نتایج جستجو برای: semiarid zones
تعداد نتایج: 50355 فیلتر نتایج به سال:
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...
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...
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...
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...
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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