Unveiling the potential of Zn–Al–NO3 LDH as nanofertilizer: effects on the maize growth and biological and chemical properties of an acidic soil

Zinc (Zn) is an essential micronutrient, and its deficiency is a global issue. Zinc fertilisers are commonly used to address this, but they often have low efficiency, limiting yields and causing environmental problems. Layered double hydroxides (LDHs) are innovative nanomaterials with potential agricultural applications. To ensure their sustainability, it is crucial to understand their behaviour, fate, and toxicity in the terrestrial ecosystem. This study evaluated Zn-Al-NO3 LDH as an alternative Zn fertiliser at relevant agronomic concentrations. Zn sulfate was tested as a conventional fertiliser, and maize (Zea mays) as a test species. The assessment included plant performance, Zn use efficiency, soil functionality indicators, and Zn fate assessments. Our study showed that Zn-Al-NO3 LDH did not affect plant development and increased root Zn content, with little to no translocation to the shoots. Soil enzymatic activity increased over time, but differences in soil ecosystem multifunctionality were negligible. Low nitrate and Zn concentrations in leachates indicated reduced leaching potential. Our study demonstrates the potential of Zn-Al-NO3 LDH as an alternative to conventional Zn fertilisers at half the recommended dose. However, further research is needed to investigate its effects across different plant species and to evaluate the fate and behaviour of these nanomaterials in various soils and environmental contexts.