A Lecithin Liposome Stimulates Soil Microbial Respiration and Nitrate Immobilization

Liposomes are microscale lipid vesicles used in pharmaceuticals, food products, and most recently, agriculture. Several studies have shown that liposomes can deliver nutrients to plant leaves, often more efficiently than traditional forms. However, the delivery of plant nutrients to soil via liposomes remains understudied. Interactions between liposomes and soil microbes, including metabolism of the lipid carbon (C) and assimilation of liposome-encapsulated nutrients into soil microbial biomass, could alter the availability of nutrients within the soil. We assessed the impact of lecithin liposomes with nitrogen (N) cargo on C and N cycling during a 7-day incubation experiment. We quantified changes in concentrations of carbon dioxide, nitrous oxide, oxygen, and soil inorganic N pools including soil extractable nitrate (NO₃^–-N) and ammonium (NH₄⁺-N). Liposome additions increased microbial respiration and resulted in rapid soil NO₃^–-N immobilization, suggesting that liposomes may be a tool to immobilize N and reduce agricultural N losses.