Different Responses of Greenhouse Gas Emissions to Straw Application at Different Seasons in Northeast China

Abstract

Although straw return plays a role in regulating greenhouse gas (GHG) emissions from rice paddy fields, little quantitative information is available on the extent at different periods. In this study, gas samples were collected during the rice growing period from an in-situ experiment comprising three treatments: no straw return (CK); straw return in the autumn (SR-A), and; straw return in the spring (SR-S). The results showed that SR-A and SR-S enhanced CO 2 and CH 4 emissions, but reduced N 2 O emissions during the growing period. The total cumulative CO 2 emissions over the entire growing period in the SR-S treatment reached 20,383.72 kg ha −1 , significantly higher than those of the SR-A and CK treatments. CH 4 emissions for all the growing periods were in the order SR-S > SR-A > CK. The CK and SR-S treatments released the most and least N 2 O during the different periods, respectively. The global warming potential (GWP) of CH 4 released by the SR