Predicting soil phosphorus (P) needs and P fertilizer requirements is important for plant nutrition and reducing environmental risk. The P requirement (PR) can be calculated from three components: the current status of soil P (P0), soil P buffer coefficient (PBC), and the soil P critical level (PCL). The PBC and PCL can be predicted from soil clay content using linear-plateau models. The PR, PB...

ABS~CT Particle-size analyses of brickearth and Clay-with-flints from Kent, England, are presented. A calcareous sample of brickearth is comparable to loess. In th~ clay fraction, there is more illite (or glauconite) than kaolin; and there is some chlorite. The clay fraction of the Clay-withflints consists of smectite, illite and quartz and is probably derived directly from the Chalk. Black san...

Clay, as a rock term, describes a soft, loose, earthy material containing particles with an average grain size of less than than 0.004 mm (4 mm) in the Wentworth grain size scale and less than 0.002 mm (2 mm) in most soil investigations. Clay is composed mostly of clay minerals, but may also contain quartz, feldspar, carbonates, ferruginous material, and other non-clay materials. All clays, apa...

Iron-bearing phyllosilicates strongly influence the redox state and mobility of uranium because of their limited hydraulic conductivity, high specific surface area, and redox reactivity. Standard extraction procedures cannot be accurately applied for the determination of clay-Fe(II/III) and U(IV/VI) in clay mineral-U suspensions such that advanced spectroscopic techniques are required. Instead,...

Naturally occurring clay colloidal particles are heavily involved in sediment processes in the subsurface soil. Due to the importance of these processes in the subsurface environment, the transport of clay colloidal particles has been studied in several disciplines, including soil sciences, petrology, hydrology, etc. Specifically, in environmental engineering, clay colloid release and transport...

Seven current methods of protein quantitation, Bradford (standard, micro, and 590/450 nm ratio), Lowry, bicinchoninic acid (BCA), UV spectrophotometry at 280 nm, and Quant-iT fluorescence-based determination, were compared with regard to their susceptibility to interferences due to the presence of suspended and not easily detectable clay particles. Bovine serum albumin (BSA) and Na-Wyoming mont...

I N T R O D U C T I O N T h e s t u d y o f c lay f o r m a t i o n i n soils m a y b e d i v i d e d i n t o t h r e e p a r t s : (1) a q u a n t i t a t i v e e v a l u a t i o n o f t h e a m o u n t o f c lay f o r m e d f r o m a g i v e n a m o u n t o f p a r e n t m a t e r i a l , (2) a q u a l i t a t i v e e v a l u a t i o n of t h e k i n d o f m i n e r a l s a n d o t h e r s u ...

Smectites or swelling clay minerals are naturally occurring nanomaterials that can be fully delaminated to elementary clay mineral platelets in dilute aqueous dispersion. This review article gives an overview of the recent progress on how the elementary clay mineral platelets can be reorganized in monolayered or multilayered hybrid nanofilms by layer-by-layer assembly or the Langmuir-Blodgett t...

-The addition of a 10% talc internal standard to North Pacific sediments allows the relative abundances of clay minerals to be determined both accurately and precisely by X-ray powder diffractometry. Linear programming can be used to generate factors for converting talc-normalized peak areas to weight percentages; hence, absolute clay-mineral abundances can be estimated. This procedure minimize...

OBJECTIVE To understand the significance of clay art therapy for psychiatric patients admitted in a day hospital. METHODOLOGY Qualitative, descriptive and exploratory research, undertaken with 16 patients in a day hospital in Londrina, in the state of Parana, Brazil, who participated in seven clay therapy sessions. Data collection took place from January to July 2012 through interviews guided...