Journal of Scientific Research and Reports

The combined effects of organic amendments and black polyethylene mulching on watermelon quality and soil properties under the agro-climatic conditions of Jorhat remain insufficiently characterised. A two-season field experiment (2021–22 and 2022–23) was conducted at Nabanita Organic Farm, Potia Fokola Gaon, Jorhat, Assam, to assess the effects of organic amendments and black polyethylene mulch on fruit quality, post-harvest behaviour and soil properties of watermelon (Citrullus lanatus) cv. Saraswati. Treatments were arranged in a split-plot design with two mulch levels and seven nutrient treatments, replicated thrice. The combined treatment of FYM (2.5 t ha⁻¹) + vermicompost (2.5 t ha⁻¹) + microbial consortium (5 kg ha⁻¹) with 50 μm black polyethylene mulch (M₁T₆; S₁₃) recorded the highest total soluble solids (12.30 °Brix), TSS:acid ratio (92.08), non-reducing sugars (2.90%), total sugars (9.01%), juice content (83.01%), ascorbic acid (6.58 mg 100 g⁻¹), anthocyanin (0.26 mg 100 g⁻¹) and lycopene (6.62 mg 100 g⁻¹), together with the lowest titratable acidity (0.13%). Maximum shelf life (24.83 days) was also recorded in S₁₃. The treatment recorded available soil N, P and K of 409.64, 24.90 and 301.77 kg ha⁻¹, respectively, organic carbon of 0.94%, pH 6.85 and soil microbial biomass carbon of 612.62 mg g⁻¹ soil. The findings indicate that the organic amendments with black polyethylene mulch improved the fruit-quality and soil indicators under the experimental conditions.