论文部分内容阅读
以川中丘陵地区典型冬水田为对象,设置了有水稻常规施肥(RF)、无水稻常规施肥(NP)、有水稻无氮肥(NN)3种处理,以静态暗箱-气相色谱法对甲烷(CH_4)排放进行了原位观测.结果表明,RF、NP和NN处理下CH_4排放通量分别为-0.0042~18.29、0.03~16.78和0.10~26.76mg·m~(-2)·h~(-1),平均排放通量分别为10.22、4.25和14.15 mg·m~(-2)·h~(-1)(以每平方米每小时消耗/产生的C量(mg)计),水稻生长季是主要排放期,但休闲季CH_4排放量仍占全年CH_4总排放量的14%.没有水稻处理的CH_4排放量显著低于有水稻处理(p<0.01);而不施氮肥处理的CH_4排放量显著高于施肥处理(p<0.01).CH_4排放通量与5 cm深土壤温度呈显著正相关(p<0.01),随着温度的升高,甲烷排放量呈指数增加.CH_4排放通量与1~4 cm的稻田水深呈显著负相关(p<0.01),随着水深的增加,甲烷的排放呈指数迅速下降;而与4~8 cm的稻田水深无相关性,甲烷的排放也变化缓慢.由此表明,土壤温度和水深在很大程度上调控着CH_4的排放.此外,研究结果也显示将冬水田休闲期改为旱作可减少CH_4排放,对环境有利.
Taking typical winter paddy fields in hilly area of central Sichuan as an example, three treatments, conventional fertilization (RF), conventional rice fertilization (NP), and nitrogen-free rice (NN) ) Emission was observed in situ.The results showed that the fluxes of CH_4 under RF, NP and NN treatments were -0.0042 ~ 18.29, 0.03 ~ 16.78 and 0.10 ~ 26.76 mg · m -2 · h -1 ), And the average emission fluxes were 10.22, 4.25 and 14.15 mg · m -2 · h -1 (calculated as C amount consumed / produced per square meter per hour) But CH_4 emissions still accounted for 14% of the total CH_4 emissions in the whole seasons, while CH_4 emissions without rice treatment were significantly lower than those with rice treatment (p <0.01), while CH_4 emissions without nitrogen application (P <0.01) .Changes of CH 4 flux and soil temperature of 5 cm were significantly and positively correlated (p <0.01), with the increase of temperature, methane emission increased exponentially.CH 4 emission flux (P <0.01). With the increase of water depth, methane emission decreased exponentially rapidly. However, there was no correlation with water depth of 4 ~ 8 cm and methane emission also changed slow The results show that changing the winter paddy field leisure time to dry farming can reduce CH_4 emission and is good for the environment.