-annual climatic variability was also observed at Clara bog, a near natural raised bog in the Irish midlands when data from 2018 and 2019 were compared. Precipitation in 2018 was ~300 mm lower than 2019 while the average mean annual temperature was 0.5&#176;C higher. The reduction in precipitation, particularly during the growing season in 2018, consistently lowered the water table where ~150 consecutive days where the water table was >5cm below the surface of the bog were observed at the central ecotope location. The differing hydrological conditions between years resulted in the study area, as determined by the flux footprint of the eddy covariance tower, acting as a net source of carbon of 53.5 g C m-2 in 2018 and a net sink of 125.2 g C m-2 in 2019. The differences in the carbon dynamics between years were primarily driven by enhanced ecosystem respiration (Reco) and lower rates of Gross Primary Productivity (GPP) in the drier year, where the maximum monthly ratio of GPP:Reco during the growing season was 0.96 g C m-2 month in 2018 and 1.14 g C m-2 month in 2019. This study highlights both the vulnerability and resilience of these ecosystems to exceptional inter-annual climatic variability and emphasises the need for long-term monitoring networks to enhance our understanding of the impacts of these events when they occur.

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Signs of wildlife activity and Eucalyptus wandoo condition

Australian Mammalogy ◽

10.1071/am13022 ◽

2014 ◽

Vol 36 (2) ◽

pp. 146 ◽

Cited By ~ 2

Author(s):

T. L. Moore ◽

M. D. Craig ◽

L. E. Valentine ◽

G. E. St J. Hardy ◽

P. A. Fleming

Keyword(s):

Western Australia ◽

Mixed Model ◽

Soil Health ◽

Ground Cover ◽

Soil Disturbance ◽

Habitat Characteristics ◽

Foraging Effort ◽

Terrestrial Vertebrates ◽

Eucalyptus Wandoo ◽

Tree Condition

Soil disturbance by terrestrial vertebrates when foraging for food and shelter is not only a sign of activity but an ecosystem function required for soil health. Many forests and woodlands worldwide are currently showing signs of a decline in condition due to various causes. Eucalyptus wandoo, endemic to south-west Western Australia, has undergone a decline in condition over the last decade. This paper explores the influence of E. wandoo condition (e.g. loss of canopy) and the associated changes in the habitat (e.g. changes in leaf litter and bare ground cover) on the foraging activities and soil disturbance by vertebrates. The number of diggings and scats, a representation of the foraging effort by some vertebrates, were recorded in Dryandra Woodland and Wandoo Conservation Park, Western Australia. Mixed-model ANOVAs were used to explore the relationships between the number of scats and diggings with tree and habitat characteristics. More vertebrate diggings and scats were recorded beneath healthier E. wandoo trees. Diggings and scats were also correlated with time since last fire and seasonal differences, with more time since last fire and wetter months related to more diggings and scats. Changes in foraging effort, or turnover of soil by vertebrates, could be a result modification of the level of soil turnover and alter many ecosystem services such as tree recruitment and nutrient cycling, in turn altering the habitat quality and even tree condition itself.

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