نتایج جستجو برای: un grazed area

تعداد نتایج: 770359  

Journal: :desert 0
a. mohebby ph.d graduate, research institute of forests and rangelands (rifr),tehran, iran m. jafari professor, faculty of natural resources, university of tehran, karaj, iran a. tavili associate professor, faculty of natural resources, university of tehran, karaj, iran s.a. javadi assistant professor, science and research branch, islamic azad university, tehran, iran e. zandi esfahan assistant professor, research institute of forests and rangelands (rifr),tehran, iran m. ramezani member of scientific board, islamic azad university, science and research branch, tehran, iran

it has often been stated or implied that grazing is an important factor in the land degradation process, a suggestion supported by various research projects, and this study investigated the effect of livestock grazing on stem height, crowncover, production, basal diameter, stem biomass, litter, leaf-stem index (leaf to stem weight) , root diameter and weight and seed production per individual o...

Journal: :مرتع و آبخیزداری 0
پریا کمالی دانشجوی کارشناسی ارشد رشتة مرتع داری، دانشکدة منابع طبیعی دانشگاه تربیت مدرس رضا عرفانزاده استادیار گروه مرتع داری دانشکدة منابع طبیعی دانشگاه تربیت مدرس حسن قلیچ نیا استادیار پژوهشی مرکز تحقیقات کشاورزی و منابع طبیعی ساری

this study aimed to investigate the effect of animal grazing on soil seed bank characteristics in the northern slopes of alborz. for this purpose, soil seed bank characteristics were compared between grazed and ungrazed areas. therefore, four transects perpendicular to the sides of exclosure inside and outside of it were established. then soil samples were collected within 28 plots inside and 2...

2008
Matthew D. Johnson Christa M. Horn

—We conducted a 4-year experiment to assess the impacts of rotational cattle grazing on rodents and raptors in a mesic coastal grassland in northwestern California. Live-trapping indicated that rodent abundance declined by 69% on the grazed area and increased by 14% on the ungrazed area. Raptor use of the grazed area declined by 15% and increased on the ungrazed area by 63%. Measures of giving-...

جهانگرد محمدی, , فایز رئیسی گهرویی, ,

Knowledge of the spatial dependency of soil properties, sensitive to grazing systems, is important from an ecosystem protection point of view. In the current study, geostatistical methods and fractal concepts have been used in order to characterize the impact of long-term grazing exclusion on the spatial variability of some soil chemical parameters including organic matter, total nitrogen, avai...

ژورنال: علوم آب و خاک 2004
جهانگرد محمدی, , فایز رئیسی گهرویی, ,

Knowledge of the spatial dependency of soil properties, sensitive to grazing systems, is important from an ecosystem protection point of view. In the current study, geostatistical methods and fractal concepts have been used in order to characterize the impact of long-term grazing exclusion on the spatial variability of some soil chemical parameters including organic matter, total nitrogen, avai...

2006
Todd Wellnitz

eaten it? Does it grow faster or differently from un-grazed algae? To address these questions, an experiment conducted in streamside channels documented the re-growth of algae following grazing by two mayfly species. We found that algal re-growth did not depend on which mayfly species ate it; rather, it was the duration of grazing that mattered. The longer algae was grazed, the faster it grew. ...

ژورنال: مرتع 2020
Bayat, Mina , Eftekhari, Alireza, Kamali, Nadia, Nateghi, Saeedeh, Soori, Mahshid,

Grazing effect on vegetation cover and soil factors in natural environments is inevitable. The present study was conducted to investigate the effect of grazing on soil factors and distribution of plant species in grazed and non-grazed areas in rangelands of western parts of Hoz-e-Soltan Lake, Qom. Systematic-randomized sampling method was used alongside of 4 transects. Adjacent to the transects...

2014
Min-yun Xu Fan Xie Kun Wang

Overgrazing has been the primary cause of grassland degradation in the semi-arid grasslands of the agro-pastoral transition zone in northern China. However, there has been little evidence regarding grazing intensity impacts on vegetation change and soil C and N dynamics in this region. This paper reports the effects of four grazing intensities namely un-grazed (UG), lightly grazed (LG), moderat...

Journal: :desert 2013
a. mohebby m. jafari a. tavili s.a. javadi e. zandi esfahan

it has often been stated or implied that grazing is an important factor in the land degradation process, a suggestion supported by various research projects, and this study investigated the effect of livestock grazing on stem height, crowncover, production, basal diameter, stem biomass, litter, leaf-stem index (leaf to stem weight) , root diameter and weight and seed production per individual o...

2015
Hans Petter Leinaas Jan Bengtsson Charlene Janion-Scheepers Steven L Chown

Biological invasions are major threats to biodiversity, with impacts that may be compounded by other forms of environmental change. Observations of high density of the invasive springtail (Collembola), Hypogastrura manubrialis in heavily grazed renosterveld vegetation in the Western Cape, South Africa, raised the question of whether the invasion was favored by changes in plant litter quality as...

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