An assessment of irrigated rice production energy efficiency and environmental footprint with in-field and off-field rice straw management practices

Assessing energy efficiencies and greenhouse gas emissions under bioethanol-oriented paddy rice production in northern Japan

05/02384 Possibility of using waste tire composites reinforced with rice straw as construction materials

A Biological year

The sustainability of the productive rice-wheat systems of Northwest India is being questioned due to the complete removal of straw for animal consumption and fuel, or the burning of straw which has reduced the soil organic matter contents. However, straw incorporation at planting can temporarily reduce the availability of fertilizer-N and reduce crop yields. In a field study on a loamy sand soil, the effect of 6 mg ha−1 rice straw incorporated into the soil 20 or 40 days before sowing (DBS) the wheat was compared with removal or burning of rice straw on the fate and balance of 120 kg ha−1 of 5 atom% 15N-urea applied to wheat and to a following crop of rice. Wheat grain yield and agronomic efficiency (AE) of applied N (kg grain/kg N applied) were not influenced by rice straw management. However, N uptake (NU), and recovery efficiency (RE) of N by the difference method were lower with rice straw incorporation than with burning. Nitrogen-15 recovery by wheat was highest (41%) when the rice straw was removed or burned and lowest (30.4%) when 30 of the 120 kg N ha−1 was applied at the time of straw incorporation at 20 DBS of wheat. However, this strategy of adding 25% of the urea-N dose at the time of straw incorporation resulted in the highest 15N losses (45.2%). Inorganic N remaining at harvest in the 0 to 60 cm soil profile, mostly NO3−, was 5.5% after wheat and 4.2% after rice. Rice grain yields, NU, and RE were not influenced by rice straw management. Nitrogen-15 losses were similar in rice and wheat (31% with straw removed) despite total irrigation and rainfall inputs of 340 and 32 cm to rice and wheat, respectively. These results suggest to the farmers of northwest India that straw incorporation does not necessarily hurt grain yields, and indicates to researchers that work is still needed to improve N use efficiency in rice and wheat.

Greenhouse gas emissions of rice straw-to-methanol chain in Southern Brazil

Rice is grown in more than 100 countries spread across six continents and in varying agroecological and socioeconomic conditions. Rice production systems were classified over years differently depending on the context. In this chapter, the method of rice establishment is considered as criteria for classifying rice production systems across the globe. An attempt is made here to summarize the information on rice production systems, resources used, crop productivity attained, the challenges encountered, and possible research needs for improving productivity in rice production systems, to meet the future food demands. Based on the major methods of rice establishment of the world, the rice production systems are categorized as (a) transplanted rice (TPR) production systems and (b) direct-seeded rice (DSR) production systems. DSR production systems are further categorized as (i) dry-seeded rice (dry-DSR) production system, (ii) wet-seeded rice (wet-DSR) production system, and (iii) water-seeded rice (water-DSR) production system. The productivity of TPR and DSR was reported to be similar when the best management practices are adopted. As already occurred in the developed world, a shift in adoption toward DSR production systems is occurring in developing world, due to advantages of DSR production systems such as lesser cost of production, increased resource (water, labor, and energy) use efficiency, and income compared to TPR. Lower environmental footprint was found to be another advantage of DSR production systems when they were combined with other conservation agricultural practices. The need for continuous research efforts was stressed for understanding the evolving rice production systems across the globe and to develop practical integrated crop management strategies that improve rice productivity and production effectively, sustainably, and economically with minimal environment footprint.

Influence of green manure and rice straw management on soil organic carbon, enzyme activities, and rice yield in red paddy soil

Rice is one of the major foods, with consumption per capita of 65 kg per year, accounting for 20% of global ingested calories. Rice production is expected to increase significantly in the near future in order to feed the rising human population. Today, paddy rice culture produces 660 million tons of rice, along with 800 million dry tons of agricultural residues, mainly straw. This biomass is managed predominantly through rice straw burning (RSB) and soil incorporation strategies. RSB leads to significant air pollution and has been banned in some regions, whereas stubble and straw incorporation into wet soil during land preparation is associated with enhanced methane emissions. Therefore, both strategies have important deleterious environmental effects and fail to take advantage of the huge energy potential of rice straw. Using rice straw as lignocellulosic biomass to produce bioethanol would appear to be a promising and ambitious goal to both manage this agricultural waste and to produce environmentally friendly biofuel. Technical difficulties, however, associated with the conversion of lignocellulose into simple, fermentable sugars, have hampered the massive development of rice‐straw‐derived bioethanol. Recent technical advances in straw pre‐treatment, hydrolysis and fermentation may, however, overcome these limitations and facilitate a dramatic turnover in biofuels production in the near future. Copyright © 2009 Society of Chemical Industry and John Wiley & Sons, Ltd

Rice straw recycling: A sustainable approach for ensuring environmental quality and economic security

Rice cultivation and energy use for rice production can produce the environmental impacts, especially related to greenhouse gas (GHG) emissions. Also, rice straw open burning by farmers generally practiced after harvesting stage in Thailand for removing the residues in the rice field is associated with emissions of air pollutants, especially particulate matter formation that affects human health and global climate. This study assessed the environmental burdens, consisting of GHG emissions, energy use, and particulate matter formation (PM10), from rice cultivation in Thailand by life cycle assessment (LCA) and compared the environmental burdens of rice straw management scenarios: open burning, incorporation into soil, and direct combustion for electricity generation. The data were collected from the rice production cooperative in Chiang Mai province, northern Thailand, via onsite records and face-to-face questionnaires in 2016. The environmental impacts were evaluated from cradle-to-farm gate. The results showed that the total GHG emissions were 0.64kg CO2-eq per kilogram of paddy rice, the total energy use was 1.80MJ per kilogram of paddy rice and the PM10 emissions were 0.42g PM10-eq per kilogram of paddy rice. The results of rice straw management scenarios showed that rice straw open burning had the highest GHG and PM10 emissions. However, rice straw utilization by incorporation into soil and direct combustion for electricity generation could reduce these impacts substantially.

ABSTRACTWater and rice straw (RS) management practices can potentially affect the accumulation of soil organic carbon (SOC) in agricultural soils. Field experiments were conducted in two consecutive rice-growing seasons (wet and dry) to evaluate SOC stocks under different water (continuous flooding [CF], alternate wetting and drying [AWD]) and RS management practices (RS incorporation [RS-I], RS burning [RS-B], without RS incorporation and burning [WRS]) in a double-cropped paddy field. RS-I under AWD had higher volumetric water content than the same RS management under CF at tillering in both growing seasons. Total SOC was significantly higher under AWD at tillering in both wet and dry seasons and after harvesting in the dry season compared with CF. The same trend was also observed for C:N ratio at tillering and after harvesting in the dry season. RS-B plots had lower SOC stocks than RS-I and WRS plots across most of the measuring periods regardless of the growing seasons. SOC stocks were 33.09 and 39.31 Mg/ha at RS-B and RS-I plots, respectively, in the wet season, whereas the respective values were 21.45 and 24.55 Mg/ha in the dry season. Incorporation of RS enhanced SOC stocks under AWD irrigation, especially in the dry season before planting. Soil incorporation of RS in combination with AWD could be a viable option to increase SOC stocks in the double-cropped rice production region as it is strongly linked with soil fertility and productivity. However, the environmental consequences of RS incorporation in irrigated lowland rice production system should be taken into consideration before its recommendation for paddy field on a large scale.

Management of rice straw with relay cropping of Chinese milk vetch improved double-rice cropping system production in southern China

The Philippines produces up to 15.2 Mt of rice straw waste annually. Unmanaged rice straw waste disposal can lead to pollution from open field burning. On the other hand, rice straw agricultural waste can be used sustainably to produce valuable products such as mushrooms, fodder, pellets, or bioenergy, in a rice straw management system. Such systems can be optimized using Process Integration tools so that the raw materials are used efficiently at the maximum profit and with a minimal carbon footprint. The P-graph framework is an efficient Process Integration tool that solves Process Network Synthesis problems. A P-graph finds the optimal and suboptimal solutions for further analysis, which is useful in decision-making. This work developed a P-graph model for a rice straw management network considering the straw collection and storage steps and the production of both bioenergy and non-bioenergy products. The model can generate optimal and sub-optimal solutions (based on profit) and can simulate raw material disruption scenarios. The model is demonstrated through a case study on three rice straw fields with a maximum total rice straw yield of 96.84 t/yr. The case study considered the operating and raw material costs but did not consider the fixed and investment costs in the calculation of the profit. The results show that mushroom production using rice straw as substrate is the optimal solution with a potential profit of US$ 14 659.60/yr, followed by pellet production with a potential profit of US$ 12 627.90/yr. Disruption scenarios at reduced diesel, manual labor, and rice straw show that mushroom production is still the optimum solution, showing the robustness of the solution. This basic model shows that P-graphs can be applied to rice straw management networks to aid with decision-making for sustainability. Caution must be exercised as the results are context- and location- specific.

Managing rice straw remains a challenge in Asia where more rice, and hence, more straw, is grown each year to meet rising demand. The widespread burning of rice straw is a major contributor to dangerously high levels of air pollution in South- and Southeast Asia associated with health issues. At the same time, researchers, engineers, and entrepreneurs are developing a range of alternative uses that turn rice straw into a commodity around which sustainable value chains can be built to benefit rural people. The best alternative to burning rice straw in any one location depends on context. However, available information remains scattered in different media and no publication yet exists that helps people learn about, and decide between, rice straw management options. This book provides a synthesis of these options and integrates knowledge on relevant areas: sustainable rice straw management practices, rice straw value chains, and business models. The book is also based on new research and practice data from research organizations and innovators in Vietnam, the Philippines, and Cambodia.

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.