Abstract

OCAMPO QUIJANO, Lucía E.; OSORIO VEGA, Walter N.; MARTINEZ ATENCIA, Judith  and  CABRERA TORRES, Kenneth R.. Soil bulk density and aggregate size control plant root growth of Megathyrsus maximus. Acta Agron. [online]. 2021, vol.70, n.4, pp.353-362.  Epub Mar 30, 2023. ISSN 0120-2812.  https://doi.org/10.15446/acag.v70n4.88785.

The importance of physicals properties of soil has an appreciable influence on their functions, water quality, climate control, nutrient cycling, and biodiversity, among others. These provide more ecosystem functions than just the nutritional contribution to agricultural production. Currently, the soil is under management pressure to the food production energy and raw material, which has led to its physical deterioration and degradation. The objective of this study is to evaluate the effects of bulk density and soil aggregate size silvopastoral systems (from tropical dry forest pastures) on the growth of guinea grass (Megathyrsus maximus) cv. Mombasa. To this end, two separate experiments were carried out under greenhouse conditions, by establishing increasing values of each variable through exerting mechanical forces (bulk density: 0.93-1.80 Mg m-3) and sieved (average size of aggregates: 0.125-7.15 mm) and then grass seeds were sown and allowed to grow for 30 days. Two functional models are found which relate the biomass of grass roots with the value of bulk density and with the average size of soil aggregates. It is concluded that for both variables, quadratic regression models are detected, namely, of optimal point; being these optimal values for the apparent density of 1.0 Mg m-3 and of aggregate size of 1.5-2.0 mm. These parameters could be used as physical indicators in the diagnosis of soil health in the Rio Sinú Valley region.

Keywords : soil densification; indicators; pasture guinea; silvopastoral systems; soil health.

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