Residual Impacts of Vermicompost-Derived Nutrients on a Strawberry–Corn Double Cropping System Under Plasticulture in South Florida

The increasing demand for sustainable agricultural practices necessitates strategies such as organic fertilizer alternatives and residual nutrient use to enhance crop productivity while maintaining soil health. This study investigates the residual effects of vermicompost on strawberry growth and physiology after a corn cropping cycle. The objectives were to assess how different vermicompost application rates impact strawberry yield, biomass, chlorophyll content, and fruit quality. The experiment was conducted over six months, using raised beds previously cultivated with corn and treated with six nutrient management strategies, namely, V0 (control), VC1, VCT100, VC1+VCT50, VC3, and VC3+VCT50. Metrics such as SPAD values, Brix sugar content, and stomatal conductance were measured throughout the growing season to assess physiological responses. Soil and plant chemical concentrations were determined at the end of the study to evaluate nutrient status. Results showed that the VC1 treatment produced the highest yield (11,573 kg/acre) and biomass (38,364 kg/acre), with significantly improved fruit quality (Brix sugar content of 8.3%) compared to the control (6.8%). SPAD values declined over time and showed no statistically significant differences among treatments. In the surface soil, VC3+VCT50 exhibited the highest N, P, Mg, Na, organic matter, and cation exchange capacity (CEC), and it also resulted in the highest leaf N. Leaves had higher N, P, K, and Mg concentrations, while Fe, Mn, and Cu were more concentrated in roots. Spectral reflectance data indicated reduced chlorophyll content in the VC3+VCT50-treated plants. These findings suggest that moderate vermicompost applications, such as VC1, can significantly contribute to sustainable agriculture by enhancing strawberry productivity and reducing dependence on synthetic fertilizers. However, high-rate applications, especially VC3 and VC3+VCT50, reduced plant vigor and yield, possibly due to salinity stress and the high sodium content in the vermicompost used in this study. Such outcomes may vary depending on feedstock composition, highlighting the importance of salinity screening when using organic amendments in salt-sensitive crops like strawberries.