Soil sickness syndrome in organic substrates repeatedly used in eggplant (Solanum melongena L.) culture

The objective of the studies was to verify the possibility of repeated use of substrate in the growing of eggplant (Solanum melongena L.). In two organic substrates (peat and bark with peat) used once, twice or thrice, the following features were determined: physical properties of substrates and their volume, salinity, C/N ratio and phenolic compounds content. Furthermore, the weight of leaves, stems and fruits of eggplant were determined. It was found that peat repeatedly used showed a negative effect on the growth and yield of eggplant due to the decrease of water in substrate and accumulation of phenolic compounds. On the other hand, in the mixture of bark and peat, a positive effect of repeated use of substrate was observed. In this type of substrate, the amount of water increased and phenolic compounds concentration was low.