نتایج جستجو برای: p in acidic soils relative to alkaline

تعداد نتایج: 18808293  

2003
W. F. Truter Wayne F. Truter

The South African mining industry has been the backbone of the country’s economy for much of the past century. Mining has, however, often caused the degradation of productive soils. The amendment of these soils is often very expensive and often not sustainable. The University of Pretoria in cooperation with Eskom TSI, has over the past seven years conducted a series of trials. These trials have...

The Eocene volcanic rocks exposed in the NW Sechangi area of Lut block, include pyroclastic deposits and lavas. These volcanic rocks are basalt, basaltic andesite, andesite, andesite-trachyandesite, trachydacite, dacite and rhyolite-ignimbrite in composition. Based on our field observations, the volcanic rocks erupted in four stages in the aquous to subaerial environments. The volcanic rocks ar...

2005
Christian Michael Baldwin

Acid soils are abundant in tropical and subtropical regions and account for approximately 40 percent of arable land in the world. Next to oxygen and silicon, aluminum (Al) is the third most abundant element in soils and is the main toxic factor for plant growth in acidic soils. Therefore, two glasshouse studies were conducted to determine the influence of Al on root and shoot mass and nutrient ...

2009
Laurent Barbiéro

In the Senegal valley, it is commonly considered that the Acid Sulfate Soils of the delta are fossil soils overlain by more recent sediments, and that the Vertisols, which abruptly overlie a thick sandy horizon, result from a change in the sedimentation mode of the river. However, we show that both soils belong to the same pedological system extending from the delta to the limit of the last mar...

Journal: :iranian endodontic journal 0
fereshte sobhnamayan safoora sahebi shiraz dental school ali alborzi saeed ghorbani shiraz dental school nooshin sadat shojaee

introduction: the aim of this study was to evaluate the compressive strength of calcium-enriched mixture (cem) cement in contact with acidic, neutral and alkaline ph values. methods and materials: the cement was mixed according to the manufacturer’s instructions, it was then condensed into fourteen split molds with five 4×6 mm holes. the specimens were randomly divided into 7 groups ( n =10) an...

پایان نامه :وزارت بهداشت، درمان و آموزش پزشکی - دانشگاه علوم پزشکی و خدمات بهداشتی درمانی مشهد - دانشکده دندانپزشکی 1390

objective: the objective of this study was to investigate the invitro fluoride release of four new self-adhesive resin cements; set (sdi, australia), breeze (pentron, usa), embrace wetbond (pulpdent, usa), g-cem (gc, japan) and to assess the bonding performance of these self-adhesive resin cements for bonding of orthodontic brackets. materials and methods: for fluoride release experiment, six ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت دبیر شهید رجایی - دانشکده علوم انسانی و پایه 1390

the present study aimed at investigating the relationship between iranian efl teachers’ classroom management orientations and their teaching styles. additionally, the difference between male and female teachers’ teaching styles and classroom management orientations and their relationship with experience and age were explored. three hundred efl teachers filled in attitudes and beliefs on classro...

Journal: :iran agricultural research 2008
h. abbaslou a. abtahi

pedogenesis and clay mineralogy of soils and rock samples were studied in a transect of calcareous, gypsiferous, saline soils and sediments of bakhtegan lake bank in southern iran. the main objectives of study were to determine the occurrence of clay minerals and factors controlling their distribution pattern and relative abundance in soils and parent materials. the soil parent material is high...

Journal: :journal of agricultural science and technology 2013
s. s. hashemi m. baghernejad m. najafi ghiri

this study investigated the relationship between clay minerals and different soil moisture regimes in gypsiferous soils of fars province in southern iran. the overall climate of the province is arid and semi-arid and, under this condition, parent material is the most important factor affecting clay minerals distribution. beside this factor, climate conditions have determining role too. palygors...

2008
G. J. Michaelson C. L. Ping H. Epstein J. M. Kimble D. A. Walker

[1] We studied soil properties of frost boils at nine zonal-vegetation locations across the North American Arctic Transect (NAAT) in order to better understand arctic soils and their interaction with other biogeophysical components of frost boil ecosystems. Soil genetic horizons were analyzed for particle size, pH, electrical conductivity, total organic carbon (OC) and nitrogen (N), bulk densit...

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