J. Calero

A Proposal of Fuzzy Correspondence Analysis Based on Flexible Data Mining Techniques

Correspondence analysis can be seen as a first stage in several information fusion tasks, specially in the case of integrating different classifications of a set of objects. Although several existing statistic tools can be applied to analyze correspondences between partitions, they seem not to be suitable when data is affected by imprecision or uncertainty. In this paper, we make a proposal of correspondence analysis in terms of data mining when fuzzy partitions are defined over a set of objects.

A new soil quality index based on morpho-pedological indicators as a site-specific web service applied to olive groves in the Province of Jaen (South Spain)

Abstract Soil quality has become a fundamental concept in soil science and agriculture, but it can be difficult to apply its theoretical and experimental approaches to poorly surveyed zones where precision techniques are far from being applied. In this paper, we propose a new technique that enables little-used qualitative morpho-pedological data to be managed and integrated into a single Field Soil Quality Index (FSQI). Nonlinear Principal Component Analysis (NLPCA), a technique able to handle categorical data, is applied here to deal with morpho-pedological indicators. When categorical values are transformed, they can be properly analyzed and interpreted. This procedure requires less expert knowledge, so it can help soil quality assessments by non-experts. We applied the FSQI protocol to soils in the most important olive-growing area in the world, Jaen Province (Southern Spain), which has serious problems with soil degradation and erosion. First, a soil database for the study area was compiled, including 18 morphological attributes for 131 surface horizons belonging to eight Land Use Types. Secondly, the NLPCA provides optimal scalings and attribute weights that transform and integrate morphological indicators into a simple weighted additive index (FSQI). Thirdly, the scaling functions and weights found were applied to the same attributes of an evaluation set comparing two soil management types (conventional vs. organic) in olive groves. The FSQI means for the first (conventional) were significantly lower than in the organic groves (0.278 vs. 0.463, P

Humic acid adsorption and its role in colloidal-scale aggregation determined with the zeta potential, surface free energy and the extended-DLVO theory

Summary The effect of colloidal forces involved in the adsorption of commercial humic acids (HA s) and particle cohesion was studied in the soil of an organic olive grove with the extended D erjaguin, L andau, V erwey and O verbeek (extended‐ DLVO) theory. Total interaction energy was determined from the zeta potential (ζ) and surface free energy, measured under different experimental conditions [natural and hydrogen peroxide (H2O2) organic matter‐free mineral surfaces]. The soil was clayey, dominated by illite and vermiculite. It showed electron‐donor behaviour, with negatively charged surfaces and zeta potential < 0 mV. Decreasing mV in the zeta potential, ζ, curves and electron‐donor component, γ –, when adding HA to natural surfaces showed effective HA adsorption, but only when soil organic matter had not been removed previously. Isotherms confirmed adsorption by natural soil (> 2.5 mg C g−1). Because the isotherms showed no relation with temperature, adsorption would be better attributed to weak physical interactions. On natural surfaces with HA, soil particle attraction forces increased slightly (≈50 kT) through decreasing soil wettability. However, this effect on total surface energy was overcome largely by increasing electrostatic repulsive energy caused by the adsorption of negatively charged HA (> 300 kT). The DLVO ‐extended model showed that natural surfaces without H2O2 treatment or added HA seem to be the most favourable state for colloidal aggregate stability. We recommend some caution about the type and quality of organic matter added to increase organic carbon in soil. HighlightsWe applied the extended DLVO model to study humic acid adsorption and its effects on soil structure.Adsorption on soil surfaces with their natural organic matter was mostly by weak physical forces.Adsorption increased the total particle interaction energy through an increase in electrostatic repulsion.Adsorption of some types of organic matter might decrease the colloidal stability of aggregates.

Análisis multivariante de los horizontes orgánico-minerales de los suelos del Parque Natural de Sierra Mágina (Jaén)

Soils are described normally using a great number of properties (variables). This generates a great quantity of data not easily understandable in a direct way. Consequently, multivariate analysis is necessary to support and confirm impressions and interpretations of investigations in field and laboratory. In the present work we quantify, through multivariate analysis, the relative influence of the different factors of soil formation that act on the soil system. We have studied 203 organo-mineral horizons, sampled to a depth between 0 and 25 cm of soils in the Sierra Magina natural park (Jaen, Spain). The studied soils are from calcareous rocks. Five factors were found to be significant and showed that the organic carbon accumulation, decarbonatation and the argillization/rubefacction, as internal variables, and the hill slope, as external variable, they are those which explain a greater percentage of the natural variability of the soil system.