نتایج جستجو برای: c 2007 influence of shrubs on soil chemical properties in alxa desert steppe

تعداد نتایج: 25085591  

اسدیان, قاسم, سالاری نیک, خدیجه, نائل, محسن ,

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...

2012
Linna Ma Wenwen Huang Chengyuan Guo Renzhong Wang Chunwang Xiao

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...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه فردوسی مشهد - دانشکده علوم 1377

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...

2007
Stephanie A. Ewing

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,...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه علامه طباطبایی 1389

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...

2015
Feng Qin Yu-Fei Wang David K. Ferguson Wen-Li Chen Ya-Meng Li Zhe Cai Qing Wang Hong-Zhen Ma Cheng-Sen Li

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...

2016
Wenjing Ma Gang Feng Qing Zhang

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,...

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

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...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سمنان - دانشکده ادبیات و علوم انسانی 1393

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...

Ehsan Zandi Esfahan Mohammad Taghi Zare Naser Baghestani Maybodi,

 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...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید