Abstract

NORENA-GRISALES, Jorge Mario; RAMIREZ PISCO, Ramiro  and  OSORIO VEGA, Nelson Walter. Soil quality indicators related to the deterioration of Kikuyu grass Cenchrus clandestinus (Hochst. ex Chiov.) Morrone. Rev. Fac. Nac. Agron. Medellín [online]. 2024, vol.77, n.3, pp.10811-10825.  Epub Sep 30, 2024. ISSN 0304-2847.  https://doi.org/10.15446/rfnam.v77n3.109829.

Inadequate grassland management has resulted in the degradation of extensive areas, loss of productivity and sustainability of many of them, reflecting a common reality among livestock farmers in Colombia. Therefore, at the Paysandú Agricultural Station of the Universidad Nacional de Colombia, located in the Santa Elena township of the city of Medellín, a study was carried out to determine a soil quality index (SQI) by evaluating the physical and chemical indicators that were most related to the deterioration and dry matter production of kikuyu grass (Cenchrus clandestinus). A minimum data set (MDS) was established for the most sensitive indicators, selected by principal component analysis (PCA), and a nonlinear scoring function was used to obtain the SQI. Statistical differences were found between all the treatments in relation to dry matter production (P<0.05: 1.91x10-32). The most sensitive indicators were bulk density BD > total porosity TP > macropores MAC > micropores MIC > penetration resistance PR > effective cation exchange capacity ECEC > pH. As a result, the following formula was obtained: SQI = (0.225×BD) + (0.224×TP) + (0.220×MAC) + (0.218×MIC) + (0.113×PR) + (0.0879×ECEC) + (0.0877×pH). This index should be tested in kikuyu grass-dominated pastures located in the Colombian high tropics. The baseline is critical at values > 0.58 Mg m-3 for BD and > 2.25 MPa for PR. In addition, the optimum pH range for kikuyu grass development was between 5.4 and 6.4.

Keywords : Degraded pastures; High Andean tropics; Principal component analysis; Soil chemical properties; Soil physical properties; Soil quality index.

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