نتایج جستجو برای: water and nutrient management

تعداد نتایج: 17084674  

Journal: :علوم باغبانی 0
مجتبی دلشاد رقیه علفتاحی تکتم سادات تقوی مسعود پارسی نژاد

abstract low water holding capacity of soilless substrates increases water stress and waste of nutrient solution. irrigation time management can reduce such problems. in this research, responses of hydroponically cultured greenhouse strawberries were evaluated under different irrigation schedules. in first step, plant daily water need was estimated and then delivered to plants through two metho...

پایان نامه :دانشگاه تربیت معلم - تهران - دانشکده ادبیات و علوم انسانی 1391

abstract global financial crisis has created too many problems in relations among governments. among these problems, the issue of global monetary management, more than every time in the past four decades, has been moved in the center of international economic attentions. a problem which is specially known with the monetary hostility between united states and public republic of china. where ar...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس 1389

abstract: country’s fiber optic network, as one of the most important communication infrastructures, is of high importance; therefore, ensuring security of the network and its data is essential. no remarkable research has been done on assessing security of the country’s fiber optic network. besides, according to an official statistics released by ertebatat zirsakht company, unwanted disconnec...

2005
B. Fu

Water quality decline is a significant environmental issue in Australia and many other countries. Much emphasis has been placed on nutrient management especially for phosphorus (P) and nitrogen (N) in an attempt to reduce their loss to water bodies. Identifying nutrient sources and their transport potential can assist catchment managers to recognise critical nutrient sources and to devise manag...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه یزد - دانشکده جغرافیا 1392

the west of esfahan province, iran, is one of the most important agricultural areas throughout the country due to the climate variability and life-giving water of zayanderood river. rice is one of the major and economic crops in this area. the most important climatic elements in agricultural activities which should be considered include temperature, relative humidity, precipitation and wind. so...

پایان نامه :دانشگاه آزاد اسلامی - دانشگاه آزاد اسلامی واحد تهران مرکزی - دانشکده مدیریت 1392

data envelopment analysis (dea) is a powerful tool for measuring relative efficiency of organizational units referred to as decision making units (dmus). in most cases dmus have network structures with internal linking activities. traditional dea models, however, consider dmus as black boxes with no regard to their linking activities and therefore do not provide decision makers with the reasons...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس - دانشکده منابع طبیعی 1391

in this study, the effects of oleothermal modification on physical and mechanical peroperties of fir wood (abeis sp.) blocks were examined. at first, some blocks of fir wood with 5 × 20 × 120 cm dimensions were prepared. the blocks were treated in soybean oil. the effects of 3 factors such as treatments temperature (180and 200 °c), holding time (12 and 15 h) and initial moisture content of wood...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی اصفهان 1389

run-out-table (rot) is located between last finishing stand and down coiler in a hot strip mill. as the hot steel strip passes from rot, water jets impact on it from top and bottom and strip temperature decreases approximately from 800-950 °c to 500-750°c. the temperature history that strip experience while passing through rot affects significantly the metallurgical and mechanical properties, s...

Journal: :Journal of environmental quality 2015
Deanna L Osmond Dana L K Hoag Al E Luloff Donald W Meals Kathy Neas

Nutrient enrichment of water resources has degraded coastal waters throughout the world, including in the United States (e.g., Chesapeake Bay, Gulf of Mexico, and Neuse Estuary). Agricultural nonpoint sources have significant impacts on water resources. As a result, nutrient management planning is the primary tool recommended to reduce nutrient losses from agricultural fields. Its effectiveness...

2007
A. Gnauck

Natural and man induced nutrient loads affect the functioning of freshwater ecosystems and restrict various water uses. In particular, internal pollution by nutrient remobilisation from sediment plays an important role in shallow water bodies. A sustainable management of such freshwater ecosystems can be achieved by using simulation models. To forecast the eutrophication process of a shallow ri...

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