International Journal of Recycling of Organic Waste in Agriculture (IJROWA) Microbial decomposer assisted in situ degradation of surface retained paddy straw Volume 12 (2023) Issue 3, July 2023 2023 11 17 Microbial decomposer assisted in situ degradation of surface retained paddy straw 10.30486/ijrowa.2022.1935169.1292 EN Priya Katyal Department of Microbiology, Punjab Agricultural University, Ludhiana-141004, India 0000-0003-4437-1164 Rachana Bhardwaj Department of Biochemistry, Punjab Agricultural University, Ludhiana-141004, India Sandeep Sharma Department of Soil Science, Punjab Agricultural University, Ludhiana-141004, India Jagroop Kaur Sekhon Department of Agronomy- Punjab Agricultural University, Ludhiana-141004, India Neemisha Pathania Department of Soil Science, Punjab Agricultural University, Ludhiana-141004, India Pratibha Vyas Department of Microbiology, Punjab Agricultural University, Ludhiana-141004, India Shammi Kapoor Department of Microbiology, Punjab Agricultural University, Ludhiana-141004, India Gurvinder Singh Kocher Department of Microbiology, Punjab Agricultural University, Ludhiana-141004, India Journal Article 2023 11 17 Purpose Paddy (rice) straw burning is an alarming issue all over India because of its huge volume generated every year. Combine harvesting results in generation of about 5-7 ton/hectare paddy straw residue that needs to be managed with in a small period (3 weeks) before sowing of wheat crop. Method Six microbial decomposer preparations including four commercial (C-1 to C-4) and two in house culture (Delftia, Microbial consortium) have been evaluated at four different sites of Central Plain Zone of Punjab during 2018-19 and 2019-20. The microbial formulations were sprayed on the surface retained paddy straw and straw samples were evaluated after 30 days of spray for percent decrease in lignin and C/N ratio.  Result A location and decomposer specific decrease in lignin (%) and C/N ratio during paddy straw surface retention trials was observed, without any significant change in wheat yield. In control (without spray), percent decrease in lignin was in the range of 2.11 to 13.57. Whereas, with microbial sprays, it varies from 7.51 to 35.79. At Ludhiana, maximum decrease in C/N ratio was obtained by C-1 and C-2 (55%), While, at Kapurthala maximum decrease in C/N ratio was obtained by Delftia (71.25%) followed by C-3 (62.62%). Conclusion The variable trend in delignification as well as C/N ratio during surface retained paddy straw trials, highlights that with microbial decomposer application the surface retained paddy straw is not appreciably decomposed in the provided window period of 3 weeks between paddy harvesting and wheat sowing.   Highlights Brief outline of steps involved in microbial decomposer assisted in situ degradation of surface retained paddy straw: Step 1: Combine harvesting of paddy straw Step 2: Microbial Spray manually or by Tractor mounted spray Step 3: Periodic sampling of straw for proximate analysis