Nitrogen (N) availability is generally a limiting factor in highly acidic soil, which could be improved by amending these soils with alkaline materials. Soil extracellular enzyme activity (EEA) plays an important role N transformation; current knowledge gap how this occurs amended material. The present 45-day incubation experiment was designed to examine the effects of different amounts materia...

In the present research, effects of UV-B radiation (5.00 kJ·m−2) on chemical composition Azolla were investigated, and decomposition residues after radiation, nitrogen form, enzyme activity, bacterial community in paddy soil analyzed. Compared to natural light treatment, total content was significantly increased by 17.0% under treatment. returned grown light, rate cellulose, lignin, increased, ...

The prospect of using wastewater containing high loads of soluble organic matter (OM) for removing residual agricultural chemicals (fertilizer, pesticide, or herbicide) in farm soil, although promising, could have adverse effects on soil agricultural quality as a result of development of redoximorphic features in the soil profile. In this study, the effect of organic carbon supplement for biore...

A well-drained soil in N-fertilized dairy pasture was amended with particulate organic carbon (POC), either sawdust or coarse woody mulch, and sampled every 4 wk for a year to test the hypothesis that the addition of POC would increase denitrification activity by increasing the number of microsites where denitrification occurred. Overall mean denitrifying enzyme activity (DEA), on a gravimetric...

Nitrate-N (NO3−) effluents from agricultural ecosystems contributing to the degradation of water quality has become a serious environmental problem. A field experiment was conducted in 1996 and 1997 at St. Emmanuel, Que., Canada, to investigate the combined effects of water table management (WTM) and N fertilization on soil NO3− level and denitrification rates in the top soil layer (0–0.15 m). ...

After consumption of molecular oxygen, anaerobic microbial communities can use a continuum of alternative electron acceptors such as nitrate, manganese oxides, iron oxides, sulfate or CO2, with decreasing spans of available free energy. The electron transfer to insoluble metal oxides or to partner organisms such as methanogens may require the employment of electron carrier systems such as soil ...

Unsaturated zone N fate and transport were evaluated at four sites to identify the predominant pathways of N cycling: an almond [Prunus dulcis (Mill.) D.A. Webb] orchard and cornfield (Zea mays L.) in the lower Merced River study basin, California; and corn-soybean [Glycine max (L.) Merr.] rotations in study basins at Maple Creek, Nebraska, and at Morgan Creek, Maryland. We used inverse modelin...

Continuously rising atmospheric CO2 concentrations may lead to an increased transfer of organic C from plants to the soil through rhizodeposition and may affect the interaction between the C- and N-cycle. For instance, fumigation of soils with elevated CO2 (eCO2) concentrations (20% higher compared to current atmospheric concentrations) at the Giessen Free-Air Carbon Dioxide Enrichment (GiFACE)...

Nitrate is an important nitrogen source used by plants. Despite of the considerable variation in the amount of soil nitrate, plants keep cytosolic nitrate at a homeostatic controlled level. Here we describe a set of homeostatic controller motifs and their interaction that can maintain robust cytosolic nitrate homeostasis at fluctuating external nitrate concentrations and nitrate assimilation le...

The effect of the time of catch crop (field pea) incorporation [catch crop incorporated in the autumn (A) or in the spring (B) versus plots without a catch crop (C)] on the soil enzymes related to N transformation (urease - UR, protease - PRO, nitrate reductase - NR, arginine ammonification rate - AAR), the total N and mineral N as well as microbial biomass N (MBN) contents were investigated in...