The high temporal and spatial variability of agricultural nitrous oxide (N2O) emissions from soil makes their measurement at regional or national scales impractical. Accordingly, robust process-based models are needed. Several detailed biochemical process-basedmodels of N-gas emissions have been developed in recent years to provide site-specific and regional scale estimates of N2O emissions. Am...

This study aimed to assess the feasibility of predicting ranges in N2O emission with a boundary line approach using a few key driving factors. Intact soil cores (9 cm dia. and ~20 cm in depth) were collected from pasture, cereal cropping and sugarcane lands and incubated at various temperature and moisture conditions after addition of different forms of mineral nitrogen (NH4 and NO3). The pastu...

Ecological processes regulating soil carbon (C) and nitrogen (N) cycles are still poorly understood, especially in the world's largest agricultural frontier in Southern Amazonia. We analyzed soil parameters in samples from pristine rainforest and after land use change to pasture and crop fields, and correlated them with abundance of functional and phylogenetic marker genes (amoA, nirK, nirS, no...

A one year field trial was carried out on three adjacent unfertilised plots; an 18 year old grassland, a 14 year old established Miscanthus crop, and a 7 month old newly planted Miscanthus crop. Measurements of N2O, soil temperature, water filled pore space (WFPS), and inorganic nitrogen concentrations, were made every one to two weeks. Soil temperature, WFPS and NO3 and NH4 concentrations were...

Intensive livestock farms emit large concentrations of NH3, most of which is deposited very close to the source. The presence of trees enhances the deposition. Rates to downwind forests can exceed 40 kg N ha−1 y−1. The steep gradient in large NH3 concentrations of 34.3±20.4, 47.6±24.9, 21.7±16.8 μg NH3 m3 at the edge of a forest 15, 30 and 45 m downwind of the farm to near background concentrat...

18 Tea fields emit large amounts of nitrous oxide (N2O) to the atmosphere. Obtaining accurate 19 estimations of N2O emissions from tea-planted soils is challenging due to strong spatial 20 variability. We examined the spatial variability of N2O emissions from a red-soil tea field in 21 Hunan province, China, on 22 April 2012 (in a wet season) using 147 static mini chambers 22 approximately regu...

The source of N2O in terrestrial ecosystems has long been debated. Both nitrification and denitrification produce N2O but their relative importance remains uncertain. Here we apply site preference, SP (the difference in d15N between the central and outer N atom in N2O), to estimate the relative importance of bacterial denitrification (including nitrifier denitrification) to total N2O production...

The source of N2O in terrestrial ecosystems has long been debated. Both nitrification and denitrification produce N2O but their relative importance remains uncertain. Here we apply site preference, SP (the difference in d15N between the central and outer N atom in N2O), to estimate the relative importance of bacterial denitrification (including nitrifier denitrification) to total N2O production...

Soil tillage practices have a profound influence on the physical properties of soil and the greenhouse gas (GHG) balance. However there have been very few integrated studies on the emission of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) and soil biophysical and chemical characteristics under different soil management systems. We recorded a significantly higher net global warming...

To better understand the role of resource heterogeneity in decomposition and nitrous oxide (N2O) flux we systematically altered the degree of plant litter aggregation in soil, from uniformly distributed to highly aggregated. In laboratory incubations, we distributed 4.5 g of dried clover shoots (Trifolium pratense L.) in two particle sizes (1 or >5 mm) into 1, 3, or 9 patches versus uniformly d...