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Carbon sequestration in soil from paddy straw derived biochar in India
... However, the use of straw is not necessarily a developed practice. According to D.P. Biswas [17] and A. Anand et al. [18], rice straw and sugarcane are well suited for creating fuel brackets, while on the contrary, J. Li et al. [19] showed that corn straw is, in many cases, simply burned by farmers directly in the fields. According to X. Zhang et al. [20], part of the straw is deliberately smeared into the soil by farmers using modern agricultural technologies to enrich it with carbon. ...
An important issue in the sustainable development of agricultural engineering today is the use of biogas plants for the production of electricity and heat from the organic waste of agricultural products and other low-quality products, which also contributes to the improvement of environmental safety. Traditional methods for assessing the apparent severity of the Roslynnytsia campaign based on statistics from the dominions proved to be ineffective. A hypothesis was proposed regarding the possibility of estimating the apparent biomass by averaging the indicators of depletion and assessing the CH4 and CO emissions based on satellite monitoring data. The aim of this work is to create a methodology for preparing a raw material base in united territorial communities to provide them with electrical and thermal energy using biogas plants. The achievement of this goal was based on solving the following tasks: monitoring biomethane emissions in the atmosphere as a result of rotting organic waste, and monitoring carbon monoxide emissions as a result of burning agricultural waste. Experimental studies were conducted using earth satellites on sites with geometric centers in the village of Gaishin in the Pereyaslav united territorial community, the city of Ovruch in the Zhytomyr region, the Oleshkovsky Sands National Park in the Kherson region (Ukraine), and the city of Jüterbog, which is located in the state of Brandenburg and is part of the Teltow-Fläming district (Germany). The most significant results of this research involve the methodology for the preparation of the raw material base in the united territorial communities for the production of biogas, based on indirect measurements of methane and carbon dioxide emissions using the process of remote sensing. Based on the use of the proposed scientific and methodological apparatus, it was found that the location of the territory with the center in the village of Gaishin has better prospects for collecting plant raw materials for biogas production than the location of the territorial district with the center in the city of Ovruch, the emissions in which are significantly lower. From March 2020–August 2023, a higher CO concentration was recorded on average by 0.0009 mol/m², which is explained precisely by crop growing practices. In addition, as a result of the conducted studies, for the considered emissions of methane and carbon monoxide for monitoring promising raw materials, carbon monoxide has the best prospects, since methane emissions can also be caused by anthropogenic factors. Thus, in the desert (Oleshkivskie Pisky), large methane emissions were recorded throughout the year which could not be explained by crop growing practices or the livestock industry.
Biochar, a carbon-rich material produced through the pyrolysis of organic biomass, has gained increasing attention as a sustainable soil amendment due to its potential to enhance soil health, improve agricultural productivity, and mitigate climate change. This review explores the multifaceted benefits of biochar, including its ability to sequester carbon for long periods, thereby reducing atmospheric greenhouse gases. Biochar’s unique properties, such as its porous structure, high cation exchange capacity, and nutrient retention capabilities, significantly enhance soil fertility, water-holding capacity, and microbial activity. These improvements increase crop resilience against drought, soil erosion, and nutrient loss, supporting climate-resilient agricultural systems. Additionally, biochar’s application can lower nitrous oxide and methane emissions from soils, further contributing to climate change mitigation. However, the effectiveness of biochar is influenced by factors such as feedstock type, pyrolysis conditions, and application rates. Understanding these variables is crucial for optimizing biochar's use in different soil types and environmental conditions.
Graphical Abstract
The burning of tonnes of paddy straw in the open field by the farmers in Punjab
has resulted in air pollutant emissions causing serious environmental and health
consequences. The paper presents a study on the utilization of the surplus paddy
straw in Punjab for biochar production by pyrolysis. From the study, 7.60 MT of
paddy straw are available in Punjab as surplus. The pyrolysis study was set at
four different operating temperature conditions 300, 400, 500 and 600oC with
biochar conversion efficiency of 57.87, 42.90, 37.19 and 35.63 % respectively.
The corresponding energy yield potential obtained from converted biochar were
77.51, 60.46, 56.25 and 55.59 PJ respectively. The analysis of air pollutant
emission from burning of paddy straw was further quantified in terms of CO2,
CH4, N2O, TPM, NMHC CO, NOx, SO2 and PM 2.5 emissions and the net GHG
CO2 emission was recorded as 8264.64 Gg/year.
Background : Biochar is a promising material in mitigating greenhouse gases (GHGs) emissions from paddy fields due to its remarkable structural properties. Rice husk biochar (RhB) and melaleuca biochar (MB) are amendment materials that could be used to potentially reduce emissions in the Vietnamese Mekong Delta (VMD). However, their effects on CH 4 and N 2 O emissions and soil under local water management and conventional rice cultivation have not been thoroughly investigated.
Methods : We conducted a field experiment using biochar additions to the topsoil layer (0-20 cm). Five treatments comprising 0 t ha ⁻¹ (CT0); 5 t ha ⁻¹ (RhB5) and 10 t ha ⁻¹ (RhB10), and 5 t ha ⁻¹ (MB5) and 10 t ha ⁻¹ (MB10) were designed plot-by-plot (20 m ² ) in triplicates.
Results : The results showed that biochar application from 5 to 10 t ha ⁻¹ significantly decreased cumulative CH 4 (24.2 – 28.0%, RhB; 22.0 – 14.1%, MB) and N 2 O (25.6 – 41.0%, RhB; 38.4 – 56.4%, MB) fluxes without a reduction in grain yield. Increasing the biochar application rate further did not decrease significantly total CH 4 and N 2 O fluxes but was seen to significantly reduce the global warming potential (GWP) and yield-scale GWP in the RhB treatments. Biochar application improved soil Eh but had no effects on soil pH. Whereas CH 4 flux correlated negatively with soil Eh ( P < 0.001; r ² = 0.552, RhB; P < 0.001; r ² = 0.502, MB). The soil physicochemical properties of bulk density, porosity, organic matter, and anaerobically mineralized N were significantly improved in biochar-amended treatments, while available P also slightly increased.
Conclusions : Biochar supplementation significantly reduced CH 4 and N 2 O fluxes and improved soil mineralization and physiochemical properties toward beneficial for rice plant. The results suggest that the optimal combination of biochar-application rates and effective water-irrigation techniques for soil types in the MD should be further studied in future works.
Different soil amendments are applied to improve soil properties and to achieve higher crop yield under drought conditions. The objective of the study was to investigate the role of biochar for the improvement of wheat (Triticum aestivum L.) growth and soil biochemical properties under drought conditions. A pot experiment with a completely randomized design was arranged with four replications in a wire house. Drought was imposed on two critical growth stages (tillering and grain filling) and biochar was applied to the soil 10 days before sowing at two different rates (28 g kg⁻¹ and 38 g kg⁻¹). Soil samples were collected to determine the soil properties including soil respiration and enzymatic parameters after crop harvesting. Results showed that water stress negatively affects all biochemical properties of the soil, while biochar amendments positively improved these properties. Application of biochar at 38 g kg⁻¹ provided significantly higher mineral nutrients, Bray P (18.72%), exchangeable-K (7.44%), soil carbon (11.86%), nitrogen mineralization (16.35%), and soil respiration (6.37%) as a result of increased microbial activities in comparison with the 28 g kg⁻¹ rate.
The application of biochar using inorganic fertilizer has been reported as being more efficient for the effective growth of soil microbes. However, there is no evidence that rice straw biochar (9 t ha-1) and different urea rates have had any effect on greenhouse gas (GHG) emissions of rice (Oryza sativa L.) production in tropical soils. Therefore, this study was conducted to investigate the effects of urea and the application of rice straw biochar (9 t ha-1) on yield and GHG emissions. Treatments were 150 kg N ha-1 (T1 control) and rice straw biochar (9 t ha-1) combined with 30, 60, 90, 120, and 150 kg N ha-1 (T2, T3, T4, T5, and T6, respectively). The experiment had a randomized complete block design with four replicates. Grain yield increased 20.7% in plants grown in T3, T4, and T5 compared with the control. Although all biochar treatments had increased cumulative CO2-C emissions compared with the control (5.0% to 7.6%), the cumulative CH4 emissions significantly decreased compared with the control (20% to 27%). Therefore, it could be suggested that T3 and T4 (9 t ha-1 rice straw biochar with 60 and 90 kg N ha-1) increase yield and reduce CH4 emissions relative to the control. Although this study was limited to a pot experiment with no nutrient leaching, the synergetic effect of rice straw biochar (9 t ha-1) and reduced urea rate is worth mentioning for acidic paddy soil; a field experiment is suggested to determine the long-term effect of biochar.
Alternate wetting and drying (AWD) is an important strategy that saves water and reduces greenhouse gases emission (GHG). Moreover, biochar (BC) has been also emerged as a promising approach to reduce GHG emissions. Hitherto, the mechanism lying behind reduction in nitrous oxide (N2O) emissions following the addition of BC are not clearly understood. Therefore, this field study was performed to assess the effects of different rates of rice straw biochar (RSB), i.e., control (0 RSB), 20 t RSB ha⁻¹, and 40 t RSB ha⁻¹ with no nitrogen (N) fertilizer (-N) and with N fertilizer (180 kg ha⁻¹: +N) on soil pH, soil N dynamics, microbial genes abundance, N2O emissions and performance of paddy. The experiment was conducted in two factors factorial design with three replications. Application of RSB enhanced the soil pH and NH4⁺ and decreased NO3⁻ therefore led to a significant reduction in the N2O emissions. However, the application of RSB (40 t ha⁻¹) significantly decreased the N2O emissions by +59% and +62% in comparison to control under -N and +N conditions. The increased soil pH augmented the abundance of nosZ and nirK genes, more following addition of 40 t RSB ha⁻¹ and therefore, leads to an appreciable reduction in the N2O compared to 20 t RSB and control under both -N and +N conditions. Additionally, 40 t RSB ha⁻¹ significantly enhanced the tillers production, kernel weight, paddy, and dry matter yield compared to control and 20 t RSB ha⁻¹ under -N and +N conditions. Conclusively, RSB application at the rate of 40 t ha⁻¹ could be a promising approach to reduce N2O emissions and increase the paddy yield.
Agricultural disturbance has significantly boosted soil greenhouse gas (GHG) emissions such as methane (CH4), carbon dioxide (CO2), and nitrous oxide (N2O). Biochar application is a potential option for regulating soil GHG emissions. However, the effects of biochar application on soil GHG emissions are variable among different environmental conditions. In this study, a dataset based on 129 published papers was used to quantify the effect sizes of biochar application on soil GHG emissions. Overall, biochar application significantly increased soil CH4 and CO2 emissions by an average of 15% and 16% but decreased soil N2O emissions by an average of 38%. The response ratio of biochar applications on soil GHG emissions was significantly different under various management strategies, biochar characteristics, and soil properties. The relative influence of biochar characteristics differed among soil GHG emissions, with the overall contribution of biochar characteristics to soil GHG emissions ranging from 29% (N2O) to 71% (CO2). Soil pH, the biochar C:N ratio, and the biochar application rate were the most influential variables on soil CH4, CO2, and N2O emissions, respectively. With biochar application, global warming potential (impact of the emission of different greenhouse gases on their radiative forcing by agricultural practices) and the intensity of greenhouse gas emissions (emission rate of a given pollutant relative to the intensity of a specific activity) significantly decreased, and crop yield greatly increased, with an average response ratio of 23%, 41%, and 21%, respectively. Our findings provide a scientific basis for reducing soil GHG emissions and increasing crop yield through biochar application.
This study aimed to explore a new way to address the burning of agricultural waste in China while achieving the sustainable use of it. Three agricultural wastes (Wheat straw, peanut shell, and rice husk) were slowly pyrolyzed into biochar, which was subsequently added to the soil to reduce CO2 emissions from the soil, and to improve soil fertility as well as microbial community structure. The biochar and raw materials were added to the soil and cultured under controlled conditions, and then the CO2 emissions produced from the mixing. At the same time, this study used pot experiments to determine the effects of biochar on tobacco soil physical and chemical properties and, therefore, the microbial communities of the soil. This study suggests that (1) biochar can effectively reduce soil CO2 emission rate. Compared with the control, peanut shell biochar could reduce the total CO2 emissions of soil by 33.41%, and the total CO2 emissions of wheat straw biochar treatment was 90.25% lower than that of wheat straw treatment. (2) The soil’s physical and chemical properties were improved. The soil bulk density of wheat straw biochar treatment kept 34.57% lower than that of the control as well as 21.15% lower than that of wheat straw treatment. The soil’s organic carbon of peanut shell biochar treatment was 87.62% more than that of peanut shell treatment. (3) Biochar changed soil microbial community structure. (4) Biochar is suitable for tobacco growth. Peanut husk biochar significantly increased the total biomass of tobacco, and wheat straw biochar significantly increased tobacco root vigor. This study concluded that processing Chinese agricultural waste into biochar and adding it to the soil instead of burning it directly would be an effective means to reduce greenhouse gas emissions, to improve soil, and to promote crop growth.
Biomass is a green energy source and is available in abundance. Biochar, a carbonrich material, derived from a wide range of biomass or organic waste through the thermochemical route. Biochar has received increasing attention because of its distinctive properties such as high carbon content, greater specific surface area, cation exchange capacity, nutrient retention capacity, and stable structure. This review paper extensively studies and reports the different pyrolysis processes, reactor types, the effect of process parameters on biochar yield, and its physicochemical properties, biochar activation methods and applications. It also details the status of the research and development (R&D) progress in biochar production through conventional and advanced technologies. The study found that unlike many products (at R &D stage) biochar has high potential to scale-up and has a direct impact on crop yield, water purification (for domestic and industrial application), alternative fuels (clean solid fuel for cook-stove), air purification, catalyst, biogas production, purification and storage, etc. Additionally, the paper lists the merits and challenges in the novel biochar applications like hydrogen storage, electrochemical capacitor and fuel cell technology, etc.
Available online: https://www.witpress.com/elibrary/sdp-volumes/13/8/2355
LUT University repository: http://urn.fi/URN:NBN:fi-fe2018122051400
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The prevailing large-scale use of chemical fertilizers has been affecting environmental degradation. a broken nutrient cycle has caused problems worldwide, which are related to the question of how to feed 9 billion people by 2050 while limiting human operations within the planetary boundaries. Indispensable nutrients, phosphorus (P) and nitrogen (N), often leak because of human activities, such as food production. efficient nutrient recycling can alleviate the problem. This study focuses on biofertilizers as a solution for the problem of a broken nutrient cycle. The study quantified the environmental benefits of using biofertilizers by calculating the carbon footprints of P and N in organic fertilizers by using the life cycle assessment (lCa) method on an existing biogas plant. The emissions from common production processes are allocated between products and co-products. however, whether a side flow is regarded as a co-product or waste is sometimes unclear. according to ISO 14040 and the greenhouse gas (GhG) protocol, if a substance does not have a value or the holder intends to dispose it, it can be regarded as waste. allocation of emission can be done according to parameters such as energy content, mass, or monetary value. The composted digestate was considered valuable; the allocation between biogas and nutrients was conducted according to the value of biogas and recycled fertilizers.
The calculated carbon footprints were 0.8 kgCO2,eq./kg for N and 1.8 kgCO2,eq./kg for P, whereas the carbon footprints for mineral fertilizers were 1.9–7.8 kgCO2,eq./kg for N and 2.3–4.5 kgCO2,eq./kg for P. The reduction of GhG emission in organic fertilizer production in comparison with the emission in mineral fertilizer production was on average 78% for N and 41% for P. On the other hand, inclusion of N2O and Ch4 emissions from composting increases the carbon footprints of nitrogen and phosphorus but there is high uncertainty included with these emissions. The value of nutrients in the biofertilizers is also uncertain but the interest towards using of them is increasing in Finland.
The study quantified the generation of surplus crop biomass at district level in three crop growing seasons (kharif, rabi and summer) for all the 662 districts of the country. A total of eleven crops, namely rice, wheat, maize, sugarcane, cotton, pulses (Gram & Tur) and oilseed (groundnut, mustard, soybean and castor) were selected for the study. The crops were selected based on their acreage and total production across the country. The total gross cultivated area of the country is about 195 million hectare. The area under cultivation for the selected eleven selected crops is 137 M ha i.e about 70% of gross cultivated area.
The assessment methodology involved four major steps: (1) compilation of area and production statistics of selected crops, (2) estimation of dry biomass generation, (3) development of surplus factors and quantification of surplus biomass generation, and (4) estimation of bioethanol production potential of surplus crop biomass. The crop biomass usage pattern by farmers for their own self as well as the biomass sold to others for industrial or any other usage was compiled to estimate the factors for surplus crop biomass generation. A novelty of this study is that it has developed crop specific season wise and district wise surplus factors and these factors were used to estimate the surplus crop biomass generated by the selected crops in the country. The study also estimated the district wise theoretical bio-ethanol production potential of surplus crop biomass generated by each crop in each season.
Of the total gross area under cultivation for the eleven selected crops, 72% area is accounted by rice, wheat, cotton and soybean crops only. These eleven crops generate about 683 million tons (MT) of total dry biomass in the three crop growing seasons. Out of this total annual crop biomass, 59% is generated during kharif season and 39% during rabi season. The remaining about 2% is generated during summer season. After different usages of this crop biomass by farmers, there is still some surplus left which can be utilized in a useful manner. The total annual surplus crop biomass is estimated to be approximately
178 MT which is about 26% of the total dry biomass generated. The season wise surplus biomass is highest in kharif season (72%) and the major crops contributing to surplus biomass are rice sugarcane cotton and soybean. In rabi season wheat, gram, rice and mustard are the crops contributing to the surplus crop biomass. The surplus biomass generated during summer is negligible. In kharif season the States of Punjab, Uttar Pradesh (U.P.), Maharashtra, Tamil Nadu (T.N.), Andhra Pradesh (A.P.), Karnataka, Telangana, Gujarat, Madhya Pradesh (M.P.), and Rajasthan generated high surplus crop biomass. Whereas in rabi season the States of Punjab, U.P., M.P., Maharashtra, Karnataka, Rajasthan, and Haryana generated high surplus crop biomass. The total annual bio-ethanol production potential from this surplus crop biomass generated in the country is 51.35 billion litres from eleven selected crops. The study provides district scale seasons wise crop area, crop dry biomass, surplus biomass and bioethanol maps for each of the eleven crops for use by different stakeholders.
It is expected that the outcome of this study shall help in developing an improved policy for 2nd generation biofuel by utilizing surplus crop residues. This will also help India in achieving the goal of bio-ethanol blending with gasoline.
Collection is still a major challenge in the supply chain of rice straw to prepare feedstock for further use. Straw needs to be gathered from the field and compressed into bales to make it compact and easy to transport. With the introduction of combine harvesters, the collection of rice straw has become harder and more costly. This created negative impacts on other businesses that use rice straw. Mechanization of rice straw collection was introduced in Vietnam in 2013 and it has rapidly developed since. Most of the rice straw produced in the dry season in the Mekong River Delta (MD) of Vietnam is collected for mushroom and for livestock fodder production or for use as mulching materials. In order to quantify the performance of the mechanical operation of rice straw collection, this study conducted an analysis of energy efficiency, greenhouse gas emission (GHGE), and cost of rice straw collection in the MD for five collection machines that operated on the same field, the same rice variety, and the same harvest time under a demonstration in the MD. With rice straw yield of 4.72t per ha, the collection machines operated at a capacity of 0.87–2.47t per hour. This mechanized operation can reduce labor requirement by 90%. Specific weight of baled straw was from 73 to 104kg per cubic meter, which is heavier by 50–100% than that of loose-form straw, at a moisture content of 12.4 (±1.21)% in wet basis. Total energy consumption, ranging from 351 to 588MJ per ton of straw collected, accounted for 10–17% of the total energy input using this collected straw for biogas production. Energy consumption from fossil fuels results in GHGE of 60–165kg CO2 equivalent per ton of collected straw. The cost of straw collection, which ranged from US18 per ton of straw in the MD, accounted for 10–20% of the total investment cost of biogas or mushroom production. This study illustrated the feasibility of the mechanization of rice straw collection for further processing. Despite the GHGE of this may cause through the consumption of fossil fuels, mechanized rice straw collection creates more benefits such as avoiding in-field burning, producing feedstock for further sustainable processing, and adding value to rice production.
Agricultural crop residue burning contribute towards the emission of greenhouse gases (CO 2 , N 2 O, CH 4), air pollutants (CO, NH 3 , NO x , SO 2 , NMHC, volatile organic compounds), particulates matter and smoke thereby posing threat to human health. In the present study a state-wise inventory of crop residue burnt in India and the air pollutants emitted was prepared using the InterGovernmental Panel on Climate Change (IPCC) national inventory preparation guidelines for the year 2008–09. Total amount of residue generated in 2008–09 was 620 Mt out of which ~15.9% residue was burnt on farm. Rice straw contributed 40% of the total residue burnt followed by wheat straw (22%) and sugarcane trash (20%). Burning of crop residues emitted 8.57 Mt of CO, 141.15 Mt of CO 2 , 0.037 Mt of SO x , 0.23 Mt of NO x , 0.12 Mt of NH 3 and 1.46 Mt NMVOC, 0.65 Mt of NMHC, 1.21 Mt of particulate matter for the year 2008–09. The variability of 21.46% in annual emission of air pollutants was observed from 1995 to 2009.
The first ever estimate of organic carbon (OC) stock in Indian soils was 24.3 Pg (1 Pg = 1015 g) based on 48 soil series taking into account of a few major soils. The present OC stock has been estimated as 63 Pg in the first 150 cm depth of soils. Soils with their geographical distribution through the country were used for computing soil organic carbon (SOC) stock in different depths in various physiographic regions. To sustain the quality and productivity of soils, the knowledge of OC in terms of its amount and quality in soils is essential. This has more relevance in soils of the tropical and subtropical parts of the globe, including the Indian sub-continent. SOC stock appears to be a single parameter that can help effectively in prioritizing the area for restoring soil health.
Accurate emission inventory (EI) is the foremost requirement for air quality management. Specifically, air quality modeling
requires EI with adequate spatial and temporal distributions. The development of such EI is always challenging, especially
for sporadic emission sources such as biomass open burning. The country of Thailand produces a large amount of various crops
annually, of which rough (unmilled) rice alone accounted for over 30 million tonnes in 2007. The crop residues are normally
burned in the field that generates large emissions of air pollutants and climate forcers. We present here an attempt at a
multipollutant EI for crop residue field burning in Thailand. Available country-specific and regional primary data were thoroughly
scrutinized to select the most realistic values for the best, low and high emission estimates. In the base year of 2007, the
best emission estimates in Gigagrams were as follows: particulate matter as PM2.5, 128; particulate matter as PM10, 143; sulfur dioxide (SO2), 4; carbon dioxide (CO2), 21,400; carbon monoxide (CO), 1,453; oxides of nitrogen (NOx), 42; ammonia (NH3), 59; methane (CH4), 132; non-methane volatile organic compounds (NMVOC), 108; elemental carbon (EC), 10; and organic carbon (OC), 54. Rice
straw burning was by far the largest contributor to the total emissions, especially during the dry season and in the central
part of the country. Only a limited number of EIs for crop residue open burning were reported for Thailand but with significant
discrepancies. Our best estimates were comparable but generally higher than other studies. Analysis for emission uncertainty,
taking into account possible variations in activity data and emission factors, shows considerable gaps between low and high
estimates. The difference between the low and high EI estimates for particulate matter and for particulate EC and OC varied
between −80% and +80% while those for CO2 and CO varied between −60% and +230%. Further, the crop production data of Thailand were used as a proxy to disaggregate
the emissions to obtain spatial (76 provinces) and temporal (monthly) distribution. The provincial emissions were also disaggregated
on a 0.1° × 0.1° grid net and to hourly profiles that can be directly used for dispersion modeling.
KeywordsCrop residue–Open burning–Air pollution–Gridded emission–Hourly emission–Thailand
An inventory of air pollutant emissions in Asia in the year 2000 is developed to support atmospheric modeling and analysis of observations taken during the TRACE-P experiment funded by the National Aeronautics and Space Administration (NASA) and the ACE-Asia experiment funded by the National Science Foundation (NSF) and the National Oceanic and Atmospheric Administration (NOAA). Emissions are estimated for all major anthropogenic sources, including biomass burning, in 64 regions of Asia. We estimate total Asian emissions as follows: 34.3 Tg SO2, 26.8 Tg NOx, 9870 Tg CO2, 279 Tg CO, 107 Tg CH4, 52.2 Tg NMVOC, 2.54 Tg black carbon (BC), 10.4 Tg organic carbon (OC), and 27.5 Tg NH3. In addition, NMVOC are speciated into 19 subcategories according to functional groups and reactivity. Thus we are able to identify the major source regions and types for many of the significant gaseous and particle emissions that influence pollutant concentrations in the vicinity of the TRACE-P and ACE-Asia field measurements. Emissions in China dominate the signature of pollutant concentrations in this region, so special emphasis has been placed on the development of emission estimates for China. China's emissions are determined to be as follows: 20.4 Tg SO2, 11.4 Tg NOx, 3820 Tg CO2, 116 Tg CO, 38.4 Tg CH4, 17.4 Tg NMVOC, 1.05 Tg BC, 3.4 Tg OC, and 13.6 Tg NH3. Emissions are gridded at a variety of spatial resolutions from 1° × 1° to 30 s × 30 s, using the exact locations of large point sources and surrogate GIS distributions of urban and rural population, road networks, landcover, ship lanes, etc. The gridded emission estimates have been used as inputs to atmospheric simulation models and have proven to be generally robust in comparison with field observations, though there is reason to think that emissions of CO and possibly BC may be underestimated. Monthly emission estimates for China are developed for each species to aid TRACE-P and ACE-Asia data interpretation. During the observation period of March/April, emissions are roughly at their average values (one twelfth of annual). Uncertainties in the emission estimates, measured as 95% confidence intervals, range from a low of ±16% for SO2 to a high of ±450% for OC.
Major crops subject to field burning of crop residue (FBCR) generated an estimated 284 Tg of residue in India, of which 40% was contributed by wheat in the year 2000. About 7.5% of this total generated wheat straw was subjected to on-site burning, that is expected to emit large amounts of trace gases and particulate matter (PM) to the atmosphere, whose country-specific estimates and emission factors (EFs) are presently not available. An in situ experiment for wheat straw burning was undertaken for developing India specific EFs. The EFs of CO2, CH4, CO, N2 O, NOx, NO and NO2 were found to be 1787 ± 36, 3.6 ± 2.7, 28.1 ± 20.1, 0.74 ± 0.46, 1.70 ± 1.68, 0.78 ± 0.71 and 0.56 ± 0.47 g kg- 1, whereas those for organic carbon (OC), black carbon (BC) and total carbon (TC) were 0.3 ± 0.1, 0.2 ± 0.1, and 0.5 ± 0.2 g kg- 1, respectively. Although these EFs have been generated from a single field experiment nevertheless they address important information gap on FBCR in the region. Further, the total emissions of CH4, CO2, CO, N2 O, NOx, NO, NO2, OC, BC and TC from wheat straw burning in India for the year 2000 was estimated as 68 ± 51, 34435 ± 682, 541 ± 387, 14 ± 9, 33 ± 32, 15 ± 14, 11 ± 9, 6 ± 2, 3 ± 1 and 10 ± 4 Gg, respectively.
Post COP-15, the push is to reduce coal dependence for electricity generation and GHG emissions from the national electrical grid. Phasing out coal-based thermal power plants (TPPs) does not favour India's economic and social interests. Therefore, it becomes imperative to make coal-based power plants clean. Biochar derived from crop residues has been considered a clean fuel and an economical substitute for coal. The present study investigated the biochar potential of crop residues from rice, wheat, maize and sugarcane cultivation, accounting for 89% of total agro production, for coal replacement in TPPs using primary & secondary data and ArcGIS for mapping agro-residue collection point and TPP. Results show that biochar produced from the identified agro resources in the temperature range of 400 °C–500 °C are suitable for cofiring with coal. 121 MT surplus residues of the selected crops could produce 40 MT biochar having 90 TWh electricity generation potential. Biochar produced from surplus residues is equivalent to 69 MT of coal, about 11% of coal consumed annually in Indian TPPs. Also, biochar cofiring could reduce 165 MT annual CO2 emissions from coal-burning in TPPs, about 14% of CO2 emissions by the energy sector and 7% of overall CO2 emissions by India. Techno-economic analysis showed that the infrastructure development & operation cost for the biochar conversion facility is in the range of 2–3 USD/MWh, which is significantly lower than that of the new biomass to electricity generation facility (43–53 USD/MWh). The results would provide baseline data for policy decisions to avoid net GHG emissions from TPPs, and site identification for additional infrastructure to develop alternative clean fuels for India's coal-based TPPs.
Crop residue management remains a major problem in the Indian agriculture sector. The in-situ firing of crop residues has been linked to air pollution, global warming, soil fertility decline and others. Biochar conversion through slow pyrolysis could be one of the techniques for the safe disposal of crop residues. 212.04 ± 44.27 MT biochar could be produced from 517.82 MT crop residues in India. Biochar conversion of crop residues can address agriculture production, safe drinking water, livelihood, energy security and environmental protection. Soil amendment with biochar sequestrate about 376.11 ± 78.52 MT CO2e carbon and help retain about 1.66 ± 0.46 MT of soil nutrients. Also, crop residues derived biochar has an estimated market value of approximately $500 billion in India. Biochar applications in the cosmetics, pharma and chemical industries offer market and employment opportunities. This review discusses the impact of in-situ crop residue burning and its biochar conversion through slow pyrolysis as part of sustainable crop residue management. Also, biochar applications and socio-economic aspects of crop residues – biochar system has been deliberated to fulfil several sustainable development goals (SDGs).
Environment-friendly rice and wheat straw management in the Indian states of Punjab and Haryana have been a significant challenge. Farmers have adopted in-situ burning of crop residues as it is almost out of no pocket expense. However, this practice amounts to releasing 42.32 MT hazardous pollutants and GHGs into the atmosphere, which has an estimated 58.62 MT CO2e GWP. The present study considered biochar conversion of surplus rice and wheat straw through slow pyrolysis to investigate biochar compatibility for cofiring with coal in power plants. Rice straw derived biochar produced at 400 °C, and wheat straw derived biochar produced at 500 °C were found most suitable for cofiring and electricity generation. It was estimated that about 10.53 MT high quality coal grade biochar could be produced from 28.35 MT of surplus rice and wheat straw in Punjab and Haryana, which has an estimated 19.80 TWh electricity generation potential. Also, electricity generation from biochar would reduce pollutant emissions imparting 30.25 MT CO2e GWP. The results of this study could provide baseline data for fuel replacement in power plants.
The main objective of the present study is to turn the wheel from waste to wealth by sustainable rice straw management practices over field burning in India. For that, slow pyrolysis of rice straw was carried out in a fixed bed reactor. The result indicated an increase in process temperature (300–600 °C) led to the decreased biochar yield, while pH (8.28–11.4), pore-volume (0.0087–0.059 cm³/g), surface area (12.78–83.06 m²/g), and HHV (17.63–20.13 MJ/kg) of biochar increased. The maximum bio-oil yield was obtained at 500 °C, and its characterization study indicated a high amount of phenol and aromatic compounds. The composition of H2 (1.9–17.72%) and CH4 (2.3–8.82%) in the gas and heating value (6.5–9.4 MJ/Nm³) of the gas increased with temperature. The energy (84.22–89.61%) and exergy efficiency (74.41–87.37%) of the pyrolysis system increased with process temperature, and the thermodynamic optimization was achieved at 600 °C.
Choosing an appropriate straw supply mode is crucial for reducing straw supply costs. This study considers four different supply modes: Farmer-Factory mode, Farmer-Broker-Factory mode, Farmer-Centralized Storage Site-Factory mode, and Farmer-Broker-Centralized Storage Site-Factory mode. Comparing the advantages and disadvantages and economic analysis of each mode are conducted. It is found that straw collection includes artificial and mechanized collection, straw transportation includes tractor and truck transportation, straw storage includes open field storage and centralized storage sites. When collecting 100,000 tons of straw, ordering the different supply modes based on cost result an order (from high to low) of 1A, 3, 2A, 1B, 4, 2B, ordering them based on equipment demand result in an order (from high to low) of 1A, 3, 2A, 1B, 2B, 4, and ordering them based on labor demand result in an order (from high to low) of 1A, 3, 2A, 1B, 4, 2B. It also can be seen that collection cost, transportation cost, and loading and unloading costs are important components of supply cost for each mode. Through the analysis of the six modes, mechanized baling collection can significantly reduce supply cost and equipment and labor requirements. Although intermediate links are added, mode 4 has become an economical supply mode that is also suitable for large-scale straw utilization due to its mechanized operations. As a conclusion, it will likely be the main straw supply mode of the future.
Conversion of biomass into biofuel and biochar with a subsequent soil storage is assumed as a prospective strategy of reducing atmospheric CO2 concentrations. However, substantial uncertainties exist in this field regarding the country-level potential of biochar carbon sequestration, indirect effects of biochar implementation on overall environment, and dominating factors. This study conducted a life cycle assessment of country-wide incorporation of biochar in agriculture, and associated potential benefits. Results showed that over 920 kg CO2e (CO2-equivalent) could be sequestrated via converting 1 t of crop residues into biochar. As an example, based on crop residues availability statistics for China in 2014, the estimated annual carbon sequestration potential could be as high as 0.50 Pg CO2e (1 Pg = 1 × 109 t). The most significant potential for biochar carbon sequestration was identified in the central south, east and northeast of China, which contributed 65% of the national biochar carbon sequestration potential. The biochar system could also contribute to mitigation of the following environmental problems: marine aquatic biodiversity destruction, surface soil and water acidification, etc. Sensitivity analysis demonstrated that biochar yield, carbon content in biochar, electricity conversion efficiencies of bio-oil and pyrolysis gas were the critical parameters determining the biochar system’s overall carbon sequestration potential and environmental effects. This study provides guidance on evaluating biochar’s potential
carbon sequestration capacity and comprehensive environmental impacts, as well as research and development needs.
With the growing population, agriculture productivity is increasing due to the high demand for food, which in turn produces a large amount of agricultural waste. Pyrolysis of crop residues is one of the suitable options to produce biochar and can be utilized as a fuel. In the present study, the slow pyrolysis of rice straw was carried out at four temperatures, 300 oC, 400 oC, 500 oC, and 600 oC. It was observed that biochar yield decreases (57.87-35.63%) with an increase in the process temperature. The physiochemical properties such as fixed carbon (43.91-57.63%), heating value (16.59-19.69 MJ/kg), carbon (63.77-85.13%) in biochar increases with temperature. Burning of rice straw (3Mt/year) emits the greenhouse gas (GHG) emission of about 10953 (CO2e) Gg/year, while the combustion of biochar produced from rice straw at different temperatures emits the emission in the range of 2131-3239 (CO2e) Gg/year. The electricity generation potential analysis for produced biochars was carried out with two different power plant efficiency 25 and 30 %. The electricity potential for power plant efficiency 25 % and 30 % was observed in the range of 1.2-1.82 TWh and 1.44-2.18 TWh, respectively.
Population growth will lead to an increase in food demand, which will exert pressure on crop production and likely increase the agricultural crop residue. The present study estimates atmospheric emissions of various pollutants from crop residue burning using the Intergovernmental Panel on Climate Change guidelines. In India 488 Mt of total crop residue was generated during 2017, and about 24% of it was burnt in agricultural fields. This resulted in emissions of 824 Gg of Particulate Matter (PM2.5), 58 Gg of Elemental Carbon (EC) and 239 Gg of Organic Carbon (OC). Additionally, 211 Tg of CO2 equivalent greenhouse gases (CO2, CH4, N2O) were also added to the atmosphere. However, crop residue can also be used for energy production in biomass power plants and has the potential of 120 TWh of electricity generation. This accounts for 10% of the total energy production of India. Trend analysis in a Business As Usual (BAU) model shows that crop residue burning emissions will increase by 45% in 2050 having 2017 as the base year. The study also examines the various sustainable approaches and proposes an integrated crop residue management model to minimize the adverse impact of agricultural waste burning on human health and the environment.
Cold waterlogged paddies typically have low to average yield due to their relatively low soil temperature, poorly developed plough layer, and lack of available nutrients. Despite the above, yield can be improved by targeted measures, such as supplementing with special organic materials. Past research has shown that biochar can play an important role in sequestering soil C, building soil fertility, and improving crop yield. However, the effects of biochar on crop yield and soil properties in cold waterlogged paddies have not been thoroughly investigated. We hypothesized that biochar improves soil fertility, and thus, increases rice grain yield in cold waterlogged paddies. A 2-year field experiment was conducted in 2011 and 2012 to investigate the effect of bamboo biochar (BB), rice straw biochar (RB), and rice straw (RS) on soil physical and chemical properties, grain yield, and yield components in a cold waterlogged paddy in Zhejiang Province, China. Results showed that both BB and RB significantly increased soil pH and soil organic carbon compared to control, whereas their effects on total N were either very small or non-significant. Application of RB significantly increased soil available P and K in both years, and the increases relative to control were greater in 2011 (by 33.9% and 99.1%, respectively) than in 2012 (by 15.3% and 28.6%, respectively). Moreover, RB application resulted in the greatest improvement in grain yield (8.5–10.7% greater than that from the control), and this may be attributed to increased nutrient availability (mainly P and K). Yield component analysis indicated that experimental treatments had the greatest effect on thousand-grain weight, followed by the number of productive tillers per plant and harvest index. Neither biochar nor RS significantly affected the total nutrient (N + P2O5 + K2O) content of grains, although the K content of grains from BB and RB plots was significantly higher than in those from control plots in 2012. The total nutrient content of straw under RB treatment was significantly higher than that under control and RS treatments in 2012, mainly due to increased K content (by 12.0%) of straw. The total nutrient uptake by grain was significantly (13.6–16.4%) higher under RB treatment than under control treatment. This was primarily due to the relatively high K uptake by RB grains (15.9–22.6% greater than that by the controls). Similarly, the total nutrient uptake by straw from RB plots was significantly greater than that of straw from the control plot. Further studies on biochar in cold waterlogged paddies are essential in order to evaluate the long-term effects of biochar and its behavior in soils.
In order to select appropriate mode of crop straw's collection-storage-transportation, and promote the large-scale use of straw resources, the mathematical model about straw's collection, storage and transportation was established, which was based on the equipment, manpower, and cost on the North China Plain. By analyzing different modes about straw's collection-storage-transportation (which was divided into centralized model, decentralized mode; collected by manpower, collected by machinery), the effect of cost and energy consumption were different. Because of the different amounts of straw collection, manpower and equipments were demanded in mathematical models. The results showed that the cost of straw's collection-storage-transportation was 120- 260 Yuan/t, the fuel consumption of straw's collection-storage-transportation was 1.2×105 - 5.5×105 kJ/t. While using machinery to collected straw in filed, the cost was lower than that by manpower; but the required equipment number was significantly more than thatneeded by manpower. Meanwhile, the energy consumption of equipment was significantly increased. On the contrary, collecting straw in filed by manpower needs a lot of manpower. The calculated results showed that the cost and energy consumption of centralized mode about equipment-manpower- cost was lower than decentralized mode when collecting by the same manner. Compared to the manpower collection, collection by machinery can reduce the total cost, but the initial investment was higher and the capacity in solving employment problem was lower. When the amount of crop straw collection increased from 5×104 to 50×104 t, the unit cost of mode A and B was monotonically increasing. As to mode C and D, it declined quickly from 5×104 to 25×104 t, then rose gradually from 25×104 to 50×104 t. Therefore, it can be concluded that the collection methods affected cost extremely. Collecting straw by manpower, the mode of A and C curved intersect at 250 000 t; Or else, the mode of B and D curved intersect at 500 000 t. When the collected amount of crop straw increased from 5×104 to 50×104 t, the unit energy consumptions of mode A and B increased, with slow upward trend rate; On the contrary, from 5×104 to 25×104 t straw collection, the unit energy consumption of mode C and D was decreasing, when the collected amount of crop straw was 18×104 and 12×104 t, the unit energy consumption curves of mode B and C2 could intersect; Similarly, the unit energy consumption curves of mode A2 and C1 also could intersect. In this circumstance, when the collected amount was less than the intersection, the energy consumption of mode B and A2 was lower than mode C2 and C1. Therefore, the energy consumption of centralized mode is lower when the crop straw amount collected is less, it is recommended to choose centralized mode; Otherwise, decentralized mode is the better choice. ©, 2014, Chinese Society of Agricultural Engineering. All right reserved.
Biomass based energy generation is one of the major focus areas of renewable energy programs in India. The strength of India's biomass resources mostly lies in the agricultural sector. A large quantity of crop residue biomass is generated in India. However, crop residue biomasses are distributed resources with variation in spatio-temporal availability and its characteristics. Competing uses of residues also vary geographically. Therefore, local biomass databases are important for decentralized bioenergy programs. However, in India, state wise crop level biomass database is limited. The present paper assessed crop residue biomass and subsequently bioenergy potential in all the 28 states of India using crop statistics and standard procedure. A total of 39 residues from 26 crops cultivated in India are considered for the study. Overall, India produces 686 MT gross crop residue biomass on annual basis, of which 234 MT (34% of gross) are estimated as surplus for bioenergy generation. At state level, Uttar Pradesh produces the highest amount of crop residue amongst all the 28 states. Amongst all the crops, sugarcane produces the highest amount of surplus residue followed by rice. The estimated annual bioenergy potential from the surplus crop residue biomass is 4.15 EJ, equivalent to 17% of India's total primary energy consumption. There exists variation from 679 MJ (West Bengal) to 16840 MJ (Punjab) of per capita crop residue bioenergy potential amongst the states of India. The information generated in this study is expected to be useful for decentralized crop residue based energy planning by the states of India which in turn would positively influence the overall renewable energy growth in India.
Agricultural residues are potentially major contributors of resources for energy and material production. We provide regional and global estimates of the amount of residues from major crops and address the sources of uncertainty in the estimation of the amount of agricultural residues produced globally. Data and methods available currently limit the use of resource estimates for energy or production planning. We develop function based multipliers to estimate the global production of agricultural residues. The multipliers are applied to the production of the, on a global scale, six most important crops: barley, maize, rice, soybean, sugar cane and wheat in 227 countries and territories of the world. We find a global production of residues from these six crops of 3.7−1.0+1.3 Pg dry matter yr−1. North and South America, Eastern, South-Eastern and Southern Asia and Eastern Europe each produce more than 200 Tg yr−1. The theoretical energy potential from the selected crop residues is estimated to 65 EJ yr−1 corresponding to 15% of the global primary energy consumption or 66% of the world's energy consumption for transport. Development towards high input agriculture can increase the global residue production by ∼1.3 Pg dry matter yr−1.
Rice husk and melaleuca biochar additions reduce soil CH4 and N
- T S Nam
- H Van Thao
- N H Chiem
- N Van Cong
- T Mitsunori
2006 IPCC Guidelines for National Greenhouse Inventories - A primer, Prepared by the National Greenhouse Gas Inventories Programme
- H S Eggleston
- K Miwa
- N Srivastava
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