Effects of Barley Straw Management Practices on Greenhouse Gases(GHGs) Emission During Rice Cultivation in Rice-barley Double Cropping System

Because main barley straw management is changing these days from off-fields to burning that may relate to air quality concerning the global warming, this study was conducted to investigate the effects of barleystraw management practices on greenhouse gas emissions during rice cultivation in rice-barley double cropping system. The treatments were barley straw burning, off-field usage of barley straw and incorporation of barley straw in paddy fields. Laboratory experiment showed that burning of barley straw at the rate of 4.5 Mg ha-1 emitted GHGs in the amounts of 4,607, 19.5, and 0.9 kg ha-1 of CO2, CH4, and N2O, respectively. During the rice cultivation of the rice-barley double cropping system, the highest GHG emission by evaluated close-static chamber method was observed from the soil incorporation of barley straw with 387 and 1.0 kg ha-1 of CH4 and N2O, respectively. The GHGs emissions from the barley straw burning and off-field usage treatments were 233 and 160 kg ha-1 for CH4 and 0.80 and 0.79 kg ha-1 for N2O, respectively. The barley straw burning treatment showed the greatest GHGs emission among barley straw management practices in rice-barley double cropping system when considering GHGs emissions both during burning and from paddy fields during the cropping seasons. As a result, the GHGs emissions recorded in the barley straw incorporation to soil and off-field usage treatments were 22.4 and 66.8%, respectively, less than sum of GHGs emissions from the burning of barley straw and from paddy fields during rice cultivation.