دانلود رایگان مقاله مدیریت کود و آب بر عملکرد برنج و شدت گاز گلخانه ای در شرایط فصلی مختلف در آب و هوای گرمسیری

abstract

Intensively double cropping rice increases greenhouse gas (GHG) emission in tropical countries, and hence, finding better management practices is imperative for reducing global warming potential (GWP), while sustaining rice yield. This study demonstrated an efficient fertilizer and water management practice targeting seasonal weather conditions effects on rice productivity, nitrogen use efficiency (NUE), GWP, and GHG intensity (GHGI). Twoseason experiments were conducted with two pot-scale experiments using urea and urea + cattle manure (CM) under continuous flooding (CF) during the wet season (2013WS), and urea with/without CaSiO3 application under alternate wetting and drying (AWD) during the dry season (2014DS). In 2013WS, 120 kg N ha−1 of urea fertilizer resulted in lower CH4 emission and similar rice production compared to urea + CM. In 2014DS, CaSiO3 application showed no difference in yields and led to significant reduction of N2O emission, but increased CH4 emission and GWP. Due to significant increases in GHG emissions in urea + CM and CaSiO3 application, we compared a seasonal difference in a local rice cultivation to test two water management practices. CF was adopted during 2013WS while AWD was adopted during 2014DS. Greater grain yields and yield components and NUE were obtained in 2014DS than in 2013WS. Furthermore, higher grain yields contributed to similar values of GHGI although GWP of cumulative GHG emissions was increased in 2014DS. Thus, utilizing urea only application under AWD is a preferred practice to minimize GWP without yield decline for double cropping rice in tropical countries.

4. Conclusion

Tropical climates allow for a double cropping rice system to be implemented during the wet season (WS) and dry season (DS). The intensively irrigated rice field increases global warming potential (GWP), resulting in elevated global average temperature near the surface of the Earth. Thus, an appropriate practice that sustains rice productivity and reduces GWP must be developed and implemented in rice cultivation in Southeast Asia. The current study evaluated the effect of fertilizer and water management on rice productivity, GWP, and greenhouse gas intensity (GHGI) in different seasonal weather conditions. During 2013WS, the combination of CM with urea fertilizer enhanced GWP more than urea alone under continuous flooding (CF). Although CaSiO3 application led to reduction of N2O emission, it also increased GWP under alternate wetting and drying (AWD) during 2014DS, as compared to the urea alone. Thus, utilizing urea fertilizer was an appropriate practice to maintain rice yield and prevent increase in GWP in the study. Moreover, alternative water management based on seasonal weather (CF in the WS vs AWD in the DS) did not exhibit differences in GHGI between the 2013WS and 2014DS.