Synergistic Effects of Humic Acid and Seaweed Extract Foliar Application on Growth, Fruit Set and Yield of Custard Apple (Annona squamosa L.) Cv. ‘Balanagar’
摘要
Low fruit set and inconsistent yield remain key constraints in custard apple (Annona squamosa L.) production under semi-arid conditions. A two-season field experiment was conducted at Jhalawar, Rajasthan, India, using a factorial randomized block design with 16 treatments and three replications to assess individual and combined effects of foliar-applied humic acid (HA) and seaweed extract (SWE) at 1000, 2000, and 3000 ppm on vegetative growth, fruit set, yield, and fruit quality. The combined application of HA 3000 ppm + SWE 2000 ppm (T15) proved most effective, increasing nodes per shoot from 9.34 to 12.50 and canopy volume by 23.6% over the control. Fruit set improved from 62.85% to 73.40% (16.8% gain) and yield per plant increased by 72.7% (14.48 to 25.02 kg). Fruit weight rose by up to 26.5% (281.16 g vs. 222.29 g), pulp percentage from 52.52% to 66.08%, and the TSS/TA ratio from 72.17 to 127.10. Stony fruit incidence was reduced by 28.3%. Integrated foliar application of HA and SWE substantially enhances productivity and commercial fruit quality of custard apple, providing a practical, sustainable biostimulant strategy for semi-arid orchard management.