Institut für Pflanzenbau und Bodenkunde
In organic farming, phosphorus must be supplied primarily from the farm's own farmyard manure and from the soil reserves. If farmyard manure is not available, organically farmed soils often have a P deficiency, because phosphorus added to the soil by fertilisation is quickly turned into poorly soluble binding forms by natural conversion processes. The use of external nutrient sources is only permitted under very strict conditions; until now, mainly softground rock phosphates are used. Due to their low solubility, rock phosphates are only poorly accessible for most crops. Therefore, promoting biological nutrient dynamics in soil is of prime importance in organic farming in order to ensure optimum P supply to crops. Dark Septate Endophytes (DSE) are a group of endophytic fungi characterised by their morphology of melanised, septate hyphae. DSE are known to supply plants with nitrogen and phosphorus. The hyphae of these fungi enlarge the space from which nutrients can be absorbed. The fungi have the enzymatic ability to mineralise poorly soluble P sources by themselves or might be able to cooperate with bacteria that have this ability. The mineralised phosphorus is then transported to the host plant via the hyphal network. The recently described DSEs Polydomus karssenii, Polyphilus sieberi and Polyphilus frankenii have been reported to colonise different host plants. In this project, we are analysing different strains of P. karssenii and other DSEs for their ability to supply their respective host plants with phosphorus. Different organic and inorganic phosphorus compounds that are difficult for the plant to access will be examined.
Federal Ministry of Food and Agriculture
