The effects of elevated CO2 on nutrient cycling and selected belowground processes in the closed-canopy sweetgum plantation were assessed as part of a free-air CO2 enrichment (FACE) experiment at Oak Ridge, Tennessee. We hypothesized that nitrogen (N) constraints to growth response to elevated CO2 would be mitigated primarily by reduced tissue concentrations (resulting in increased biomass prod...

Boone, 1994). Despite these efforts, no single fractionation method has been shown to cleanly distinguish Nitrogen mineralization in irrigated lowland rice (Oryza sativa L.) SOM fractions based on their contributions to soil N soils is poorly predicted by total soil C and N. To improve its prediction, two humic acid fractions were extracted with NaOH from lowland mineralization across a wide ra...

The present investigation aimed to analyze the role of agroforestry systems in improving soil organic matter status, microbial activity and nitrogen availability with a view to effective management of the fertility of moderately alkaline soils. The study site was located at Karnal (29◦59′N, 76◦51′E, 250 m.s.l.) and the systems were characterized by a rice–berseem crop rotation; agrisilvicultura...

Intensification of droughts may aggravate the generally low capacity Mediterranean soils to store C and nutrients induce soil C:N:P stoichiometric imbalances through its impact on microbial biomass activity. Soil microbes nonetheless have different responses seasonal chronic drought, but very few studies investigate long-term drought periods under field conditions. This study compares effects v...

The dynamics and persistence of proteinaceous compounds during pedogenesis are major mechanisms of soil formation and determinants of organic matter (OM) turnover. We investigated the accumulation patterns of proteinogenic amino acids associated with minerals dominated by permanently negative charges (primary silica minerals) and related these to vegetative and belowground microbial succession ...

Increasing wildfire activity in Alaska's boreal forests has led to greater fuel-reduction management. Management has been implemented to reduce wildfire spread, but the ecological impacts of these practices are poorly known. We quantified the effects of hand-thinning and shearblading on above- and belowground stand characteristics, plant species composition, carbon (C) and nitrogen (N) pools, a...

Research on nitrogen (N) mineralization from organic residues is important to understand N cycling in soils. Here we review research on factors controlling net N mineralization as well as research on laboratory and field modeling efforts, with the objective of highlighting areas with opportunities for additional research. Among the factors controlling net N mineralization are organic compositio...

Turbic Cryosols (permafrost soils characterized by cryoturbation, i.e., by mixing of soil layers due to freezing and thawing) are widespread across the Arctic, and contain large amounts of poorly decomposed organic material buried in the subsoil. This cryoturbated organic matter exhibits retarded decomposition compared to organic material in the topsoil. Since soil organic matter (SOM) decompos...

the slow pool, with decadal turnover times, while 5% of the SOC is found in the rapidly cycling active fraction, Previous studies of no-till management in the Great Plains have with turnover times ranging from hours to months (Folshown that increased cropping intensity increased soil organic carbon (SOC). The objectives of this study were to (i) determine which soil lett, 2001; Shaffer et al., ...

Land use and soil management affects soil organic carbon (SOC) pools, chemical composition of stabilized SOC fractions, and the depth distribution. No-till production of corn (Zea mays L.) is a recommended management practice that reduces soil losses and increases SOC concentration, but the scientific knowledge of the mechanisms of C sequestration and protection is scanty. Therefore, the object...