Sustainable fertilization strategies for climate-resilient vegetable production: Optimizing yield, nutritional quality, and mitigating nitrate risks in the Lake Sevan basin

Résumé

Background: Climate change challenges vegetable production by altering yield potential and nutrient dynamics, affecting food security and functional quality. Potatoes, table beet, and white cabbage are key dietary staples rich in bioactive compounds. Therefore, developing ecologically sustainable cultivation practices is essential for public health and food safety.

Objective: This study evaluated the effects of six fertilization systems on yield, nitrate accumulation, and post-harvest nitrate reduction in potatoes, table beet, and white cabbage cultivated in Armenia’s Lake Sevan basin.

Materials and Methods: Field experiments were conducted from 2020 to 2022 in the Martuni district on floodplain soils using a randomized complete block design (n = 3). Treatments included: (1) Control (no fertilizer), (2) N₁₆₀P₁₆₀K₁₆₀, (3) Manure (35 t ha⁻¹), (4) Biohumus (8 t ha⁻¹), (5) Manure (25 t ha⁻¹) + N₅₀P₅₀K₅₀, and (6) Biohumus (6 t ha⁻¹) + N₃₅P₃₅K₄₀. Yields were expressed as centners per hectare (c ha⁻¹), and nitrate contents were compared with maximum permissible concentrations (MPC). Post-harvest treatments—including controlled storage (10 °C, 50% RH), washing, peeling, and boiling—were assessed for nitrate reduction. Statistical analyses were performed using ANOVA, and data were expressed as mean ± SD (n = 3). Significance was determined using the LSD test at p < 0.05.

Results: The highest yields were obtained under Biohumus (8 t ha⁻¹) and Biohumus + N₃₅P₃₅K₄₀, reaching 420–440 c ha⁻¹ in potatoes, 230–240 c ha⁻¹ in table beet, and 500–520 c ha⁻¹ in cabbage, while nitrate levels remained within MPC limits. Excessive nitrogen from Manure (35 t ha⁻¹) or N₁₆₀P₁₆₀K₁₆₀ led to nitrate accumulation beyond safe thresholds. Controlled storage and processing reduced nitrate content by 30–60%, with the most pronounced decline observed after boiling. Biohumus-based fertilization also increased dry matter (DM), starch, Total sugar, and Vitamin C in all crops, enhancing both yield and functional quality.

Conclusion: Integrated fertilization with Biohumus—alone or with reduced mineral fertilizer—achieves high yields, safe nitrate levels, and improved nutritional quality of potatoes, table beet, and white cabbage. Combined with post-harvest treatments, this holistic approach ensures food safety, maximizes functional quality, and provides a sustainable protocol linking field practices to public health outcomes.

Keywords: integrated fertilization, biohumus, nitrate mitigation, functional quality, post-harvest reduction, food safety, potato, table beet, white cabbage