Impact of Prescribed Fire on Nitrogen Mineralization in Three Different Ecosystems of the North-western Himalaya: An Insurance to Wildfire-prone Ecosystems

To understand the dynamics of nitrogen pools in response to prescribed fire, a study was carried out with four land uses, viz. chir pine forest (Pinus roxburghii), grassland, scrubland and non-fire site in chir pine (control) at three soil depths (0–5, 5–10 and 10–15 cm) for a period of one year. The results revealed that ammonification rate increased initially for few months post-fire up to the rainy season and then showed a declining trend in all the burnt land uses, and decreased with increasing soil depth. The nitrification rate was almost the same as pre-fire levels in the initial few months after fire, and then started increasing from August onwards till the end of the study period. Post-fire, the net nitrogen mineralization was found higher in all the burnt land uses over control. Prescribed fire accelerates the rate of net N mineralization which contributes to ecosystem productivity.