Wollastonite powder application increases rice yield and CO₂ sequestration in a paddy field in Northeast China

Enhanced silicate rock weathering (ERW) on cropland soils can increase crop yield and promote carbon dioxide (CO₂) sequestration. Applying silicate rock powder to flooded rice paddies can promote weathering, but the effects of ERW on rice production and CO₂ removal rates in the field remain unclear.

We investigated the effects of adding wollastonite (CaSiO₃) powder (5 t ha⁻¹) to rice paddy plots on soil properties, rice yield, rice grain quality, grain arsenic, grain cadmium, and soil CO₂ sequestration in Liaoning Province, Northeast China.

Wollastonite application increased soil pH, soil available silicon (Si) content, and Si uptake by rice. Wollastonite application increased grain number by 10% per panicle (15 ± 2), total grain number by 15%, and rice yield by 12% (1.4 ± 0.1 t ha⁻¹). After five months of rice growth, soil inorganic carbon (SIC) content in the surface soil increased by 1.20 ± 0.03 t CO₂ ha⁻¹ in wollastonite treatments. We estimated a net profit of $300 (U.S.) ha⁻¹ from yield increase and carbon trade with wollastonite application to this paddy field.

Wollastonite application to paddy fields in Northeast China promoted rice yield and CO₂ sequestration in the surface soil. This soil CO₂ sequestration triples that from the control soil and is comparable to prior pot trials. Although field trials are needed on the limits to CO₂ sequestration and rice yield increases with wollastonite application, such applications promise to increase soil CO₂ sequestration and profits for a key crop.