Impact of Paddy Straw Incorporation along with Different Fertilizer Doses on Mineral N Dynamics and GHG Emissions

Aim: An incubation experiment was conducted, which aimed to investigate NH4+ and NO3- release pattern and GHG emissions as influenced by paddy residue decomposition over 120 days. Study Design: Completely randomized block design. Place and Duration of Study: The study was conducted at Agrometerology laboratory, CRIDA, Hyderabad. The experiment was conducted between 2021-22. Methodology: Sampling was performed at 2, 4, 6, 8, 10, 20, 30, 45, 60, 75, 90, 105 and 120 days after incubation (DAI). The treatments included control (T1), soil + N (T2), paddy residue + 100% RDN (Recommended dose of Nitrogen) - 33:33:33 (T3), paddy residue + 100% RDN - 43:23:33 (T4), paddy residue + 100% RDN - 43:33:23 (T5), paddy residue + 10% extra RDN - 43:23:33 (T6). Fertilizer N was applied in three splits (first at initiation of experiment, second and third at 30 and 60 DAI respectively). RDN used in the study was 240 kg ha-1 (i.e., maize). Results: Residue incorporation along with inorganic fertilizer significantly influenced NH4+ - N and NO3- - N, as well as GHG emissions. After addition of each split, there was an increase in NH4+ - N and NO3- - N contents. Significantly higher NH4+ - N and NO3- - N was recorded in T6, compared to other treatments. The cumulative CO2 and N2O emissions were significantly higher in paddy residue + 10 % extra RDN – 43:23:33 i.e., 296.63 µg C g-1 of soil and 1.81 µg N g-1 of soil respectively, while lowest (42.59 µg C g-1 of soil and 0.09 µg N g-1 of soil respectively) was observed in control.