Speakers - 2026

Title: Growing media and organic nutrient management effects on seedling quality, growth rate and yield of chili pepper in two agro-ecological zones in ghana

Abstract

Chilli pepper (Capsicum annuum) production in Ghana is constrained by declining soil fertility and poor transplant quality, which often leads to poor seedling establishment. Sustainable alternatives to the traditional soil-based production system are needed to improve transplant quality, field establishment, and fruit yield and quality. This study assessed the growth, yield, nutritional quality, and postharvest shelf life of selected pepper varieties cultivated in soilless media across two agroecological zones in Ghana. A two-phase experiment, consisting of a nursery trial (assess transplant quality) and an open-field pot trial, was conducted in the Forest Zone (Kade) and the Coastal Savannah (Legon). Both nursery and field trials used a split-plot design with three chilli pepper varieties (Bird’s Eye, Habanero, Legon 18) as main plots and five growing media treatments as subplots. The growing media treatments consisted of a soil-only as control (M0), sourced locally from each site, and four composted soilless formulations prepared from sawdust, poultry manure, and rice husk biochar, mixed in different volume ratios: M1 (1:1:1), M2 (1:1:2), M3 (1:2:1), and M4 (2:1:1). The soilless media (M1–M4) had higher water-holding capacity (3.25–5.76 vs 0.47–0.90 g g-1) and greater organic C (31.9–43.2% vs 1.2–1.8%), N (0.84–1.30% vs 0.17%), P (0.70–1.25% vs 0.02–0.06%), and K (4.52–6.37% vs 0.80–1.36%) than the soil-only control (M0). In the Kade nursery, pepper seedlings grown in soilless media (M1–M4) performed better than those in soil-only media (M0), Media M2 produced the tallest seedlings, thickest stems, and most leaves across all three chilli pepper varieties. At Legon, seedling quality, as measured by the Dickson Quality Index, was highest in M2 across all varieties, while at Kade, M2 and M4 supported the best growth in Bird’s Eye and Legon 18. In open-field pot experiments at Kade, the media M2 had the highest yield per plant (489.1 g/plant), followed by M3 (456.6 g), M1 (363.7 g), M0 (291.6 g), and M4 (169.8 g). A similar order was observed at Legon, though with lower yields: M2 (341.0 g), M3 (312.6 g), M1 (251.6 g), M0 (224.4 g), and M4 (121.9 g). Across locations, Bird’s Eye produced the highest yield per plant, followed by Habanero. Fruits grown in soilless media (M1–M4) contained, on average, 19.4%, 44.9%, 128.1%, and 25.9% more protein, calcium, iron, and phosphorus, respectively, then the soil-only control (M0), which had the lowest concentrations across all nutrients. Among the treatments, M3 produced fruits with the highest protein (4.58 g/100 g) and phosphorus (60.248 mg/100 g). Calcium and iron were highest under M1, at 24.273 and 3.061 mg/100 g, respectively. Strong correlations were found between nutrient concentrations in the growing media and those in the fruit, particularly between media nitrogen and fruit calcium (R2= 0.92), media nitrogen and fruit protein (R2= 0.66), and media phosphorus and fruit phosphorus (R2 = 0.77), indicating that nutrient enrichment of the media directly enhances fruit quality. Habanero fruits had the best shelf-life performance, showing the lowest fruit weight loss (4.7–81.4%) and reduced width shrinkage under M2 and M4. In contrast, Bird’s Eye and Legon 18 deteriorated more rapidly, particularly under M0. These results show that compost-based soilless media, especially M2 and M3, increase fruit nutrient quality and yield while also prolonging shelf life. They provide a viable alternative for producing organic chili peppers that raises their market value and lowers postharvest losses.