Estimated nutrient mineralization in northern nutrient-poor ecosystems, measured as differences in soil inorganic nutrients before and after a period of soil incubation in the absence of plants and litter, usually shows a discrepancy of much lower rates than plant nutrient uptake rates. In plots that had been pre-treated by 12 year of warming and fertilizer addition, we incubated soils together...

Pyrogenic carbon (PyC) is produced by the thermal decomposition of organic matter in the absence of oxygen (O). PyC affects nutrient availability, may enhance post-fire nitrogen (N) mineralization rates, and can be a significant carbon (C) pool in fire-prone ecosystems. Our objectives were to characterize PyC produced by wildfires and examine the influence that contrasting types of PyC have on ...

A Janthinobacterium sp. and an actinomycete, both capable of mineralizing 2,4-dinitrophenol (DNP), were used to construct a consortium to mineralize DNP in nonaxenic bench-scale sequencing batch reactors (SBRs). Average K(m) values for DNP mineralization by pure cultures of the Janthinobacterium sp. and the actinomycete were 0.01 and 0.13 mug/ml, respectively, and the average maximum specific g...

Clearing tropical forests of the Amazon Basin for pasture alters rates of soil nitrogen cycling. Previous studies have shown that rates of soil net N mineralization and net nitri®cation are lower in established pastures than in forests. We compared soil inorganic N concentrations, rates of net and gross mineralization and net and gross nitri®cation in a chronosequence and an experimental slash-...

The effects of select monoterpenes on nitrogen (N) mineralization and nitrification potentials were determined in four separate laboratory bioassays. The effect of increasing monoterpene addition was an initial reduction in NO3 -N production (nitrification inhibition), followed by a reduction in the sum of N N N-N and N -N (inhibition of net N mineralization and net immobilization at high monot...

Traits that permit successful invasions have often seemed idiosyncratic, and the key biological traits identified vary widely among species. This fundamentally limits our ability to determine the invasion potential of a species. However, ultimately, successful invaders must have positive growth rates that longer term result in higher biomass accumulation than competing established species. In m...

Steven D. Allison Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697, USA Correspondence: E-mail: [email protected] Abstract Extracellular enzymes allow microbes to acquire carbon and nutrients from complex molecules and catalyse the rate-limiting step in nutrient mineralization. Because the factors regulating enzyme production are poorly understood, I use...

Organic N mineralization by extracellular proteases affects inorganic N availability and loss. Soil Nmineralization is slowed by addition of purified protease inhibitors. We hypothesized that elevated concentrations of protease inhibitors in plant residues would reduce soil and plant residue N mineralization. Isogenic controls and transgenic plants of Brassica (Brassica napus L.), Japonicum ric...

Two studies were conducted for this research. First, a laboratory incubation to quantify broiler litter N mineralization with the following treatments: two soil moisture regimes, constant at 60% water fill pore space (WFPS) and fluctuating (60-30% WFPS), three soil types, Brooksville silty clay loam, Ruston sandy loam from Mississippi, and Catlin silt loam from Illinois. Second, a field incubat...

In the last 80 years, a number of mathematical models of different level of complexity have been developed to describe biogeochemical processes in soils, spanning spatial scales from few mm to thousands of km and temporal scales from hours to centuries. Most of these models are based on kinetic and stoichiometric laws that constrain elemental cycling within the soil and the nutrient and carbon ...