Sphagneticola trilobata Compost as a Sustainable Substitute for Synthetic Nitrogen in Sweet Corn Cultivation

Abstract

Sustainable fertilization strategies are essential for improving crop productivity while maintaining soil health. This study evaluated the effects of partial substitution of synthetic nitrogen (N) fertilizer with Sphagneticola trilobata (L.) Pruski compost on soil nitrogen and sweet corn (Zea mays saccharata Sturt.) growth and yields. A greenhouse experiment was conducted from June to August 2024 using a completely randomized design with six treatments: P0 (control), P1 (0% compost + 100% N), P2 (25% compost + 75% N), P3 (50% compost + 50% N), P4 (75% compost + 25% N), and P5 (100% compost + 0% N), each replicated four times. Vegetative parameters—including plant height, leaf area, leaf greenness, stem diameter, and leaf number—were measured, alongside yield components such as cob weight (husked & unhusked) and kernel sweetness. Post-harvest soil samples were analyzed for total nitrogen using Kejdahl Method. Fertilization significantly enhanced vegetative growth and yield compared to the unfertilized control. Sole synthetic N application (P1) promoted rapid growth but may threaten long-term soil fertility, whereas sole compost (P5) improved soil properties but resulted in lower yield and sweetness. Optimal performance was observed under P3 (50% compost + 50% N), which achieved the highest plant height, leaf area, cob weight, and kernel sweetness, demonstrating a synergistic effect between organic and inorganic inputs. Soil nitrogen after harvest was the highest in treatments with greater compost proportions, reflecting improved nutrient content in soil. These results indicate that partial substitution of synthetic N with S. trilobata compost effectively balances immediate nutrient supply with long-term soil fertility. This integrated fertilization approach provides a practical strategy to enhance sweet corn productivity while sustaining soil health.