Rice straw incorporation is labor-intensive and influences greenhouse gas emissions but can increase soil organic carbon (C) and recycle nutrients. Rice straw contains about 80, 40, and 30% of the potassium (K), nitrogen (N), and phosphorus (P), respectively, taken up by rice and thus its incorporation can reduce the fertilizer requirement of the subsequent crop. However, because of rice straw’s low quality, its decomposition is slow. So, the timing of this operation, in combination with water management, becomes important. Composting rice straw with the addition of farmyard manure can improve quality and nutrient supply. Similarly, biochar from thermal combustion of rice straw for energy production can be added to the soil to improve soil organic C. This chapter highlights the benefits derived from incorporating straw into the soil. Alternative forms of straw that can be used by farmers, depending on local situations, are discussed.

Reducing methane (CH₄) emission from paddy rice production is an important target for many Asian countries in order to comply with their climate policy commitments. National greenhouse gas (GHG) inventory approaches like the Tier-2 approach of the Intergovernmental Panel on Climate Change (IPCC) are useful to assess country-scale emissions from the agricultural sector. In paddy rice, alternate wetting and drying (AWD) is a promising and well-studied water management technique which, as shown in experimental studies, can effectively reduce CH₄ emissions. However, so far little is known about GHG emission rates under AWD when the technique is fully controlled by farmers. This study assesses CH4 and nitrous oxide (N₂O) fluxes under continuous flooded (CF) and AWD treatments for seven subsequent seasons on farmers’ fields in a pumped irrigation system in Central Luzon, Philippines. Under AWD management, CH₄ emissions were substantially reduced (73% in dry season (DS), 21% in wet season (WS)). In all treatments, CH₄ is the major contributor to the total GHG emission and is, thus, identified as the driving force to the global warming potential (GWP). The contribution of N₂O emissions to the GWP was higher in CF than in AWD, however, these only offset 15% of the decrease in CH₄ emission and, therefore, did not jeopardize the strong reduction in the GWP. The study proves the feasibility of AWD under farmers’ management as well as the intended mitigation effect. Resulting from this study, it is recommended to incentivize dissemination strategies in order to improve the effectiveness of mitigation initiatives. A comparison of single CH₄ emissions to calculated emissions with the IPCC Tier-2 inventory approach identified that, although averaged values showed a sufficient degree of accuracy, fluctuations for single measurement points have high variation which limit the use of the method for field-level assessments.

Lowland rice is a significant source of anthropogenic greenhouse gas emissions (GHGEs) and the primary source of agricultural emissions for many developing countries in Asia. At the same time, rice soils represent one of the largest global soil organic carbon sinks. Straw management is a key factor in controlling the emissions and mitigation potential of rice primarily by affecting methane (CH₄) from anaerobic decomposition and carbon losses from burning. Achieving climate-smart management of rice while also improving yields and farm profits, however, is challenging due to economic-environmental trade-offs. This balance could be met with appropriate site-specific practices. This chapter discusses these straw management practices that affect yield-scaled GHGEs and mitigation options in different rice environments.

Current practices in rice production leave a huge amount of wet straw on the field, which cannot be used as feed or for food production. Compost production is one way of effectively utilizing rice straw. Spent rice straw from mushroom production is also used as compost but this has low nutrient value and is poorly decomposed when using it as a soil improver. This wet, low-quality straw, as well as byproducts from mushroom and cattle feed production, could be used to produce better-quality compost to return nutrients back to the field. Mechanization in mixing the materials, i.e., a compost turner, is necessary to have good aeration, increase the decomposition process, and reduce labor cost. This chapter provides an overview of composting technology and current practices of rice-straw composting. Updated information on this topic, resulting under the current BMZ-funded IRRI rice-straw management project (2016–2019), which has been implemented in Vietnam and the Philippines, is also included here, particularly in the sections on vermin-composting and mechanized composting.

In Nigeria, rice remains a major staple food source for the rapidly growing population of an estimated 210 million people. However, traditional rice production carried out in flooded soil is associated with greenhouse gas (GHG) emissions, mainly anthropogenic methane (CH₄) and nitrous oxide (N2O) in Nigeria. Both CH4 and N2O are harmful GHGs that raise the temperature of the planet by retaining heat in the atmosphere. Reduction of GHG emissions is critical, and understanding farmers' knowledge of GHG emission mitigation strategies would be crucial to reducing emissions from rice fields and producing rice in a cleaner environment. Incidentally, there is a dearth of empirical evidence in the current debate. The absence of this study creates a gap in research and makes it extremely pertinent that the study be systematically undertaken. Our study described the socio-economic characteristics of the rice farmers and ascertained their knowledge level on GHG mitigation strategies. We utilized questionnaire and focused group discussion (FGD) as the primary methods of data collection. Descriptive statistics and mean score analysis were used to analyze the data collected. On average, we found that the rice farmers were 45 years old. Most (72%) were male. Only 31% of the farmers had contacted extension agents and were visited twice per calendar year. We found that among various GHG emission mitigation strategies identified in the area, the farmers had significant knowledge of the use of Aerobic Rice Varieties (ARV) (x̄ = 3.61; σ = 0.87) but low knowledge of the use of Alternate Wetting and Drying (AWD) (x̄ = 1.88; σ = 0.45). Our findings confirmed the incidence of GHG emissions in rice fields and that farmers have started practicing GHG mitigation strategies to reduce emissions from rice in the area. However, among various constraints, our study observed that inadequate technical know-how is negatively challenging rice farmers’ capacity to implement and scale-up GHG emissions mitigation strategies. Therefore, our study recommends that the government should strengthen and support agricultural extension service systems to enable them to visit farmers’ farms regularly to transmit and build farmers capacity in the use of recent GHG emission mitigation strategies and innovations in rice fields.

In Nigeria, climate change is not a new phenomenon and arable crop production is vulnerable to climate change. Arable crop farmers have always responded to climate change with local strategies believed to be climate-smart. Arable crop farmers' knowledge of climate change is an important step in understanding any action to be taken to reduce its effect. However, empirical studies on the link between climate change and crop farmers’ adaptation strategies are still relatively scanty in the area. This presents a dearth in research. Therefore, our paper examined how arable crop farmers adapt to climate change using cross-sectional data obtained through a structured focused group discussion and questionnaire from 120 arable farmers across critical farming communities in Imo State, Nigeria. We utilized multistage and purposive sampling procedure in the selection of arable crop farmers. The reason we utilized purposive sampling procedure was to select areas with high intensity of arable crop farmers and farming. Data collected was analyzed using descriptive statistical tools and mean (x̄) score analysis. Our result shows that the mean age was 42.00 years. Greater proportions (73.00%) were female. The average farm size was 1.45 hectares. Vegetables (100.00%), maize (99.17%), cassava (98.33%) and rice (96.67%) were among the crops produced in the area. The result confirmed the incidence of climate change in the area and farmers perceived rightly the direction of the change, which includes declining crop yields (x̄ = 3.00; σ = 0.50), increased in new pests and diseases infestation (x̄= 2.88; σ = 0.58); unstable decrease and increase in temperature and rainfall (x̄=3.63, σ = 0.83) among others. Our study further shows that the major climate change adaptation measures farmers practiced were diversification of livelihood (99.17%) and changing planting/harvesting dates (97.50%). Farmers identified inadequate information (99.17) and inadequate climate change adaptation fund (98.33%) among others as the barriers they faced in adapting to climate change in the area. We recommend that, since arable crop farmers are members of cooperatives, they are encouraged to take advantage of their strength to collectively project a common demand in obtaining funds and other necessary inputs in adapting to climate change in the area. Finally, our study also suggests that the agricultural extension service system should be strengthened so as to provide farmers with stable and right early warning signs which will be critical in minimizing risks of climatic threats in the area.