Effect of Residue Management and Nitrogen Fertilization On Emissions of Different Greenhouse Gases From Subtropical Sugarcane Production.

Agricultural production contributes significantly to the emissions of major greenhouse gases (GHGs) such as carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O), accounting for approximately one-fifth of the annual increase in radiative forcing of climate change. Sugarcane is one of the major row crops in Louisiana and its cultivation involves intensive fertilization and special land management practices.  This purpose of this study was to investigate the effect of different N-fertilizers and harvesting residue management techniques on GHGs emissions from soils under sugarcane production. Two sources of N fertilizers namely urea and urea ammonium nitrate (UAN) and two residue management practices namely residue retained (RR) and residue burned (RB) were evaluated in a plant cane and ratoon crop based on the close chamber method.  The results showed that average N₂O and CO₂ emissions were much higher from urea-treated plots as compared to UAN whereas CH₄ emission was slightly higher in UAN-treated plots than urea-treated plots. The residue retained soil had higher emissions of all three gases than the residue-burned soil. In addition, soil temperature and water filled pore space (%) showed significant effects on all emission of the three gases. The results obtained from field observations were consistent with a similar study conducted in greenhouse.