نتایج جستجو برای: point nitrogen pollution and soil erosion

تعداد نتایج: 16946384  

Journal: :Environmental science & technology 2011
Patrick Belmont Karen B Gran Shawn P Schottler Peter R Wilcock Stephanie S Day Carrie Jennings J Wesley Lauer Enrica Viparelli Jane K Willenbring Daniel R Engstrom Gary Parker

Although sediment is a natural constituent of rivers, excess loading to rivers and streams is a leading cause of impairment and biodiversity loss. Remedial actions require identification of the sources and mechanisms of sediment supply. This task is complicated by the scale and complexity of large watersheds as well as changes in climate and land use that alter the drivers of sediment supply. P...

Journal: :مدیریت خاک و تولید پایدار 0
حیدر غفاری دانشگاه تهران منوچهر گرجی دانشگاه تهران

maintaining soil productivity is one of the key factors in sustainable agriculture. soil erosion reduces soil productivity over a long-term period of time. therefore, determining soil erosion tolerance is necessary for sustainable agriculture production. in this study, the long-term effects of erosion on soil productivity in the typical kohin watershed were evaluated. the soil productivity inde...

2005
Silvio Simonit Charles Perrings

We consider the potential for using prices as leading indicators of changes in stocks and yields in the freshwater capture fishery in Lake Victoria. Fertilizer run-off from agricultural land is a major cause of nutrient loading, along with soil erosion, atmospheric deposition, and point pollution from industrial and domestic affluent. The interactions between fertilizer applications, water qual...

Journal: :Earth Science Informatics 2015
Md. Rejaur Rahman Zhihua Shi Chongfa Cai Dun Zhu

Soil erosion is one of the most serious environmental problems affecting the quality of soil, land, and water resources upon which humans depend for their sustenance. A soil erosion hazard map is highly useful for environmental planning, soil conservation and management in soil erosion prone areas. In order to assess the soil erosion hazard, remote sensing (RS) and geographical information syst...

Journal: :آب و خاک 0
مجتبی محمودی رسول راهنمایی علی اسحاقی محمد جعفر ملکوتی محبوبه جلالی

abstract herbicides are the main sources of soil and water pollution in paddy fields. herbicides mobility to the surface and ground water is a major concern for human health and the environment. it is, therefore, necessary to investigate their fate and their interactions in natural ecosystems. to meet this purpose, field experiments were conducted to measure kinetic of thiobencarb dissipation i...

Journal: :Environmental science & technology 2007
Andrew R Bukata T Kurtis Kyser

Increasing anthropogenic pollution from urban centers and fossil fuel combustion can impact the carbon and nitrogen cycles in forests. To assess the impact of twentieth century anthropogenic pollution on forested system carbon and nitrogen cycles, variations in the carbon and nitrogen isotopic compositions of tree-rings were measured. Individual annual growth rings in trees from six sites acros...

2005
Alfred E. Hartemink

Plantation agriculture is more than 400 years old and contributes to the regional and national economies in many tropical countries. This paper reviews some of the main environmental issues related to plantation agriculture with perennial crops, including soil erosion, soil fertility decline, pollution, carbon sequestration and biodiversity. Soil erosion and soil fertility decline are of concer...

Journal: :تحقیقات آب و خاک ایران 0
فریده عباس زاده افشار شمس اله ایوبی احمد جلالیان حسین خلقی فرید اصغری زاده

soil erosion and its associated land degradation represent major problems for development as well as for environmental resources protection. there is an urgent need to obtain reliable quantitative data on the extent and rates of soil erosion worldwide. the use of 137cs radionuclide for studying soil erosion and deposition is a valuable tool employed throughout the world. in the present study, u...

Journal: :مرتع و آبخیزداری 0
فریبا علوی زاده دانشجوی کارشناسی ارشد مرتع داری، دانشکده منابع طبیعی و محیط زیست، دانشگاه فردوسی مشهد کمال الدین ناصری استادیار دانشکدة منابع طبیعی و محیط زیست، دانشگاه فردوسی مشهد علی گلکاریان استادیار دانشکده منابع طبیعی و محیط زیست، دانشگاه فردوسی مشهد علی طویلی دانشیار دانشکده منابع طبیعی، دانشگاه تهران

soil erosion is a main hazard in most area of the country specially in arid and semi-arid regions and itis very important because of sedimentation, pollution, increased flooding and its negative effects onsoil productivity. one of the features of arid and semi-arid areas is the presence of low cover ofvascular plants. these empty spaces are usually good niches for biological soil crusts or cryp...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه ارومیه - دانشکده کشاورزی 1393

چکیده کنه تارتن دو لکه ای tetranychus urticae koch یکی از چندخوارترین آفات شناخته شده محصولات کشاورزی دنیا به حساب می آید. در این بررسی جمعیت تخم و مراحل فعال این کنه در شرایط آلودگی طبیعی و مصنوعی در برگ های 8 رقم لوبیا در سال 1392 در گلخانه و مزرعه تحقیقاتی دانشکده کشاورزی دانشگاه ارومیه موردمطالعه قرار گرفت. آزمایش به صورت طرح کاملاً تصادفی برای شرایط مزرعه در10 تکرار و برای شرایط گلخانه ای...

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