Functional Glass‐based Fertilizer Implementing Bacterial Nitrogen Fixation

ABSTRACT Fertilizers are indispensable in modern agriculture, with >200 Mt of nitrate and mineral fertilizers being consumed globally each year. Sustainable agricultural intensification requires nutrient‐efficient fertilization strategies that avoid environmental damage and preserve finite resources. All‐inorganic glass fertilizers offer controlled nutrient release over a long and adaptable period of time, but they lack the essential macronutrient nitrogen, due to challenges in incorporation into the glass without compromising solubility. Here, we bypass this issue through a functional glass fertilizer with the ability to promote the reproduction of nitrogen‐fixing bacteria instead of incorporating nitrogen into the fertilizer itself. This is achieved by using molybdenum as the triggering species, incorporated into the glass lattice and released together with phosphate and potassium during fertilization. Such a material promotes the growth of Azotobacter vinelandii , which uses an enzymatic reaction to transform ambient nitrogen into bioavailable ammonia, thus reducing the need for nitrogen fertilization. We argue that such fertilizers are superior to conventional slow‐release materials in terms of reducing the ecological footprint of fertilization. The nitrogenase cycle is potentially self‐regulating, avoiding the risk of over‐fertilization when ammonia is applied directly. Furthermore, all‐inorganic glass fertilizers do not introduce auxiliary organic compounds and exhibit highly tailorable and temperature‐invariant dissolution rates. By reducing tailing effects, batched phosphate can then be used more efficiently.