نتایج جستجو برای: toposequence

تعداد نتایج: 111  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی اصفهان - دانشکده کشاورزی 1386

در سال های اخیر تجمع عناصر سنگین در خاک در بسیاری از نقاط جهان به یک مشکل زیست محیطی مهم تبدیل شده است. عوامل مختلفی در افزایش عناصر سنگین به خاک و در نتیجه آلودگی آن نقش دارند که از جمله می توان به فعالیت های صنعتی و کشاورزی اشاره نمود. آلودگی خاک به عنوان جزیی از اکوسیستم می تواند به آلودگی آب و هوا منجر شده و در نهایت آلودگی زنجیره غذایی را به دنبال داشته باشد. در ارتباط با وضعیت پراکنش عناص...

Journal: :آب و خاک 0
سپیده اکبری علیرضا کریمی کارویه امیر لکزیان امیر فتوت

introduction: parent materials as one of the main soil formation factors have a great impact on the concentration of heavy metals in the soil. heavy metals are released to the soil during weathering and pedogenic processes. ultrabasic rocks are known as the potential natural source of heavy metals, especially ni, cr and mn in the soil. average concentrations of ni and cr in the soils are 84 and...

2002
GARCÍA-OCAMPO Alvaro

Abtract The Mg +2 accumulation on the exchange complex of soils to a very high saturation levels affect their chemical, physical and biological properties. Magnesium has some capacity to develop higher exchangeable sodium levels in clays and soil materials. Colombia has a large area of these soils, located mainly in the main rivers valleys and in the Caribbean Region. In the Cauca River Valley ...

ژورنال: علوم آب و خاک 2008
جعفری, اعظم , خادمی , حسین , رضائی نژاد, یحیی , شریعتمداری, حسین,

Mineralogy is one of the most influential soil properties that change from upper- to lower slope positions, depending on the climate differences. Such changes affect soil properties such as phosphorus sorption and desorption processes differently. Therefore, this study was carried out to investigate the clay mineralogy of soils in four toposequences from arid (Isfahan) and semiarid (Chaharmahal...

2006
Boonrat Jongdee Grienggrai Pantuwan Shu Fukai Ken Fischer

A large portion of the world’s poor farm in rainfed systems where the water supply is unpredictable and droughts are common. In Thailand there are approximately 6.2 million ha of rain fed lowland rice, which account for 67% of the country’s total rice-growing area. This rice system is often characterised by too much and too little water in the same season. Farmers’ estimates of their annual los...

جعفری, اعظم , خادمی , حسین , رضائی نژاد, یحیی , شریعتمداری, حسین,

Mineralogy is one of the most influential soil properties that change from upper- to lower slope positions, depending on the climate differences. Such changes affect soil properties such as phosphorus sorption and desorption processes differently. Therefore, this study was carried out to investigate the clay mineralogy of soils in four toposequences from arid (Isfahan) and semiarid (Chaharmahal...

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