Organic sources of nutrient supply for tomatoes and Asian herbaceous vegetables in soilless culture systems
Organic farming is increasing in many countries in the world, in Germany as well. In soilless culture systems, predominantly mineral fertilizers are used to prepare the nutrient solution. The research question was which organic material or liquid can be used for supply of nutrients in soilless culture systems. The number of biogas plants in Germany is increasing, therefore, digestate of a biogas plant was tested as organic fertilizer, as a supplement to the growing media in an amount of 5, 15, and 25%, compared with a treatment of lupine coarse meal and mineral fertiliser. The tomato yield was highest with mineral fertilisation, the yield with 25% digestate was only a little lower. Further experiments are necessary regarding the amount and frequency of fertilization with digestate from biogas plants. More and more customers are asking for organic vegetables, therefore experiments were conducted to replace mineral fertilisation by nutrient solution as typical for substrate culture with solid and liquid organic fertilizers. In an experiment with cultivation of tomatoes in perlite and an organic substrate using as organic fertilizers sheep wool pellets, lupine wholemeal and castor wholemeal in solid and liquid form was conducted. The tomato plants growing in perlite showed weak growth if fertilized with organic fertilizers. In organic substrates, in cultivated tomatoes the growth parameters were better, but also not satisfying in particular if liquid organic fertilizers were used. South-East-Asian leafy vegetables, holy basil and Vietnamese balm were used in a substrate culture experiment with organic fertilizers as castor coarse meal and sheep wool pellets added to the substrate in different amounts by using trickle irrigation, as control mineral nutrient solution was used. The growth was highest in the treatments with mineral nutrient solution, with only small differences between the organic treatments.
Böhme, M.H. (2021). Organic sources of nutrient supply for tomatoes and Asian herbaceous vegetables in soilless culture systems. Acta Hortic. 1321, 157-164
organic fertilisation, digestate, sheep wool pellets, substrate culture, Asian leafy vegetables