覆膜和氮肥用量对雨养春玉米农田甲烷吸收的影响

摘要

为了研究覆膜与氮肥用量对雨养春玉米农田CH4吸收的影响,在覆膜(刚)与不覆膜(BP)条件下分别设置了0、100、250、400kg·hm-24个氮肥水平,共8个处理,采用静态暗箱-气相色谱法对农田CH4的吸收通量进行连续观测,同时观测影响通量变化的温度、水分以及硝铵态氮等环境因子.结果表明:旱作春玉米农田是甲烷的汇,休闲期的累积吸收量占年总吸收量48％ ～60％,在年总吸收量中占了不可忽视的一部分;FM0、FM100、FM250、FM400和BP0、BP100、BP250、BP400在2014-2015年的年总吸收量分别为0.99、1.38、1.3、1.37 C H4-C kg·hm-2和1.43、1.77、1.68、1.56CH4-C kg·hm-2,地膜覆盖和施氮量的增加均未显著改变雨养春玉米农田对CH4的吸收量;雨养春玉米农田土壤CH4的吸收速率与0、10 cm土层土壤温度呈极显著正相关,与土壤孔隙含水量(WFPS)、NH4+-N之间呈极显著负相关,不覆膜条件下与NO3--N之间呈负相关关系,且达到极显著水平(P＜0.01).%Understanding the response of CH4 absorption to film mulching and nitrogen fertilizer is of value for improving management practices.We monitored the CH4 absorption from plastic film-mulched and no-mulched maize fields that received different N application rates (0,100,250 kg·hm-2 and 400 kg·hm-2) using the static chamber technique.In addition,the impact factors (soil inorganic nitrogen,soil temperature and moisture,etc.) were estimated.The results showed that the rain-fed maize fields acted as a sink for CH4,and 48％ ～ 60％ of the annual uptake was during the fallow period.The annual CH4 uptake rate was 0.99,1.38,1.3,1.37,1.43,1.77,1.68,1.56 CH4-C kg ·hm-2 for FM0,FM100,FM250,FM400,BP0,BP100,BP250 and BP400 treatment in 2014-2015,respectively.Both film mulching and N fertilizer did not increase the CH4 uptake.The soil C H4 uptake was positively correlated with 0 cm and 10 cm soil temperature,but negatively correlated with soil WFPS and soil NH4 +-N concentration.The CH4 up-take was negatively correlated with soil NO3--N concentration under no-mulched treatments.