Abstract

PEREZ ATEHORTUA, Maritza et al. Carbon stocks of Cenchrus clandestinus grass (Poaceae) in traditional and silvopastoral systems, in different reliefs. Rev. biol. trop [online]. 2019, vol.67, n.4, pp.769-783. ISSN 0034-7744.  http://dx.doi.org/10.15517/rbt.v67i4.34529.

The increase of Greenhouse Gases (GHG) emissions derived from human activities are considered the main cause of current climate change and the livestock sector is responsible for 18 % of the GHG emissions in CO2 equivalent. Kikuyu grass can optimize both carbon capture and carbon fixation. The aim of this paper was to identify carbon stocks in the kikuyu grass in its different compartments, above-ground biomass (AB) and below-ground biomass (BB) at 20 and 40 cm soil depth, under the traditional and silvopastoral systems in different reliefs. Six successive samplings (M) were taken according to the grazing system (traditional and silvopastoral system), and the geoform of the terrain (concave flank (CCF), convex flank (CXF), rectilinear flank (RF) and flat relief (FR)). The above-ground biomass and below-ground biomass were sampled. The statistical method used was a design in incomplete randomized blocks, two treatments were evaluated (T) (T1: traditional system and T2: silvopastoral system) with four blocks (B) in each one (B1: CCF, B2: CXF, B3: RF, B4: FR). This experiment was done from June 2016 to June 2017 in San Pedro de los Milagros, Antioquia, Colombia. The results allowed to determine that the roots at 20 cm depth, the dead creeping stems, and the leaves were the compartments with the highest carbon stocks (4.52, 3.58 and 1.9 ton of C ha-1, respectively). Differences were found (P < 0.05) between flat and rectilinear relief for the biomass of leaves, and between the flat relief with the other reliefs evaluated for the variable thick roots at 20 cm depth. The biomass produced by the plant is directly proportional to the incorporated carbon. The root biomass, both fine and thick roots, contributes to capture on average 2 820 kg and 655 kg of carbon per hectare at of 20 and 40 cm depth respectively. Kikuyu grass contributes to keep carbon reserves in the grasslands. Due to the high production of below-ground biomass and creeping stems, and its high capacity of regrowth under adverse conditions, this grass plays an important role in the reduction of GHG and the conservation of high tropical soils under specialized dairy systems.

Keywords : carbon capture; creeping stems; greenhouse gases; pastures; stoloniferous roots.

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