Unveiling Chemical Gradients in the Fertosphere: A Paradigm Shift to Enhance Fertilizer Efficiency and Decrease the Environmental Impact of Overfertilisation
Enzo Lombi, Casey L. Doolette, Rodrigo C. da Silva, Brigid A. McKenna, Peter M. Kopittke
Abstract
The need to increase food production means that fertilizers will continue to play a key role in farming systems. However, current formulation and practices are increasingly being scrutinized due to the low efficiency of applied nutrients with negative economic and environmental consequences. Enhance nutrient use efficiency requires a comprehensive understanding of soil-fertilizer interactions. Here, we contend that this knowledge has been generated by 'bulk' soil approaches that, while providing useful information, oversimplify these interactions by neglecting the strong chemical gradients occurring in the soils around fertilizers (i.e., in the fertosphere). Progress in non-destructive, in situ, and spatially resolved analytical techniques now allow a paradigm shift in the investigation of fertilizer chemistry in soil. For instance, mapping of diffusive gradients in thin films (DGT) allows for nutrient availability to be quantified in 2D. Complementing DGT information with imaging X-ray absorption near-edge structure (XANES-imaging) provides an avenue to understand how chemical speciation along chemical gradients in the fertosphere controls nutrient availability. This information is essential to improve agronomic practices and for the development of novel fertilizers. This is particularly important in developing fertilizers from recycled materials and return nutrient cycles within, or at least closer to, their planetary boundaries.