Effects of Different Cultivation Systems and Fruit Parts on Mineral Composition: a Case Study on Kumquat

This study investigates the impact of open-field and greenhouse cultivation systems on the mineral composition of kumquat (Fortunella margarita), with particular attention to variations between fruit peel and pulp. The research utilized fruits harvested from 4-year-old plants cultivated in Muğla, Turkey. Elemental analysis of nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), calcium (Ca), iron (Fe), manganese (Mn), copper (Cu), and zinc (Zn) was conducted using inductively coupled plasma atomic emission spectroscopy (ICP-AES) and UV/VIS spectrometry. Results indicated significantly higher mineral concentrations under greenhouse conditions, with Mg increasing from 0.86 g kg-1 in open-field cultivation to 1.25 g kg-1 in greenhouse conditions, and Fe rising from 60.83 mg kg-1 to 67.85 mg kg-1. The peel exhibited a higher mineral density compared to the pulp, as evidenced by Fe levels of 66.74 mg kg-1 in the peel versus 61.94 mg kg-1 in the pulp. Macronutrient concentrations, including N (1.03 g kg-1 vs. 0.83 g kg-1) and K (1.68 g kg-1 vs. 1.24 g kg-1), were also elevated in greenhouse-grown fruits. Correlation analysis revealed strong positive relationships between K and Ca (r = 0.77), Mg and K (r = 0.72), and Mg and Ca (r = 0.81), emphasizing their synergistic roles in nutrient transport and photosynthetic processes. These findings underscore the efficacy of greenhouse cultivation in optimizing nutrient uptake, distribution, and fruit quality, providing critical insights for enhancing kumquat production practices.