نتایج جستجو برای: plant stands have significant difference

تعداد نتایج: 4135721  

2015
Débora Cristina Rother Marco Aurélio Pizo Tadeu Siqueira Ricardo Ribeiro Rodrigues Pedro Jordano

Several factors decrease plant survival throughout their lifecycles. Among them, seed dispersal limitation may play a major role by resulting in highly aggregated (contagious) seed and seedling distributions entailing increased mortality. The arrival of seeds, furthermore, may not match suitable environments for seed survival and, consequently, for seedling establishment. In this study, we inve...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شیراز - دانشکده علوم 1391

in this research we have studied the effect of some transition-metals (cu, ag and au) substitutions on two-electron reduction potential of flavins by application of dft method. all geometries have been optimized at blyp level of theory and “6-31+g** + lanl2dz” mixed basis set. the frequency job at the same method and basis sets has been performed to obtain gibbs free energy of compounds. it h...

Journal: :مرتع و آبخیزداری 0
رویا وزیریان کارشناس ارشد مدیریت بیابان، دانشگاه علوم کشاورزی و منابع طبیعی گرگان حمید رضا عسگری استادیار دانشگاه علوم کشاورزی و منابع طبیعی گرگان مجید اونق استاد دانشگاه علوم کشاورزی و منابع طبیعی گرگان چوقی بایرام کمکی استادیار دانشگاه علوم کشاورزی و منابع طبیعی گرگان

understanding the relationship between soil and plant is essential for reclamation of degraded lands. in order to investigate the relationship between atriplex halimus density with carbon sequestration the rangeland of incheborun was studied. soil samples were collected randomly by auger in the depth of 0-30 cm of the soil profile in three different plant densities (400 stand per hectare) with ...

2017
Peipei Jiang Yunming Chen Yang Cao

Large-scale Quercus variabilis natural secondary forests are protected under the Natural Forest Protection (NFP) program in China to improve the ecological environment. However, information about nutrient characteristics and carbon (C) storage is still lacking. Plant biomass and C, nitrogen (N) and phosphorus (P) stoichiometry of tree tissues, shrubs, herbs, litter, and soil were determined in ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه الزهراء - دانشکده علوم تربیتی و روانشناسی 1391

abstract: research purpose: the purpose of this research is to identify academic databases assessment factors and criteria at law and political science majors. the necessity of this research is to distinguish academic databases assessment factors and criteria and to identify the most important ones and rank them in order to select an appropriate database according to students’ and faculty memb...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه فردوسی مشهد - پژوهشکده ادبیات 1393

1.0 overview it seems that grammar plays a crucial role in the area of second and foreign language learning and widely has been acknowledged in grammar research. in other words, teaching grammar is an issue which has attracted much attention to itself, and a lot of teachers argue about the existence of grammar in language teaching and learning. this issue will remind us a famous sentence f...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس - دانشکده علوم پزشکی 1389

introduction: diabetes mellitus is an growing national and international public health concern. the number of people affected by diabetes in world by 2030 will be 69% in developing countries. regular physical activity plays a key role in the management of type 2 diabetes melitus, particularly glycemic control. it has been recommended that peoples with type 2 diabetes participate in moderate-int...

Natural regeneration ensures the survival of forest stands and sustainable forest development. The present study was conducted to investigate the natural regeneration of Persian oak (Quercus macranthera fisch. & C.A.Mey. Ex Hohen) stands in Arasbaran protected forest. Measurement of the frequency of standard and coppice regenerations was carried out in one-hectare square plots (100 × 100 m) in ...

Journal: :Biological Invasions 2021

Abstract Plant invasions can have major impacts on ecosystems and influence global species diversity. In Central Europe, Himalayan balsam ( Impatiens glandulifera ) American goldenrods Solidago canadensis S. gigantea are important invaders often establishing dense homogeneous stands, especially in urban other disturbed habitats. We investigated their plant-dwelling spiders (abundance, family st...

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