Effect of shading and biofertilizer-enhanced fertilization on yield, fruit quality and soil fertility of Tejakula mandarin (Citrus reticulata cv. Tejakula)

Tejakula mandarin cultivation in Bali faces challenges from soil degradation and fruit dryness. This study evaluated the effects of shading and biofertilizer-enhanced fertilization on the yield, fruit quality, and soil fertility of Tejakula mandarin (Citrus reticulata cv. Tejakula). A field experiment was conducted from November 2024 to November 2025 in Bali, Indonesia, using a split-plot randomized block design with four replications. The main plot factor was shading with two levels: open field (Sn) and natural shade (Ss). The sub-plot factor consisted of five fertilization packages: inorganic control (Fi), organic-inorganic blend (Fb), mycorrhiza-enhanced (Fm), probiotic-enhanced (Fp), and integrated biofertilizer (Fc). Results showed that natural shade (Ss) significantly increased total fruit yield per tree by 87.80% and reduced the incidence of fruit dryness by 77.90% by weight compared to open field (Sn). Among fertilization packages, the integrated biofertilizer (Fc) was superior, yielding 32.31 kg fruit per tree, which was a 244.50% increase over the inorganic control (Fi), and also reduced fruit dryness by 90.90%. The Fc treatment also resulted in the highest soil organic carbon (2.62%), available phosphorus (342.50 ppm), and leaf relative water content (79.74%). Key fruit quality attributes, including total soluble solids, vitamin C content, and firmness, were significantly improved under the combined treatment of shading and biofertilizer packages. In conclusion, integrating natural shading with an enhanced biofertilizer package is a highly effective strategy for sustainably increasing productivity, improving fruit quality, and enhancing soil health in Tejakula mandarin orchards.