Increased phosphorus availability from sewage sludge ashes to maize in a crop rotation with clover

A recycling of Phosphorus (P) from the human food chain is mandatory to secure future P supply for production. However, many available recycled fertilizers sewage sludge do not have an adequate bioavailability and, thus, are suitable their application in soils with pH >5.5–6.0, unless being combined efficient mobilization measures. The aim study was test ability red clover (Trifolium pratense L.) two thermally a subsequently grown maize. Two ashes (SSA) were investigated pot experiment at soil 7.5 differing its nitrogen (N) (added N fertilizer or biological N2 fixation (BNF)), followed by maize (Zea L.). Shoot dry matter almost doubled when previous covered BNF, instead receiving added fertilizer. Similarly, shoot removal following BNF significantly increased. It suggested that related and proton release fixing roots led measured decrease thereby increased availability tested fertilizers.