The Experts below are selected from a list of 2754 Experts worldwide ranked by ideXlab platform
Ian A. Merwin - One of the best experts on this subject based on the ideXlab platform.
-
soil erosion runoff and nutrient losses in an avocado persea americana mill hillside orchard under different Groundcover management systems
Plant and Soil, 2013Co-Authors: Amaya Atucha, Ian A. Merwin, Michael G. Brown, Francisco Gardiazabal, Francisco Mena, Cecilia Adriazola, Johannes LehmannAbstract:Aims Assess the influence of different Groundcover management systems on erosion and runoff processes associated with extremely steep hillside avocado (Persea americana Mill) orchards, in a Mediterranean climate with high rainfall variability. Methods We compared several Groundcover management systems at a steep hillside avocado planting in a three-year study: 1) Bare soil (BS), pre- and postemergence herbicides; 2) Vegetation strip (VS), postemergence herbicide applied in a 1-m wide strip on the tree row plus Groundcover seeded between tree rows; 3) Groundcover (GC), over the entire plot surface. Results Trees in the BS plots were 44 and 53 % bigger, and had 150 and 250 % higher yields than trees in VS and GC, respectively. Runoff volumes, soil losses, dissolved organic carbon, PO4-P and total N losses were significantly higher in BS than VS and CG treatments. Total soil nitrogen (N) and carbon (C) content, C-to-N ratios, and essential plant nutrient availability were greater in the GC soil than in other treatments. Soil macroporosity and aggregate stability were 8– 27 % and 25 % lower, and soil bulk density significantly higher in the BS than the VS and GC systems at the end of the study. Terbuthylazine herbicide concentrations in runoff water from BS plots ranged from 55.4 to 79.9 μgL −1 , exceeding maximum allowed levels for drinking water (0.1 μgL −1 ). Conclusion Soil erosion and runoff rates from newly planted hillside orchards are not environmentally sustainable under current growing practices where Groundcover vegetation is completely suppressed. High sediment losses and herbicide residues in runoff water present serious risk of water source pollution, but these impacts can be reduced by alternative soil management systems.
-
soil erosion runoff and nutrient losses in an avocado persea americana mill hillside orchard under different Groundcover management systems
Plant and Soil, 2013Co-Authors: Amaya Atucha, Ian A. Merwin, Michael G. Brown, Francisco Gardiazabal, Francisco Mena, Cecilia Adriazola, Johannes LehmannAbstract:Aims Assess the influence of different Groundcover management systems on erosion and runoff processes associated with extremely steep hillside avocado (Persea americana Mill) orchards, in a Mediterranean climate with high rainfall variability.
-
Root distribution and demography in an avocado (Persea americana) orchard under Groundcover management systems
Functional Plant Biology, 2013Co-Authors: Amaya Atucha, Ian A. Merwin, Michael G. Brown, Francisco Gardiazabal, Francisco Mena, Cecilia Adriazola, Marc Goebel, Taryn L. BauerleAbstract:The effect of Groundcover management systems on root demography and distribution of newly planted avocado (Persea americana Mill) trees was examined using minirhizotron techniques. We evaluated three Groundcover systems: (1) bare soil (BS), pre- and post-emergence herbicides; (2) vegetation strip (VS), post-emergence herbicide applied in a 1-m wide strip centred on the tree row plus a Groundcover mixture seeded between tree rows; and (3) complete Groundcover (GC), covering the entire surface of the plots. Root production was higher in the non-bearing year (2009–10) than in the bearing year (2010–11). Trees in the BS plots had more roots of bigger diameter in the top 30 cm of soil and trees in VS and GC plots had more roots in the 30–60 cm depth and of smaller diameter. Lifespan of spring-born roots were 61 and 59% greater than those born during autumn and summer, respectively and soil depth and root diameter were positively correlated with root longevity. Lifespan of thinner roots (
-
root distribution and demography in an avocado persea americana orchard under Groundcover management systems
Functional Plant Biology, 2013Co-Authors: Amaya Atucha, Ian A. Merwin, Michael G. Brown, Francisco Gardiazabal, Francisco Mena, Cecilia Adriazola, Marc Goebel, Taryn L. BauerleAbstract:The effect of Groundcover management systems on root demography and distribution of newly planted avocado (Persea americana Mill) trees was examined using minirhizotron techniques. We evaluated three Groundcover systems: (1) bare soil (BS), pre- and post-emergence herbicides; (2) vegetation strip (VS), post-emergence herbicide applied in a 1-m wide strip centred on the tree row plus a Groundcover mixture seeded between tree rows; and (3) complete Groundcover (GC), covering the entire surface of the plots. Root production was higher in the non-bearing year (2009–10) than in the bearing year (2010–11). Trees in the BS plots had more roots of bigger diameter in the top 30 cm of soil and trees in VS and GC plots had more roots in the 30–60 cm depth and of smaller diameter. Lifespan of spring-born roots were 61 and 59% greater than those born during autumn and summer, respectively and soil depth and root diameter were positively correlated with root longevity. Lifespan of thinner roots (<0.2 mm) in the BS and VS plots were 49 and 33% greater than GC respectively. Avocado trees grown in contrasting condition compared with their native habitat show high morphological root plasticity, in response to resource and non-resource competition when grown in mixed stands.
-
long term effects of four Groundcover management systems in an apple orchard
Hortscience, 2011Co-Authors: Amaya Atucha, Ian A. Merwin, Michael G. BrownAbstract:Additional index words. soil management, tree nutrition, soil health, orchard sustainability Abstract. Groundcover management systems (GMSs) are essential for fruit production, but very few long-term studies have evaluated orchard GMS sustainability. We eval- uated four GMSs—pre-emergence soil-active herbicides (PreHerb), post-emergence her- bicide (PostHerb), a turfgrass cover crop (Sod), and hardwood bark mulch (Mulch)—in an apple (Malus domestica Borkh.) orchard over 16 years of continuous observation. There were no consistent long-term trends in fruit yields among GMSs, although during the first 5 years, yields were lower in trees on Sod. Tree growth was greater in PostHerb and Mulch than in Sod during the first 5 years, and during the next decade, trees in Mulch plots were consistently larger than in other GMSs. Total soil nitrogen (N) and carbon (C) content, C-to-N ratios, and essential plant nutrients were much greater in the Mulch soil after 16 years of treatments. Long-term responses of trees to Groundcover vegetation indicated that apple trees respond adaptively to compensate for weed and grass com- petition. Year-round elimination of surface vegetation with residual soil active herbicides may be unnecessary or even detrimental for orchard productivity and soil fertility in established orchards. Post-emergence herbicides that reduce weed competition primar- ily during the summer months may offer an optimal combination of weed suppression and soil conservation.
Jacqueline Stol - One of the best experts on this subject based on the ideXlab platform.
-
temporal monitoring of Groundcover change using digital cameras
International Journal of Applied Earth Observation and Geoinformation, 2012Co-Authors: A. Zerger, Curt Crossman, Philip Valencia, Tim Wark, R N Handcock, David Gobbett, Micah J Davies, Jacqueline StolAbstract:Abstract This paper describes the development and testing of an automated method for detecting change in Groundcover vegetation in response to kangaroo grazing using visible wavelength digital photography. The research is seen as a precursor to the future deployment of autonomous vegetation monitoring systems (environmental sensor networks). The study was conducted over six months with imagery captured every 90 min and post-processed using supervised image processing techniques. Synchronous manual assessments of Groundcover change were also conducted to evaluate the effectiveness of the automated procedures. Results show that for particular cover classes such as Live Vegetation and Bare Ground, there is excellent temporal concordance between automated and manual methods. However, litter classes were difficult to consistently differentiate. A limitation of the method is the inability to effectively deal with change in the vertical profile of Groundcover. This indicates that the three dimensional structure related to species composition and plant traits play an important role in driving future experimental designs. The paper concludes by providing lessons for conducting future Groundcover monitoring experiments.
-
Temporal monitoring of Groundcover change using digital cameras
International Journal of Applied Earth Observation and Geoinformation, 2012Co-Authors: A. Zerger, Curt Crossman, Philip Valencia, Tim Wark, R N Handcock, David Gobbett, M Davies, Jacqueline StolAbstract:This paper describes the development and testing of an automated method for detecting change in Groundcover vegetation in response to kangaroo grazing using visible wavelength digital photography. The research is seen as a precursor to the future deployment of autonomous vegetation monitoring systems (environmental sensor networks). The study was conducted over six months with imagery captured every 90 min and post-processed using supervised image processing techniques. Synchronous manual assessments of Groundcover change were also conducted to evaluate the effectiveness of the automated procedures. Results show that for particular cover classes such as Live Vegetation and Bare Ground, there is excellent temporal concordance between automated and manual methods. However, litter classes were difficult to consistently differentiate. A limitation of the method is the inability to effectively deal with change in the vertical profile of Groundcover. This indicates that the three dimensional structure related to species composition and plant traits play an important role in driving future experimental designs. The paper concludes by providing lessons for conducting future Groundcover monitoring experiments. © 2012 Published by Elsevier B.V.
Leslie A Weston - One of the best experts on this subject based on the ideXlab platform.
-
Evaluation of Herbaceous Perennials as Weed Suppressive Groundcovers for Use Along Roadsides or in Landscapes
Journal of environmental horticulture, 2020Co-Authors: Andrew F. Senesac, Irene Tsontakis-bradley, Leslie A WestonAbstract:Abstract Fifteen herbaceous perennials were evaluated in field experiments in two New York State locations to determine their utility in roadside and landscape areas as weed suppressive Groundcovers. Four species, Alchemilla mollis, Nepeta x faassenii, Phlox subulata, and Solidago sphacelata were strongly weed suppressive in both managed (weeds removed) plots and unmanaged (weeds not removed) plots. Weed suppressivity of perennial Groundcovers was significantly increased in year two in both locations when perennials were well established. The most suppressive perennials showed several similar characteristics likely associated with their successful establishment. Successful Groundcovers possessed dense foliage which strongly reduced light transmittance at the soil surface and emerged relatively early in spring. Lamiastrum galeobdolon and Thymus praecox proved to be more successful over a 2-year period when managed by weed removal in early spring. Although Leymus arenarius, a relatively tall monocot, also i...
-
Utilization of Stress Tolerant, Weed Suppressive Groundcovers for Low Maintenance Landscape Settings
Allelopathy in Sustainable Agriculture and Forestry, 2020Co-Authors: Leslie A WestonAbstract:The recent emphasis on development of alternative, non-chemical weed strategies for landscape and roadside management has led to the study and utilization of well-adapted landscape Groundcovers, including turfgrass and herbaceous ornamentals that can successfully withstand and suppress weed invasion. By selecting Groundcovers which exhibit growth characteristics that result in consistent interference with weed establishment, one can successfully achieve effective long-term weed control in the landscape using reduced herbicide and labor inputs. In addition to allelopathic characteristics resulting in enhanced weed suppression due to the production and release of phytoinhibitors in the landscape, some Groundcovers effectively suppress weedy invaders through competition for space, sunlight, moisture, nutrients and even direct alteration of the rhizosphere environment. Additional information related to weed biology and the impact of cultural practices used in the landscape on weed infestation are also critical when considering long-term and sustainable weed suppression for landscape and natural settings. Until recently, little information was available regarding the development of low maintenance landscapes for use in the Northeastern United States, with the exception of roadside trials documenting utilization of certain direct-seeded Groundcovers in highway medians. Recent studies in both landscape and roadside settings have indicated that the selection and utilization of certain herbaceous perennial Groundcovers and turfgrasses may not only result in lower labor inputs with respect to maintenance, they may further prevent the spread of noxious invasive weeds by severely limiting their ability to establish. When surveyed, stakeholders reported that weed suppressive Groundcovers had much greater aesthetic appeal than those that were partially infested. Many of these Groundcovers suppress weeds effectively by intense competition for resources, particularly by reduction in the amount of available light at the soil surface due to dense canopy cover. In addition, some Groundcovers such as Nepeta x faasennii and Festuca rubra inhibit weed seedlings by their potential release of allelochemicals into the rhizosphere. Although still relatively novel, allelopathic Groundcovers and turfgrasses offer interesting possibilities for future development of allelochemicals as bioherbicides and attractive, stress-tolerant and pest-resistant landscape plantings.
-
An Evaluation of the Allelopathic Potential of Selected Perennial Groundcovers: Foliar Volatiles of Catmint (Nepeta × faassenii) Inhibit Seedling Growth
Journal of Chemical Ecology, 2006Co-Authors: Seok Hyun Eom, Hyun Seuk Yang, Leslie A WestonAbstract:Six perennial Groundcovers including Alchemilla mollis , Nepeta × faassenii , Phlox subulata , Sedum acre , Solidago cutleri , and Thymus praecox were investigated for the allelopathic potential of their respective foliar tissues via evaluation of volatile constituents produced by foliage. These Groundcovers were selected for further laboratory evaluation because of superior performance as weed-suppressive Groundcovers in previous field experiments. Foliar volatile components of N. × faassenii exhibited the strongest inhibitory effects on seedling growth of curly cress ( Lepidium sativum ), but S. cutleri also showed allelopathic potential by reducing shoot growth of curly cress seedlings with extracted volatiles. Although A. mollis and P. subulata exhibited strong weed-suppressive traits in past field experiments, weed suppression is apparently associated with either competition for resources or other allelopathic mechanisms rather than an allelopathic effect caused by volatiles. Volatiles of N. × faassenii were further evaluated with gas chromatography coupled to mass spectrometry (GC-MS). A total of 21 chemical constituents were identified in the volatile cocktail; 17 components were identified from a direct crude leaf sample extraction, including sabinene, β-pinene, β-myrcene, 2-(2-ethoxyethoxy)-ethanol, 1,8-cineole, ocimene, neryl Acetate, 4aα,7α,7aα-nepetalactone, α-copaene, trans -caryophyllene, alloaromadendrene, 4aβ,7α,7aβ-nepetalactone, germacrene D, β-farnesene, χ-cadinene, germacrene B, and β-sesquiphellandrene. Five additional constituents were identified in a methanolic extract of dried of N. × faassenii foliage, but not the volatile cocktail collected from N. × faassenii foliage. These included methyl benzoate, 2,4-decadienal, neryl acetate, isodihydronepetalactone, and caryophyllene oxide. Three components, 2-(2-ethoxyethoxy)-ethanol, alloaromadendrene, and χ-cadinene, were not only detected in both the volatile mixture and the methanolic extract, but also in an aqueous foliar extract that exhibited potential allelopathic activity.
A. Zerger - One of the best experts on this subject based on the ideXlab platform.
-
temporal monitoring of Groundcover change using digital cameras
International Journal of Applied Earth Observation and Geoinformation, 2012Co-Authors: A. Zerger, Curt Crossman, Philip Valencia, Tim Wark, R N Handcock, David Gobbett, Micah J Davies, Jacqueline StolAbstract:Abstract This paper describes the development and testing of an automated method for detecting change in Groundcover vegetation in response to kangaroo grazing using visible wavelength digital photography. The research is seen as a precursor to the future deployment of autonomous vegetation monitoring systems (environmental sensor networks). The study was conducted over six months with imagery captured every 90 min and post-processed using supervised image processing techniques. Synchronous manual assessments of Groundcover change were also conducted to evaluate the effectiveness of the automated procedures. Results show that for particular cover classes such as Live Vegetation and Bare Ground, there is excellent temporal concordance between automated and manual methods. However, litter classes were difficult to consistently differentiate. A limitation of the method is the inability to effectively deal with change in the vertical profile of Groundcover. This indicates that the three dimensional structure related to species composition and plant traits play an important role in driving future experimental designs. The paper concludes by providing lessons for conducting future Groundcover monitoring experiments.
-
Temporal monitoring of Groundcover change using digital cameras
International Journal of Applied Earth Observation and Geoinformation, 2012Co-Authors: A. Zerger, Curt Crossman, Philip Valencia, Tim Wark, R N Handcock, David Gobbett, M Davies, Jacqueline StolAbstract:This paper describes the development and testing of an automated method for detecting change in Groundcover vegetation in response to kangaroo grazing using visible wavelength digital photography. The research is seen as a precursor to the future deployment of autonomous vegetation monitoring systems (environmental sensor networks). The study was conducted over six months with imagery captured every 90 min and post-processed using supervised image processing techniques. Synchronous manual assessments of Groundcover change were also conducted to evaluate the effectiveness of the automated procedures. Results show that for particular cover classes such as Live Vegetation and Bare Ground, there is excellent temporal concordance between automated and manual methods. However, litter classes were difficult to consistently differentiate. A limitation of the method is the inability to effectively deal with change in the vertical profile of Groundcover. This indicates that the three dimensional structure related to species composition and plant traits play an important role in driving future experimental designs. The paper concludes by providing lessons for conducting future Groundcover monitoring experiments. © 2012 Published by Elsevier B.V.
Curt Crossman - One of the best experts on this subject based on the ideXlab platform.
-
temporal monitoring of Groundcover change using digital cameras
International Journal of Applied Earth Observation and Geoinformation, 2012Co-Authors: A. Zerger, Curt Crossman, Philip Valencia, Tim Wark, R N Handcock, David Gobbett, Micah J Davies, Jacqueline StolAbstract:Abstract This paper describes the development and testing of an automated method for detecting change in Groundcover vegetation in response to kangaroo grazing using visible wavelength digital photography. The research is seen as a precursor to the future deployment of autonomous vegetation monitoring systems (environmental sensor networks). The study was conducted over six months with imagery captured every 90 min and post-processed using supervised image processing techniques. Synchronous manual assessments of Groundcover change were also conducted to evaluate the effectiveness of the automated procedures. Results show that for particular cover classes such as Live Vegetation and Bare Ground, there is excellent temporal concordance between automated and manual methods. However, litter classes were difficult to consistently differentiate. A limitation of the method is the inability to effectively deal with change in the vertical profile of Groundcover. This indicates that the three dimensional structure related to species composition and plant traits play an important role in driving future experimental designs. The paper concludes by providing lessons for conducting future Groundcover monitoring experiments.
-
Temporal monitoring of Groundcover change using digital cameras
International Journal of Applied Earth Observation and Geoinformation, 2012Co-Authors: A. Zerger, Curt Crossman, Philip Valencia, Tim Wark, R N Handcock, David Gobbett, M Davies, Jacqueline StolAbstract:This paper describes the development and testing of an automated method for detecting change in Groundcover vegetation in response to kangaroo grazing using visible wavelength digital photography. The research is seen as a precursor to the future deployment of autonomous vegetation monitoring systems (environmental sensor networks). The study was conducted over six months with imagery captured every 90 min and post-processed using supervised image processing techniques. Synchronous manual assessments of Groundcover change were also conducted to evaluate the effectiveness of the automated procedures. Results show that for particular cover classes such as Live Vegetation and Bare Ground, there is excellent temporal concordance between automated and manual methods. However, litter classes were difficult to consistently differentiate. A limitation of the method is the inability to effectively deal with change in the vertical profile of Groundcover. This indicates that the three dimensional structure related to species composition and plant traits play an important role in driving future experimental designs. The paper concludes by providing lessons for conducting future Groundcover monitoring experiments. © 2012 Published by Elsevier B.V.
