Phosphorus (P) is essential for global food production, but managing its quantities in the soil is a global challenge. In many regions, there is not enough of it, which reduces crop yields. In other regions, there is too much P – that causes a threat of water pollution and other environmental problems.
For Prof. Dr Bettina Eichler-Löbermann and other researchers at the University of Rostock (UROS), this topic sits at the centre of their scientific work. Their studies explore how organic fertilisers, beneficial microbes, and diverse cropping systems can improve P availability in the soil, reduce dependency on synthetic fertilisers, and write a new chapter for resilient, climate-smart agriculture.
Organic fertilisers: a better, cleaner source of nutrients
One recent study examined how organic materials such as compost, sewage sludge, and digestates (animal waste, for example) contribute to phosphorus pools in the soil. Findings showed that organic fertilisers can provide as much – or even more – available P than conventional synthetic fertilisers. Using multiple measurement methods, the researchers also found that phosphorus behaves differently in soil depending on fertiliser type and that organic amendments help maintain readily available P pools over time. Based on these findings, the research team concluded that high-quality organic waste products could sustainably replace chemical fertilisers in the long run.
Fertilising the depleted African soil
Another study focused on smallholder farmers in Africa, where phosphorus deficiency and limited access to fertilisers severely restrict agricultural productivity. According to UROS researchers, microbe-based solutions show promise for helping plants access more P naturally, but their effectiveness is not yet fully understood. Their recent study emphasised the need for extensive field testing and better analytical tools to clarify how microbes mobilise phosphorus in complex farming systems. According to them, bridging these gaps could unlock the potential of microbial innovations in African agriculture.
Plants helping plants: could mixed cropping be our next solution?
A third recent study published by the research team at UROS investigated how cereal–legume mixtures perform under different phosphorus fertilisation strategies. Across three years of field experiments, maize grown alone produced the highest yields overall, but mixed cropping provided clear advantages under phosphorus-deficient conditions. Even when no P fertiliser was applied, cereal–legume mixtures often matched or exceeded the performance of cereals grown alone. The co-existence of legumes in the same field improved soil biological activity, suggesting better use of organic phosphorus in the soil. These findings show that mixed cropping can be a valuable strategy, especially in low-input systems and regions with limited fertiliser availability.
Together, these three studies illustrate the multifaceted nature of sustainable phosphorus management. Organic fertilisers, beneficial soil microbes, and mixed cropping systems all offer pathways toward more efficient, environmentally sound nutrient use. The work of Prof. Dr Bettina Eichler-Löbermann and her colleagues contributes essential knowledge for developing agricultural practices that maintain productivity while reducing reliance on finite mineral fertilisers. This is an increasingly important goal for global food security and ecosystem protection in the long run.
References
- Bettina Eichler-Löbermann, Theresa Zicker, Mareike Kavka, Stephanie Busch, Christine Brandt, Philipp Stahn, Konrad Miegel. Mixed cropping of maize or sorghum with legumes as affected by long-term phosphorus management, Field Crops Research, Volume 265, 2021, 108120, ISSN 0378-4290.
- Eichler-Löbermann, B., Blossei, J. & Kim, DG. Microbial strategies to alleviate phosphorus deficiency in African smallholder farms: Inoculation and soil microbiome enhancement. Plant Soil (2025). https://doi.org/10.1007/s11104-025-07707-w.
- Hu, Yue & Jarosch, Klaus & Kavka, Mareike & Eichler-Lobermann, Bettina. (2022). Fate of P from organic and inorganic fertilizers assessed by complementary approaches. Nutrient Cycling in Agroecosystems. 124. 10.1007/s10705-022-10237-x.
