Analysis Distribution of Biomass Carbon of Grasslands, Shrubs, and Rainfed Rice Fields on Dry Land in the Aceh Besar District Indonesia

This research was conducted to determine plant biomass, carbon potential, and CO₂ reserve potential in understory vegetation in general, namely grasslands, shrubs, and rainfed rice fields. The sampling of the research was carried out randomly and intentionally, and was limited to the vegetation of reeds, shrubs and rainfed land bushes in the Aceh Besar District of Indonesia. The sample was taken based on a digitized map obtained from overlaying the land use map, slope map, soil type map, and Aceh Besar government map. Measurement of biomass in the vegetation of Imperata, shrubs, and rainfed rice fields is in accordance with procedures from the Indonesian National Standard (2011) and the World Agroforestry Center. The area of bush vegetation is larger than that of rainfed rice fields and grasslands. In general, the plants found in bush vegetation are Acacia leucoeplhoea, Mimosa pudica, Cyperus rotundus, and Eleusine indica. Grassland vegetation has one plant only, namely, Pennisetum purpureum. The vegetation of rainfed rice fields consists of the Oryza sativa type of plant. Plant biomass, carbon [C] content, and carbon potential in bush vegetation are greater than that of grassland and rainfed rice fields, as well as plant biomass reserves, plant biomass carbon and total CO₂ reserves. Shrubs and woody plants render the potential for biomass, carbon, and CO₂ absorption greater than that of grassland and rainfed rice fields. This is in accordance with the research that the increase in biomass is followed by an increase in potential carbon storage. Parameters that affect biomass indirectly will also affect carbon storage in a biomass and in an ecosystem, namely, individual density, stem diameter, tree species diversity, and soil. The density of trees in an area will affect the increase in carbon stocks through an increase in biomass. This is because the vegetation of shrubs does not only consist of undergrowth, but also of woody stems such as Acacia leucoeploea, making carbon stock potential in bush vegetation greater than that of grassland and rainfed rice fields, as shrubs cover an area of 96,962.2 ha, hence larger than that of grasslands and rainfed rice fields.