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Potential carbon and nitrogen mineralization in soils from a perennial forage production system amended with class B biosolids
- Jin, Virginia L., Johnson, Mari-Vaughn V., Haney, Richard L., Arnold, Jeffrey G.
- Agriculture, ecosystems & environment 2011 v.141 no.3-4 pp. 461
- biosolids, carbon, carbon dioxide, fertilizer rates, forage production, mineralization, nitrate nitrogen, nitrogen, nutrient transport, production technology, soil, soil organic carbon
- The effects of biosolids application rate and history on soil potential C and N mineralization were measured over a 112-day laboratory incubation. Soils were collected from a large-scale biosolids recycling operation that surface-applies anaerobically digested Class B biosolids for commercial forage production. Five treatments were evaluated: unamended control; 22Mgdrybiosolidsha⁻¹y⁻¹ applied for 25 years; 22, 45, and 67Mgha⁻¹y⁻¹ applied for 8 years. Biosolids additions enhanced total soil organic C by 32–92% and total N by 30–157% compared to unamended soils. Total N increased with application rate and was dominated by nitrate-N. Potential C mineralization (cumulative CO₂ produced) was 11–62% greater in amended soils compared to controls and highest at 67Mgha⁻¹y⁻¹. Net N mineralization and immobilization were highest early in the incubation for 45 and 67Mgha⁻¹y⁻¹ treatments. No significant differences in potential C and N mineralization between controls and soils amended at the lowest rate for 8 or 25 years suggests that biosolids applications at 22Mgha⁻¹y⁻¹ are sustainable over the long-term. Higher potential N mineralization rates and soil nitrate concentrations under higher application rates may increase the risk of off-site nutrient transport and requires further evaluation.