Development of novel formulations for improved molybdenum fertilization (DEMOFERTILIZER)

The use of mineral fertilizers in crop production systems is strongly contributing to the competiveness of the agricultural sector as a whole, yet the importance of essential micronutrients, such as molybdenum, is often overlooked. Molybdenum (Mo) is of key importance for plant growth as an essential component of the cofactor for enzymes in the N-metabolism. Mo deficiency in plants is often associated with N deficiency, and can thus have far-reaching consequences in agricultural systems. To overcome Mo deficiency, fertilizer Mo needs to be applied, which typically contain highly water-soluble forms of Mo, e.g. Na2MoO4. In acid Fe/Al-oxide rich soils, the fast release of Mo from soluble forms causes Mo to be quickly sorbed; in sandy soils fast Mo release results in high losses of Mo through leaching. In this project, the use of slow-release fertilizer (SRF) Mo compounds instead of water-soluble Mo compounds will be explored to better match nutrient release with plant demand and reduce Mo fixation and leaching. SRF formulations will be synthesized using different approaches (LDH and mechanochemical synthesis). Feedback between Mo desorption/solubility experiments and material synthesis will optimize the new SRF compounds. The new Mo fertilizer forms will be embedded in different macronutrient carriers, after which batch and column experiment will be performed to characterize the Mo release in an aqueous and a soil system to compare the release with that of soluble Mo fertilizers. Finally, a pot trial will be performed to assess Mo use efficiency and leachability of a new Mo SRF in comparison with soluble Mo fertilizers. Next to this research objective, the applicant will improve his research skills by receiving training in mechano-chemical synthesis, fertilize shaping and fertilizer testing (University of Adelaide), and in modelling and LA-ICP-MS (KU Leuven). The applicant will also gain experience in teaching, project management, dissimilation and communication.