Comparing GHG Emissions from Drained Oil Palm and Recovering Tropical Peatland Forests in Malaysia

For agricultural purposes, the drainage and deforestation of Southeast Asian peatland resulted in high greenhouse gases’ (GHGs, e.g., CO2, N2O and CH4) emission. A peatland regenerating initiative, by rewetting and vegetation restoration, reflects evidence of subsequent forest recovery. In this study, we compared GHG emissions from three Malaysian tropical peatland systems under the following different land-use conditions: (i) drained oil palm plantation (OP), (ii) rewetting-restored forest (RF) and (iii) undrained natural forest (NF). Biweekly temporal measurements of CO2, CH4 and N2O fluxes were conducted using a closed-chamber method from July 2017 to December 2018, along with the continuous measurement of environmental variables and a one-time measurement of the soil physicochemical properties. The biweekly emission data were integrated to provide cumulative fluxes using the trapezoidal rule. Our results indicated that the changes in environmental conditions resulting from draining (OP) or rewetting historically drained peatland (RF) affected CH4 and N2O emissions more than CO2 emissions. The cumulative CH4 emission was significantly higher in the forested sites (RF and NF), which was linked to their significantly higher water table (WT) level (p < 0.05). Similarly, the high cumulative CO2 emission trends at the RF and OP sites indicated that the RF rewetting-restored peatland system continued to have high decomposition rates despite having a significantly higher WT than the OP (p < 0.05). The highest cumulative N2O emission at the drained-fertilized OP and rewetting-restored RF sites was linked to the available substrates for high decomposition (low C/N ratio) together with soil organic matter mineralization that provided inorganic nitrogen (N), enabling ideal conditions for microbial mediated N2O emissions. Overall, the measured peat properties did not vary significantly among the different land uses. However, the lower C/N ratio at the OP and the RF sites indicated higher decomposition rates in the drained and historically drained peat than the undrained natural peat (NF), which was associated with high cumulative CO2 and N2O emissions in our study.

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Greenhouse gas emissions from fen soils used for forage production in northern Germany

Biogeosciences ◽

10.5194/bg-13-5221-2016 ◽

2016 ◽

Vol 13 (18) ◽

pp. 5221-5244 ◽

Cited By ~ 15

Author(s):

Arne Poyda ◽

Thorsten Reinsch ◽

Christof Kluß ◽

Ralf Loges ◽

Friedhelm Taube

Keyword(s):

Ghg Emissions ◽

Farming Systems ◽

Forage Yield ◽

N2o Emissions ◽

Net Energy ◽

Forage Production ◽

Climatic Impact ◽

Northern Germany ◽

Ch4 And N2o

Abstract. A large share of peatlands in northwestern Germany is drained for agricultural purposes, thereby emitting high amounts of greenhouse gases (GHGs). In order to quantify the climatic impact of fen soils in dairy farming systems of northern Germany, GHG exchange and forage yield were determined on four experimental sites which differed in terms of management and drainage intensity: (a) rewetted and unutilized grassland (UG), (b) intensive and wet grassland (GW), (c) intensive and moist grassland (GM) and (d) arable forage cropping (AR). Net ecosystem exchange (NEE) of CO2 and fluxes of CH4 and N2O were measured using closed manual chambers. CH4 fluxes were significantly affected by groundwater level (GWL) and soil temperature, whereas N2O fluxes showed a significant relation to the amount of nitrate in top soil. Annual balances of all three gases, as well as the global warming potential (GWP), were significantly correlated to mean annual GWL. A 2-year mean GWP, combined from CO2–C eq. of NEE, CH4 and N2O emissions, as well as C input (slurry) and C output (harvest), was 3.8, 11.7, 17.7 and 17.3 Mg CO2–C eq. ha−1 a−1 for sites UG, GW, GM and AR, respectively (standard error (SE) 2.8, 1.2, 1.8, 2.6). Yield-related emissions for the three agricultural sites were 201, 248 and 269 kg CO2–C eq. (GJ net energy lactation; NEL)−1 for sites GW, GM and AR, respectively (SE 17, 9, 19). The carbon footprint of agricultural commodities grown on fen soils depended on long-term drainage intensity rather than type of management, but management and climate strongly influenced interannual on-site variability. However, arable forage production revealed a high uncertainty of yield and therefore was an unsuitable land use option. Lowest yield-related GHG emissions were achieved by a three-cut system of productive grassland swards in combination with a high GWL (long-term mean ≤  20 cm below the surface).

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The Evaluation of the Levels of Greenhouse Gases due to Activities Carried Out on a Livestock Farm

Revista de Chimie ◽

10.37358/rc.17.8.5747 ◽

2017 ◽

Vol 68 (8) ◽

pp. 1700-1702

Author(s):

Valeriu Danciulescu ◽

Andrei Vasile ◽

Luoana Florentina Pascu ◽

Bogdan Stanescu ◽

Ileana Nicolescu

Keyword(s):

Agricultural Sector ◽

Ghg Emissions ◽

Pollutant Dispersion ◽

Ambient Air ◽

N2o Emissions ◽

Measured Temperature ◽

Animal Shelters ◽

Livestock Sector ◽

Land Cultivation ◽

Ch4 And N2o

The paper presents the results of tests carried out on a Romanian farm with the purpose of assessing greenhouse gas (GHG) emissions specific to agricultural activities. GHG emissions from the agricultural sector come mainly from the livestock sector, manure management, land cultivation and fertilization. The tests carried out mainly focused on the CO2 , CH4 and N2O emissions generated from related manure storage activities as well as the emission level identified in animal shelters. For a correct interpretation of the results obtained, at the same time with the measurement of the GHG concentration, the weather parameters were measured: temperature, humidity and wind direction. The results obtained revealed the presence of these compounds in the air in the animal shelters and in the ambient air (CO2 and CH4) in concentrations that are in the range identified in similar studies around the world. The pollutant dispersion in the air leads to a reduction in the pollutant concentration with increasing distance from the observed source as well as the measurement points at 50, 100 and 500 m, that reaches values below the detection limit of the instrument for CH4 and N2O, whereas in the case of CO2 it reaches the level of the usual concentration in the ambient air.

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Emisi Gas Rumah Kaca dan Hasil Padi dari Cara Olah Tanah dan Pemberian Herbisida Di Lahan Sawah MK 2015

Jurnal Ilmu Lingkungan ◽

10.14710/jil.15.2.74-82 ◽

2018 ◽

Vol 15 (2) ◽

pp. 74 ◽

Cited By ~ 3

Author(s):

Miranti Ariani ◽

Hesti Yulianingrum ◽

Prihasto Setyanto

Keyword(s):

Rice Yield ◽

Ghg Emissions ◽

Conservation Agriculture ◽

Soil Disturbance ◽

N2o Emissions ◽

No Tillage ◽

Zero Tillage ◽

Deep Tillage ◽

Tillage Treatment ◽

Ch4 And N2o

Tanpa olah tanah (NT) telah banyak ditunjukkan sebagai praktik pengelolaan lahan sawah yang mampu mengurangi emisi gas rumah kaca (GRK) karena kemampuannya untuk menyerap karbon dalam tanah. Di luar negeri, bahkan juga oleh FAO, sekarang ini sedang banyak dikembangkan apa yang disebut dengan conservation agriculture, yaitu cara bercocok tanam dengan meminimalkan gangguan pada tanah atau dikenal juga dengan istilah No tillage/Zero Tillage (tanpa olah tanah). Penelitian ini bertujuan untuk memperoleh informasi emisi CH4 dan N2O dari lahan sawah di daerah tropis dengan perlakuan cara olah tanah. Percobaan disusun dengan rancangan faktorial acak kelompok 3 ulangan. Perlakuan yang dicobakan terdiri dari 2 faktor, yaitu faktor I cara olah tanah (1) Olah tanah sempurna, (2) tanpa olah tanah, dan faktor II adalah pemberian herbisida berupa (1) glifosat, (2) paraquat dan (3) tanpa herbisida. Jarak tanam adalah tegel 20 cm x 20 cm. Emisi CH4 pada MK 2015 yang terendah adalah pada perlakuan tanpa olah tanah (TOT) dan pemberian herbisida glifosat, yaitu sebesar 201 kg CH4/ha/musim dan yang tertinggi pada perlakuan olah tanah sempurna tanpa penambahan herbisida yaitu sebesar 353 kg CH4/ha/musim. Tanpa olah tanah menghasilkan rerata fluks harian CH4 yang lebih rendah dibanding perlakuan olah tanah sempurna. Emisi N2O terendah dihasilkan pada perlakuan olah tanah sempurna dengan penambahan herbisida glifosat, yaitu sebesar 0,34 kg N2O/ha/musim, dan tertinggi pada perlakuan tanpa olah tanah dengan penambahan herbisida paraquat yaitu sebesar 0,65 kg N2O/ha/musim. Hasil padi pada semua perlakuan menunjukkan nilai yang tidak berbeda nyata. Faktor emisi N2O langsung dari lahan padi sawah irigasi dengan perlakuan olah tanah dan herbisida berkisar antara 0,0008 – 0,0015 kg N2O-N/kg N dengan kisaran hasil padi sebesar 4,96 – 5,12 t/ha GKG. Secara total, yang dinyatakan dengan GWP, perlakuan tanpa olah tanah menimbulkan emisi GRK yang lebih kecil dibanding perlakuan olah tanah sempurnaKata kunci: olah tanah, herbisida, GWP, CH4, N2OABSTRACTNo-tillage (NT) management has been promoted as a practice capable of offsetting greenhouse gas (GHG) emissions because of its ability to sequester carbon in soils. Even FAO and many countries, are now being widely developed what so called conservation agriculture, on how to grow crops with minimize soil disturbance or also known as No tillage/Zero tillage. This study aimed to obtain information CH4 and N2O emissions and grain yield from rice fields in the tropics with tillage treatments. The experiment was arranged in a randomized factorial design with 3 replications. The treatments tested consisted of two factors, namely the first factor was tillage (1) deep tillage, (2) zero tillage, and the second factor is application of herbicide in the form of (1) glyphosate, (2) paraquat and (3) without herbicides, using tiles row spacing (20 x 20 cm). In DS 2015, the lowest CH4 emissions resulted from no-tillage (TOT) treatment combined with the application of glyphosate, which amounted to 201 kg CH4/ha/ season and the highest resulted from deep tillage treatment combined with no herbicide, which amounted to 353 kg CH4/ha/season. Daily CH4 fluxes from No tillage treatment are lower than those from deep tillage treatments. The lowest N2O emissions resulted from deep tillage treatments combined with the application of glyphosate, which amounted to 0.34 kg N2O/ha/season, and the highest resulted from no-tillage treatment combined with paraquat, which amounted to 0.65 kg N2O/ha/season. Rice yield were not significantly different among treatments. Direct N2O factors emissions from irrigated rice field applied tillage and herbicide treatments ranged from 0.0008 to 0.0015 kg N2O-N/kg N with rice yield range of 4.96 to 5.12 t/ha. In total, expressed by GWP, no tillage treatment resulted lower GHG emissions than deep tillage treatments.Keywords: tillage, herbicide, GWP, CH4, N2OCitation: Ariani, M., Yulianingrum, H. dan Setyanto, P. (2017). Emisi Gas Rumah Kaca dan Hasil Padi dari Cara Olah Tanah dan Pemberian Herbisida Di Lahan Sawah MK 2015. Jurnal Ilmu Lingkungan, 15(2), 74-82, doi:10.14710/jil.15.2.74-82

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Effects of nitrogen fertiliser and wheat straw application on CH4 and N2O emissions from a paddy rice field

Soil Research ◽

10.1071/sr07039 ◽

2007 ◽

Vol 45 (5) ◽

pp. 359 ◽

Cited By ~ 98

Author(s):

J. Ma ◽

X. L. Li ◽

H. Xu ◽

Y. Han ◽

Z. C. Cai ◽

...

Keyword(s):

Wheat Straw ◽

N2o Emission ◽

Application Rate ◽

N2o Emissions ◽

Ch4 Emission ◽

Nitrogen Fertiliser ◽

Paddy Rice Field ◽

Straw Incorporation ◽

Ch4 And N2o ◽

Fertiliser Application

A 3-year field experiment was conducted to study the effects of nitrogen fertiliser and straw application on CH4 and N2O emissions from a paddy rice field in China from 2003 to 2005. Three rates of nitrogen fertiliser (0, 200, and 270 kg N/ha) and 2 levels of wheat straw (0 and 3.75 × 103 kg/ha) were adopted in this experiment. The effect of nitrogen fertiliser application on CH4 emission seemed to be affected by application rate. Nitrogen fertiliser decreased CH4 emission relative to the control when applied at a rate of 200 kg N/ha, but the effect lessened if the application rate was further increased to a rate of 270 kg N/ha. The depressive effect of nitrogen fertiliser application on CH4 emissions from rice fields became more pronounced when wheat straw was also incorporated with fertiliser, compared with nitrogen fertiliser application alone. Straw incorporation significantly enhanced CH4 emission by 3–11 times (P < 0.05). Nitrogen fertiliser application increased N2O emission by 5–6 times when applied at a rate of 200 kg N/ha and by 10–14 times when applied at a rate of 270 kg N/ha. On average, straw incorporation tended to decrease N2O emission by about 30% significant (P > 0.05). More than 50% of seasonal total amount of N2O was emitted within 11 days after fertiliser application at panicle initiation. The global warming potential caused by both CH4 and N2O emissions was affected by nitrogen fertiliser application rate and significantly stimulated by wheat straw incorporation. The global warming potential was lowest when nitrogen fertiliser was applied at a rate of 200 kg N/ha.

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Food Security and Climate Stabilization: Can Cereal Production Systems Address Both?

Sustainability ◽

10.3390/su13031223 ◽

2021 ◽

Vol 13 (3) ◽

pp. 1223

Author(s):

Long Liang ◽

Bradley G. Ridoutt ◽

Liyuan Wang

Keyword(s):

Production Systems ◽

Ghg Emissions ◽

Soil Nutrient ◽

N2o Emissions ◽

World Population ◽

Emission Data ◽

Carbon Footprints ◽

Grain Yields ◽

Rotation System ◽

Cereal Production

There is abundant evidence that greenhouse gas (GHG) emissions of cereal products, expressed per ton of grain output, have been trending downward over the past 20 years. This has largely been achieved through agricultural intensification that has concurrently increased area-based GHG emissions. The challenge is for agriculture to increase grain yields to meet the food demands of a growing world population while also contributing to climate stabilization goals by reducing net GHG emissions. This study assessed yield-based and area-based emissions and efficiencies for the winter wheat–summer maize (WWSM) rotation system over the period 1996 to 2016 using long-term, longitudinal, farm survey data and detailed soil emission data in Huantai county, Shandong Province, which is an archetype for cereal production across the North China Plain (NCP). In this region, yields have been increasing over time. However, nitrogen fertilizer inputs have decreased substantially with greater adoption of soil nutrient testing. In addition, there has been widespread adoption of residue incorporation into soils. As such, since 2002, the product carbon footprints of wheat and maize have reduced by 25% and 30%, respectively. Meanwhile, area-based carbon footprints for the rotation system have reduced by around 15% over the same period. These findings demonstrate the importance of detailed assessment of soil N2O emissions and rates of soil organic carbon sequestration. They also show the potential for net reductions in GHG emissions in cropping without loss of grain yields.

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Greenhouse gas emissions from fen soils used for forage production in northern Germany

10.5194/bg-2015-635 ◽

2016 ◽

Author(s):

Arne Poyda ◽

Thorsten Reinsch ◽

Christof Kluß ◽

Ralf Loges ◽

Friedhelm Taube

Keyword(s):

Ghg Emissions ◽

Forage Yield ◽

N2o Emissions ◽

Net Energy ◽

Forage Production ◽

Climatic Impact ◽

Northern Germany ◽

Northwest Germany ◽

Ch4 And N2o

Abstract. A large share of peatlands in northwest Germany is drained for agricultural purposes, thereby emitting high amounts of greenhouse gases (GHG). In order to quantify the climatic impact of fen soils in dairy farming systems of northern Germany, GHG exchange and forage yield were determined on four experimental sites which differed in terms of management and drainage intensity: a) rewetted and unutilized grassland (UG), b) intensive and 'wet' grassland (GW), c) intensive and 'moist' grassland (GM) and d) arable forage cropping (AR). Net ecosystem exchange (NEE) of CO2 and fluxes of CH4 and N2O were measured using closed manual chambers. CH4 fluxes were significantly affected by groundwater level (GWL) and soil temperature, whereas N2O fluxes showed a significant relation to the amount of nitrate in top soil. Annual balances of all three gases, as well as the global warming potential (GWP), were significantly correlated to mean annual GWL. Two-year mean GWP, combined from C2-C-equivalents of NEE, CH4 and N2O emissions, as well as C input (slurry) and C output (harvest), was 3.8, 11.7, 17.7 and 17.3 Mg CO2-C-eq ha−1 a−1 for sites UG, GW, GM and AR, respectively (standard error (SE) 2.8, 1.2, 1.8, 2.6). Yield related emissions for the three agricultural sites were 201, 248 and 269 kg CO2-C-eq (GJ net energy lactation (NEL))−1 for sites GW, GM and AR, respectively (SE 17, 9, 19). The carbon footprint of agricultural commodities grown on fen soils depended on long-term drainage intensity rather than type of management, but management and climate strongly influenced interannual on-site variability. However, arable forage production revealed a high uncertainty of yield and therefore was an unsuitable land use option. Lowest yield related GHG emissions were achieved by a three-cut system of productive grassland swards in combination with a high GWL (long-term mean ≤ 20 cm below the surface).

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Modelling the influence of soil carbon on net greenhouse gas emissions from grazed pastures

Animal Production Science ◽

10.1071/an15508 ◽

2016 ◽

Vol 56 (3) ◽

pp. 585 ◽

Cited By ~ 6

Author(s):

Rachelle Meyer ◽

Brendan R. Cullen ◽

Richard J. Eckard

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Annual Variation ◽

Ghg Emissions ◽

C Sequestration ◽

N2o Emissions ◽

Soil C ◽

High Rainfall ◽

Sequestration Potential ◽

Ch4 And N2o

Sequestering carbon (C) in soil organic matter in grassland systems is often cited as a major opportunity to offset greenhouse gas (GHG) emissions. However, these systems are typically grazed by ruminants, leading to uncertainties in the net GHG balance that may be achieved. We used a pasture model to investigate the net balance between methane (CH4), nitrous oxide (N2O) and soil C in sheep-grazed pasture systems with two starting amounts of soil C. The net emissions were calculated for four soil types in two rainfall zones over three periods of 19 years. Because of greater pasture productivity, and consequent higher sheep stocking rates, high-rainfall sites were associated with greater GHG emissions that could not be offset by C sequestration. On these high-rainfall sites, the higher rate of soil organic carbon (SOC) increase on low-SOC soils offset an average of 45% of the livestock GHG emissions on the modelled chromosol and 32% on the modelled vertosol. The slow rate of SOC increase on the high-SOC soils only offset 2–4% of CH4 and N2O emissions on these high-rainfall sites. On low-rainfall sites, C sequestration in low-SOC soils more than offset livestock GHG emissions, whereas the modelled high-C soils offset 75–86% of CH4 and N2O emissions. Greater net emissions on high-C soils were due primarily to reduced sequestration potential and greater N2O emissions from nitrogen mineralisation and livestock urine. Annual variation in CH4 and N2O emissions was low, whereas annual SOC change showed high annual variation, which was more strongly correlated with weather variables on the low-rainfall sites compared with the high-rainfall sites. At low-soil C concentrations, with high sequestration potential, there is an initial mitigation benefit that can in some instances offset enteric CH4 and direct and indirect N2O emissions. However, as soil organic matter increases there is a trade-off between diminishing GHG offsets and increasing ecosystem services, including mineralisation and productivity benefits.

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Soil N2O Emissions under Different N Rates in an Oil Palm Plantation on Tropical Peatland

Agriculture ◽

10.3390/agriculture9100213 ◽

2019 ◽

Vol 9 (10) ◽

pp. 213 ◽

Cited By ~ 2

Author(s):

Auldry Chaddy ◽

Lulie Melling ◽

Kiwamu Ishikura ◽

Ryusuke Hatano

Keyword(s):

Oil Palm ◽

N Uptake ◽

N2o Emission ◽

N Fertilization ◽

Mitigation Strategies ◽

N2o Emissions ◽

N Availability ◽

Tropical Peatland ◽

Oil Palm Plantation ◽

N Rates

(1) Background: Nitrogen (N) fertilization on drained tropical peatland will likely stimulate peat decomposition and mineralization, enhancing N2O emission from the peat soil. (2) Methods: A field experiment was conducted to quantify the N2O emissions from soil in an oil palm plantation (Elaeis guineensis Jacq.) located in a tropical peatland in Sarawak, Malaysia, under different rates of N fertilizers. The study was conducted from January 2010 to December 2013 and resumed from January 2016 to December 2017. Nitrous oxide (N2O) flux was measured every month using a closed chamber method for four different N rates; control—without N (T1), 31.1 kg N ha−1 yr−1 (T2), 62.2 kg N ha−1 yr−1 (T3), and 124.3 kg N ha−1 yr−1 (T4); (3) Results: Application of the N fertilizer significantly increased annual cumulative N2O emissions for T4 only in the years 2010 (p = 0.017), 2011 (p = 0.012), 2012 (p = 0.007), and 2016 (p = 0.048). The highest average annual cumulative N2O emissions were recorded for T4 (41.5 ± 28.7 kg N ha−1 yr−1), followed by T3 (35.1 ± 25.7 kg N ha−1 yr−1), T1 (25.2 ± 17.8 kg N ha−1 yr−1), and T2 (25.1 ± 15.4 kg N ha−1 yr−1), indicating that the N rates of 62.2 kg N ha−1 yr−1 and 124.3 kg N ha−1 yr−1 increased the average annual cumulative N2O emissions by 39% and 65%, respectively, as compared to the control. The N fertilization had no significant effect on annual oil palm yield (p = 0.994). Alternating between low (deeper than −60 cm) and high groundwater level (GWL) (shallower than −60 cm) enhanced nitrification during low GWL, further supplying NO3− for denitrification in the high GWL, and contributing to higher N2O emissions in high GWL. The emissions of N2O ranged from 17 µg N m−2 hr−1 to 2447 µg N m−2 hr−1 and decreased when the water-filled pore space (WFPS) was between 70% and 96%, suggesting the occurrence of complete denitrification. A positive correlation between N2O emissions and NO3− at 70–96% WFPS indicated that denitrification increased with increased NO3− availability. Based on their standardized regression coefficients, the effect of GWL on N2O emissions increased with increased N rate (p < 0.001). Furthermore, it was found that annual oil palm yields negatively correlated with annual N2O emission and NO3− for all treatments. Both nitrification and denitrification increased with increased N availability, making both processes important sources of N2O in oil palm cultivation on tropical peatland.; and (4) Conclusions: To improve understanding of N2O mitigation strategies, further studies should consider plant N uptake on N2O emissions, at least until the completion of the planting.

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Characterizing Greenhouse Gas Emissions and Global Warming Potential of Wheat-Maize Cropping Systems in Response to Organic Amendments in Eutric Regosols, China

Atmosphere ◽

10.3390/atmos11060614 ◽

2020 ◽

Vol 11 (6) ◽

pp. 614

Author(s):

Hamidou Bah ◽

Xiao Ren ◽

Yanqiang Wang ◽

Jialiang Tang ◽

Bo Zhu

Keyword(s):

Global Warming ◽

Greenhouse Gas ◽

Global Warming Potential ◽

Cropping Systems ◽

Inorganic Nitrogen ◽

Ghg Emissions ◽

Organic Amendments ◽

Mineral Fertilizers ◽

N2o Emissions ◽

Pig Slurry

Characterizing greenhouse gas (GHG) emissions and global warming potential (GWP) has become a key step in the estimation of atmospheric GHG concentrations and their potential mitigation by cropland management. However, the impacts of organic amendments on GHG, GWP, and yield-scaled GWP on cropland have not been well documented. Here, we investigate four amendment treatments (no amendment, mineral fertilizers, and pig slurry or crop residue combined with mineral fertilizers) during a two-year field experiment in rain-fed wheat-maize cropping systems. The results show that the average annual cumulative methane (CH4) flux ranged from −2.60 to −2.97 kg·C·ha−1 while nitrous oxide (N2O) flux ranged from 0.44 to 4.58 kg·N·ha−1 across all four treatments. N2O emissions were significantly correlated with soil inorganic nitrogen (i.e., NH4+-N and NO3−-N), and soil dissolved organic carbon (DOC) during both the winter wheat and summer maize seasons. On average, organic amendments combined with mineral fertilizers increased the annual GWP by 26–74% and yield-scaled GWP by 19–71% compared to those under only mineral fertilizers application. This study indicates that the fertilization strategy for Eutric Regosols can shift from only mineral fertilizers to organic amendments combined with mineral fertilizers, which can help mitigate GHG emissions and GWP while maintaining crop yields.

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EMISIÓN DE METANO Y ÓXIDO NITROSO DE LOS SEDIMENTOS DE MANGLAR DE LA CIÉNAGA GRANDE DE SANTA MARTA, CARIBE COLOMBIANO

Bulletin of Marine and Coastal Research ◽

10.25268/bimc.invemar.2013.42.1.64 ◽

2016 ◽

Vol 42 (1) ◽

Author(s):

Julián Mauricio Betancourt Portela ◽

Juan Pablo Parra ◽

Carlos Villamil

Keyword(s):

Ghg Emissions ◽

N2o Emissions ◽

Mangrove Forests ◽

Agricultural Systems ◽

Release Rates ◽

Mangrove Sediments ◽

Ch4 And N2o ◽

Magdalena River ◽

Global Carbon

In Colombia there is little information on the role of mangroves in relation to greenhouse gases (GHG), their release rates under different environmental conditions, or their role in the global carbon cycle. For these reasons, in this study we evaluated the fluxes of CH4 and N2O, in four sectors of the Ciénaga Grande de Santa Marta (CGSM) with different degrees of conservation of mangrove forests, to determine their role as a source or sink of GHG. The fluxes were measured by the method of the static chambers and showed variations between 34.7-1179.7 and nd-31569.2 μg.m-2.h-1 for N2O and CH4, respectively, showing that mangrove sediments of CGSM are a net source of GHG, and furthermore are of the same magnitude as levels recorded world-wide in mangroves subjected to sewage input. Statistical analyses showed differences between sectors but not between climatic periods. N2O emissions were highest in the Agua Negras station (AN, 847.3 ± 265.7 μg.m-2.h-1), a locality in the process of natural regeneration with a direct influence from the Magdalena River and in Caño Dragado (CD, 438.7 ± 235.3 μg.m-2.h-1); while emissions were lower in the recovery sites Caño Grande (CG) and Rinconada (RIN), (104.7 ± 49.4 and 152.1 ± 36.0 μg.m-2.h-1, respectively). The highest CH4 emission was recorded in recovery sectors: CG and AN (9573.4 ± 8623.8 and 4328.2 ± 7569.5 μg.m-2.h-1, respectively). In terms of CO2-equivalent, N2O emissions account for over 50% of the total, and this has been documented for agricultural systems and constitutes evidence of deterioration of CD. A correlation analysis with environmental factors showed that N2O emissions vary inversely with salinity and positively with nitrites, suggesting production mainly via nitrification. Finally, a coarse estimation of GHG emissions per hectare indicated that, depending on the state of conservation or deterioration of the mangrove, emissions can vary from 10.2 to 27.1 tCO2-eq.ha-1.a-1.

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