scholarly journals Effect of chemical and mechanical grassland conversion to cropland on soil mineral N dynamics and N2O emission

2020 ◽  
Vol 298 ◽  
pp. 106975
Author(s):  
Mirjam Helfrich ◽  
Greta Nicolay ◽  
Reinhard Well ◽  
Caroline Buchen-Tschiskale ◽  
René Dechow ◽  
...  
Keyword(s):  
N2o Emission ◽  
Soil Mineral N ◽  
Soil Mineral ◽  
Mineral N ◽  
N Dynamics ◽  
Grassland Conversion

scholarly journals Greenhouse gas (N2O and CH4) fluxes under nitrogen-fertilised dryland wheat and barley on subtropical Vertosols: risk, rainfall and alternatives

Soil Research ◽  
2016 ◽  
Vol 54 (5) ◽  
pp. 634 ◽  
Author(s):  
Graeme D. Schwenke ◽  
David F. Herridge ◽  
Clemens Scheer ◽  
David W. Rowlings ◽  
Bruce M. Haigh ◽  
...  
Keyword(s):  
N Uptake ◽  
Nitrification Inhibitor ◽  
N2o Emission ◽  
N2o Emissions ◽  
Soil Mineral N ◽  
Soil Mineral ◽  
Mineral N ◽  
Before And After ◽  
Ch4 Uptake ◽  
Crop N Uptake

The northern Australian grains industry relies on nitrogen (N) fertiliser to optimise yield and protein, but N fertiliser can increase soil fluxes of nitrous oxide (N2O) and methane (CH4). We measured soil N2O and CH4 fluxes associated with wheat (Triticum aestivum) and barley (Hordeum vulgare) using automated (Expts 1, 3) and manual chambers (Expts 2, 4, 5). Experiments were conducted on subtropical Vertosol soils fertilised with N rates of 0–160kgNha–1. In Expt 1 (2010), intense rainfall for a month before and after sowing elevated N2O emissions from N-fertilised (80kgNha–1) wheat, with 417gN2O-Nha–1 emitted compared with 80g N2O-Nha–1 for non-fertilised wheat. Once crop N uptake reduced soil mineral N, there was no further treatment difference in N2O. Expt 2 (2010) showed similar results, however, the reduced sampling frequency using manual chambers gave a lower cumulative N2O. By contrast, very low rainfall before and for several months after sowing Expt 3 (2011) resulted in no difference in N2O emissions between N-fertilised and non-fertilised barley. N2O emission factors were 0.42, 0.20 and –0.02 for Expts 1, 2 and 3, respectively. In Expts 4 and 5 (2011), N2O emissions increased with increasing rate of N fertiliser. Emissions were reduced by 45% when the N fertiliser was applied in a 50:50 split between sowing and mid-tillering, or by 70% when urea was applied with the nitrification inhibitor 3,4-dimethylpyrazole-phosphate. Methane fluxes were typically small and mostly negative in all experiments, especially in dry soils. Cumulative CH4 uptake ranged from 242 to 435g CH4-Cha–1year–1, with no effect of N fertiliser treatment. Considered in terms of CO2 equivalents, soil CH4 uptake offset 8–56% of soil N2O emissions, with larger offsets occurring in non-N-fertilised soils. The first few months from N fertiliser application to the period of rapid crop N uptake pose the main risk for N2O losses from rainfed cereal cropping on subtropical Vertosols, but the realisation of this risk is dependent on rainfall. Strategies that reduce the soil mineral N pool during this time can reduce the risk of N2O loss.

Linking N2O emission to soil mineral N as estimated by CO2 emission and soil C/N ratio

2009 ◽  
Vol 41 (12) ◽  
pp. 2593-2597 ◽  
Author(s):  
Zhijian Mu ◽  
Aiying Huang ◽  
Sonoko D. Kimura ◽  
Tao Jin ◽  
Shiqiang Wei ◽  
...  
Keyword(s):  
Co2 Emission ◽  
N2o Emission ◽  
Soil Mineral N ◽  
Soil Mineral ◽  
Mineral N ◽  
Soil C

Experimental and simulated soil mineral N dynamics for long-term tillage systems in northern France

2007 ◽  
Vol 94 (2) ◽  
pp. 441-456 ◽  
Author(s):  
K OORTS ◽  
F LAURENT ◽  
B MARY ◽  
P THIEBEAU ◽  
J LABREUCHE ◽  
...  
Keyword(s):  
Soil Mineral N ◽  
Soil Mineral ◽  
Tillage Systems ◽  
Mineral N ◽  
N Dynamics ◽  
Northern France

scholarly journals Soil mineral N dynamics beneath mixtures of leaves from legume and fruit trees in Central Amazonian multi-strata agroforests

2007 ◽  
Vol 37 (3) ◽  
pp. 313-320 ◽  
Author(s):  
Carol Melanie Schwendener ◽  
Johannes Lehmann ◽  
Marco Rondon ◽  
Elisa Wandelli ◽  
Erick Fernandes
Keyword(s):  
N Mineralization ◽  
Dominant Factor ◽  
Soil N ◽  
Soil Mineral N ◽  
Residue Quality ◽  
Soil Mineral ◽  
Mineral N ◽  
N Dynamics ◽  
Soil N Mineralization ◽  
N Release

Long term applications of leguminous green mulch could increase mineralizable nitrogen (N) beneath cupuaçu trees produced on the infertile acidic Ultisols and Oxisols of the Amazon Basin. However, low quality standing cupuaçu litter could interfere with green mulch N release and soil N mineralization. This study compared mineral N, total N, and microbial biomass N beneath cupuaçu trees grown in two different agroforestry systems, north of Manaus, Brazil, following seven years of different green mulch application rates. To test for net interactions between green mulch and cupuaçu litter, dried gliricidia and inga leaves were mixed with senescent cupuaçu leaves, surface applied to an Oxisol soil, and incubated in a greenhouse for 162 days. Leaf decomposition, N release and soil N mineralization were periodically measured in the mixed species litter treatments and compared to single species applications. The effect of legume biomass and cupuaçu litter on soil mineral N was additive implying that recommendations for green mulch applications to cupuaçu trees can be based on N dynamics of individual green mulch species. Results demonstrated that residue quality, not quantity, was the dominant factor affecting the rate of N release from leaves and soil N mineralization in a controlled environment. In the field, complex N cycling and other factors, including soil fauna, roots, and microclimatic effects, had a stronger influence on available soil N than residue quality.

Soil mineral N dynamics and N 2 O emissions following grassland renewal

2017 ◽  
Vol 246 ◽  
pp. 325-342 ◽  
Author(s):  
Caroline Buchen ◽  
Reinhard Well ◽  
Mirjam Helfrich ◽  
Roland Fuß ◽  
Manfred Kayser ◽  
...  
Keyword(s):  
Soil Mineral N ◽  
Soil Mineral ◽  
Mineral N ◽  
N Dynamics
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