The low greenhouse gas emission intensity in water-saving and drought-resistance rice in a rainfed paddy field in Southwest China

Abstract

Water shortage has become one of the major threats to global food security. To meet the challenge of increasing food demand and water scarcity, water-saving and drought-resistant rice (WDR) is increasingly cultivated in China. However, there are few comprehensive studies on the effect of WDR on grain yields as well as CH4 and N2O emissions in the literature. A three-year field experiment was conducted with one common rice (CR) and three WDR varieties in a rainfed paddy field in Southwest China. The results showed that in the WDR treatments, both CH4 emissions and the global warming potential of CH4 and N2O emissions decreased by 6.2–15% on average. Seasonal CH4 emission was positively correlated with the mean tiller number but negatively correlated with the harvest index. Moreover, WDR increased the mean grain yield by 18–23% compared to CR, and especially in 2017, an increase within the range of 31–61% was observed when precipitation was low. The increasing grain yield was mainly due to the rise in the percentage of filled grains, and as a result, the greenhouse gas emission intensity was higher by 12–83% in CR than in WDR, while the lowest value was observed in one of the WDR varieties (Hanyou 73). Here, we report for the first time that planting water-saving and drought-resistance rice, especially the Hanyou 73 variety, under rainfed conditions would increase plant grain yield and decrease greenhouse gas emission intensity in regions with water shortage in Southwest China.