Influence of Soilless and Soil-based nursery media on emergence and early seedling growth of Pawpaw (Carica papaya L.)

Providing alternative sources of nursery media compositions is important to reduce soil mining which causes soil erosion, land degradation and nutrient leaching. This study evaluated soil-based and soilless-based nursery media on emergence, early growth and dry matter accumulation of pawpaw seedlings for two cropping seasons. Materials utilized for the nursery media were topsoil (TS), poultry manure (PM), river sand (RS), sawdust (SD) and rice husk (RH). Eight nursery media were composted and evaluated namely: TS+PM+RS (3:2:1), TS+PM+RS (1:2:3), RS+PM+SD (3:2:1), RS+PM+SD (1:2:3), RH+PM+SD (1:1:1), topsoil (100%), RH+PM (3:1) and SD+PM (3:1). These were laid in a completely randomized design in five replications. The findings revealed that the nursery media had significant (P<0.05) influence on emergence and growth parameters of pawpaw seedlings. TS+PM+RS (3:2:1) enhanced earliest days to 100% emergence (15 days in 2022) but this value did not significantly vary with 18-21 days obtained with RS+PM+SD (3:2:1), RH+PM+SD (1:1:1), RH+PM (3:1) and SD+PM (3:1). Seedlings from RS+PM+SD (3:2:1) and RS+PM+SD (1:2:3) at 10 weeks after emergence significantly produced more leaves (9.47%, 19.29% and 27.03%, 13.42%), in 2022 and 2023, respectively compared to TS+PM+RS (3:2:1). Seedlings from RH+PM+SD (1:1:1) medium consistently allocated highest (45% and 62.4%) dry matter to the leaves in 2022 and 2023, respectively. It was therefore concluded that the investigated soilless-based nursery media particularly RS+PM+SD (3:2:1), RS+PM+SD (1:2:3), RH+PM+SD (1:1:1) and RH+PM (3:1) nursery media can serve as alternatives to the commonly utilized soil-based media (topsoil and TS+PM+RS) for production of vigorous pawpaw seedlings.