effects of calcium carbonate and ph on the kinetics of p fixation were studied on four non-calcareous soils treated with different levels of pure caco3, and also on six soils which were adjusted for ph within the range of 5 to 9. soils were also treated with k2hpo4 at the rate of 45 mg p/kg before they were incubated for a period of 100 days at 25○c. soil samples were taken at certain predeterm...

in calcareous soils of the southern Everglades and of adjacent areas is needed urgently. The understanding of P sorption and desorption by soils is imporThe relationships between P-sorption capacity, P tant for safeguarding water quality and for fertilizer management. availability and soil components in calcareous soils have Little is known about the P-sorption characteristics of the calcareous...

the release of fe from soil solid phases into soil solution is a dynamic process that regulates the continuous supply of this element to growing plants. to ascertain the pattern of fe release, the kinetics of fe release from six soils by diethylenetriaminepentaacetic acid (dtpa) solution were investigated using soil samples taken from two different agroclimatic regions of iran. all soils were c...

Hydroxyapatite (HA) or calcium carbonate (CaCO3) formed on an organic polymer of agarose gel is a biomaterial that can be used for bone tissue regeneration. However, in critical bone defects, the regeneration capability of these materials is limited. Mesenchymal stem cells (MSCs) are multipotent cells that can differentiate into bone forming osteoblasts. In this study, we loaded MSCs on HA- or ...

the rehabilitation of sandy desertified land in various dryland ecosystems by different management practices has a great potential to increase aggregate stability and improve soil quality. however, plants in general may have a different ability to sustain soil. the objective was to determine the effects of reclamation practices including haloxylon ammodendron and atriplex canescens plantation o...

was dissolved from the soil; Le., equilibrium was ap­ Soils in the laboratory were reacted with agricultural drainage­ and distilled waters at various carbon dioxide (COl) levels. The soil water solutions yielded different Ion activity product (lAP) values than that of calcite, depending on experimental technique and whether calcite "equilibrium" is approached from supersaturation or under­ sat...

macro and micromorphological investigations were conducted on selected xerepts soils from southern iran to identify changes in soil characteristics with time. soil samples from similar pedons of four irrigated orchards ranging in age from 20 to 100 years were studied and compared with soil samples of a pedon of non-irrigated land. in addition to routine analyses, undisturbed blocks of soils...

abstract infiltration is a significant process which controls the fate of water in the hydrologic cycle. the direct measurement of infiltration is time consuming, expensive and often impractical because of the large spatial and temporal variability. artificial neural networks (anns) are used as an indirect method to predict the hydrological processes. the objective of this study was to develop ...

Forty-seven patients with mild hypertension and 48 normotensive patients entered a blinded, parallel study in which they received a placebo, 10 mmol/day calcium carbonate (CaCO3), or 20 mmol/day CaCO3. There were no significant differences in blood pressure changes among the groups. In the hypertensive group and in patients with the highest blood pressure there were individual falls in systolic...