Rice Straw Burning Research Articles

Influence of rice straw incorporation and recommended dose of primary nutrients on growth, productivity and nutrient use efficiency of Rabi maize (Zea mays L.)

Rice-maize-based cropping system is one of the important agricultural practices in India. Maize has a wider range of adaptability to various climatic and soil conditions, which allows the farmers to cultivate the crop at various locations throughout the year. During the present days, straw handling after rice crop harvesting has become a major problem to the farmers and the burning of rice straw is considered as a serious environmental threat causing air pollution. In this scenario, incorporation of rice straw in succeeding maize cultivation can be beneficial in various aspects like soil health improvement, increased productivity and proper waste management. Considering these, the present field study was conducted at the Post Graduate Research Farm of Centurion University of Technology and Management, Gajapathi, Odisha, India. The experiment was laid out in randomized complete block design with 8 treatments and each treatment was replicated 4 times. The details of the treatment are as follows, T1: absolute control, T2: 100 % RDF, T3: 100 % RDF + rice straw incorporation (RSI) at 2 t/ha, T4: 100 % RDF + RSI at 4 t/ha, T5: 100 % RDF + RSI at 6 t/ha, T6: 100 % RDF + RSI at 8 t/ha, T7: 75 % RDF + RSI at 2 t/ha and T8: 75 % RDF + RSI at 4 t/ha. The experimental results found that the superior values of growth attributes were obtained highest in treatments T2: 100 % RDF, T3: 100 % RDF + RSI at 2 t/ha. Further, the incorporation of rice straw at the rate of 2 t/ha (T3) accounted for maximum grain yield (6354 kg/ha), stover yield (8429 kg/ha) and biological yield (14783 kg/ha) of maize and this treatment remained at par with T2: 100 % RDF. The experiment concludes that application of the optimum dose of fertilizers (100 % RDF) along with the incorporation of 2 t/ha of rice straw can be recommended for better growth, yield and nutrient use efficiency of Rabi maize.

Enhancing carbon reduction and sustainable agriculture in Thailand: An assessment of rice straw utilization strategies

This research explores strategies for carbon reduction through the utilization of rice straw waste in Thailand, focusing on three project approaches: (1) converting rice straw into biomass fuel pellets for power plants, (2) transforming rice straw into biochar using high-tech systems and blending it with fertilizers, and (3) using conventional systems for biochar production. The study assesses the greenhouse gas (GHG) reduction potential of these approaches compared to traditional open-field burning of rice straw. The results indicate that Project 2, which involves high-tech biochar production, exhibits the highest potential for GHG reduction and carbon sequestration, with a potential to reduce emissions by approximately 12.19–13.05 MTCO2e/year. This approach also has potential for generating valuable carbon credits due to biochar’s long-term carbon sequestration and soil enhancement benefits. In contrast, Project 1 yields a reduction of about 4.06–4.35 MTCO2e/year, while Project 3 results in negative emission reduction. The study recommends prioritizing and incentivizing biochar production projects, upgrading low-tech systems, balancing the use of biomass fuel pellets, leveraging carbon credits for funding, and enhancing public awareness.

Assessing and enhancing sustainable rice straw management for environmental conservation in Yen Thanh District, Nghe An Province, Vietnam

This study assessed the current management of rice straw in Yen Thanh District, Nghe An Province, and propose solutions for sustainable agricultural development. A survey was conducted with 120 households in four communes to determine straw use and management practices. The findings revealed six common methods of using and managing rice straw in Yen Thanh District: open burning, burying, mushroom plantation, using it for husbandry feeding, selling, and giving it to others. These practices vary based on the crop season. Open burning is the most prevalent practice, accounting for 98.15% and 89.52% during the winter-spring and summer-autumn harvests, respectively. A crucial step in establishing a pollution control and management database is a comprehensive inventory of emissions. Consequently, authorities and environmental scientists are currently focusing on the emission inventory, particularly emissions resulting from open-burning rice straws. The estimated total amount of rice straw produced annually is 159,732 tons, with 151,384 tons being directly burned in the fields. This burning releases significant emissions, including 1,005.18 tons of PM2.5, 1,102.08 tons of PM10, 21.80 tons of SO2, 142,543.18 tons of CO2, and more, negatively impacting the environment, human health, and agriculture. Additionally, it was observed that most farmers are inclined to continue burning rice straw out of habit in the upcoming years. The study suggests promoting alternative straw management practices such as mushroom cultivation, biochar production, and organic fertilizer production to reduce burning and its associated negative consequences. This information would be invaluable for managers to effectively plan for the future management of rice straw

Residues of atrazine and diuron in rice straw, soils, and air post herbicide-contaminated straw biomass burning

This study investigates the environmental impact of burning herbicide-contaminated biomass, focusing on atrazine (ATZ) and diuron (DIU) sprayed on rice straw prior to burning. Samples of soil, biomass residues, total suspended particulate (TSP), particulate matter with an aerodynamic diameter ≤ 10 µm (PM10), and aerosols were collected and analyzed. Soil analysis before and after burning contaminated biomass showed significant changes, with 2,4-dichlorophenoxyacetic acid (2,4-D) initially constituting 79.2% and decreasing by 3.3 times post-burning. Atrazine-desethyl, sebuthylazine, and terbuthylazine were detected post-burning. In raw rice straw biomass, terbuthylazine dominated at 80.0%, but burning ATZ-contaminated biomass led to the detection of atrazine-desethyl and notable increases in sebuthylazine and terbuthylazine. Conversely, burning DIU-contaminated biomass resulted in a shift to 2,4-D dominance. Analysis of atmospheric components showed changes in TSP, PM10, and aerosol samples. Linuron in ambient TSP decreased by 1.6 times after burning ATZ-contaminated biomass, while atrazine increased by 2.9 times. Carcinogenic polycyclic aromatic hydrocarbons (PAHs), including benzo[a]anthracene (BaA), benzo[a]pyrene (BaP), and benzo[b]fluoranthene (BbF), increased by approximately 9.9 to 13.9 times after burning ATZ-contaminated biomass. In PM10, BaA and BaP concentrations increased by approximately 11.4 and 19.0 times, respectively, after burning ATZ-contaminated biomass. This study sheds light on the environmental risks posed by burning herbicide-contaminated biomass, emphasizing the need for sustainable agricultural practices and effective waste management. The findings underscore the importance of regulatory measures to mitigate environmental contamination and protect human health.

Estimation of greenhouse gas emission due to open burning of rice straw using Sentinel data

In recent decades, Vietnam has gradually become a critical global rice producer. During that production process, residual straw becomes an environmental pollutant due to open burning, raising greenhouse gas emissions. This study combines the optical images of the Sentinel-2 satellite and the radar images of the Sentinel-1 satellite to estimate the dry biomass of rice and to determine gas emissions due to rice straw burning over the fields in Quoc Oai district, Hanoi city for urban environmental management purposes. Sentinel-2 images have been classified into the land covers, thereby identifying the areas of ​​rice cultivation and the areas of ​​burned straw. Meanwhile, the Sentinel-1 radar image has been used to calculate the dry biomass of rice due to its ability to penetrate clouds, an obstacle to optical images in tropical regions. Furthermore, a field trip during harvesting season allows us to measure aboveground dry biomass. Then, the analysis shows a high correlation between the backscatter V.V. and V.H. of the radar image and the in-situ dry biomass (R=0.923 and R2=0.852), with a relatively low average error (RMSE = 6.58 kg/100 m2). By linear regression method, the study found the total rice dry biomass of 28728.5 tons, which was obtained after the Summer rice crop 2020 for the whole Quoc Oai district, of which 2037.91 tons of rice straw have been burned, releasing a large amount of greenhouse gas emission with 2398.6 tons of CO2, 189.5 tons of CO, 18.8673 tons of PM10 dust, 17.2087 tons of PM2.5 dust and some other gases. The identical procedure has also been applied to the western region of Hanoi city center to estimate the amount of gas emissions. This study has proven the effectiveness of an approach and contributed to supporting urban managers in proposing appropriate policies to monitor and protect the environment.

Integrating bioprocess and metagenomics studies to enhance humic acid production from rice straw.

Rice straw burning annually (millions of tons) leads to greenhouse gas emissions, and an alternative solution is producing humic acid with high added-value. This study aimed to examine the influence of a microbial consortium and other additives (chicken manure, urea, olive mill waste, zeolite, and biochar) on the composting process of rice straw and the subsequent production of humic acid. Results showed that among the fungal species, Thermoascus aurantiacus exhibited the most prominent impact in expediting maturation and improving compost quality, and Bacillus subtilis was the most abundant bacterial species based on metagenomics analysis. The highest temperature, C/N ratio reduction, and amount of humic acid production (Respectively in lab 61°C, 54.67%, 298 gkg-1 and in pilot level 65°C, 72.11%, 310gkg-1) were related to treatments containing these microorganisms and other additives except urea. Consequently, T. aurantiacus and B. subtilis can be employed on an industrial scale as compost additives to further elevate quality. Functional analysis showed that the bacterial enzymes in the treatments had the highest metabolic activities, including carbohydrate and amino acid metabolism compared to the control. The maximum enzymatic activities were in the thermophilic phase in treatments which were significantly higher than that in the control. The research emphasizes the importance of identifying and incorporating enzymatically active strains that are suitable for temperature conditions, alongside the native strains in decomposing materials. This strategy significantly improves the composting process and yields high-quality humic acid during the thermophilic phase.

Investigating the potential of delignified rice husk as a carbon-rich resource for extracting glucose and its utilization in biocement production through fungal isolates.

Burning rice straw is now a significant issue faced by different regions in India, as its burning releases harmful gases, mainly carbon dioxide. Various techniques are now in trend to utilize the rice straw, e.g., producing compressed natural gas using rice straw, bioethanol, etc., as a substrate for various microorganisms. A high quantity of non-utilized rice husk generates more ideas for its proper utilization. The cellulose, hemicellulose, and lignin found in rice straws can be a fungi growth medium. In this research, the delignification of rice husk is done by acid (2% and 4% H2SO4) and alkali (2% and 4% NaOH) at 121°C at 103kPa for 1h to obtain crude carbon source which is further utilized for biomineralization. The glucose is subjected to qualitative and quantitative analysis using Molisch's and Dinitro salicylic tests. The delignification process showed a positive outcome when 2% H2SO4 is utilized maximum yield of 5.9 ug/ml free sugar concentration. Representing the highest glucose yield compared to the experiment's other acid and base substances used. Various techniques such as field emission-scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and Fourier transformed infra-red (FTIR) spectroscopy are employed to examine surface and chemical alterations. The 2% H2SO4 pretreated rice husk is utilized for microbial-induced calcite precipitation using fungal isolates S1 (3), S1 (18), and S4 (1). The calcite and vaterite produced by biomineralization are confirmed using XRD for fungal isolates namely, S1 (3), S1 (18), and S4 (1) having percentage crystallinity of 59%, 46.428%, and 62.69% percentage crystallinity respectively.

Unambiguous Analysis and Systematic Mapping of Oxygenated Aromatic Compounds in Atmospheric Aerosols Using Ultrahigh-Resolution Mass Spectrometry.

Compositional analysis of organic aerosols (OAs) at the molecular level has been a long-standing challenge in field and laboratory studies. In this work, we applied different extraction protocols to aerosol samples collected from the ambient atmosphere and biomass burning sources, followed by Orbitrap mass spectrometric analysis with a soft electrospray ionization source operating in both positive and negative ionization modes. To systematically map the distribution of mono- and dioxygenated aromatic compounds (referred to as aromatic CHO1 and CHO2 formulas) in OA, we developed a unique two-dimensional Kendrick mass defect (2D KMD) framework. Our analysis unveiled a total of (76, 64, 70) aromatic CHO1 formulas and (103, 110, 106) CHO2 formulas, corresponding to samples obtained from ambient air, rice straw burning, and sugarcane leaf burning, respectively. These results reveal a significant number of additional distinct formulas exclusively present in ambient samples, suggesting a significant chemical transformation of OAs in the atmosphere. The analytical approach can be further extended to incorporate multiple layers of 2D KMD, enabling systematic mapping of the unexplored chemical space for complex environmental samples.

Conversion of Rice Straw to Biochar Through Microwave Pyrolysis for its Use as Partial Replacement of Cement

Background: An experimental study was conducted to explore the feasibility of partially substituting biochar in cement, for making concrete mixture in civil infrastructures. The biochar was derived from the pyrolysis process in thermo-chemical conversion of the most under-utilized agricultural residue i.e. rice straw. Demand of cement is increasing day by day due to fast growth of construction sector all around the world. The current scenario of rampant on-farm burning of rice straw is a great concern not only for maintaining the fertility aspects of the cultivating land but also for the degradation of surrounding environment. Production of cement is equally very energy intensive and contributes a lot in emitting greenhouse gases, mostly carbon dioxide to the environment. An attempt was therefore made in the present study to partially replace the rice straw biochar with cement to reduce the production of the later and to evaluate the key performance parameters of biochar based concrete. Methods: The study was carried out in the Department of Agricultural Structures, Civil and Environmental Engineering, Odisha University of Agriculture and Technology, Bhubaneswar, Odisha, India during 2021-22. Microwave assisted pyrolysis was followed for quick and efficient heating of the biomass feedstock. Efforts was also made to supply power to the microwave pyrolyser from a reliable source of power i.e. solar photovoltaic system for its popularization even in remote and off-grid rural areas. Result: The yield of biochar was found to be higher (about 28%) at 600 W input power to the microwave reactor and 15 minutes’ reaction time in the pyrolysis process of rice straw. The performance parameters of biochar based concrete such as initial setting times, final setting times and workability were found to be decreased by 8, 5 and 9% respectively and compressive, split tensile and flexural strengths were increased by 13, 18 and 5% respectively compared to the reference concrete. Biochar from rice straw can hence ultimately be utilized as partial replacement of cement for use in construction industry.

Unveiling the Aftermath: Exploring Residue Profiles of Insecticides, Herbicides, and Fungicides in Rice Straw, Soils, and Air Post-Mixed Pesticide-Contaminated Biomass Burning.

This study delved into the impact of open biomass burning on the distribution of pesticide and polycyclic aromatic hydrocarbon (PAH) residues across soil, rice straw, total suspended particulates (TSP), particulate matter with aerodynamic diameter ≤ 10 µm (PM10), and aerosols. A combination of herbicides atrazine (ATZ) and diuron (DIU), fungicide carbendazim (CBD), and insecticide chlorpyriphos (CPF) was applied to biomass before burning. Post-burning, the primary soil pesticide shifted from propyzamide (67.6%) to chlorpyriphos (94.8%). Raw straw biomass retained residues from all pesticide groups, with chlorpyriphos notably dominating (79.7%). Ash residue analysis unveiled significant alterations, with elevated concentrations of chlorpyriphos and terbuthylazine, alongside the emergence of atrazine-desethyl and triadimenol. Pre-burning TSP analysis identified 15 pesticides, with linuron as the primary compound (51.8%). Post-burning, all 21 pesticides were detected, showing significant increases in metobromuron, atrazine-desethyl, and cyanazine concentrations. PM10 composition mirrored TSP but exhibited additional compounds and heightened concentrations, particularly for atrazine, linuron, and cyanazine. Aerosol analysis post-burning indicated a substantial 39.2-fold increase in atrazine concentration, accompanied by the presence of sebuthylazine, formothion, and propyzamide. Carcinogenic PAHs exhibited noteworthy post-burning increases, contributing around 90.1 and 86.9% of all detected PAHs in TSP and PM10, respectively. These insights advance understanding of pesticide dynamics in burning processes, crucial for implementing sustainable agricultural practices and safeguarding environmental and human health.

Improving Soil Quality and Crop Yields Using Enhancing Sustainable Rice Straw Management Through Microbial Enzyme Treatments.

This study develops a model to raise public awareness about the consequences of burning rice straw after harvest, including environmental pollution, soil degradation, and increased CO2 emissions that contribute to the greenhouse effect. The distinctive feature of the research is the introduction of a post-harvest rice straw treatment process using microbial products capable of secreting cellulase enzymes, which can break down the cellulose in the straw. This process shortens the decomposition time and produces natural organic fertilizer, thus reducing cultivation costs by 60% and increasing crop yields by 20%. The experimental model was carried out in Cam My district, Dong Nai province, Vietnam, including 4 models: no microbial products; using Bio Decomposer; using NTT-01; and using NTT-02. Each experimental field had an area of 650 m². The results showed a significant reduction in straw decomposition time after 14 days of use of the products, with a decomposition rate of up to 80%, nearly twice as fast as without the products. This helps save time, produce natural organic fertilizers, reduce care costs, and increase rice yields, resulting in more income for local residents. These findings demonstrate the effectiveness of microbial treatments in sustainable agriculture and their potential for a broader application in the management of agricultural waste.

Insights of Circular economics practices in rice cultivation and processing - a review

Reusing waste through various activities and efficient and effective use of resources have led to the circular economy as a further growth opportunity. The circular economy has spread in various directions like agriculture and industry. The main focus of circular economy is to minimize or eliminate the use of non-renewable inputs in a production system and to maximize or optimize the reuse of these materials within the same system. In addition, circular agriculture is expected to reduce environmental impacts through soil regeneration and input use. Activities in rice cultivation include sowing, fertilizing, watering, and harvesting, and these activities can be done using biological and other agricultural methods in an environmentally friendly way instead of chemical fertilizers, pesticides, and herbicides, and further minimizing the accumulation of waste. Burning rice straw and husks emits lot of CO2 into the environment. However, these can be used as raw materials for various industries. Rice residue is an excellent source of nutrients and beneficial for human health. Thus, circular economy methods can be used in rice cultivation by cultivating more productive and suitable rice varieties, reducing the amount of waste released into the environment in various ways, and using discarded waste as raw materials for industries. This study focuses on determining the applicability of circular economy methods to rice cultivation and processing. Accordingly, it appears that in the rice industry, circular economy methods are applied to reduce the release of unnecessary air and waste into the environment and effectively reuse the waste. This will create an eco-friendly and safe environment.

Crop Residue Management Options in Rice - Wheat Cropping Systems: A Case Study of the Indian Experience

The dominant agricultural system in India is the rice-wheat system, and the problems posed by climate change and declining soil health are endangering the system's sustainability. High yields from the irrigated rice-wheat system have resulted in a substantial amount of wasted food. In northwest India, burning rice straw is a frequent practice that results in significant air pollution that is harmful to human health and nutritional losses. Crop residue management improvements should help achieve sustainable productivity, enable farmers to minimize nutrient and water inputs, and lower the risk associated with climate change-all of which will help prevent straw burning. The rice-wheat system's nutrition management will benefit from the prudent application of crop residues, which contain substantial amounts of plant nutrients. Long-term research on residue recycling has shown improvements in the soil's chemical, biological, and physical health. Another viable approach to managing crop residues is to use some of the excess residues to make biochar, which can be added to the soil to enhance its health, maximize its ability to use nutrients, and reduce air pollution. Mushroom cultivation may convert non-edible crop leftovers into a nutritious food source, surface mulch can suppress weed growth and retain soil moisture, and compost and biofuel can all be made from these materials. The decomposition of residues considerably boosts the soil's organic carbon and nitrogen levels. This review looks at the residues that can form in a rice-wheat farming system and how those residues can be effectively managed.

Response Surface Methodology Approaches in Producing Amorphous Silica from Rice Straw Ash

A large amount of rice straw is produced as crop residue from rice production as an underutilization waste material. The open burning of rice straw can lead to environmental pollution by forming an abundant amount of rice straw ash (RSA) and exposing harmful gases to the atmosphere. Thus, RSA can be used as a cement replacement material due to its high amount of silica. Silica is a helpful additive to cement mix by accelerating the hydration process of cement because of its high reactivity and improving mortar performance. This study focuses amount of high silica of RSA in modified concrete through thermochemical pretreatment via response surface methodology (RSM). The factors involved in the pretreatment of RSA are 0.01M – 0.1M HCl hydrochloric acid, 1 – 3 hours soaking duration, and 60 - 80℃ soaking temperature, and a response is the percentage of reactive compound content (SiO2, Al2O3, and Fe2O3). Therefore, central composite design (CCD) in the RSM and the analysis of variance (ANOVA) have been used to evaluate the interaction between the factors and response, then simulated and further assess the accuracy of the model to achieve the accurate prediction. As a result, RSM observed that the optimum silica amount in the treated RSA (98.34%) was produced using parameters of 0.06 M HCl, 2 hours of soaking duration, and 70℃ soaking temperature in the pretreatment process. After that, it is followed by a burning process at a controlled temperature and a grinding process to produce treated RSA. The prediction given by the RSM was not the sole result but was proved through X-Ray Fluorescence (XRF) analysis. The result of XRF analysis obtained for each model with the same value of each factor (HCl concentration = 0.06 M, soaking duration = 2 hours, and soaking temperature = 70℃) is more than 97.00% and falls between the prediction index range. Thus, the model is validated since the actual experimental result is within the expected range for any involved factor. Hence, the treated RSA was considered a high-quality pozzolanic material incorporated in the mortar production.

Developing sustainable and energy efficient process to obtain high purity cellulose and its value-added chemicals from rice straw

This study addresses the environmental impact of traditional rice straw burning practices in agriculture and explores sustainable alternatives. Utilizing lignocellulose waste, the research developed an energy-efficient process involving Alkali Pretreatment and Acid & Bleaching Pretreatment to obtain highly purified cellulose, after that analysed by qualitative and quantitative analysis, FT-IR and the Van Soest method were used, respectively. Thermal stability and crystallinity of acid-treated rice straw and bleached-treated rice straw were evaluated via DSC. The outcomes showed that different pretreatments produced purified cellulose and removed 93 % of the lignin. By using transition metal catalysts for depolymerization, value-added chemicals were produced, as measured by HPLC, generated glucose, Sorbitol, Arabinose, Ribose, and organic acids (HMF, THF). Overall, this study provides insights into the potential use of rice straw as a substrate for extraction of high-purity cellulose and value-added chemicals production, offering a reliable and energy-efficient process.

Estimation Inventories of Persistent Organic Pollutants from Rice Straw Combustion as an Agricultural Waste

Rice cultivation stands as the primary agricultural activity in Asia, generating a substantial amount of agricultural waste. Unfortunately, this waste is often disposed of through burning, contributing to severe environmental, health and climate issues. This study presents the characterization of PCDD/Fs, PCBs and PAHs. The emissions were quantified using a fixed-grid-system biomass plant and measuring the macro-pollutants online and sampling the organic micro-pollutants and metals in isokinetic mode, followed by ISO and CEN standards methods. Additionally, the role of agrochemicals was monitored in terms of metal catalysis resulting in POP emissions. This study provides the comprehensive characterization of the most relevant groups of pollutants (metals, PCDD/Fs, PCBs and PAHs) resulting from agricultural waste combustion. Prominent catalytic metals quantified were Cu (22–48 µg/Nm3) and Fe (78–113 µg/Nm3). Rice straw samples from AJK exhibited higher values of organochlorine micro-pollutants compared to those from Punjab and Sindh, i.e., ∑PCDD/F (2594 > 1493 > 856 pg/Nm3) and ∑PCB (41 > 38 > 30 pg/Nm3), respectively, whereas the organic micro-pollutants ∑c-PAH, indicators of incomplete combustion (PICs), were recorded high in the samples from Sindh followed by Punjab and AJK. The average EF is 100 pg/kg, 2.2 pg/kg and 1053.6 µg/kg for ∑PCDD/F, ∑PCB and ∑c-PAH. This study supports the idea that the phenomena leading to the formation of dioxin and dioxin-like compounds are influenced not only by poor combustion but also by the presence of metal catalysts in the burned fuel.

In situ biomass burning enhanced the contribution of biogenic sources to sulfate aerosol in subtropical cities

Sulfurous gases released by biogenic sources play a key role in the global sulfur cycle. However, the contribution of biogenic sources to sulfate aerosol in the urban atmosphere has received little attention. Emission sources and formation process of sulfate in Guangzhou, a subtropical mega-city in China, were clarified using multiple methods, including isotope tracers and chemical markers. The δ18O of sulfate suggested that secondary sulfate was the dominant component (84 %) of sulfate aerosol, which mainly formed by transition metal ion (TMI) catalyzed oxidation (31 %) and OH radical oxidation (30 %). The factors driving secondary sulfate formation were revealed using a tree boosting model, which suggested that NH3, temperature, and oxidants were the most important factors. The δ34S of sulfate indicated that biogenic sources accounted for annual average of 26.0 % of the sulfate, which increased to 30.4 % in winter monsoon period. Rice straw burning enhanced sulfate formation by promoting the release of reduced sulfur from soil, which is rapidly converted into sulfate under a subtropical urban atmosphere with high concentration of NH3 and oxidants. This study revealed the important influence of rice straw burning on biogenic sulfur emission during the rice harvest, thereby providing insight into the sulfur cycle and regional air pollution.

Rice Straw Management Practices in Rupandehi District, Nepal

Rice straw management has been a serious issue after the increasing use of combine harvesters to harvest rice in southern plains of Nepal since these machines cut rice 15-20 cm above the ground and leaves huge amount of residues in the field. A face-to-face semi-structured questionnaire survey was carried out in 60 households of straw burning, and 60 households of straw incorporation to find out straw management practices adopted by farmers, their motive behind choosing those practices and timing of carrying out those practices. Farmers practicing those straw management practices for at least five years was considered as final respondent. Respondents were selected by using purposive sampling technique. Survey was carried out in six places of Rupandehi district where the problem of rice residue burning is severe mainly due to the use of combine harvesters in rice and wheat. Study resulted soil fertility enhancement as the primary reason behind both straw burning practice as well as straw incorporation practice adopted by farmers. Timing of rice straw burning was within 1 week of harvesting rice by majority of farmers. Timing of soil incorporation of rice straw followed by majority of farmers was 8-12 days after harvesting rice. Straw burning results the nutrients imbalance and creates environmental pollution. So, soil incorporation of rice straw is suggested to return nutrients back to the soil.

Performance evaluation of petroleum hard pitch modified with rice straw bio-oil

In this present study, bio-binder was made using the bio-oil obtained from rice straw and petroleum hard pitch to reduce the air pollution caused by the burning of waste rice straw in the field. The physical, rheological, and chemical tests were conducted on the viscosity-grade binders (VG30 and VG40), petroleum hard pitch, and bio-binders prepared with a blending of petroleum hard pitch with 20 and 30 wt.%. The performance of bituminous mixes made with viscosity-grade binders and bio-binder was evaluated by using the dynamic creep, resilient modulus, and tensile strength tests. The results of the frequency sweep and Fourier transform infrared tests indicate that bio-binders have poor resistance to aging. The rut resistance of the bio-binder modified mix was better than that of the VG30 mix. There is no significant difference in moisture resistance of bituminous mixes prepared with bio-binder and viscosity-grade binders.

Soil type and integrated nitrogen nutrient-rice straw residue management techniques affect soil microbes, enzyme activities and yield of wheat crop

Sporadic burning of rice straw and the particulate air pollution caused consequently have created a pressing need for identification of practical environmentally sound in situ rice residue management methods. However, the agronomic interventions associated with the agri-inputs particularly the type of nitrogen fertilizer source must be worked out for these interventions. In a two-year field study performed at two different locations representing sandy loam and clay loam soil types, zero tillage with application of nitrophosphate (applied as basal dose through drilling) in combination with urea (applied at 1st irrigation + 3 foliar sprays of urea at weekly interval) significantly enhanced the grain and straw yield of wheat. The soil microbial viable cell counts and dehydrogenase and urease enzyme activities were also recorded to be highest in this treatment indicating the occurrence of higher living microbial population. The treatment × response variable Principle component analysis (PCA) biplot depicted relative variation among the residue management treatments/Nitrogen fertilizer sub-treatments and the enzyme activities as response variables. A variation in the soil organic content components was recognized through Fourier transform infra-red spectroscopy (FT-IRS) studies. Irrespective of the soil types under study, the FT-IR spectra exhibited presence of the aromatic carbon functional groups in residue incorporated treatments as compared to the no residue incorporation treatment.