Organic Inputs for Climate-Smart Agriculture: Effects of Sunflower ( Tithonia diversifolia ) Leaf Residues and Extracts on Tomato ( Lycopersicum esculentum Mill.) Yield and Soil Nutrient Dynamics

Abstract Tomato ( Solanum lycopersicum L.), a widely cultivated and consumed vegetable crops worldwide, a was an object of a field trial for two seasons [early (rainy) and late (dry)] seasons, 2023–2024) at NIHORT, Ibadan to evaluate sunflower ( Tithonia diversifolia ) based organic inputs for tomato ( Solanum lycopersicum L.) production. Using a 2 × 5 factorial RCBD with three replicates, treatments combined four rates of sun-dried sunflower compost (0, 1, 2, 3 t ha −1 ) and three foliar spray rates of sunflower leaf compost extract (0; 1,000; 2,000 dm 3 ha −1 ). The dry leaves were incorporated two weeks before transplant, while the compost extracts were applied at four and six weeks after transplant. During the 2023 season, the application of 3 t ha −1 of leaves compost increased early-season fresh fruit weight from 724.5 to 1,045.5 kg ha −1 and late-season weight from 280.0 to 818.0 kg ha −1 . The foliar compost extract at 2 000 dm 3 ha −1 raised fresh yield from 831.5 to 907.0 kg ha −1 and fruit number per plant from 146.0 to 200.5. while the 2024 season, 3 t ha −1 of leaf compost boosted early-season yield from 64.0 to 333.0 kg ha −1 and fruit count per plot from 28 to 316, while compost extract increased fresh yield from 832.0 to 907.0 kg ha −1 . All main effects were significant ( p ≤ 0.05); while there was no significance in the interactions. This discovery demonstrated that 3 t ha −1 of dry sunflower leaf compost substantially enhanced the tomato growth and yield, and that 3 000 dm 3 ha −1 of leaf compost extract provides additional biostimulant benefits. Hence the incorporation of sunflower compost biomass and fresh extracts offered a low-cost, sustainable alternative to synthetic fertilizers, therefore, advancing climate-smart tomato production in tropical agroecosystems, while further research is needed in other area of climate smart agriculture.