Cation Interactions Governing the Nutritional Status of Serpentine Soils under Red Pepper (Capsicum annuum L.) Cultivation

Abstract

Serpentine-derived soils are characterized by limiting conditions for plant growth. The combined effects of the physical, chemical, and biological properties of these soils create a stress condition known as the ‘serpentine syndrome’. This study aimed to investigate calcium (Ca), magnesium (Mg), and potassium (K) nutrition in red pepper cultivation on serpentine soils, and to evaluate the relationships among key cation ratios. Soil and plant samples were taken from 20 red pepper fields in the İslahiye region, followed by analysis using standard laboratory procedures. Data derived from soil and plant analyses were evaluated using correlation analysis and principal component analysis (PCA) to examine the relationships among the variables. Soil analysis results showed low Ca levels, adequate K concentrations, and excessive Mg levels. Meanwhile, leaf analyses showed that Mg and Ca concentrations in pepper leaves were above sufficiency thresholds, whereas plant K concentrations were below the recommended sufficiency ranges. The combined results of correlation and principal component analyses (PCA) indicate that cation ratios play a decisive role in plant nutrient uptake in serpentine soils. These results further show that the negative relationships between Mg-related ratios and plant K and Ca concentrations, together with their opposite positioning in the PCA, indicate a pronounced competitive interaction among these elements