Research on nutrient controls of planktonic productivity tends to focus on a few standard fractions of inorganic or total nitrogen (N) and phosphorus (P). However, there is a wide range in the degree to which land-derived dissolved organic nutrients can be assimilated by biota. Thus, in systems where such fractions form a majority of the macronutrient resource pool, including many boreal inland...

The kinetics of sulfate reduction and inorganic nutrient production (~C02' ammonium, and phosphate) were examined in the sediments at five sites in the southern Chesapeake Bay, using long term (> 200 d) sediment decomposition experiments. Average first order rate constants for these processes (at 25°C) decreased from 8.2 to 3.7 yrin the surface sediments (0-2 em), to 2.1 to 0.2 yrat 12-14 em. T...

Although soil phosphorus is essential for vegetation growth it not always found in labile forms, hampering its absorption by plants, and limited forest ecosystems. This study explores P state availability calcareous soils, determining which processes affect different pools parameters influence productivity of a Mediterranean pine species. We used sequential fractionation method to determine fra...

Young seedlings of maritime pine (Pinus pinaster Soland in Aït.) were grown in rhizoboxes using intact spodosol soil samples from the southwest of France, in Landes of Gascogne, presenting a large variation of phosphorus (P) availability. Soils were collected from a 93-year-old unfertilized stand and a 13-year-old P. pinaster stand with regular annual fertilization of either only P or P and nit...

GOAL, SCOPE AND BACKGROUND Biosolids, i.e., treated sewage sludge, are commonly used as a fertilizer and amendment to improve soil productivity. Application of biosolids to meet the nitrogen (N) requirements of crops can lead to accumulation of phosphorus (P) in soils, which may result in P loss to water bodies. Since 1996, biosolids have been applied to a Pinus radiata D. Don plantation near N...

The similarities and differences in the structures of the nifH gene pools of six different soils (Montrond, LCSA-p, Vernon, Dombes, LCSA-c, and Thysse Kaymor) and five soil fractions extracted from LCSA-c were studied. Bacterial DNA was directly extracted from the soils, and a region of the nifH gene was amplified by PCR and analyzed by restriction. Soils were selected on the basis of differenc...

since particulate matter (total suspended particles and particulate matter with median aerodynamic diameter less than 10 µm) is one of the important pollutants in the ambient air of tehran, the capital of iran, organic substances, inorganic substances and lead levels in tsp and pm10, correlation between tsp and pm10 concentrations, ratio among the two fractions and relation between tsp and pm10...

Phosphorus often limits bacterial production in freshwater ecosystems. However, little is known on whether different bacteria contribute to inorganic and organic phosphorus uptake proportionally to their relative abundance and production. Here, we followed the temporal dynamics of the main heterotrophic bacterial taxa taking up inorganic phosphate (33 P-Pi) and organic phosphorus (33 P-ATP) in ...

Abstract. Conservation tillage has attracted increasing attention over recent decades, mainly due to its benefits for improving soil organic matter content and reducing erosion. However, the effects of long-term straw mulching under a no-till system on physicochemical properties bacterial communities at different depths are still unclear. In this 12-year experiment removal (CK) (SM) treatments,...