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ARS Home » Southeast Area » Florence, South Carolina » Coastal Plain Soil, Water and Plant Conservation Research » Research » Publications at this Location » Publication #388918
Research Project: Innovative Manure Treatment Technologies and Enhanced Soil Health for Agricultural Systems of the Southeastern Coastal Plain

Location: Coastal Plain Soil, Water and Plant Conservation Research

Title: Biomass production, metal and nutrient content in sorghum plants grown on soils amended with sewage sludge

Author
item ARLO, LAURA - Universidad Del La Republica
item BERETTA, ANDRES - Universidad Del La Republica
item Szogi, Ariel
item PINO, AMAMBELILA DEL - Universidad Del La Republica

Submitted to: Heliyon
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/20/2021
Publication Date: 1/4/2022
Publication URL: https://handle.nal.usda.gov/10113/7612563
Citation: Arlo, L., Beretta, A., Szogi, A.A., Pino, A. 2022. Biomass production, metal and nutrient content in sorghum plants grown on soils amended with sewage sludge. Heliyon. https://doi.org/10.1016/j.heliyon.2021.e08658.
DOI: https://doi.org/10.1016/j.heliyon.2021.e08658

Interpretive Summary: The generation of sludge from wastewater treatment plants and the building of new municipal plants increased the generation of sewage sludge in Uruguay, South America. Applying sewage sludge to soils is one of the possible disposal alternatives to conventional land filling and recycling plant nutrients for crop production. A greenhouse experiment was conducted to quantify the effect of municipal sludge on: 1) plant biomass production and nutrient concentration of sorghum plants; 2) the chemical properties of amended soils; and 3) assess whether heavy metal concentrations in sludge are appropriate according to environmental regulations. Two Uruguayan soils (Mollisols) were amended with pure sludge (PS) and limed sludge (LS). Sludge increased plants' nutrients absorption and dry matter production. Lime addition to PS favored production, whose increase depended on soil pH and nutrient availability. Sludge effect on elements concentration in aboveground biomass, depended on the element, treatments and soil type. The mineralized nitrogen and soil phosphorus values increased with the addition of sludge without exceeding the critical levels of nutrient crop requirements. The PS did not increase metal concentration in soils. The LS slightly decreased soil lead but slightly increased soil chromium and zinc concentrations. These heavy metal levels were acceptable according to Uruguayan environmental guidelines. Therefore, agriculture soils are a viable final destination for both PS and LS.

Technical Abstract: Sludge generation from wastewater treatment plants in Uruguay has increased in recent years. Agricultural soils may be a final destination. A greenhouse experiment was conducted to quantify the effect of this sludge on 1) plant biomass production and nutrient concentration of sorghum (Sorghum bicolor var. vulgare); 2) the chemical properties of amended soils; and 3) assess whether heavy metal concentrations in sludge are appropriate according to environmental regulations. Two soils (S1 and S2) were amended with pure sludge (PS) and limed sludge (LS), with low dose (LD) of 16.0 and 17.3 Mg ha1 and high dose (HD) of 32.0 and 34.6 Mg ha1, respectively. Sludge treatments increased plants' nutrient absorption and dry matter production. The LS treatments incremented plant biomass production, depending on soil pH and nutrient availability. The effect of sludge treatments on elemental concentration in aboveground biomass depended on the element, treatments, and soil type. Mineralized nitrogen (N) and plant available phosphorus (P-Bray 1) values increased with sludge addition without exceeding Uruguay's critical soil level of P-Bray 1 for the sorghum crop. The PS did not increase metal concentration in soils. The LS slightly decreased soil Pb and slightly increased Cr and Zn soil concentration; levels were according to Uruguayan environmental guidelines. Therefore, agriculture soils are a viable final destination for PS and LS. Land applied sludge has acceptable levels of metals and promotes crop development.