Evaluation of physical and chemical soil properties under different management types in the south-western Colombian Andes

Abstract

Aim of study: Evaluating the variability of physical and chemical soil properties under different soil uses in an experimental farmland of the southwestern Colombian Andes.Area of study: This research was conducted at the Botana Experimental Farm in the mountainous area of Nariño, at the south-western Colombia.Material and methods: nine soil variables were measured under six soil uses which included traditional agriculture, agroforestry systems, and a 67-year-old secondary forest that was used as a reference for comparisons with other soil uses. Data was analyzed through Principal Component Analysis and Duncan’s tests.Main results: organic carbon, cation exchange capacity, clay contents and base saturation were the variables with higher variability among soil uses. The secondary forest and an agroforestry system with alley-cropped wax laurel showed the best soil conditions, whilst pastures and monoculture potato crop plots showed the least desirable conditions for all variables.Research highlights: We found that soils under alley-crop with wax laurel presented the characteristics most similar to the secondary forest. Conversely, soils under alley-crop with alder resembled the soils under intensive management (pasture and potato monocrop); which is related to the inadequate management of this agroforestry systems, provoking that the woody component does not accomplish its goal when implemented.Keywords: soil; agroforestry systems; Andes; forest.Abbreviations used: ACAL, Alley cropping of Alder Trees, ACWL; Alley cropping of Wax Laurel; AFS, agroforestry systems; AWC, available water capacity; BD, Bulk Density; BS, Base saturation; CEC, Cation Exchange Capacity; CLA, Clay; CI, Confidence Intervals, INF, Infiltration; ANOVA, Analysis of Variance; OC, Soil Organic Carbon;  PAST, Pasture; PCA, Principal Component Analysis; PC, Principal Component; POCR, Potato Crop; POR, Soil Porosity; SCAL, Scattered Alder Trees; SEFO, Secondary Forest; SU, soil uses; AU, Animal unit.