Effect of pine bark goat manure medium on seedling growth and N, P, K concentration of various vegetables

Abstract

Pine bark compost is the medium of choice for seedling growers in South Africa due to its availability, low cost and good physical properties. However, it is acidic, has low electrical conductivity (EC) and nutrient content such that fortification and liming is necessary. In a bid to improve the properties of pine bark compost, at a low cost, pine bark was co-composted with goat manure (PBG), and compared with commercial pine bark compost (PBCO) as a growing medium for vegetable amaranth, cabbage, tomato, and lettuce seedlings with and without Horticote (a slow release fertiliser). The water holding capacities of both PBCO and PBG media were higher than the minimum required but their air filled porosities were below optimum. Neither medium nor fertiliser levels had an effect on emergence of all the test crops. The different vegetable seedlings grew better in PBG than the PBCO medium. Addition of the slow-release fertiliser had similar positive effects on growth of seedlings grown on both media. Significant interactions between fertiliser and growing medium were observed in fresh weights of shoots for all the seedling crops evaluated. Results of this study revealed that PBG medium supported good seedling growth and could thus be a good substitute for PBCO as a growing medium. Use of a slow release fertiliser is highly encouraged as this can lower both nutrient losses through leaching and production costs.