Substrate Cultivation of Chrysanthemum: Plant performance in 6 cropping systems and the effect of parameters associated with root environment

Summary Chrysanthemum is an important greenhouse crop in Holland and is still cultivated in soil. To prevent the emission of nutrients and crop protecting agents, an emission:free cropping system should be developed. This experiment was conducted to that purpose. The objectives of this experiment were: (1) to compare the plant growth performance among six closed systems and thereby evaluate the priority of each system; (2) to investigate the impact of some indexes associated with rhizosphere on plant growth and thereby optimize the corresponding system. Six candidate systems were deep soil system (S1), sand bed (S2), peat bed (S3), lily crate (S4), cassette bed (S5) and cassette box system (S6). In S5 and S6, substrate volume, anti root barrier, foil and irrigation regime were varied as factors of possible influence on the rhizosphere. Growing period, above ground growth parameters (including fresh weight, dry weight, plant height and leaf number) and root performance were recorded and used to evaluate plant growth performance. The results showed that the latter four high:tech systems could shorten the growing period by about 12 d in comparison to S1 and S2. After in depth discussion, however, four systems including S1, S2, S3 and S5 were suggested for next round trial. The results also showed fresh weight and dry weight advantage for the S5 system combined with 10 cm height of substrate, an anti:root fabric and a sprinkling irrigation or normal sub irrigation. Plants in S6 showed a lower fresh weight yield and a slightly lower dry weight yield as the amount of water and nutrients supplied was just not enough to meet the plant demands. Consequently for S6, plants grown in substrate wrapped with complete foil gave the best performance as the foil reduced water loss due to evaporation.