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.

This paper examines how a move from traditional post-harvest operations of smallholder rice farms in the Ayeyarwaddy delta, Myanmar, to improved post-harvest operations affected income, energy efficiency and greenhouse gas emissions (GHGE). Harvest and post-harvest losses were investigated in a field experiment with 5 replications per scenario. A comparative analysis on energy efficiency and cost-benefits was conducted for different practices of rice production from cultivation to milling. GHGE of different practices were also considered using a life-cycle assessment approach. The study demonstrates that the mechanized practices increased the net income by 30–50% compared with traditional practices. Despite using additional energy for machine manufacturing and fuel consumption, the mechanized practices significantly reduced postharvest losses and did not increase the total life-cycle enegy and GHGE. Combine harvesting helped to significantly reduce harvesting loss in a range of 3 to 7% (by weight of the rice product). Improved post-harvest management practices with a flatbed dryer and hermetic storage reduced the discoloration of rice grains by 3 to 4% and increased head-rice recovery by 20 to 30% (by weight of rice product). The research findings provide empirical evidence that improved post-harvest management of rice in the Ayeyarwaddy delta, compared to traditional post-harvest operations by smallholder farmers, reduce post-harvest losses and improve the quality of rice. The findings provide valuable information for policy makers involved in formulating evidence-based mechanization policies in South and Southeast Asia.

Biomass conversion into various forms of energy, such as heat, power, or biofuels using thermal processes, involves the decomposition of biomass by exposure to heat, typically above 300 °C. Thermal conversion processes include pyrolysis, gasification, and direct combustion. Several factors affect the yields and energy recovery from these processes including temperature, reaction time, heating rate, absence, or presence of oxygen, use of catalysts, and pressure. Due to rice straw’s relatively high carbon and hydrogen contents, it contains a considerable amount of energy that make it a suitable feedstock for thermal conversion. In this chapter, the basic principles and factors affecting the thermal conversion of biomass into energy are discussed. Studies on the use of rice straw as feedstock to produce heat, power, and biofuels via thermal conversion are reviewed. Utilization of thermal conversion byproducts including biochar and ash will are presented. Thermal processes are compared in terms of energy conversion, possible environmental impacts, and technological and commercial maturity.

Climate change will continue to have a largely detrimental impact on the agricultural sector worldwide because of predicted rising temperatures, variable rainfall, and an increase in extreme weather events. Reduced crop yields will lead to higher food prices and increased hardship for low income populations, especially in urban areas. Action on climate change is one of the Sustainable Development Goals (SDG 13) and is linked to the Paris Climate Agreement. The research challenge posed by climate change is so complex that a trans-disciplinary response is required, one that brings together researchers, practitioners, and policy-makers in networks where the lines between “research” and “development” become deliberately blurred. Fostering such networks will require researchers, throughout the world, not only to work across disciplines but also to pursue new South–North and South–South partnerships incorporating policy-makers and practitioners. We use our diverse research experiences to describe the emergence of such networks, such as the Direct Seeded Rice Consortium (DSRC) in South and Southeast Asia, and to identify lessons on how to facilitate and strengthen the development of trans-disciplinary responses to climate change.

Rice production can be carried out using a wide set of cultivation techniques. Different land preparation, crop establishment, crop care, harvesting, and straw management techniques lead to different environmental impacts. Life-cycle assessment (LCA) is a reliable tool for assessing the environmental load of agricultural processes and can be used to compute or simulate energy balance and environmental impact categories such as climate change, ozone depletion, terrestrial acidification, freshwater eutrophication, and marine eutrophication. This chapter comprises the following sections: (1) LCA overview and application in agriculture, (2) case studies of LCA to identify the best rice straw management practices, and (3) summary and suggestions for further applications.

Rice is a staple food crop, and its production generates large volumes of agricultural waste, rice straw. Several studies have proven that open-field burning and soil incorporation are unsustainable practices of managing rice straw, but remain as prevalent methods of treating and disposing of rice straw. An alternative solution is to harness the energy from rice straw via a small-scale heat conversion system for paddy drying applications, which can reduce rice grain post-processing costs and improve paddy storage conditions. This study investigated the energy flow, Greenhouse Gas (GHG) emissions, and cost of a small-scale rice-straw-based heat generation (RBHG) system using a downdraft furnace and a dryer simulator setup. The highest input energy and GHG emissions of 92% and 68%, respectively, were from the heat generation stage. The RBHG energy ratio was between 1.4 and 1.7, and the percent net energy was between 39 and 67%. The best case of RBHG offers a possibility of a net GHG avoided (−61 kg CO₂-eq Mg⁻¹), while the worst case (856 kg CO₂-eq Mg⁻¹) has a net GHG emission comparable with soil incorporation. The average total cost of RBHG is 0.096 USD kWh⁻¹. Overall, RBHG technology has the potential to improve energy flow, GHG emissions, and the cost of rice production systems.