He specialises in environmental microbiology with emphasis on climate change and carbon sequestration, pesticide biodegradation and bioremediation, rhizosphere microbiology, wetland microbial diversity. A former Director of the National Rice Research Institute and a fellow of several Indian Academies with several national awards, he co-edited the Indian Nitrogen Assessment and is currently co-leading the South Asian Nitrogen Assessment under the GEF-UNEP-INI project, 'Towards International Nitrogen Management System', apart from being the Co-director (Science) for the UKRI-GCRF South Asian Nitrogen Hub. He has published over 130 research articles and books/chapters.
His research on greenhouse gas emission from tropical rice ecosystem indicates that Indian paddy contributes around 4-6 Tg methane per annum, a value which is almost 1/10th of the US-EPA estimate and has now been registered in the Inter-Governmental Panel on Climate Change (IPCC) database. His group also identified flooded paddy as an important source of N2O, another greenhouse gas. He contributed to India's first National Communication (NATCOM) on GHGs as required under Article 12 of the statute of UNFCCC. He participated in the Expert Review of the First Order Draft of the 2006 IPCC inventory guidelines as member of the Elite Panel of Reviewers of WMO/UNEP. He has been the leader of the Team of Excellence on Greenhouse Gas Emission under National Technology Project (NATP) funded by World Bank and has been the collaborator and site leader of the IRRI-UNDP-US-EPA Interregional Research Project on 'Methane Emission from Rice Fields'. He is serving as the Editor of the Indian Journal of Microbiology and Member, Ediorial Board Biology and Fertility of Soils and Agricultural Research Journal, all published by Springer.