Using P‐Mobilization Traits in Modern Maize Varieties for Optimizing the P Fertiliser Use Efficiency of Struvite Under P Limitation: First Evidence From a Pot and Field Trial
Michelle Natalie Herrmann, Daniel Wanke, Peteh Mehdi Nkebiwe, Torsten MüllerABSTRACT
Introduction
Current recycling measures for closing the phosphorus (P) cycle are limited by the lower fertiliser use efficiencies of recycled products. Increasing P use efficiency (PUE) through maize genotype selection and management may offer a sustainable solution, but the potential of variety choice and its interaction with placed fertilisation for enhancing recycled fertilisers' efficiency remains unclear.
Material and Methods
Four maize genotypes differing in P efficiency were tested in a pot trial, where microbial P, phosphatase activity, and Olsen‐P were measured and their links to PUE were investigated. Three of these genotypes were examined in a two year field trial comparing two fertiliser types (diammonium phosphate (DAP); struvite) and application methods (broadcast vs. placed).
Results
Stabil showed higher microbial biomass P and LG_30258 higher phosphatase activity than other varieties. Although not significant, the PUE, expressed as biomass divided by fertilisation, varied among genotypes ( Amaroc 3.4 x higher than Ricardinio ). In the field, no genotype × management interaction was detected and genotypic differences became minimal ( LG_30258 1.4 x higher than Stabil ). Struvite performed comparably to DAP across both years, while fertiliser placement only increased biomass and P offtake in the drier year, 2022. P mobilisation traits could not predict PUE, however, P offtake in the pot and field trial followed the same ranking order as the P mobilization traits.
Conclusion
This study highlights that the slow‐release fertiliser, struvite, has a comparable fertiliser efficiency than DAP, and fertiliser placement can further enhance PUE in dry seasons, independent of the fertiliser source. Although slight genotypic variance in P mobilisation exists in modern maize varieties and can predict P responsiveness, the influence of genotype choice and management options appeared additive rather than synergistic since genotype x management interaction was not significant. Future research should further explore how to exploit synergies between genotypes, management, and fertilisers.