Nitrous oxide fluxes from tropical peat with different disturbance history and management

Abstract. Tropical peatlands are one of the most important terrestrial ecosystems in terms of C stocks, and greenhouse gas emissions following disturbances such as deforestation, drainage or wildfire. Nitrous oxide dynamics in tropical peat systems is still poorly known. We quantified in situ N2O fluxes using closed chamber methods and compared them with CO2 and CH4 fluxes at sites representing differing land uses and land use change intensities, i.e. non-drained and drained selectively logged peat swamp forest, clear-felled drained recovering forest, deforested drained and burned peat, and agriculture on peat. The mean N2O flux rates (N2O-N ± SD, mg m−2 h−1) varied as follows: drained forest (0.112 ± 0.293) > agricultural peat in Kalampangan site (0.012 ± 0.026) > drained burned peat (0.011 ± 0.018) > agricultural peat in Marang site (0.0072 ± 0.028) > nondrained forest (0.0025 ± 0.053) > clear-felled drained recovering forest (0.0022 ± 0.021). Most N2O fluxes were < 0.05 mg N2O-N m−2 h−1 efflux, but some modest peat N2O influx readings were also detected. Many very high flux rates (deviating markedly from the majority of observations) occurred both spatially and over time, and further studies using continuous flux monitoring methods are needed to better understand the contribution of these to cumulative emissions. The widest N2O flux amplitude was detected in the drained forest with moderately drained peat (max. 2.312 and min. −0.043 mg N2O-N m−2 h−1. At the other sites the flux amplitude remained about 10 × smaller. Annual cumulative peat surface N2O emissions expressed as CO2 equivalents as a percentage of the total greenhouse gas (N2O, CO2 and CH4) emissions was at the highest 9.2 %, but typically ~1 %.

Download Full-text

Nitrous oxide fluxes from tropical peat with different disturbance history and management

Biogeosciences ◽

10.5194/bg-9-1337-2012 ◽

2012 ◽

Vol 9 (4) ◽

pp. 1337-1350 ◽

Cited By ~ 25

Author(s):

J. Jauhiainen ◽

H. Silvennoinen ◽

R. Hämäläinen ◽

K. Kusin ◽

S. Limin ◽

...

Keyword(s):

Nitrous Oxide ◽

Greenhouse Gas ◽

Nitrogen Availability ◽

N2o Emissions ◽

Forest Site ◽

N2o Flux ◽

Water Tables ◽

Tropical Peatlands ◽

Peat Surface ◽

N2o Fluxes

Abstract. Tropical peatlands are one of the most important terrestrial ecosystems in terms of impact on the atmospheric greenhouse gas composition. Currently, greenhouse gas emissions from tropical peatlands following disturbances due to deforestation, drainage or wildfire are substantial. We quantified in situ nitrous oxide (N2O) fluxes during both dry and wet seasons using a closed chamber method at sites that represented differing land uses and land use change intensities in Central Kalimantan, Indonesia. Cumulative N2O fluxes were compared with carbon dioxide (CO2) and methane (CH4) fluxes. The mean N2O flux rates (N2O-N &plusmn: SD, mg m−2 h−1) varied as follows: drained forest (0.112 ± 0.293) > agricultural peat at the Kalampangan site (0.012 ± 0.026) > drained burned peat (0.011 ± 0.018) > agricultural peat at the Marang site (0.0072 ± 0.028) > undrained forest (0.0025 ± 0.053) > clear-felled, drained, recovering forest (0.0022 ± 0.021). The widest N2O flux range was detected in the drained forest (max. 2.312 and min. −0.043 mg N2O-N m−2 h−1). At the other flux monitoring sites the flux ranges remained at about one tenth that of the drained forest site. The highest N2O emission rates were observed at water tables close to the peat surface where also the flux range was widest. Annual cumulative peat surface N2O emissions (expressed in CO2 equivalents as a percentage of the total greenhouse gas (N2O, CO2 and CH4) emissions) were 9.2 % at highest, but typically ~1 %. Average N2O fluxes and also the total of monitored GHG emissions were highest in drainage-affected forest which is characterized by continuous labile nitrogen availability from vegetation, and water tables typically below the surface.

Download Full-text

Nitrous oxide emission hotspots from organic soils in Europe

Biogeosciences Discussions ◽

10.5194/bgd-11-9135-2014 ◽

2014 ◽

Vol 11 (6) ◽

pp. 9135-9182

Author(s):

T. Leppelt ◽

R. Dechow ◽

S. Gebbert ◽

A. Freibauer ◽

A. Lohila ◽

...

Keyword(s):

Nitrous Oxide ◽

Greenhouse Gas ◽

Ph Value ◽

A Priori ◽

Emission Factors ◽

Organic Soils ◽

N2o Emissions ◽

The European Union ◽

Study Results ◽

N2o Fluxes

Abstract. Organic soils are a main source of direct nitrous oxide (N2O) emissions, an important greenhouse gas (GHG). Observed N2O emissions from organic soils are highly variable in space and time which causes high uncertainties in national emission inventories. Those uncertainties could be reduced when relating the upscaling process to a priori identified key drivers by using available N2O observations from plot scale in empirical approaches. We used the empirical fuzzy modelling approach MODE to identify main drivers for N2O and utilize them to predict the spatial emission pattern of European organic soils. We conducted a meta study with a total amount of 659 annual N2O measurements which was used to derive separate models for different land use types. We applied our models to available, spatial explicit input driver maps to upscale N2O emissions on European level and compared the inventory with recently published IPCC emission factors. The final statistical models explained up to 60% of the N2O variance. Our study results showed that cropland and grasslands emitted the highest N2O fluxes 0.98 ± 1.08 and 0.58 ± 1.03 g N2O-N m−2 a−1, respectively. High fluxes from cropland sites were mainly controlled by low soil pH-value and deep drained groundwater tables. Grassland hotspot emissions were strongly related to high amount of N-fertilizer inputs and warmer winter temperatures. In contrast N2O fluxes from natural peatlands were predominantly low (0.07±0.27 g N2O-N m−2 a−1) and we found no relationship with the tested drivers. The total inventory for direct N2O emissions from organic soils in Europe amount up to 149.5 Gg N2O-N a−1, which included also fluxes from forest and peat extraction sites and exceeds the inventory calculated by IPCC emission factors of 87.4 Gg N2O-N a−1. N2O emissions from organic soils represent up to 13% of total European N2O emissions reported in the European Union (EU) greenhouse gas inventory of 2011 from only 7% of the EU area. Thereby the model demonstrated that with up to 85% the major part of the inventory is induced by anthropogenic management, which shows the significant reduction potential by rewetting and extensivation of agricultural used peat soils.

Download Full-text

Magnitude and Edaphic Controls of Nitrous Oxide Fluxes in Natural Forests at Different Scales

Forests ◽

10.3390/f11030251 ◽

2020 ◽

Vol 11 (3) ◽

pp. 251 ◽

Cited By ~ 1

Author(s):

Kerou Zhang ◽

Haidong Wu ◽

Mingxu Li ◽

Zhongqing Yan ◽

Yong Li ◽

...

Keyword(s):

Nitrous Oxide ◽

Explanatory Power ◽

Regional Scale ◽

Global Scale ◽

N2o Emission ◽

N2o Emissions ◽

Control Analysis ◽

Edaphic Factors ◽

N2o Flux ◽

N2o Fluxes

Forest nitrous oxide (N2O) emission plays an important role in the greenhouse gas budget of forest ecosystems. However, spatial variability in N2O fluxes complicates the determination of key factors of N2O fluxes at different scales. Based on an updated database of N2O fluxes and the main edaphic factors of global forests, the magnitude of N2O fluxes from forests and the relationships between edaphic factors and N2O fluxes at different scales were analyzed. According to the results, the average annual N2O flux of the global forest was 142.91 ± 14.1 mg N m−2 year−1. The range of total forest estimated N2O emission was 4.45–4.69 Tg N in 2000. N2O fluxes from forests with different leaf traits (broadleaved and coniferous) have significant differences in magnitude, whereas the leaf habit (evergreen and deciduous) was an important characteristic reflecting different patterns of N2O seasonal variations. The main factors affecting N2O fluxes on the global scale were ammonium (NH4+) and nitrate (NO3−) concentrations. With an increasing scale (from the site scale to the regional scale to the global scale), the explanatory power of the five edaphic factors to N2O flux decreased gradually. In addition, the response curves of N2O flux to edaphic factors were diversified among different scales. At both the global and regional scales, soil hydrothermal condition (water filled pore space (WFPS) and soil temperature) might not be the main spatial regulation for N2O fluxes, whereas soil nutrient factors (particularly NO3− concentration) could contribute more on N2O flux spatial variations. The results of site-control analysis demonstrated that there were high spatial heterogeneity of the main N2O controls, showing N2O fluxes from low latitude forests being more likely associated with soil WFPS and temperature. Thus, our findings provide valuable insights into the regulatory edaphic factors underlying the variability in N2O emissions, when modeling at different scales.

Download Full-text

Nitrous oxide emission from highland winter wheat field after long-term fertilization

Biogeosciences Discussions ◽

10.5194/bgd-7-4539-2010 ◽

2010 ◽

Vol 7 (3) ◽

pp. 4539-4563 ◽

Cited By ~ 2

Author(s):

X. R. Wei ◽

M. D. Hao ◽

X. H. Xue ◽

P. Shi ◽

A. Wang ◽

...

Keyword(s):

Nitrous Oxide ◽

Winter Wheat ◽

N2o Emission ◽

N Fertilizer ◽

N2o Emissions ◽

N2o Flux ◽

Mineral N ◽

Wheat Field ◽

N2o Fluxes ◽

Nitrogen Phosphorus

Abstract. Nitrous oxide (N2O) is an important greenhouse gas. N2O emissions from soils vary with fertilization and cropping practices. The response of N2O emission to fertilization of agricultural soils plays an important role in global N2O emission. The objective of this study was to assess the seasonal pattern of N2O fluxes and the annual N2O emissions from a rain-fed winter wheat (Triticum aestivum L.) field in the Loess Plateau of China. A static flux chamber method was used to measure soil N2O fluxes from 2006 to 2008. The study included 5 treatments with 3 replications in a randomized complete block design. Prior to initiating N2O measurements the treatments had received the same fertilization for 22 years. The fertilizer treatments were unfertilized control (CK), manure (M), nitrogen (N), nitrogen + phosphorus (NP), and nitrogen + phosphorus + manure (NPM). Soil N2O fluxes in the highland winter wheat field were highly variable temporally and thus were fertilization dependent. The highest fluxes occurred in the warmer and wetter seasons. Relative to CK, M slightly increased N2O flux while N, NP and NPM treatments significantly increased N2O fluxes. The fertilizer induced increase in N2O flux occurred mainly in the first 30 days after fertilization. The increases were smaller in the relatively warm and dry year than in the cold and wet year. Combining phosphorous and/or manure with mineral N fertilizer partly offset the nitrogen fertilizer induced increase in N2O flux. N2O fluxes at the seedling stage were mainly controlled by nitrogen fertilization, while fluxes at other plant growth stages were influenced by plant and environmental conditions. The cumulative N2O emissions were always higher in the fertilized treatments than in the non-fertilized treatment (CK). Mineral and manure nitrogen fertilizer enhanced N2O emissions in wetter years compared to dryer years. Phosphorous fertilizer offset 0.78 and 1.98 kg N2O ha−1 increases, while manure + phosphorous offset 0.67 and 1.64 kg N2O ha−1 increases by N fertilizer for the two observation years. Our results suggested that the contribution of single N fertilizer on N2O emission was larger than that of NP and NPM and that manure and phosphorous had important roles in offsetting mineral N fertilizer induced N2O emissions. Relative to agricultural production and N2O emission, manure fertilization (M) should be recommended while single N fertilization (N) should be avoided for the highland winter wheat due to the higher biomass and grain yield and less N2O flux and annual emission in M than in N.

Download Full-text

Nitrous oxide emission from highland winter wheat field after long-term fertilization

Biogeosciences ◽

10.5194/bg-7-3301-2010 ◽

2010 ◽

Vol 7 (10) ◽

pp. 3301-3310 ◽

Cited By ~ 30

Author(s):

X. R. Wei ◽

M. D. Hao ◽

X. H. Xue ◽

P. Shi ◽

R. Horton ◽

...

Keyword(s):

Nitrous Oxide ◽

Winter Wheat ◽

N2o Emission ◽

N Fertilizer ◽

N2o Emissions ◽

N2o Flux ◽

Mineral N ◽

Wheat Field ◽

N2o Fluxes ◽

Nitrogen Phosphorus

Abstract. Nitrous oxide (N2O) is an important greenhouse gas. N2O emissions from soils vary with fertilization and cropping practices. The response of N2O emission to fertilization of agricultural soils plays an important role in global N2O emission. The objective of this study was to assess the seasonal pattern of N2O fluxes and the annual N2O emissions from a rain-fed winter wheat (Triticum aestivum L.) field in the Loess Plateau of China. A static flux chamber method was used to measure soil N2O fluxes from 2006 to 2008. The study included 5 treatments with 3 replications in a randomized complete block design. Prior to initiating N2O measurements the treatments had received the same fertilization for 22 years. The fertilizer treatments were unfertilized control (CK), manure (M), nitrogen (N), nitrogen + phosphorus (NP), and nitrogen + phosphorus + manure (NPM). Soil N2O fluxes in the highland winter wheat field were highly variable temporally and thus were fertilization dependent. The highest fluxes occurred in the warmer and wetter seasons. Relative to CK, m slightly increased N2O flux while N, NP and NPM treatments significantly increased N2O fluxes. The fertilizer induced increase in N2O flux occurred mainly in the first 30 days after fertilization. The increases were smaller in the relatively warm and dry year than in the cold and wet year. Combining phosphorous and/or manure with mineral N fertilizer partly offset the nitrogen fertilizer induced increase in N2O flux. N2O fluxes at the seedling stage were mainly controlled by nitrogen fertilization, while fluxes at other plant growth stages were influenced by plant and environmental conditions. The cumulative N2O emissions were always higher in the fertilized treatments than in the non-fertilized treatment (CK). Mineral and manure nitrogen fertilizer enhanced N2O emissions in wetter years compared to dryer years. Phosphorous fertilizer offset 0.50 and 1.26 kg N2O-N ha−1 increases, while manure + phosphorous offset 0.43 and 1.04 kg N2O-N ha−1 increases by N fertilizer for the two observation years. Our results suggested that the contribution of single N fertilizer on N2O emission was larger than that of NP and NPM and that manure and phosphorous had important roles in offsetting mineral N fertilizer induced N2O emissions. Relative to agricultural production and N2O emission, manure fertilization (M) should be recommended while single N fertilization (N) should be avoided for the highland winter wheat due to the higher biomass and grain yield and lower N2O flux and annual emission in m than in N.

Download Full-text

Nitrous oxide emission budgets and land-use-driven hotspots for organic soils in Europe

Biogeosciences ◽

10.5194/bg-11-6595-2014 ◽

2014 ◽

Vol 11 (23) ◽

pp. 6595-6612 ◽

Cited By ~ 40

Author(s):

T. Leppelt ◽

R. Dechow ◽

S. Gebbert ◽

A. Freibauer ◽

A. Lohila ◽

...

Keyword(s):

Land Use ◽

Nitrous Oxide ◽

Greenhouse Gas ◽

Ph Value ◽

Emission Factors ◽

Organic Soils ◽

N2o Emissions ◽

The European Union ◽

Study Results ◽

N2o Fluxes

Abstract. Organic soils are a main source of direct emissions of nitrous oxide (N2O), an important greenhouse gas (GHG). Observed N2O emissions from organic soils are highly variable in space and time, which causes high uncertainties in national emission inventories. Those uncertainties could be reduced when relating the upscaling process to a priori-identified key drivers by using available N2O observations from plot scale in empirical approaches. We used the empirical fuzzy modelling approach MODE to identify main drivers for N2O and utilize them to predict the spatial emission pattern of European organic soils. We conducted a meta-study with a total amount of 659 annual N2O measurements, which was used to derive separate models for different land use types. We applied our models to available, spatially explicit input driver maps to upscale N2O emissions at European level and compared the inventory with recently published IPCC emission factors. The final statistical models explained up to 60% of the N2O variance. Our study results showed that cropland and grasslands emitted the highest N2O fluxes 0.98 ± 1.08 and 0.58 ± 1.03 g N2O-N m−2 a−1, respectively. High fluxes from cropland sites were mainly controlled by low soil pH value and deep-drained groundwater tables. Grassland hotspot emissions were strongly related to high amount of N-fertilizer inputs and warmer winter temperatures. In contrast, N2O fluxes from natural peatlands were predominantly low (0.07 ± 0.27 g N2O-N m−2 a−1) and we found no relationship with the tested drivers. The total inventory for direct N2O emissions from organic soils in Europe amount up to 149.5 Gg N2O-N a−1, which also included fluxes from forest and peat extraction sites and exceeds the inventory calculated by IPCC emission factors of 87.4 Gg N2O-N a−1. N2O emissions from organic soils represent up to 13% of total European N2O emissions reported in the European Union (EU) greenhouse gas inventory of 2011 from only 7% of the EU area. Thereby the model demonstrated that the major part (85%) of the inventory is induced by anthropogenic management, which shows the significant reduction potential by rewetting and extensification of agriculturally used peat soils.

Download Full-text

Pineapple Residue Ash Reduces Carbon Dioxide and Nitrous Oxide Emissions in Pineapple Cultivation on Tropical Peat Soils at Saratok, Malaysia

Sustainability ◽

10.3390/su13031014 ◽

2021 ◽

Vol 13 (3) ◽

pp. 1014

Author(s):

Liza Nuriati Lim Kim Choo ◽

Osumanu Haruna Ahmed ◽

Nik Muhamad Nik Majid ◽

Zakry Fitri Abd Aziz

Keyword(s):

Carbon Dioxide ◽

Nitrous Oxide ◽

Peat Soil ◽

Nitrous Oxide Emissions ◽

N2o Emissions ◽

Peat Soils ◽

Closed Chamber ◽

Npk Fertilizers ◽

Npk Fertilizer ◽

Carbon Dioxide Co2

Burning pineapple residues on peat soils before pineapple replanting raises concerns on hazards of peat fires. A study was conducted to determine whether ash produced from pineapple residues could be used to minimize carbon dioxide (CO2) and nitrous oxide (N2O) emissions in cultivated tropical peatlands. The effects of pineapple residue ash fertilization on CO2 and N2O emissions from a peat soil grown with pineapple were determined using closed chamber method with the following treatments: (i) 25, 50, 70, and 100% of the suggested rate of pineapple residue ash + NPK fertilizer, (ii) NPK fertilizer, and (iii) peat soil only. Soils treated with pineapple residue ash (25%) decreased CO2 and N2O emissions relative to soils without ash due to adsorption of organic compounds, ammonium, and nitrate ions onto the charged surface of ash through hydrogen bonding. The ability of the ash to maintain higher soil pH during pineapple growth primarily contributed to low CO2 and N2O emissions. Co-application of pineapple residue ash and compound NPK fertilizer also improves soil ammonium and nitrate availability, and fruit quality of pineapples. Compound NPK fertilizers can be amended with pineapple residue ash to minimize CO2 and N2O emissions without reducing peat soil and pineapple productivity.

Download Full-text

Spatial and temporal variability of nitrous oxide emissions in a mixed farming landscape of Denmark

Biogeosciences ◽

10.5194/bg-9-2989-2012 ◽

2012 ◽

Vol 9 (8) ◽

pp. 2989-3002 ◽

Cited By ~ 18

Author(s):

K. Schelde ◽

P. Cellier ◽

T. Bertolini ◽

T. Dalgaard ◽

T. Weidinger ◽

...

Keyword(s):

Land Use ◽

Nitrous Oxide ◽

Agricultural Land ◽

Nitrous Oxide Emissions ◽

Soil Conditions ◽

Spatial And Temporal Variability ◽

N2o Emissions ◽

N2o Production ◽

Mixed Farming ◽

N2o Fluxes

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.

Download Full-text

Short-term effects of biogas digestate and cattle slurry application on greenhouse gas emissions from high organic carbon grasslands

Biogeosciences Discussions ◽

10.5194/bgd-11-5765-2014 ◽

2014 ◽

Vol 11 (4) ◽

pp. 5765-5809 ◽

Cited By ~ 4

Author(s):

T. Eickenscheidt ◽

A. Freibauer ◽

J. Heinichen ◽

J. Augustin ◽

M. Drösler

Keyword(s):

Organic Carbon ◽

Application Rate ◽

Organic Fertilizers ◽

Organic Soils ◽

N2o Emissions ◽

Cattle Slurry ◽

Closed Chamber ◽

Chamber Method ◽

Biogas Digestate ◽

N2o Fluxes

Abstract. The change in the German energy policy resulted in a strong development of biogas plants in Germany. As a consequence, huge amounts of nutrient rich residues remain from the fermentative process, which are used as organic fertilizers. Drained peatlands are increasingly used to satisfy the huge demand for fermentative substrates and the digestate is returned to the peatlands. However, drained organic soils are considered as hot spots for nitrous oxide (N2O) emissions and organic fertilization is additionally known to increase N2O emissions from managed grasslands. Our study addressed the questions (a) to what extent biogas digestate and cattle slurry application increase N2O, methane (CH4) and ammonia (NH3) fluxes as well as the mineral nitrogen use efficiency (NUEmin), and (b) how different soil organic matter contents (SOM) promote the production of N2O. The study was conducted at two areas within a grassland parcel, which differed in their soil organic carbon (SOC) contents. At each area (named Corg-medium and Corg-high) two sites were established, one was fertilized five times with biogas digestate and one with cattle slurry. For each treatment, fluxes of N2O and CH4 were measured over two years using the closed chamber method. For NH3 measurements we used the calibrated dynamic chamber method. On an annual basis the application of biogas digestate significantly enhanced the N2O fluxes compared to the application of cattle slurry and additionally increased the NUEmin. Furthermore, N2O fluxes from the Corg-high site significantly exceeded N2O fluxes from the Corg-medium sites. Annual cumulative emissions ranged from 0.91 ± 0.49 kg N ha−1 yr−1 to 3.14 ± 0.91 kg N ha−1 yr−1. Significantly different CH4 fluxes between the investigated treatments or the different soil types were not observed. Cumulative annual CH4 exchange rates varied between −0.21 ± 0.19 kg C ha−1 yr−1 and −1.06 ± 0.46 kg C ha−1 yr−1. Significantly higher NH3 losses from treatments fertilized with biogas digestate compared to those fertilized with cattle slurry were observed. The total NH3 losses following splash plate application were 18.17 kg N ha−1 for the digestate treatments and 3.48 kg N ha−1 for the slurry treatments (36% and 15% of applied NH4&plus;-N). The observed linear increase of 16 days cumulative N2O-N exchange or rather annual N2O emissions, due to a higher mean groundwater level and a higher application rate of NH4+-N, reveal the importance of site adapted N fertilization and the avoidance of N surpluses in Corg rich grasslands.

Download Full-text

Toward Modeling of Nitrous Oxide Emissions Following Precipitation, Urine, and Feces Deposition on Beef Cattle Feedyard Surfaces

Transactions of the ASABE ◽

10.13031/trans.13847 ◽

2020 ◽

Vol 63 (5) ◽

pp. 1371-1384

Author(s):

David B. Parker ◽

Kenneth D. Casey ◽

Kristin E. Hales ◽

Heidi M. Waldrip ◽

Byeng Min ◽

...

Keyword(s):

Nitrous Oxide ◽

Beef Cattle ◽

Greenhouse Gas ◽

Empirical Modeling ◽

Nitrous Oxide Emissions ◽

N2o Emissions ◽

List Type ◽

Equivalent Mass ◽

Fresh Feces ◽

Feces Deposition

HighlightsNitrous oxide is a greenhouse gas emitted from feedyard pen surfaces.Experiments were conducted to quantify nitrous oxide emissions from precipitation, urine, and feces.Nitrous oxide emissions from urine were about 30% of those from equal amounts of precipitation.Regression equations were developed for empirical modeling of emissions.Abstract. The amount of moisture deposited annually as urine (~320 mm) and feces (~95 mm) on typical semi-arid Texas beef cattle feedyard pens is considerable compared to the regional 470 mm mean annual precipitation. Precipitation is a primary factor affecting nitrous oxide (N2O) emissions from manure, but specific effects of urine and feces deposition are unknown. The objectives of this research were to (1) quantify N2O emissions following precipitation, urine, and feces deposition on a dry feedyard manure surface, and (2) develop equations for future empirical modeling of these emissions. Four experiments (Exp.) were conducted using recirculating flux chambers to quantify N2O emissions. Exp. 1 had treatments (TRT) of water (W), artificial urine (AU), and two urines collected from beef cattle fed high-quality forage (FU) or corn-based concentrate (CU). Exp. 2 had TRT of W, AU, and two feces levels (Fx1 and Fx2). In Exp. 3, N2O emissions were quantified from fresh feces pats. In Exp. 4, the effect of rainfall pH on N2O emissions was evaluated. Results from Exp. 1 showed that the W TRT had the highest mean cumulative N2O emission, while AU, FU, and CU ranged from 31.0% to 70.0% of W on an equal volume-applied basis. There was little correlation between N2O emissions and urine or water nitrogen (N) content. In Exp. 2, W again had the highest cumulative N2O. Cumulative N2O emissions expressed per unit of water added were 29.0, 3.8, 4.5, and 5.1 mg N kg-1 water added for W, AU, Fx1, and Fx2, respectively. In Exp. 3, fresh feces pats emitted no direct N2O, but N2O originated from the dry manure beneath the feces pat due to wetting. In Exp. 4, the highest N2O emissions occurred at pH 5 and pH 8, with lower emissions at pH 6 and pH 7. This research has shown that the addition of moisture to the pen surface from urine and feces contributes considerably to N2O emissions as compared to precipitation alone. The following recommendations were developed for future empirical modeling purposes: (1) N2O emissions from urine should be calculated as 32.7% of those emissions from the equivalent mass deposition of water, and (2) N2O emissions resulting from the mass of water in feces should be calculated as 15.6% of those emissions from the equivalent mass deposition of water. Keywords: Beef cattle, Greenhouse gas, Manure, Nitrous oxide, Urine, Precipitation.

Download Full-text