scholarly journals New estimates of direct N<sub>2</sub>O emissions from Chinese croplands from 1980 to 2007 using localized emission factors

2011 ◽  
Vol 8 (4) ◽  
pp. 6971-7006 ◽  
Author(s):  
B. Gao ◽  
X. T. Ju ◽  
Q. Zhang ◽  
P. Christie ◽  
F. S. Zhang
Keyword(s):  
North China ◽  
Agricultural Land ◽  
Original Data ◽  
Emission Factors ◽  
Paddy Fields ◽  
Nitrogen Fertilizers ◽  
Annual Rate ◽  
Anthropogenic Sources ◽  
Cube Root ◽  
N2o Emissions

Abstract. Nitrous oxide (N2O) is a long-lived greenhouse gas with a large radiation intensity and it is emitted mainly from agricultural land. Accurate estimates of total direct N2O emissions from croplands on a country scale are important for global budgets of anthropogenic sources of N2O emissions and for the development of effective mitigation strategies. The objectives of this study were to re-estimate direct N2O emissions using localized emission factors and a database of measurements from Chinese croplands. We obtained N2O emission factors for paddy fields (0.41 %) and uplands (1.05 %) from a normalization process through cube root transformation of the original data after comparing the results of normalization from the original values, logarithmic and cube root transformations because the frequency of the original data was not normally distributed. Direct N2O emissions from Chinese croplands from 1980 to 2007 were estimated using IPCC (2006) guidelines combined with separate localized emission factors for paddy fields and upland areas. Direct N2O emissions from paddy fields showed little change, increasing by 11 % with an annual rate of increase of 0.4 % from 29.8 Gg N2O-N in 1980 to 33.1 Gg N2O-N in 2007. In contrast, emissions from uplands changed dramatically, increasing by 296 % with an annual rate of 10.9 % from 64.4 Gg N2O-N in 1980 to 255.3 Gg N2O-N in 2007. Total direct N2O emissions from Chinese croplands increased by 206 % with an annual rate of 7.6 % from 94.2 Gg N2O-N in 1980 to 288.4 Gg N2O-N in 2007, and were determined mainly by upland emissions (accounting for 68.4–88.5 % of total emissions from 1980 to 2007). Synthetic nitrogen fertilizers played a major role in N2O emissions from agricultural land, and the magnitude of the contributions to total direct N2O emissions made by different amendments was synthetic N fertilizer > manure > straw, representing about 77, 16, and 6.5 % of total direct N2O emissions, respectively, between 2000 and 2007. The spatial pattern of total N2O emissions in 2007 in China shows that high direct N2O emissions occurred mainly in north China and in the Sichuan Basin in the southwest. The provinces with the highest emissions were Henan (32.6 Gg) and Shandong (29.1 Gg) and Tibet had the lowest (0.6 Gg). High direct N2O emissions per unit of arable land occurred mainly on the North China Plain and the southeast coast. The mean value nationally was 2.36 kg N ha−1, with 17 provinces above this, and with emissions of >4.0 kg N ha−1 in Beijing and in Jiangsu and Henan provinces.

scholarly journals New estimates of direct N<sub>2</sub>O emissions from Chinese croplands from 1980 to 2007 using localized emission factors

2011 ◽  
Vol 8 (10) ◽  
pp. 3011-3024 ◽  
Author(s):  
B. Gao ◽  
X. T. Ju ◽  
Q. Zhang ◽  
P. Christie ◽  
F. S. Zhang
Keyword(s):  
Agricultural Land ◽  
Original Data ◽  
Emission Factors ◽  
Paddy Fields ◽  
Annual Rate ◽  
Anthropogenic Sources ◽  
Cube Root ◽  
N2o Emissions ◽  
The North ◽  
Rate Of Increase

Abstract. Nitrous oxide (N2O) is a long-lived greenhouse gas with a large radiation intensity and it is emitted mainly from agricultural land. Accurate estimates of total direct N2O emissions from croplands on a country scale are important for global budgets of anthropogenic sources of N2O emissions and for the development of effective mitigation strategies. The objectives of this study were to re-estimate direct N2O emissions using localized emission factors and a database of measurements from Chinese croplands. We obtained N2O emission factors for paddy fields (0.41 ± 0.04%) and uplands (1.05 ± 0.02%) from a normalization process through cube root transformation of the original data. After comparing the results of normalization from the original values, Logarithmic and cube root transformations were used because the frequency of the original data was not normally distributed. Direct N2O emissions from Chinese croplands from 1980 to 2007 were estimated using IPCC (2006) guidelines combined with separate localized emission factors for paddy fields and upland areas. Direct N2O emissions from paddy fields showed little change, increasing by 10.5% with an annual rate of increase of 0.4% from 32.3 Gg N2O-N in 1980 to 35.7 Gg N2O-N in 2007. In contrast, emissions from uplands changed dramatically, increasing by 308% with an annual rate of 11% from 68.0 Gg N2O-N in 1980 to 278 Gg N2O-N in 2007. Total direct N2O emissions from Chinese croplands increased by 213% with an annual rate of 7.6% from 100 Gg N2O-N in 1980 to 313 Gg N2O-N in 2007, and were determined mainly by upland emissions (accounting for 67.8–88.6% of total emissions from 1980 to 2007). Synthetic N fertilizers played a major role in N2O emissions from agricultural land, and the magnitude of the contributions to total direct N2O emissions made by different amendments was synthetic N fertilizer > manure > straw, representing about 78, 15, and 6% of total direct N2O emissions, respectively, between 2000 and 2007. The spatial pattern of total N2O emissions in 2007 in China shows that high direct N2O emissions occurred mainly in the north and in the Sichuan Basin in the southwest. The provinces with the highest emissions were Henan (35.4 Gg) and Shandong (31.6 Gg) and Tibet had the lowest (0.65 Gg). High direct N2O emissions per unit of arable land occurred mainly on the North China Plain and the southeast coast. The mean value nationally was 2.52 kg N ha−1, with 18 provinces above this value and with emissions of >4.0 kg N ha−1 in Beijing, Tianjin and in Jiangsu, Shandong, Fujian and Henan provinces.

scholarly journals Modelling Methane and Nitrous Oxide Emissions from Rice Paddy Wetlands in India Using Artificial Neural Networks (ANNs)

Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2169 ◽  
Author(s):  
Tabassum Abbasi ◽  
Tasneem Abbasi ◽  
Chirchom Luithui ◽  
Shahid Abbas Abbasi
Keyword(s):  
Nitrous Oxide ◽  
Paddy Fields ◽  
Anthropogenic Sources ◽  
Nitrous Oxide Emissions ◽  
Soil Conditions ◽  
N2o Emissions ◽  
Ch4 Emissions ◽  
Artificial Neural ◽  
Ch4 And N2o

Paddy fields, which are shallow man-made wetlands, are estimated to be responsible for ~11% of the total methane emissions attributed to anthropogenic sources. The role of water use in driving these emissions, and the apportioning of the emissions to individual countries engaged in paddy cultivation, are aspects that have been mired in controversy and disagreement. This is largely due to the fact that methane (CH4) emissions not only change with the cultivar type but also regions, climate, soil type, soil conditions, manner of irrigation, type and quantity of fertilizer added—to name a few. The factors which can influence these aspects also encompass a wide range, and have origins in causes which can be physical, chemical, biological, and combinations of these. Exceedingly complex feedback mechanisms, exerting different magnitudes and types of influences on CH4 emissions under different conditions, are operative. Similar is the case of nitrous oxide (N2O); indeed, the present level of understanding of the factors which influence the quantum of its emission is still more patchy. This makes it difficult to even understand precisely the role of the myriad factors, less so model them. The challenge is made even more daunting by the fact that accurate and precise data on most of these aspects is lacking. This makes it nearly impossible to develop analytical models linking causes with effects vis a vis CH4 and N2O emissions from paddy fields. For situations like this the bioinspired artificial intelligence technique of artificial neural network (ANN), which can model a phenomenon on the basis of past data and without the explicit understanding of the mechanism phenomena, may prove useful. However, no such model for CH4 or N2O has been developed so far. Hence the present work was undertaken. It describes ANN-based models developed by us to predict CH4 and N2O emissions using soil characteristics, fertilizer inputs, and rice cultivar yield as inputs. Upon testing the predictive ability of the models with sets of data not used in model development, it was seen that there was excellent agreement between model forecasts and experimental findings, leading to correlations coefficients of 0.991 and 0.96, and root mean square error (RMSE) of 11.17 and 261.3, respectively, for CH4 and N2O emissions. Thus, the models can be used to estimate CH4 and N2O emissions from all those continuously flooded paddy wetlands for which data on total organic carbon, soil electrical conductivity, applied nitrogen, phosphorous and potassium, NPK, and grain yield is available.

scholarly journals Sustaining Rice Production through Biofertilization with N2-Fixing Cyanobacteria

2021 ◽  
Vol 11 (10) ◽  
pp. 4628
Author(s):  
Macarena Iniesta-Pallarés ◽  
Consolación Álvarez ◽  
Francisco M. Gordillo-Cantón ◽  
Carmen Ramírez-Moncayo ◽  
Pilar Alves-Martínez ◽  
...  
Keyword(s):  
Agricultural Practices ◽  
Vital Role ◽  
Rice Production ◽  
Point Of View ◽  
Paddy Fields ◽  
Nitrogen Fertilizers ◽  
Trophic Chain ◽  
Agricultural Practice ◽  
Biotechnological Potential

Current agricultural productivity depends on an exogenous nutrient supply to crops. This is of special relevance in cereal production, a fundamental part of the trophic chain that plays a vital role in the human diet. However, our agricultural practices entail highly detrimental side-effects from an environmental point of view. Long-term nitrogen fertilization in croplands results in degradation of soil, water, and air quality, producing eutrophication and subsequently contributing to global warming. In accordance with this, there is a biotechnological interest in using nitrogen-fixing microorganisms to enhance crop growth without adding chemically synthesized nitrogen fertilizers. This is particularly beneficial in paddy fields, where about 60% of the synthetic fertilizer that has been applied is dissolved in the water and washed away. In these agricultural systems, N2-fixing cyanobacteria show a promising biotechnological potential as biofertilizers, improving soil fertility while reducing the environmental impact of the agricultural practice. In the current study, Andalusian paddy fields have been explored to isolate N2-fixing cyanobacteria. These endogenous microorganisms have been subsequently re-introduced in a field trial in order to enhance rice production. Our results provide valuable insights regarding the use of an alternative natural source of nitrogen for rice production.

scholarly journals Czech Building Stock: Renovation Wave Scenarios and Potential for CO2 Savings until 2050

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2455
Author(s):  
Antonín Lupíšek ◽  
Tomáš Trubačík ◽  
Petr Holub
Keyword(s):  
Climate Change ◽  
Carbon Dioxide ◽  
Carbon Dioxide Emissions ◽  
Climate Change Mitigation ◽  
Emission Factors ◽  
Anthropogenic Sources ◽  
Building Stock ◽  
National Debate ◽  
Energy Consumptions ◽  
Change Mitigation

One of the major anthropogenic sources of greenhouse gases is the operation of building stock. Improving its energy efficiency has the potential to significantly contribute to achieving climate change mitigation targets. The purpose of this study was to roughly estimate such potential for the operation of the national building stock of Czechia to steer the national debate on the development of related national plans. The estimation is based on a simplified energy model of the Czech building stock that consists of sub-models of residential and nonresidential building stocks, for which their future energy consumptions, shares of energy carriers and sources, and emission factors were modeled in four scenarios. Uncertainties from the approximation of the emission factors were investigated in a sensitivity analysis. The results showed that the operation of the Czech building stock in 2016 totaled 36.9 Mt CO2, which represented 34.6% of the total national carbon dioxide emissions. The four building stock scenarios could produce reductions in the carbon dioxide emissions of between 28% and 93% by 2050, when also considering on-side production from photovoltaics. The implementation of the most ambitious scenario would represent a drop in national CO2 yearly emissions by 43.2% by 2050 (compared to 2016).

scholarly journals Groundwater N<sub>2</sub>O emission factors of nitrate-contaminated aquifers as derived from denitrification progress and N<sub>2</sub>O accumulation

2008 ◽  
Vol 5 (5) ◽  
pp. 1215-1226 ◽  
Author(s):  
D. Weymann ◽  
R. Well ◽  
H. Flessa ◽  
C. von der Heide ◽  
M. Deurer ◽  
...  
Keyword(s):  
Emission Factor ◽  
Noble Gas ◽  
N2o Emission ◽  
Emission Factors ◽  
N2o Emissions ◽  
Northern Germany ◽  
Stable Component ◽  
Sand And Gravel ◽  
First Time ◽  
Ipcc Default

Abstract. We investigated the dynamics of denitrification and nitrous oxide (N2O) accumulation in 4 nitrate (NO−3) contaminated denitrifying sand and gravel aquifers of northern Germany (Fuhrberg, Sulingen, Thülsfelde and Göttingen) to quantify their potential N2O emission and to evaluate existing concepts of N2O emission factors. Excess N2 – N2 produced by denitrification – was determined by using the argon (Ar) concentration in groundwater as a natural inert tracer, assuming that this noble gas functions as a stable component and does not change during denitrification. Furthermore, initial NO−3 concentrations (NO−3 that enters the groundwater) were derived from excess N2 and actual NO−3 concentrations in groundwater in order to determine potential indirect N2O emissions as a function of the N input. Median concentrations of N2O and excess N2 ranged from 3 to 89 μg N L−1 and from 3 to 10 mg N L−1, respectively. Reaction progress (RP) of denitrification was determined as the ratio between products (N2O-N + excess N2) and starting material (initial NO−3 concentration) of the process, characterizing the different stages of denitrification. N2O concentrations were lowest at RP close to 0 and RP close to 1 but relatively high at a RP between 0.2 and 0.6. For the first time, we report groundwater N2O emission factors consisting of the ratio between N2O-N and initial NO−3-N concentrations (EF1). In addition, we determined a groundwater emission factor (EF2) using a previous concept consisting of the ratio between N2O-N and actual NO−3-N concentrations. Depending on RP, EF(1) resulted in smaller values compared to EF(2), demonstrating (i) the relevance of NO−3 consumption and consequently (ii) the need to take initial NO−3-N concentrations into account. In general, both evaluated emission factors were highly variable within and among the aquifers. The site medians ranged between 0.00043–0.00438 for EF(1) and 0.00092–0.01801 for EF(2), respectively. For the aquifers of Fuhrberg and Sulingen, we found EF(1) median values which are close to the 2006 IPCC default value of 0.0025. In contrast, we determined significant lower EF values for the aquifers of Thülsfelde and Göttingen. Summing the results up, our study supports the substantial downward revision of the IPCC default EF5-g from 0.015 (1997) to 0.0025 (2006).

Perspectives on greenhouse gas emission estimates based on Australian wastewater treatment plant operating data

2013 ◽  
Vol 69 (3) ◽  
pp. 451-463 ◽  
Author(s):  
D. W. de Haas ◽  
C. Pepperell ◽  
J. Foley
Keyword(s):  
Wastewater Treatment ◽  
Steady State ◽  
Greenhouse Gas ◽  
Greenhouse Gas Emission ◽  
Electrical Power ◽  
Research Work ◽  
Treatment Plant ◽  
Emission Factors ◽  
N2o Emissions ◽  
Operating Data

Primary operating data were collected from forty-six wastewater treatment plants (WWTPs) located across three states within Australia. The size range of plants was indicatively from 500 to 900,000 person equivalents. Direct and indirect greenhouse gas emissions were calculated using a mass balance approach and default emission factors, based on Australia's National Greenhouse Energy Reporting (NGER) scheme and IPCC guidelines. A Monte Carlo-type combined uncertainty analysis was applied to the some of the key emission factors in order to study sensitivity. The results suggest that Scope 2 (indirect emissions due to electrical power purchased from the grid) dominate the emissions profile for most of the plants (indicatively half to three quarters of the average estimated total emissions). This is only offset for the relatively small number of plants (in this study) that have significant on-site power generation from biogas, or where the water utility purchases grid electricity generated from renewable sources. For plants with anaerobic digestion, inventory data issues around theoretical biogas generation, capture and measurement were sometimes encountered that can skew reportable emissions using the NGER methodology. Typically, nitrous oxide (N2O) emissions dominated the Scope 1 (direct) emissions. However, N2O still only accounted for approximately 10 to 37% of total emissions. This conservative estimate is based on the ‘default’ NGER steady-state emission factor, which amounts to 1% of nitrogen removed through biological nitrification-denitrification processing in the plant (or indicatively 0.7 to 0.8% of plant influent total nitrogen). Current research suggests that true N2O emissions may be much lower and certainly not steady-state. The results of this study help to place in context research work that is focused on direct emissions from WWTPs (including N2O, methane and carbon dioxide of non-biogenic origin). For example, whereas non-biogenic CO2 contributions are relatively minor, it appears that opportunities to reduce indirect emissions as a result of modest savings in power consumption are at least in the same order as those from reducing N2O emissions. To avoid potentially high reportable emissions under NGER guidelines, particularly for methane, the onus is placed on WWTP managers to ensure that accurate plant monitoring operating records are kept.

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

2012 ◽  
Vol 9 (8) ◽  
pp. 2989-3002 ◽  
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.

scholarly journals SVM ALGORITHM FOR PREDICTING RICE YIELDS

2020 ◽  
Vol 13 (2) ◽  
pp. 50-54
Author(s):  
Nur Nafi'iyah
Keyword(s):  
Agricultural Land ◽  
Rice Yield ◽  
Weather Conditions ◽  
Original Data ◽  
Research Process ◽  
Svm Algorithm ◽  
Food Shortages ◽  
Rice Yields ◽  
The Government ◽  
Linear Svm

Agriculture in Indonesia is highly dependent on reservoir irrigation water sources and rain. Because some agricultural land in Indonesia is rainfed. Plants in Indonesia rely on water from rain and irrigation. Weather conditions greatly affect the number of farmers' harvest. Farmers often experience crop failures due to changing weather. From data from the Central Statistics Agency, it is stated that the number of rice yields in 2019 decreased by 7.76% compared to 2018. In order to avoid rice imports and rice food shortages, a breakthrough is needed that can help the government in making policies. One of the breakthroughs is creating a rice yield prediction system. The research process consisted of collecting data via the web: https://www.pertanian.go.id/home/?show=page&act=view&id=61. The data shows the variables of province, year, land area, production. The total number of data is 170 rows, with a division of 130 lines for training, and 40 for testing. Furthermore, the data is processed and processed and normalized. The results of data processing are then trained and predicted with a linear SVM kernel. The results of SVM prediction with original data without normalization of MAPE 6635.53%, and RMSE 1094810.74. The results of SVM prediction with normalized data first, the MAPE value was 9427.714%, and RMSE 0.017.

scholarly journals Dampak Alih Fungsi Lahan Sawah Terhadap Kondisi Sosial Ekonomi Masyarakat Kecamatan Baitussalam Kabupaten Aceh Besar

2018 ◽  
Vol 3 (4) ◽  
pp. 219-226
Author(s):  
Yasfir Ma'arif ◽  
Teuku Fauzi ◽  
Safrida Safrida
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Agricultural Land ◽  
Paddy Fields ◽  
Selling Price ◽  
Land Conversion ◽  
Family Needs ◽  
A Value ◽  
The Social ◽  
Positive Results

Abstrak  Pertumbuhan  penduduk dan dinamika pembangunan telah menggeser pemanfaatan lahan yang akhirnya menimbulkan kompleksitas permasalahan lahan yang semula berfungsi sebagai media bercocok tanam (pertanian), berangsur-angsur berubah menjadi multifungsi pemanfaatan. Berubahnya pemanfaatan lahan pertanian ke non pertanian dapat disebut juga sebagai alih fungsi lahan. Kabupaten Aceh Besar adalah salah satu kabupaten yang terus menghadapi permasalahan alih fungsi lahan, khususnya lahan sawah. Alih fungsi lahan ini mengakibatkan luas lahan sawah di Aceh Besar terus menurun. Lahan yang paling banyak mengalami alih fungsi lahan adalah jenis lahan sawah yang menjadi lahan non pertanian. Penelitian ini bertujuan untuk mengidentifikasi faktor-faktor yang menyebabkan terjadinya alih fungsi lahan sawah dan mengidentifikasi dampak sosial dan ekonomi yang dialami petani mantan pemilik lahan akibat alih fungsi lahan sawah menjadi lahan non pertanian. Berdasarkan hasil regresi secara parsial dari analisis regresi faktor harga jual, kebutuhan hidup dan kondisi lahan berpengaruh nyata terhadap konversi lahan sawah di  Kecamatan Baitussalam Kabupaten Aceh Besar. Bedasarkan hasil regresi secara serempak dari hasil regresi didapatkan bahwa harga jual, kebutuhan hidup dan kondisi lahan secara serempak mempengaruhi konversi lahan sawah di Kecamatan Baitussalam Kabupaten Aceh Besar. Berdasarkan isu dampak sosial sebagai akibat alih fungsi lahan di lihat dari keinginan kondisi lama, meningkatkan rasa kerjasama dan kekeluargaan, serta kemampuan memenuhi kebutuhan keluarga mendapatkan hasil yang positif dengan nilai ≥ 50%. Berdasarkan isu dampak ekonomi sebagai akibat alih fungsi lahan di lihat dari peningkatan pendapatan mendapatkan hasil yang positif dengan nilai ≥ 50%.Impact Of Paddy Fields Function  On Community Socio-Economic Conditions Of Baitussalam District, Aceh Besar RegencyAbstract  Population growth and the dynamics of development have shifted land use which eventually led to the complexity of the problem of land that used to function as a farming medium (agriculture), gradually becoming a multifunctional use. Changing the use of agricultural land to non-agriculture can also be referred to as land conversion. Aceh Besar District is one of the districts that continues to face the problem of land conversion, especially rice fields. The conversion of this land function has caused the area of paddy fields in Aceh Besar to continue to decline. The land that has experienced the most land use change is the type of rice field that becomes non-agricultural land. This study aims to identify the factors that cause the conversion of paddy fields and identify the social and economic impacts experienced by farmers former landowners due to the conversion of paddy fields to non-agricultural land. Based on the partial regression results from the regression analysis, the factors of selling price, life necessity and land conditions have a significant effect on the conversion of paddy fields in Baitussalam District, Aceh Besar District. Based on the simultaneous regression results from the regression results, it was found that the selling price, life needs and land conditions simultaneously affected the conversion of paddy fields in Baitussalam District, Aceh Besar District. Based on the issue of social impacts as a result of land use change seen from the desires of the old conditions, increasing the sense of cooperation and kinship, as well as the ability to meet family needs get positive results with a value of ≥ 50%. Based on the issue of economic impact as a result of the transfer of land functions, it can be seen from the increase in income that has a positive result with a value of ≥ 50%.

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