High Resolution Refined Methane Budget Estimates From Paddy Fields of Karnal Using Remote Sensing and GIS.

Atmospheric methane (CH₄) is an important climate forcing agent. In absence of data on paddy water regimes and other emission-influencing factors, global budget of  CH₄ is still estimated with large scale uncertainties at regional and global scales. The objective of the study, therefore, was to estimate high resolution CH₄ budget by integrating the emission factors related to various crop establishment and management practices using remote sensing and spatial modeling. Using multi-temporal LISS III composite NDVI data of kharif season 2006, we estimated 176552 ha area of paddy harvest in Karnal. The CH₄ emission factors obtained from Gas chamber experiments conducted at farmer fields of Karnal, were 6.65 ± 0.79 , 7.65 ± 0.91 and 12.77 ± 1.52 g m^-2 for MA, SA and CF water regimes, respectively. Acreage under water regimes, cultivar type, organic amendments and seedling age was calculated using the spatial modeling; and scaling factors were applied to arrive at total CH₄ budget (12.69 ± 1.50 Gg y^-1).  The enhancement in CH₄ emissions was from 26.18 ± 3.11 to 29.71 ± 3.53 Gg y^-1 when factors like organic amendment, rice cultivar variety and rice seedling age were applied. The maximum (59%) emissions were observed in MA paddy water regime. Nissing, Assandh and Nilokheri accounted for 59% of total CH₄ budget and were identified as “hot spot” blocks.