نتایج جستجو برای: soil aggregates

تعداد نتایج: 208406  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سیستان و بلوچستان - دانشکده مهندسی عمران 1392

abstract in aggregate, active forms of reactive silica with mineral names are sometimes associated with sand and gravel in concrete mixture. alkali hydroxides originated from alkalis in the cement or other resources form an alkaline silica gel with this reactive silica which becomes swallowed and expanded during time causing damage to concrete. there have been growing researches on alkaline r...

ژورنال: علوم آب و خاک 2014
اسمعیلی دستجردی پور, عاطفه, سرچشمه پور, مهدی, فرپور, محمد هادی,

Organic substances produced by cyanobacteria and some polymeric compounds play a role in soil aggregation and increase soil structure stability in sandy soils. Effects of biological soil crusts and some polymeric compounds on some properties of a sandy soil were investigated in this research. Inoculation of three cyanobacterial treatments (Nostoc sp., Phormidium sp. and their combination) and f...

Journal: :Journal of environmental quality 2003
Tetsu K Tokunaga Jiamin Wan Terry C Hazen Egbert Schwartz Mary K Firestone Stephen R Sutton Matthew Newville Keith R Olson Antonio Lanzirotti William Rao

Biogeochemical transformations of redox-sensitive chemicals in soils can be strongly transport-controlled and localized. This was tested through experiments on chromium diffusion and reduction in soil aggregates that were exposed to chromate solutions. Reduction of soluble Cr(VI) to insoluble Cr(II) occurred only within the surface layer of aggregates with higher available organic carbon and hi...

2011
Xiaohong Tang Youjin Luo Jiake Lv Chaofu Wei

Abstract: Ridge culture is a special conservation tillage method, but the long-term influence of this tillage system on soil aggregate-size stability in paddy fields is largely unknown in southwest of china. The objectives of this paper are to evaluate soil aggregates stability and to determine the relationship between SOC and soil aggregate stability.Soil samples at 0-20 cm layer were adopted ...

Journal: :desert 0
n. mashhadi international research center for living with desert, university of tehran, iran m. hanifehpoor faculty of natural resources, university of tehran, karaj, iran f. amiraslani rs & gis dept., faculty of geography, university of tehran, tehran, iran sh. mohamadkhan natural geography dept., faculty of geography, university of tehran, tehran, iran

aeolian process and subsequently soil erosion are key factors in dryland environments. such phenomena are related not only to geoecological factors (lithology, topography, and climatology) but also to land-use and plant cover changes. formation of new sand dunes in damghan explains the development of human activities over the past. the aim of this study is to explain the land use changes and th...

Journal: :تحقیقات آب و خاک ایران 0
علی واعظی دانشیار گروه خاک شناسی دانشکدة کشاورزی دانشگاه زنجان سعیده اکبری دانشجوی کارشناسی ارشد، گروه خاک شناسی دانشکدة کشاورزی دانشگاه زنجان محمد حسین محمدی دانشیار گروه خاک شناسی دانشکدة کشاورزی دانشگاه زنجان

rainfall erosion processes a long with the rainfall characteristics can be affected by soil properties. the study was conducted to investigate the susceptibility of the aggregates in different soil textures to the rainfall erosion processes. the experiment was done on thirty soil samples recognized in four soil textures with different replications as the completely randomized design. ninety box...

2006
J. R. Nimmo

A soil aggregate is “a group of primary soil particles that cohere to each other more strongly than to other surrounding particles.” Soil aggregates form through the combined action of aggregation and fragmentation processes. That is, attractive and disruptive forces act on the particles in the soil to cause greater cohesion among some particles, and groups of particles, than others. Most soils...

Journal: :مرتع و آبخیزداری 0
لیلا زندی دانشجوی کارشناسی ارشد مرتعداری، دانشکده منابع طبیعی و علوم دریایی، دانشگاه تربیت مدرس رضا عرفانزاده دانشیار دانشکده منابع طبیعی و علوم دریایی، دانشگاه تربیت مدرس حامد جنیدی جعفری استادیار گروه مرتعداری دانشکده منابع طبیعی، دانشگاه کردستان، ایران

this study aimed to determine the effect of land use changes from rangeland to horti-agricultural lands on the most important qualitative characteristics of soil such as total soil carbon and particulate organic matter, in salavatabad region, sanandaj. in the present study, one rangeland, two cultivated pea lands, two cultivated wheat lands and two gardens were selected in growth season in the ...

ژورنال: علوم آب و خاک 2011
آزاده وکیلی, , محمد جواد روستا, , کوکب عنایتی, ,

Soil structure and aggregate stability affect soil erodibility. There is a necessity for increasing aggregate stability against erosive factors such as wind and water. This study was conducted on surface soil samples (0-20cm) collected from agricultural land susceptible to erosion located in Chahoo, southeast of Fars province. The experimental design was CRD with 10 treatments and was replicate...

2005
Humberto Blanco-Canqui R. C. Izaurralde

gregate formation (Horn, 1990; Zhang, 1994). Understanding of mechanical properties of aggregates is cruAggregate properties determine the macroscale structural condicial to explain the macroscale functions of soil for plant tion of the soil. Understanding of impacts of no-till and traditional growth (DeFreitas et al., 1996). agricultural practices on the mechanical properties of aggregates is ...

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