scholarly journals Biochar, soil and land-use interactions that reduce nitrate leaching and N2O emissions: A meta-analysis

2019 ◽  
Vol 651 ◽  
pp. 2354-2364 ◽  
Author(s):  
Nils Borchard ◽  
Michael Schirrmann ◽  
Maria Luz Cayuela ◽  
Claudia Kammann ◽  
Nicole Wrage-Mönnig ◽  
...  
2015 ◽  
Vol 12 (23) ◽  
pp. 7299-7313 ◽  
Author(s):  
J. van Lent ◽  
K. Hergoualc'h ◽  
L. V. Verchot

Abstract. Deforestation and forest degradation in the tropics may substantially alter soil N-oxide emissions. It is particularly relevant to accurately quantify those changes to properly account for them in a REDD+ climate change mitigation scheme that provides financial incentives to reduce the emissions. With this study we provide updated land use (LU)-based emission rates (104 studies, 392 N2O and 111 NO case studies), we determine the trend and magnitude of flux changes with land-use change (LUC) using a meta-analysis approach (44 studies, 135 N2O and 37 NO cases) and evaluate biophysical drivers of N2O and NO emissions and emission changes for the tropics. The average N2O and NO emissions in intact upland tropical forest amounted to 2.0 ± 0.2 (n = 90) and 1.7 ± 0.5 (n = 36) kg N ha−1 yr−1, respectively. In agricultural soils annual N2O emissions were exponentially related to N fertilization rates and average water-filled pore space (WFPS) whereas in non-agricultural sites a Gaussian response to WFPS fit better with the observed NO and N2O emissions. The sum of soil N2O and NO fluxes and the ratio of N2O to NO increased exponentially and significantly with increasing nitrogen availability (expressed as NO3− / [NO3−+NH4+]) and WFPS, respectively; following the conceptual Hole-In-the-Pipe model. Nitrous and nitric oxide fluxes did not increase significantly overall as a result of LUC (Hedges's d of 0.11 ± 0.11 and 0.16 ± 0.19, respectively), however individual LUC trajectories or practices did. Nitrous oxide fluxes increased significantly after intact upland forest conversion to croplands (Hedges's d = 0.78 ± 0.24) and NO increased significantly following the conversion of low forest cover (secondary forest younger than 30 years, woodlands, shrublands) (Hedges's d of 0.44 ± 0.13). Forest conversion to fertilized systems significantly and highly raised both N2O and NO emission rates (Hedges's d of 1.03 ± 0.23 and 0.52 ± 0.09, respectively). Changes in nitrogen availability and WFPS were the main factors explaining changes in N2O emissions following LUC, therefore it is important that experimental designs monitor their spatio-temporal variation. Gaps in the literature on N oxide fluxes included geographical gaps (Africa, Oceania) and LU gaps (degraded forest, wetland (notably peat) forest, oil palm plantation and soy cultivation).


2015 ◽  
Vol 12 (15) ◽  
pp. 12783-12821 ◽  
Author(s):  
J. van Lent ◽  
K. Hergoualc'h ◽  
L. V. Verchot

Abstract. Deforestation and forest degradation in the tropics may substantially alter soil N-oxide emissions. It is particularly relevant to accurately quantify those changes to properly account for them in a REDD+ climate change mitigation scheme that provides financial incentives to reduce the emissions. With this study we provide updated land use (LU)-based emission rates (103 studies, 387 N2O and 111 NO case studies), determine the trend and magnitude of flux changes with land-use change (LUC) using a meta-analysis approach (43 studies, 132 N2O and 37 NO cases) and evaluate biophysical drivers of N2O and NO emissions and emission changes for the tropics. The average N2O and NO emissions in intact upland tropical forest amounted to 2.0 ± 0.2 (n = 88) and 1.7 ± 0.5 (n = 36) kg N ha−1 yr−1, respectively. In agricultural soils annual N2O emissions were exponentially related to N fertilization rates and average water-filled pore space (WFPS) whereas in non-agricultural sites a Gaussian response to WFPS fit better the observed NO and N2O emissions. The sum of soil N2O and NO fluxes and the ratio of N2O to NO increased exponentially and significantly with increasing nitrogen availability (expressed as NO3−/[NO3−+NH4+]) and WFPS, respectively; following the conceptual Hole-In-the-Pipe model. Nitrous and nitric oxide fluxes did not overall increase significantly as a result of LUC (Hedges's d of 0.11 ± 0.11 and 0.16 ± 0.19, respectively), however individual LUC trajectories or practices did. Nitrous oxide fluxes increased significantly after intact upland forest conversion to croplands (Hedges's d = 0.78 ± 0.24) and NO increased significantly following the conversion of low forest cover (secondary forest younger than 30 years, woodlands, shrublands) (Hedges's d of 0.44 ± 0.13). Forest conversion to fertilized systems significantly and highly raised both N2O and NO emission rates (Hedges's d of 1.03 ± 0.23 and 0.52 ± 0.09, respectively). Changes in nitrogen availability and WFPS were the main factors explaining changes in N2O emissions following LUC, therefore it is important that experimental designs monitor their spatio-temporal variation. Gaps in the literature on N oxide fluxes included geographical gaps (Africa, Oceania) and LU gaps (degraded forest, wetland (notably peat) forest, oil palm plantation and soy cultivation).


Ecosystems ◽  
2019 ◽  
Vol 22 (6) ◽  
pp. 1424-1443 ◽  
Author(s):  
M. D. McDaniel ◽  
D. Saha ◽  
M. G. Dumont ◽  
M. Hernández ◽  
M. A. Adams

2021 ◽  
Author(s):  
Katrin Karner ◽  
Hermine Mitter ◽  
Erwin Schmid

<p>In the semi-arid Seewinkel region in Austria, competing demands exist for land and water such as from agriculture, nature protection, tourism and settlements. In addition, water quality problems are prevalent due to nitrate leaching in groundwater in the region. Climate change likely will amplify existing resource demands and environmental impacts, imposing considerable challenges for adapting and regulating agriculture in the Seewinkel. Hence, compromises between competing policy objectives are needed. <br>The aim of this presentation is to assess efficient land and water management strategies considering several economic and agro-ecological policy objectives in the Seewinkel region in context of climate scenarios. A multi-objective optimization experiment was performed with an integrated modelling framework to compute agro-economic-ecological Pareto frontiers. The frontiers combine levels of (i) net benefits from agricultural production, (ii) groundwater extraction for agricultural irrigation, (iii) nitrate leaching from agricultural production, and (iv) topsoil organic carbon stocks. 30 stochastic realizations of three climate scenarios are considered for a future period of 31 years: WET, SIMILAR and DRY, which mainly differ regarding annual precipitation volumes. <br>Model results show that a 1% (20%) reduction of agricultural net benefits can lower groundwater extraction by 11-83% (61-100%) and nitrate leaching by 18-19% (49-53%) as well as increase topsoil organic carbon sequestration by 1% (5%) depending on the climate scenario. However, substantial changes in land use and management would be required. For instance, less groundwater extraction by 11-83% requires a 6-21% reduction of irrigated cropland, a 21-33% reduction of highly fertilized cropland, a 10-24% increase of grassland, and a 23-52% increase of abandoned land depending on the climate scenario. Less nitrate leaching by 18-19% (or higher topsoil organic carbon stocks by 1%) require that highly fertilized cropland decreases by 9-13% (4-7%), abandoned land increases by 5-9% (19-49%) and grassland either declines by 3% (14%) or increases by up to 5% (32%) depending on the climate scenario. In general, the share of grassland increases in the wetter climate scenario.<br>Overall, the analysis reveals that especially groundwater extraction and nitrate leaching can be reduced substantially for fairly small reduction in agricultural net benefits in all climate scenarios. 50% of maximum modelled improvements of agro-ecological objectives can be already achieved at 1-15% reductions of agricultural net benefit depending on climate scenarios. Thus, respective land use policies would allow considerable improvements of the agro-ecological performance at relatively low costs. However, improving the agro-ecological performance beyond a particular level can quickly lead to high reductions of agricultural net benefits, as depicted by the non-linear form of the Pareto frontiers. This is mainly related to large declines of cropland and increases in grassland or abandoned land. Furthermore, the results indicate that water management policies are less costly than climate change mitigation policies, at least in the Seewinkel region.</p>


2018 ◽  
Vol 626 ◽  
pp. 1394-1401 ◽  
Author(s):  
Di Sun ◽  
Hong Yang ◽  
Dexin Guan ◽  
Ming Yang ◽  
Jiabing Wu ◽  
...  

2012 ◽  
Vol 9 (8) ◽  
pp. 2989-3002 ◽  
Author(s):  
K. Schelde ◽  
P. Cellier ◽  
T. Bertolini ◽  
T. Dalgaard ◽  
T. Weidinger ◽  
...  

Abstract. Nitrous oxide (N2O) emissions from agricultural land are variable at the landscape scale due to variability in land use, management, soil type, and topography. A field experiment was carried out in a typical mixed farming landscape in Denmark, to investigate the main drivers of variations in N2O emissions, measured using static chambers. Measurements were made over a period of 20 months, and sampling was intensified during two weeks in spring 2009 when chambers were installed at ten locations or fields to cover different crops and topography and slurry was applied to three of the fields. N2O emissions during spring 2009 were relatively low, with maximum values below 20 ng N m−2 s−1. This applied to all land use types including winter grain crops, grasslands, meadows, and wetlands. Slurry application to wheat fields resulted in short-lived two-fold increases in emissions. The moderate N2O fluxes and their moderate response to slurry application were attributed to dry soil conditions due to the absence of rain during the four previous weeks. Cumulative annual emissions from two arable fields that were both fertilized with mineral fertilizer and manure were large (17 kg N2O-N ha−1 yr−1 and 5.5 kg N2O-N ha−1 yr−1) during the previous year when soil water conditions were favourable for N2O production during the first month following fertilizer application. Our findings confirm the importance of weather conditions as well as nitrogen management on N2O fluxes.


2019 ◽  
Vol 657 ◽  
pp. 96-102 ◽  
Author(s):  
Yingcheng Wang ◽  
Hao Ying ◽  
Yulong Yin ◽  
Huifang Zheng ◽  
Zhenling Cui

2001 ◽  
Vol 1 ◽  
pp. 312-319 ◽  
Author(s):  
Eric A. Davidson ◽  
Mercedes M.C. Bustamante ◽  
Alexandre de Siqueira Pinto

This paper reviews reports of nitrous oxide (N2O) and nitric oxide (NO) emissions from soils of the Amazon and Cerrado regions of Brazil. N2O is a stable greenhouse gas in the troposphere and participates in ozone-destroying reactions in the stratosphere, whereas NO participates in tropospheric photochemical reactions that produce ozone. Tropical forests and savannas are important sources of atmospheric N2O and NO, but rapid land use change could be affecting these soil emissions of N oxide gases. The five published estimates for annual emissions of N2O from soils of mature Amazonian forests are remarkably consistent, ranging from 1.4 to 2.4 kg N ha–1 year–1, with a mean of 2.0 kg N ha–1 year–1. Estimates of annual emissions of NO from Amazonian forests are also remarkably similar, ranging from 1.4 to 1.7 kg N ha–1 year–1, with a mean of 1.5 kg N ha–1 year–1. Although a doubling or tripling of N2O has been observed in some young (<2 years) cattle pastures relative to mature forests, most Amazonian pastures have lower emissions than the forests that they replace, indicating that forest-topasture conversion has, on balance, probably reduced regional emissions slightly (<10%). Secondary forests also have lower soil emissions than mature forests. The same patterns apply for NO emissions in Amazonia. At the only site in Cerrado where vegetation measurements have been made N2O emissions were below detection limits and NO emissions were modest (~0.4 kg N ha–1 year–1). Emissions of NO doubled after fire and increased by a factor of ten after wetting dry soil, but these pulses lasted only a few hours to days. As in Amazonian pastures, NO emissions appear to decline with pasture age. Detectable emissions of N2O have been measured in soybean and corn fields in the Cerrado region, but they are modest relative to fluxes measured in more humid tropical agricultural regions. No measurements of NO from agricultural soils in the Cerrado region have been made, but we speculate that they could be more important than N2O emissions in this relatively dry climate. While a consistent pattern is emerging from these studies in the Amazon region, far too few data exist for the Cerrado region to assess the impact of land use changes on N oxide emissions.


2016 ◽  
Author(s):  
Karen A. Thompson ◽  
Bill Deen ◽  
Kari E. Dunfield

Abstract. Dedicated biomass crops are required for future bioenergy production. However, the effects of large-scale land use change (LUC) from traditional annual crops, such as corn-soybean rotations to the perennial grasses (PGs) switchgrass and miscanthus on soil microbial community functioning is largely unknown. Specifically, ecologically significant denitrifying communities, which regulate N2O production and consumption in soils, may respond differently to LUC due to differences in carbon (C) and nitrogen (N) inputs between crop types and management systems. Our objective was to quantify bacterial denitrifying gene abundances as influenced by corn-soybean crop production compared to PG biomass production. A field trial was established in 2008 at the Elora Research Station in Ontario, Canada (n = 30), with miscanthus and switchgrass grown alongside corn-soybean rotations at different N rates (0 and 160 kg N ha-1) and biomass harvest dates within PG plots. Soil was collected on four dates from 2011–2012 and quantitative PCR was used to enumerate the total bacterial community (16S rRNA), and communities of bacterial denitrifiers by targeting nitrite reductase (nirS) and N2O reductase (nosZ) genes. Miscanthus produced significantly larger yields and supported larger nosZ denitrifying communities than corn-soybean rotations regardless of management, indicating large-scale LUC from corn-soybean to miscanthus may be suitable in variable Ontario conditions while potentially mitigating soil N2O emissions. Harvesting switchgrass in the spring decreased yields in N-fertilized plots, but did not affect gene abundances. Standing miscanthus overwinter resulted in higher 16S rRNA and nirS gene copies than in fall-harvested crops. However, the size of the total (16S rRA) and denitrifying communities changed differently over time and in response to LUC, indicating varying controls on these communities.


2018 ◽  
Author(s):  
Sissel Hansen ◽  
Randi Berland Frøseth ◽  
Maria Stenberg ◽  
Jarosław Stalenga ◽  
Jørgen E. Olesen ◽  
...  

Abstract. The emissions of nitrous oxide (N2O) and leaching of nitrate (NO3) have considerable negative impacts on climate and the environment. Although these environmental burdens are on average less per unit area in organic than in non-organic production, they are not smaller per unit of product. If organic farming is to maintain its goal of being an environmentally friendly production system, these emissions should be mitigated. We discuss the impact of possible triggers within organic arable farming practice for the risk of N2O emissions and NO3 leaching under European climatic conditions, and possible strategies to reduce these. Organic arable crop rotations can be characterised as diverse with frequent use of legumes, intercropping and organic fertilizers. The soil organic matter content and share of active organic matter, microbial and faunal activity are higher, soil structure better and yields lower, than in non-organic, arable crop rotations. Soil mineral nitrogen (SMN), N2O emissions and NO3 leaching are low under growing crops, but there is high potential for SMN accumulation and losses after crop termination or crop harvest. The risk for high N2O fluxes is increased when large amounts of herbage or organic fertilizers with readily available nitrogen (N) and carbon are incorporated into the soil or left on the surface. Freezing/thawing, drying/rewetting, compacted and/or wet soil and mixing with rotary harrow further enhance the risk for high N2O fluxes. These complex soil N dynamics mask the correlation between total N-input and N2O emissions from organic arable crop rotations. Incorporation of N rich plant residues or mechanical weeding followed by bare fallow increases the risk of nitrate leaching. In contrast, strategic use of deep-rooted crops with long growing seasons in the rotation reduces nitrate leaching risk. Reduced tillage can reduce N leaching if yields are maintained. Targeted treatment and use of herbage from green manures, crop residues and catch crops will increase N efficiency and reduce N2O emissions and NO3 leaching. Continued regular use of catch crops has the potential to reduce NO3 leaching but may enhance N2O emissions. A mixture of legumes and non-legumes (for instance grasses or cereals) are as efficient a catch crop as monocultures of non-legume species.


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