Heavy metals from phosphate fertilizers in maize based food-feed-energy systems
Phosphate fertilization is potentially accompanied by the risk of heavy metal input into crop production systems. To avoid contamination in maize based food-feed-energy systems is an important issue and will become even more important when the phosphate cycle has to become more closed due to the diminishing phosphate rock reserves. We postulate that phosphate fertilizer management (across a range of options from mineral phosphate sources vs. organic phosphate sources and mixtures or adding of biochar) as well as crop management (crop rotation systems from maize monocultures to sophisticated, multi-crop rotation systems tailored to provide an optimal balance between yield, resilience, and minimized pollution load) will allow to avoid or at least minimize heavy metal pollution problems in maize production and its utilization chain.
Among the heavy metals, cadmium (Cd) and uranium (U) are two most important elements in phosphate fertilizers. Cd is a very toxic element to both animals and human beings; while U is a radioactive element and its accumulation in soils may damage the environment for hundred thousands of years. Therefore, it is an urgent need to quantify the impact of large amount application of phosphate fertilizers on Cd and U along the phosphate-rock - phosphate fertilizer - soil - maize (as food and feed and energy crop) - animal - human chain.The proposed research training group offers a unique opportunity for an overarching analysis of the pathway of heavy metals in multifunctional agroecosystems under varying and optimised phosphate management. We will use the various approaches applied in the research training group by analysing heavy metal pools, uptake, allocation, re-distribution, transfer through trophic levels and through phosphate recycling and recovery processes. While doing so, we will make use of the full spectrum of maize-based food-feed-energy systems to be investigated both in Germany and in China. Samples will be obtained from the various approaches across the full phosphate cycle.
