Slow Release Nanofertilizers for Bumper Crops

The Haber–Bosch process for the commercial production of ammonia demonstrated in 1913 was a watershed event in the mass production of urea, the principal nitrogen fertilizer for modern agriculture. Today, thanks to the so-called “green revolution” starting in in the 1960s, nearly half of the world population relies on increased crop yields, through the use of nitrogen fertilizers, to access affordable food. Urea, CO(NH2)2, is the principal nitrogen fertilizer (46% N by weight). Sadly, urea’s chief strengths—water solubility and ready plant availability—also provide its Achilles’ heel. About three-quarters of urea is lost during fertilization due to volatilization and leaching.1 This not only increases the cost but also has severe negative environmental implications. Specifically, the inefficiency of fertilizer delivery is associated with contaminated groundwater and water bodies suffused with nitrates, expanding coastal water dead zones, and nitrous oxide getting into the atmosphere. Nitrous oxide is the third most abundant greenhouse gas, with a higher Global Warming Potential than either carbon dioxide or methane.2 Our dependence on synthetic nitrogen fertilizer has dramatically increased anthropogenic interference with the nitrogen cycle, key for protein production for all life forms. Modern food production releases nearly as much nitrogen (150 Mt/year) as is generated by bio fixation and lightning