Greenhouse gas emission mitigation from rice through efficient use of industrial and value-added agricultural wastes: a review

Globally, enormous amounts of agricultural wastes, primarily rice straw (731 million tons), and industrial wastes (basic slag, phosphogypsum, and fly ash from the steel, fertilizer, and coal industries, respectively) are produced annually. The air pollution and greenhouse gas (GHG) emissions linked to climate change and global warming are caused by the burning of rice straw and the disposal of these industrial wastes. As rice fields significantly contribute towards global GHGs emissions (approximately 9–13%), the application of those waste as soil amendments not only mitigates the GHGs emissions, but also enhances crop production. Although studies have shown the effectiveness of different industrial and agricultural waste, further operational research is needed globally as this field is still in its early stages. With this hypothesis, we have reviewed 160 individual data sets from recent literature and our own data to focus on the mechanism, effect, limitation and future recommendation of these wastes in rice on climate change mitigation. The CH₄ emission could be reduced by 28, 30 and 16% by application of basic slag, phosphogypsum and fly-ash, respectively and by application of biochar and Rice straw it could be enhanced by 25 and 58% respectively. The N₂O emission could be reduced by 27, 18, 11, 35 and 13% by application of basic slag, phosphogypsum, fly ash, biochar and rice straw, respectively. The mechanism behind the GHGs emission mitigation potential of those wastes in rice fields is discussed briefly. Utilization of wastes to mitigate global warming and alternative nutrient sources for the crop could be a win–win green technology in the future. We perceived this review would give significant information on the impact of those wastes as soil amendments on climate change mitigation, which is beneficial for the stakeholders and policy makers.