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ARS Home » Plains Area » Lincoln, Nebraska » Agroecosystem Management Research » Research » Publications at this Location » Publication #257117
Title: Potential carbon and nitrogen mineralization in soils from a perennial forage production system amended with Class B biosolids

Author
item Jin, Virginia
item Johnson, Mari-Vaughn
item Haney, Richard
item Arnold, Jeffrey

Submitted to: Agriculture, Ecosystems and Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/29/2011
Publication Date: 6/7/2011
Citation: Jin, V.L., Johnson, M., Haney, R.L., Arnold, J.G. 2011. Potential carbon and nitrogen mineralization in soils from a perennial forage production system amended with Class B biosolids. Agriculture, Ecosystems and Environment. 141:461-465. Available: DOI: 10.1016/j.agee.2011.03.016.

Interpretive Summary: Nutrient management is the most critical issue for land application of biosolids, and effective management practices must be used to ensure the long-term agronomic and economic benefits from land-based biosolids recycling. Soils are an integral component of these beneficial reuse systems, and changes in soil microbial activities could change how soils store carbon (C) and provide nutrients such as nitrogen (N) for agricultural production. In this study, we found that surface applications of Class B municipal biosolids to a coastal Bermudagrass hay production system resulted in increased soil C and N concentrations. Readily available forms of soil C as water soluble organic C (WSOC) derived from biosolids were higher in more-recently applied soils, regardless of application rate. Biosolids additions stimulated microbial activity, but increases in soil C due to amendments were greater than potential soil C losses from microbial respiration (i.e. losses through CO2). In conclusion, surface applications of Class B municipal biosolids at the lowest rate could provide C storage while plant growth derived from the nutrients in the biosolids would limit environmental impacts of biosolids-derived N, as well as other compounds (i.e. phosphorus, trace metals). Long-term applications at the lowest rates, however, may still result in excess soil N levels and must be monitored.

Technical Abstract: The long-term sustainability of land-application for biosolids management depends on its impacts on soil carbon (C) and nutrient pools (i.e. nitrogen, N) and soil microbial activities. The effects of land-applying Class B biosolids on soil C, N, and microbial activities were measured over a 112-day laboratory incubation. Surface soils (0 10 cm) were collected from coastal Bermudagrass hay production fields. Treatments included an un-amended control site and four sites with different biosolids surface application rates/histories: 22 Mg ha 1 y 1 for 25 years; and 22, 45, and 67 Mg ha 1 y 1 for 8 years. Relative to unamended soils, biosolids additions enhanced total soil organic C (SOC) by 32-92% and total N (TN) by 30-157%. Both SOC and TN concentrations increased with application rate. Initial water-soluble organic C concentrations did not differ across treatments, but initial water-soluble organic N (WSON) was highest in the 45 and 67 Mg ha 1 y 1 treatments (P < 0.05). Application duration only impacted TN concentrations, which were greatest in soils treated for 25-y, but soil inorganic N, primarily nitrate, increased with application rate. Biosolids additions increased cumulative CO2 production by 11-62% compared to control. Cumulative and daily CO2 production rates were highest in the 67 Mg ha 1 y 1 treatment (P < 0.05). Net N mineralization/immobilization rates were highest at the beginning of the incubation for the 45 and 67 Mg ha 1 y 1 treatments, consistent with high initial WSON. Greater relative increases in SOC compared to respiratory C losses from biosolids-amended soils suggest potential C storage in this beneficial reuse system, even at the lowest application rate.