نتایج جستجو برای: c 2007 influence of shrubs on soil chemical properties in alxa desert steppe
تعداد نتایج: 25085591 فیلتر نتایج به سال:
The knowledge of rangeland vegetation types and factors influencing on their establishment and stability is essential for sustainable management and regeneration of rangeland areas. With this aim, Gonbad watershed, due to different vegetation types, environmental conditions and grazing managements was studied. The watershed was stratified to homogenous units based on morphology of vegetation ty...
BACKGROUND Global climatic change is generally expected to stimulate net primary production, and consequently increase soil carbon (C) input. The enhanced C input together with potentially increased precipitation may affect soil microbial processes and plant growth. METHODOLOGY/PRINCIPAL FINDINGS To examine the effects of C and water additions on soil microbial properties and plant growth, we...
chapter one is devoted to a moderate discussion on preliminaries, according to our requirements. chapter two which is based on our work in (24) is devoted introducting weighted semigroups (s, w), and studying some famous function spaces on them, especially the relations between go (s, w) and other function speces are invesigated. in fact this chapter is a complement to (32). one of the main fea...
469 Soil Sci. Soc. Am. J. 71:469–475 doi:10.2136/sssaj2005.0283 Received 26 Aug. 2005. *Corresponding author ([email protected]). © Soil Science Society of America 677 S. Segoe Rd. Madison WI 53711 USA The patchy distribution of soil nutrients in shrub–desert ecosystems has been well characterized (Schlesinger et al., 1990), but less is known about how soil microbial community composition,...
the caspian sea contains great resources of oil and gas. the caspian sea is a 700- mile- long body of water in central asia, land located between azerbaijan, iran, kazakhstan, russia and turkmenistan. iran was challenges and opportunities in the caspian region. key question in this thesis includes three section that first question, opportunities of iran in the caspian region, second question ch...
Modern pollen records have been used to successfully distinguish between specific prairie types in North America. Whether the pollen records can be used to detect the occurrence of Eurasian steppe, or even to further delimit various steppe types was until now unclear. Here we characterized modern pollen assemblages of meadow steppe, typical steppe and desert steppe from eastern Eurasia along an...
Nature reserves are an important component of the strategy to halt biodiversity loss caused by habitat fragmentation and loss, climate change and other anthropogenic factors. In the past decades, 184 nature reserves were designed for biodiversity conservation in Inner Mongolia. However, no studies have quantified the general condition of these reserves. In this paper, we summarized the history,...
testing plays a vital role in any language teaching program. it allows teachers and stakeholders, including program administrators, parents, admissions officers and prospective employers to be assured that the learners are progressing according to an accepted standard (douglas, 2010). the problems currently facing language testers have both practical and theoretical implications but the first i...
from its emergence till present time marxist principles has undergone great changes since their promulgation by marx. many theorists and thinkers set at rectifying marxist tenets and introducing those of their own while others advocated its main concepts and attempted at improving them. among marxist philosophers who had an intensive study of marxs ideology, is louis althusser whose reflections...
Knowledge of the Saxaul dimensions used in sand dunes stabilization is considered essential for designing live windbreak in desert regions. This research aimed to collect and analysis data and was performed on the pruned and control shrubs of Haloxylon aphyllum L. in Yazd province, Iran in the last two decades. Our review clearly showed the superiority of shrubs pruned at the height of 35 cm i...
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