Melastoma Affine D.Don Compost as a Substitute for Synthetic N Fertilizer in Sweet Corn

The study aims to compare various combinations of Melastoma compost and synthetic nitrogen fertilizer and evaluate their effects on plant growth and yield of sweet corn (Zea mays var. saccharata). The experiment was conducted in a greenhouse using a Completely Randomized Design (CRD) with one factor consisting of five fertilizer combinations, namely P1 (100% N), P2 (25% compost + 75% N), P3 (50% compost + 50% N), P4 (75% compost + 25% N), and P5 (100% compost). Each treatment was repeated four times. Plant growth parameters (height, number of leaves, leaf area, and stem diameter) and cob yield (weight, length, and kernel characteristics) were measured. The findings revealed that P3 (50% compost + 50% N) resulted in better plant growth, exhibiting significantly greater height, a higher number of leaves, and a larger diameter than P1. Meanwhile, no significant differences were observed between P2, P3, and P4, suggesting that compost can partially substitute synthetic fertilizer without negatively affecting plant growth. Using 100% compost (P5) resulted in significantly lower cob yields than all other treatments. The study concluded that combining Melastoma affine compost with synthetic nitrogen fertilizer improves sweet corn growth while maintaining cob weight. A 50:50 ratio of compost and synthetic nitrogen (P3) was the most effective combination. However, using 100% compost (P5) led to poor plant growth and yield, likely due to allelopathic effects. Further research is necessary to explore strategies to mitigate these effects for optimal compost utilization.