太湖流域不同再生稻品种的温室气体排放强度

为明确太湖流域种植再生稻的可行性及其对温室气体排放的影响，于2021年4—10月采用静态箱-气相色谱法观测了旱优73、甬优2640、丰两优香1号、两优6326和C两优华占5个品种再生稻的CH₄和N₂O排放通量以及产量。结果表明：稻季观测期内，CH₄排放峰分别出现在中稻季分蘖期和抽穗前后以及再生季前期；两季CH₄累积排放量为209~289 kg·hm^-2，再生季占比为8.3%~23.0%，其中两优6326的值最高，显著高于旱优73、甬优2640和丰两优香1号（P<0.05）。N₂O排放峰主要出现在肥料施用后和土壤水分发生剧烈变化时；两季N₂O累积排放量为0.386~0.548 kg·hm^-2，再生季占比为0.5%~2.4%，5个品种间N₂O排放量无显著差异。不同处理两季水稻总产量为6.12~12.62 t·hm^-2，再生季占比为23.8%~36.7%，其中甬优2640和丰两优香1号的两季总产量相对较高。不同处理的温室气体排放强度为0.50~1.35 t CO₂ e·t^-1，其中甬优2640最低，两优6326最高（P<0.05）。研究表明，甬优2640和丰两优香1号的两季总产量较高，且温室气体排放强度相对较低。

Greenhouse gas intensity from different cultivars of ratoon rice fields in Taihu Lake region, China

To clarify the feasibility of ratoon rice cultivation in the Taihu Lake region and its effect on greenhouse gas emissions, a field experiment was conducted from April to October in 2021, using the static chamber-gas chromatography technique and adopting five cultivars of ratoon riceHanyou 73(H73), Yongyou 2640(Y2640), Fengliangyouxiang 1(F1), C Liangyouhuazhan(CZ), and Liangyou 6326 (L6326)]. The results showed that the CH₄ fluxes reached peak during the tillering and heading of main rice crop season and early ratoon season. Seasonal cumulative CH₄ emissions ranged from 209 to 289 kg·hm^-2, of which 8.3%~23.0% was attributed to the ratoon season. Total CH₄ emission from L6326 was the highest, which was obviously higher than that from H73, Y2640, and F1(P<0.05). The N₂O flux peaks were mainly measured during the periods of nitrogen fertilization and soil moisture drastic changes. The seasonal N₂O emissions ranged from 0.386 to 0.548 kg·hm^-2, with 0.5%~2.4% in ratoon season. There was no significant difference in N₂O emissions among the five rice cultivars. Total rice yield was 6.12~12.62 t·hm^-2, and the ratoon rice contributed 23.8%~36.7%. The yields of Y2640 and F1 were relatively higher than those of other three rice cultivars. As a whole, the greenhouse gas intensity ranged from 0.50 to 1.35 t CO₂ e·t^-1, with the lowest and highest values observed in Y2640 and L6326, respectively. Based on these findings, the Y2640 and F1 rice cultivars could be potentially planted in Taihu Lake region owing to their relatively higher yields and lower greenhouse gas intensity.