Organic-rich Carboniferous shales with associated coal seams, from the Bacia Carbonífera do Douro-Beira (north Portugal), have been studied by TEM as well as by a variety of other methods. NH4 and K micas and berthierine form small subparallel packets of a few layers separated by lowangle boundaries. Oneand two-layer ordered polytypes, with some spot enlargement typical of minor disorder, occur...

BACKGROUND AND AIMS There is increased evidence that partial nitrate (NO3-) nutrition (PNN) improves growth of rice (Oryza sativa), although the crop prefers ammonium (NH4+) to NO3- nutrition. It is not known whether the response to NO3- supply is related to nitrogen (N) use efficiency (NUE) in rice cultivars. Methods Solution culture experiments were carried out to study the response of two ri...

We monitored the water quality and hydrological conditions of a horizontal subsurface constructed wetland (HSSF-CW) in Beijing, China, for two years. We simulated the area-based constant and the temperature coefficient with the first-order kinetic model. We examined the relationships between the nitrogen (N) removal rate, N load, seasonal variations in the N removal rate, and environmental fact...

The present lab-scale research reveals the potential of implementation of an oxygen-limited autotrophic nitrification-denitrification (OLAND) system with normal nitrifying sludge as the biocatalyst for the removal of nitrogen from nitrogen-rich wastewater in one step. In a sequential batch reactor, synthetic wastewater containing 1 g of NH4+-N liter-1 and minerals was treated. Oxygen supply to ...

Selenomonas ruminantium was found to possess two pathways for NH4+ assimilation that resulted in net glutamate synthesis. One pathway fixed NH4+ through the action of an NADPH-linked glutamate dehydrogenase (GDH). Maximal GDH activity required KCl (about 0.48 M), but a variety of monovalent salts could replace KCl. Complete substrate saturation of the enzyme by NH4+ did not occur, and apparent ...

Appropriate and simple analysis methods for an accurate estimation of soil N mineralization potential are required to optimize N fertilizer recommendations. We used soils from non-cultivated and cultivated plots in central Côte d’Ivoire to investigate the quantum of ammonium (NH4 ) that could potentially be mineralized. The soil was first treated with H2O2 at 60°C for 2, 4, 6 or 8 h (and referr...

This paper presents the results of a study of variation in the chemical composition of wet precipitation over a 16-year period. The ions SO4 2, NO3 , Cl , Ca 2+ , Mg 2+ K + , Na + , NH4 + and H + were analyzed. The correlation analysis showed a high positive correlation among these ions, indicating that anthropogenic emissions were the most important source. Trends in annual concentrations of S...