Abstract

MEDINA SIERRA, Marisol et al. Organic carbon stocks in soils cultivated with kikuyu grass in northern Antioquia. Acta Agron. [online]. 2022, vol.71, n.2, pp.119-129.  Epub May 31, 2023. ISSN 0120-2812.  https://doi.org/10.15446/acag.v71n2.97692.

Cattle systems are considered greenhouse gas emitters. However, some of their components, such as soil, allow carbon sequestration. The objective of this work was to compare carbon stocks in soils cultivated with kikuyu grass for several years and soils with forest or fern cover under different geoforms, in farms in the north of Antioquia. A randomized block design was used, in which the blocks corresponded to the type of plant cover. Treatments, in a 3x5 factorial arrangement, corresponded to the geoforms and sampling. The effects of geoforms (concave, convex and flat), type of plant cover (kikuyu, forest, and fern), and sampling depth (0-20, 20-40, 40-60, 60-80 y 80-100 cm) were considered in the model. Analyses of variance were performed for the variables: amount of carbon in the soil and fine and thick roots, stems, leaves, stolons and dead biomass; and also soil bulk density and soil pH. Carbon stocks in the first 0-20 cm depth were 100 t ha-1 and only 20 t ha-1 at 80-100 cm depth (p<0.05). There was a difference in carbon stocks contributed by the roots at 0-20 and 20-40 cm depth. The different plant covers analyzed did not affect soil bulk density and its value was low for the concave relief soil. Contrary to the expected effect of pasture planting on soil carbon stocks, the change of land use from forest to kikuyu pasture has no significant effect on soil carbon stocks from the soil surface to a depth of one meter under the conditions evaluated.

Keywords : Biomass; climate change; dairy cattle; greenhouse gases; relief.

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