Comparative analysis of spectroradiometric and chemical methods for nutrient detection in black gram leaves

This study evaluated the nutrient content in Vigna mungo leaves using a visible near-infrared spectroradiometer (VNIR 650-900 nm) and compared it with traditional chemical analysis. Nutrient deficiencies were induced in a controlled environment, focusing on Nitrogen (N), Phosphorus (P), and Potassium (K). The VNIR spectroradiometer measured the spectral reflectance of the leaves at different intervals. Peak reflectance for N, P, and K deficiencies occurred at 716 nm, 737 nm, and 720 nm, respectively. A 30% deficiency in N, P, and K resulted in reflectance values of 45%, 42%, and 41%, respectively, while a 40% deficiency increased these values to 48%, 46%, and 43%. Results showed a strong correlation between nutrient deficiency and spectral reflectance, providing a quicker, more economical method than traditional chemical analysis. The study concludes that VNIR spectroradiometry is an effective tool for non-destructive, real-time assessment of nutrient status in Vigna mungo, which could lead to optimized fertilizer application and improved crop management. • Spectroradiometry accurately detects nutrient deficiencies in Vigna mungo leaves. • Phosphorus and potassium deficiencies are more pronounced than nitrogen in sandy loam soil. • Real-time spectral reflectance offers a non-destructive method for nutrient assessment. • Study links specific wavelengths to nutrient content for precision agriculture applications. • Optimized fertilization strategies improve Vigna mungo growth and yield.