Abstract

TOMAZ, Alexandra et al. Spatial and temporal discrimination of soil attributes through multivariate statistical analysis: A case study in irrigated annual crops in South Portugal. Rev. de Ciências Agrárias [online]. 2022, vol.45, n.4, pp.161-170.  Epub Dec 01, 2022. ISSN 0871-018X.  https://doi.org/10.19084/rca.28414.

A study of temporal and spatial variability of soil variables was carried out during three years, in three farm plots with irrigated annual crops, in two layers (0-20 cm and 20-40 cm), using Factor Analysis (FA) and Discriminant Analysis (DA). With FA, the observed parameters were grouped into a smaller number of latent variables related to soil attributes. DA was used to classify and identify the most influential attributes in time and space discrimination. The FA performed for the surface layer included factors related to texture, water and nutrient retention capacity, chemical composition, and soil fertility. In the subsurface layer, the factor structure was similar, with four factors related to texture, chemical composition, nutrient availability, and soil fertility. The most influential factors in temporal discrimination (sampling dates) in both layers were those related to chemical composition. As for the spatial differentiation (plots), the dominant factor in the surface layer was texture and in the sub-surface layer, the availability of nutrients. The results obtained show potential for the determination of soil quality indicators or for the multidimensional and integrated assessment of patterns of temporal and spatial variation of soil functions resulting from management practices or degradation processes.

Keywords : soil attributes; multivariate statistical analysis; factorial analysis; discriminant analysis; irrigated crops.

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