This study aims to explore the effect of cover crops on soil enzyme activity (Ecoplate, Biology) and early growth of sweet corn. A pot experiment was conducted using a soil mix (60% Andosol, 40% field soil) with seven different treatments: Rye, HV (Hairy Vetch), MA (Manure), CC (Rye+HV), CC+MA, CF (Chemical Fertilizer), and N0 (No Nitrogen Fertilizer). The amendments were incorporated into the soil three weeks before sowing, and sweet corn was seeded on July 2, 2024. Data were collected before seeding (BS), 15 days after sowing (DAS15), and 30 days after sowing (DAS30).
The soil enzymatic activity was different only before seeding. MA exhibited the highest enzymatic activity, followed by HV and Rye, while N0 showed the lowest activity at the BS stage. A PCA analysis of Ecoplate data indicated no differences in soil microbial community structure after DAS15. These results indicated increased soil enzymatic activity by organic amendments only shortly after incorporation. The dry matter weight of sweet corn showed no significant differences among amendment treatments at DAS15 and DAS30, but the shoot-root ratio (SR ratio) decreased in N0 and Rye at DAS30. The lower SR ratio in N0 and Rye at DAS30 suggested that reduced nutrient use efficiency, rather than microbial community differences, may be responsible for these observations.