The effect of fire on carbon sequestration of soil and plant biomass in Semi-Steppe rangelands of Central Zagros region, Iran

Rangeland ecosystems are occupied about half of the world’s lands and contain more than a third of the world’s terrestrial carbon reserves. Therefore, this type of ecosystems has an important role and high potential for carbon sequestration. One of the important disturbances in the rangelands is the fire, which could have a significant role in the global carbon cycle. This study is an evaluation on the effect of fire to soil carbon sequestration and plant biomass and the distribution on total carbon sequestration in central Zagros region. The case study consists of three sites (as the repeat) located in the Buin & Miandasht district within Isfahan province, they were selected whereas one year was passed after the last fire, then cases were compared with the neighbor region. The content of carbon in above and underground biomass, litter carbon and soil organic carbon (in two depths 0-15 cm, 15-30 cm) were measured. The results showed that the total carbon sequestration in control regions was 39.4 ton/ha-1s and in burned region was ton/ha-1. Carbon distribution also showed that the soil organic carbon contents were higher than 90% of total carbon sequestration. It was concluded that the fire in rangelands decreases the carbon sequestration approximately 8.5 ton/ha-1, where soil's share in this reduction was 5.1 ton/ha-1 and total plant biomass share was 3.4 ton/ha-1. Therefore, fire management plays an important role in maintaining carbon sequestrates in vegetation cover and soil.