Organic plant nutrients in combination with inorganic sources of nutrients influence the productivity, quality, soil microbes, and nutrient use efficiency of bitter gourd (Momordica charantia L.)

Sustainable bitter gourd production requires optimising the combined organic and inorganic nutrient management. Hence, a field experiment was conducted to evaluate the impact of combined organic and inorganic nutrient amendments on bitter gourd productivity, quality, nutrient use efficiency, soil microbial activity, soil health, and profitability. Treatments were T1: control, T2: recommended dose of inorganic N-P-K-S-Zn-B at 120-40-85-20-3-2 kg <middle dot> ha-1, T3: 5 t <middle dot> ha-1 vermicompost (VC) + 50% of NPKSZnB, T4: 2.5 t <middle dot> ha-1 poultry manure (PM) + 50% of NPKSZnB, T5: 5 t <middle dot> ha-1 VC + 75% of NPKSZnB, T6: 2.5 t <middle dot> ha-1 PM + 75% of NPKSZnB, T7: 5 t <middle dot> ha-1 cow dung (CD) + 75% of NPKSZnB, T8: 5 t <middle dot> ha-1 VC + 5 t <middle dot> ha-1 CD + 50% of NPKSZnB, and T9: 5 t <middle dot> ha-1 VC + 5 t <middle dot> ha-1 CD + 25% of NPKSZnB. Integrating 5 t <middle dot> ha-1 VC + 5 t <middle dot> ha-1 CD with 50% of NPKSZnB fertiliser (T8) significantly boosted the bitter gourd fresh fruit yield (13.1 t <middle dot> ha-1), a 192% higher over control, with larger fruits, higher fruit count, and greater vine length. Treatment T8 also excelled in vitamin C (77.6 mg <middle dot> 100 g-1), beta-carotene (122 mcg <middle dot> 100 g-1), protein (18.1%), moisture content (93.4%), and total soluble solids (4.0 degrees Brix), alongside enhanced nutrient uptake, soil health, robust microbial populations, and economic returns (4552 US$ <middle dot> ha-1). Treatment T4 exhibited the highest agronomic and removal efficiencies for key nutrients. Therefore, combined application of 5 t <middle dot> ha-1 VC + 5 t <middle dot> ha-1 CD with 50% of NPKSZnB fertiliser offer a promising approach for sustainable bitter gourd production. This method not only boosts yield and quality but also improves soil health and minimises environmental risks through reducing chemical fertiliser use.