نتایج جستجو برای: forty plots were established
تعداد نتایج: 3689276 فیلتر نتایج به سال:
rivers and runoff have always been of interest to human beings. in order to make use of the proper water resources, human societies, industrial and agricultural centers, etc. have usually been established near rivers. as the time goes on, these societies developed, and therefore water resources were extracted more and more. consequently, conditions of water quality of the rivers experienced rap...
to study the impact of growth factor bacteria , humic acid and alga extract in drought stress condition a test is established in form of completely random blocks and spilt plot in 4 replications in a field in mahallat in arak province in 1389. two primary plots including irrigation and stress and secondary plots including growth factor bacteria ,humic acid and alga extract, ascophylu...
We studied 11 gaps covered with beech saplings (< 1.30 m tall) in a reserve compartment (compartment 139, district one, Langa forest, watershed 36: Kazemrood) of the Caspian beech forest in N Iran. Two transects, each 2 m wide, were laid along the longest (N-S) and shortest (E-W) axis of each gap. Five micro sample plots, each 4 m2, were established: one at the center, and one at each corner. Q...
1. Biological invasion can permanently alter ecosystem structure and function. Invasive species are difficult to eradicate, so methods for constraining invasions would be ecologically valuable. We examined the potential of ecological restoration to constrain invasion of an old field by Agropyron cristatum , an introduced C 3 grass. 2. A field experiment was conducted in the northern Great Plain...
Major changes in the vegetation and consequently in the ecosystem functioning of mountainous meadows has been reported in response to herbivore grazing. Nevertheless, effects of protection from herbivores on the vegetation of High-elevation meadows in Iran have not been studied so far. To assess effects of experimentally short-term exclosure treatment on production of mountainous meadows, two m...
the present dissertation aims to investigate four-word lexical bundles in applied linguistics research articles by iranian and internationally-published writers. the aims of this study are two-fold: first of all, attempts have been made to create a comprehensive list of the most commonly used four-word lexical bundles categorized by their type and token frequency, their structural characteristi...
Some criteria of density in beech saplings were studied in various forest associations (mainly Galio odorati-Fagetum typicum) growing in the submontane region near Zurich (Swiss Central Plateau). The sample plots were established in regeneration gaps resulting from Swiss irregular shelter wood system (Femelschlag). Five sample plots, each 2x2m in 3 transects (a total of 15 plots in each gap, x...
abstract. the purpose of this study was to investigate vegetation dynamics and range conditions considering the climatic conditions and soil properties in haftooman, khoor and biabanak deserts, iran. for this purpose, after determining vegetation types and the associated species, the type of rangeland utilization, grazing season, the livestock type, the other relevant information, vegetation da...
We sought to assess impacts of fire and grazing by reindeer and caribou on lichen communities in northwestern Alaska. Macrolichen abundance was estimated from 45, 0.38-ha plots. Eighteen of those plots, scattered throughout the southern Seward Peninsula, represented two levels of grazing, heavy and light. We found lightly grazed areas had taller lichens and greater total lichen cover than heavi...
we studied 11 gaps covered with beech saplings (< 1.30 m tall) in a reserve compartment (compartment 139, district one, langa forest, watershed 36: kazemrood) of the caspian beech forest in n iran. two transects, each 2 m wide, were laid along the longest (n-s) and shortest (e-w) axis of each gap. five micro sample plots, each 4 m2, were established: one at the center, and one at each corner. q...
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