نتایج جستجو برای: semiarid zones

تعداد نتایج: 50355  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شهید باهنر کرمان - دانشکده علوم 1391

نظر به اهمیت کنودونت‎ها در تقسیمات چینه‎نگاری پالئوزوئیک و گسترش قابل توجه نهشته‎های دونین پسین و کربونیفر پیشین در منطقه کرمان سه برش چینه‎شناسی (حور، هوتک و شمس آباد) در شمال استان کرمان انتخاب و بویژه بر اساس کنودونت‎ها و بقایای ماهیان مورد مطالعه قرار گرفتند. مجموعه کنودونت‎های بدست آمده از برش حور شامل 20 گونه متعلق به دو جنس polygnathus و icriodus بوده و سنی معادل فرازنین پسین را نشان می‎...

Journal: :Hydrology 2023

The availability of water in Chile has shown signs decline recent decades. This is problematic because Chile’s economy depends on mining, forestry, and agricultural activities, all limited by the resources. In this study, daily, monthly annual flows 31 basins located arid–semiarid zones (29°12′ S–33°58′ S) humid–subhumid (34°43′ S–38°30′ were evaluated using Mann–Kendall trend test quantile–Ken...

2006

Semiarid environments throughout the world have lost a major part of their woody vegetation and biodiversity due to the effects of wood cutting, cattle grazing and subsistence agriculture. The resulting state is typically used for cattle production, but the productivity of these systems is often very low, and erosion of the unprotected soil is a common problem. Such dry-land degradation is of g...

Journal: :Environmental science & technology 2008
Bridget R Scanlon Robert C Reedy Kevin F Bronson

Nitrate (NO3) profiles in semiarid unsaturated zones archive land use change (LUC) impacts on nitrogen (N) cycling with implications for agricultural N management and groundwater quality. This study quantified LUC impacts on NO3 inventories and fluxes by measuring NO3 profiles beneath natural and rainfed (nonirrigated) agricultural ecosystems in the southern High Plains (SHP). Inventories of NO...

Journal: :Environmental management 2009
Ryan F Limb Samuel D Fuhlendorf Darrel E Townsend

Ecologists are beginning to recognize the effect of heterogeneity on structure and function in arid and semiarid ecosystems. Additionally, the influences of temperature on ecosystems are widely documented, but landscape temperature patterns and relationships with vegetation are rarely reported in ecological studies. To better understand the importance of temperature patterns to the conservation...

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