Potential nitrogen mineralization and nitrification were measured in soils from a primary successional sequence developed on sand dunes and from a secondary successional sequence on old fields. Potential nitrogen mineralization in soils from the primary sere increased through the first five stages and then leveled off. Nitrogen mineralization was relatively constant in soils from the secondary ...

Remote sensing studies suggest that savannahs are transforming into more tree-dominated states; however, progressive nitrogen limitation could potentially retard this putatively CO2-driven invasion. We analysed controls on nitrogen mineralization rates in savannah by manipulating rainfall and the cover of grass and tree elements against the backdrop of the seasonal temperature and rainfall vari...

abstract biological and chemical changes in rhizosphere following organic residues as well as manures application are important processes which influence nitrogen mineralization and nutrients bioavailibity in soils. this study was done to evaluation of organic residues effect on growth, nitrogen supply and rhizosphere characteristics of corn and sunflower plants in greenhouse experiment using s...

land use change of forest ecosystems in northern iran changes the soil quality of paresar (gilan province) and gorgan (gorgan province) regions. in order to study changes in some biological soil quality indices due to land use change from forest to cultivated lands, composite soil samples from two depths (0-20 and 20-40 cm) were taken from paresar and gorgan regions and urease, alkaline and aci...

The. seasonal pattern of nitrogen mineralization is described and compared with the potential demand for nitrogen by grasses. Peak mineralization rates occur in spring but are quite inadequate for expression of potential grass growth. Nitrogen fixation by clovers provides a significant input into the system over a short period. Consideration of the fate of fixed nitrogen shows that losses large...

Effects of warming and nutrient enrichment on intact unvegetated shallow-water sediment were investigated for 5 weeks in the autumn under simulated natural field conditions, with a main focus on trophic state and benthic nitrogen cycling. In a flow-through system, sediment was exposed to either seawater at ambient temperature or seawater heated 4°C above ambient, with either natural or nutrient...

We report changes in nitrogen cycling in Florida scrub oak in response to elevated atmospheric CO2 during the ®rst 14 months of experimental treatment. Elevated CO2 stimulated above-ground growth, nitrogen mass, and root nodule production of the nitrogen-®xing vine, Galactia elliottii Nuttall. During this period, elevated CO2 reduced rates of gross nitrogen mineralization in soil, and resulted ...

Organic wastes in selected waste dumpsites in Port Harcourt were successively incubated with sandy-loam soils for days at 27oC, under aerobic conditions. The results showed marked decrease in total nitrogen in the organic wastes which was observed as loss of nitrogen. The process of nitrification and incorporation of (NH4)2SO4 affected the pH which ranged from 5.9 to 7.9. The cumulative mineral...

We measured annual net nitrogen (N) mineralization, nitrification, and amino acid production in situ across a primary successional sequence in interior Alaska, USA. Net N mineralization per gram dry soil increased across the successional sequence, but with a sharp decline in the oldest stage (black spruce). Net N mineralization expressed per gram soil organic matter exhibited the opposite patte...

the objective of this work was to study the effects of tillage and liquid manure applications on some physical and chemical properties as well as on the carbon and nitrogen mineralization potential of a meadow soil. our results indicated that tillage and manure applications had no effect on the concentration of cu, mn, total n and organic c in 0-15 cm layer of soil after 15 years of treatment. ...