Abstract:

To compare the differences in ammonia volatilization emission of early season rice-ratooning rice field under different tillage methods, four tillage methods, including plowing once and rotary tillage once (T1), plowing once and rotary tillage 2 times (T2), no plowing of field and rotary tillage 2 times (T3) and no plowing of field and rotary tillage 3 times(T4), were set up according to whether the plowing before winter and the rotary tillage status before transplanting. Using a random block design with Fengliangyouxiang 1 as the material, the changes of soil ammonia volatilization and NH₄⁺-N in paddy field water during the rice grown season as well as rice yield were measured to provide scientific basis for reducing nitrogen loss from early season rice-ratooning rice field. The results showed that, the cumulative amount of ammonia volatilization of different treatments accounted for 6.6%?18.8%, 5.6%?13.7%, 9.5%?25.2% and 7.9%?21.9% of the nitrogen input rate, respectively. The emission intensity of ammonia volatilization for each treatment in early rice season and ratooning rice season reached a significant level. The order of ammonia volatilization flux, cumulative amount and emission intensity of each treatment were as following T3>T4>T1>T2. Tillage methods had significant effects on the ammonia volatilization and the yield of early rice. The rice yield of the different tillage methods showed a trend that T2>T1>T4>T3, that was, the amount of ammonia volatilization decreased with the increase in the rice yield. The T2 treatment resulted in the smallest amount of ammonia volatilization and the greatest rice yield. This was mainly owing to the reduced nitrogen loss by improving soil structure. These results suggest that plowing once and then double rotation tillage (T2) is beneficial to reduce ammonia volatilization emission, promote rice growth and development, and improve rice yield. Therefore, plowing once and then double rotation tillage is a recommended tillage method for a production mode of early season rice-ratooning rice.

Key words: ammonia volatilization flux, ammonia volatilization intensity, tillage methods, NH₄⁺-N content in the surface water, early rice-ratooning rice, Jianghan Plain

摘要：

为比较不同耕作方式下早稻-再生稻稻田的氨挥发排放差异,采用随机区组设计,以中稻品种丰两优香1号为材料,按冬前是否翻耕和插秧前旋耕情况,设置4种耕作方式：翻耕一次旋耕一次（T1）、翻耕一次旋耕两次（T2）、不翻耕旋耕两次（T3）和不翻耕旋耕3次（T4）,观察4种耕作方式下土壤氨挥发、田面水NH₄⁺-N变化及产量,以期为早稻-再生稻稻田有效降低氨挥发提供理论依据。结果表明,2019年水稻各生育期不同处理的氨挥发累积量分别占施氮量的6.6%—18.8%、5.6%—13.7%、9.5%—25.2%和7.9%—21.9%,其早稻和再生稻各处理氨挥发排放强度均达到显著水平,各处理氨挥发通量、累积量及排放强度大小均为T3>T4>T1>T2;耕作方式既影响氨挥发又影响早稻产量,不同耕作处理下水稻产量均呈现T2>T1>T4>T3的趋势,即氨挥发与水稻产量呈现此消彼长的关系,T2的氨挥发损失最小而产量最高,主要原因是该耕作方式通过改善土壤结构减少了氮素损失。以上分析表明,翻耕一次旋耕两次（T2）可减少氨挥发排放,促进水稻生长发育,有利于提高水稻产量,是值得推荐采用的适宜早稻-再生稻生产的耕作方式。

关键词: 氨挥发通量, 氨挥发强度, 耕作方式, 田面水NH₄⁺-N, 早稻-再生稻, 江汉平原