Mississippi River Basin

Study finds agricultural lime acts as a net CO2 sink in Mississippi basin

A new analysis by Suhrhoff et al. published in Nature examined water chemistry across the Mississippi River basin and found that agricultural liming, long classified by the IPCC as a greenhouse-gas source, has actually removed more CO2 from the atmosphere than it released. US farmers apply over 30 million tonnes of lime annually to manage soil pH, and the reaction was previously assumed to emit CO2 directly.

nature.com · 2026-09-23

Study finds farm lime use in Mississippi River Basin acts as CO2 sink, not source

Researchers combined century-long river chemistry records, reconstructed acidity and alkalinity inputs, and reactive transport modeling to assess whether agricultural liming in the Mississippi River Basin has released or absorbed CO2 over time. Using discharge and alkalinity data, historic Ca/Mg/SO4/nitrate measurements, and a model called SCEPTER, they built a spatial budget comparing acid inputs from fertilizer, manure and atmospheric deposition against alkalinity from lime application.

nature.com · 2026-09-23