The effect of biodynamic preparations on growth and fruit quality of giant pumpkin (Cucurbita maxima D.)

Background Food quality of agricultural crops depends on environmental conditions, production system and cultivation method. A plant-based nutrition with food rich in vitamins, minerals and secondary plant compounds with antioxidative properties promotes human health. This investigation was inspired by an increasing global issue on how to improve product quality while using alternative preparations. The main aim of a 3-year study was to investigate the influence of fermented manure and silica products on yield and nutritive components in peel, fruit and seeds of three pumpkin cultivars. In four replicates as block design, the effects of individually as well as combined application of biodynamic horn manure and horn silica preparation were compared to a control variant. Results Horn manure application significantly increased total and marketable yield. Marketable yield, contents of macroelements, total carotenoids, single carotenoids (lutein + zeaxanthin, lycopene, ß-carotene) and antioxidants (catechins, total phenols, leuco-anthocyanins) were significantly increased by horn silica use. The combination of both biodynamic preparations had a significantly increasing effect on total and marketable yield, net photosynthetic productivity, dry matter content and total and single carotenoid contents (lutein + zeaxanthin, lycopene, ß-carotene). Conclusions The pumpkin trial results indicated a general growth-promoting effect by horn manure, a quality-enhancing effect by horn silica and a compensatory effect through both preparations on a high qualitative level. In accordance with other investigations, these effects did not occur in the same way in all plant species. Therefore, the effects of the biodynamic preparations should be tested in further trials on a plant species-specific basis.