نتایج جستجو برای: and plant cover
تعداد نتایج: 16893867 فیلتر نتایج به سال:
this study was conducted to determine soil properties that correlate with the arbuscular mycorrhizal fungal (amf) spore numbers in semiarid calcareous soils of hamadan province in northwestern of iran. soil samples from six sites managed differently were collected from a 0 to 30 cm depth. the results showed that land use and management systems had a significant effect on amf spore number in soi...
the history of plant’s used for mankind is as old as the start of humankind. initially, people used plants for their nutritional proposes but after the discovery of medicinal properties, this natural ?ora became a useful source of disease cure and health improvement across various human communities. berberis vulgaris is one of the medicinal plants used in iranian traditional medicine. berberis ...
this study intends to investigate samuel beckett’s waiting for godot and endgame under the lacanian psychoanalysis. it begins by explaining the most important concepts of lacanian psychoanalysis. the beckettian characters are studied regarding their state of unconscious, and not the state of consciousness as is common in most beckett studies. according to lacan, language plays the sole role in ...
background and objectives: suitable tillage methods and planting cover crops are such factors in sustainable agricultural systems, which play an important role in the sustainability of agricultural production systems. minimum and no-tillage systems methods that leave instead of usually more than 30 percent of crop residue on the soil surface, are used to reduce soil erosion, improve soil physic...
Plant species distribution, composition and diversity in deserts of arid and semi-arid areas, especially saltland; depend on soil physical and chemical gradients. The aim of this research was to investigate changes in the plant species diversity and richness along a soil salinity gradient in the margin rangelands of Petregan Playa. After vegetation zoning in relation to soil salinity, random-sy...
nowadays, air pollution is a global problem that has had significant growth by technology development, population growth andindustrial development. industrial development brought natural resources deterioration, more manufacturing products, and more environmental pollutants. if pollutant won’t be controlled, human-being and wildlife will face the critical risks. significant release and critical...
in arid and semi-arid rangelands, grazing as one of the natural or human induced processes has direct and indirect effects on structure and dynamics of plant community and ecosystems. a study was done to analyze the effects of grazing on plant species diversity and plant functional types‘ (pfts) diversity of arid and semi-arid rangelands. we analyzed plant richness and diversity data from 75 sa...
insurers have in the past few decades faced longevity risks - the risk that annuitants survive more than expected - and therefore need a new approach to manage this new risk. in this dissertation we survey methods that hedge longevity risks. these methods use securitization to manage risk, so using modern financial and insurance pricing models, especially wang transform and actuarial concepts, ...
plant biomass is an important factor for determining arid and semi-aridrangelands capacity. due to the lack of proper and annual sampling of rangelands, there areno suitable data to determine biomass, range condition and proper range managementoperations. plant biomass is one of the measurable attributes that can be assessed inrangeland studies. since the clip and weight method is destructive a...
this research was conducted to compare plant functional types (pft) and traits in an old-field (abandoned for 28 years) and a control site, in the baharkish rangelands, quchan, iran. in the both sites, 40 randomized quadrates were established. floristic list, frequency, canopy cover and 20 vegetative, phenological and morphological plant traits were measured for all plant species, within each q...
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