Evaluation of Nutrient Status and Cation Balance in Wheat Cultivated on Serpentine-Derived Soils

Abstract

Serpentine soils are derived from the serpentinization of ultramafic parent materials and are characterized by distinctive chemical and physical properties. The combined stress conditions imposed on plants growing in these soils are commonly known as the “serpentine problem.” The present study was conducted to evaluate the nutritional status of wheat cultivated on serpentine-derived soils and to investigate soil–plant relationships. A total of 15 soil and plant samples were collected from serpentine-origin agricultural fields located in the İslâhiye–Nurdağı region. Selected macro- and micronutrients together with several basic soil properties were determined in soil samples, whereas nutrient element analyses were performed in plant samples. The obtained data were further evaluated to assess the effects of soil–plant relationships and cation ratios on wheat nutrition. The soils of the study area were generally characterized as neutral to slightly alkaline, low in lime content, and non-saline. Soil analyses revealed high exchangeable Mg concentrations, whereas Ca levels were comparatively lower. In addition, available P and exchangeable K concentrations were determined to be above sufficiency levels. Mean concentrations were 37.2 mg kg⁻¹ for P, 239.67 mg kg⁻¹ for K, 558 mg kg⁻¹ for Ca, and 2615 mg kg⁻¹ for Mg. The average Fe, Zn, Cu, and Mn concentrations in soils were determined as 25.67, 0.95, 1.89, and 3.79 mg kg⁻¹, respectively. Soil Ni concentrations ranged between 14.88 and 112.06 mg kg⁻¹, confirming the characteristic accumulation of Mg and Ni in serpentine soils. Ni concentrations ranged between 14.88 and 112.06 mg kg⁻¹, confirming the characteristic accumulation of Mg and Ni in serpentine soils. Evaluation of cation ratios demonstrated that low Ca/Mg and high Mg/K ratios reflected a pronounced cation imbalance. Plant analyses indicated that the average N, P, and K concentrations in wheat were 4.38%, 0.37%, and 2.07%, respectively. In contrast, plant Ca concentrations were relatively low (0.02–0.13%), whereas the average Mg concentration was determined as 0.33%. Micronutrient concentrations were generally within sufficiency ranges. Evaluation of soil and plant data revealed a negative correlation between soil Mg/K ratio and plant K concentration, while elevated Mg levels were also associated with plant Ca and K nutrition. Overall, the findings demonstrated that Mg dominance in serpentine soils induces cation antagonism, thereby adversely affecting particularly Ca and K nutrition in wheat.