Annual ryegrass (Lolium multiflorum Lam.) growth response to nitrogen in a sandy soil amended with acidified manure and municipal sludge after “quick wash” treatment

Authors: Paye, Wooiklee; Szogi, Ariel; Shumaker, Paul; Billman, Eric

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/19/2023
Publication Date: 10/22/2023
Citation: Paye, W.S., Szogi, A.A., Shumaker, P.D., Billman, E.D. 2023. Annual ryegrass (Lolium multiflorum Lam.) growth response to nitrogen in a sandy soil amended with acidified manure and municipal sludge after “quick wash” treatment. Agronomy Journal. 13(10):2655. https://doi.org/10.3390/agronomy13102655.
DOI: https://doi.org/10.3390/agronomy13102655

Interpretive Summary: Land disposal of animal manure and municipal sludge is an environmental concern due to an imbalance of the nitrogen to phosphorus (N:P) ratio for crop production leading to excess phosphorus (P) in soils and potential risks of water pollution. A process called "Quick Wash" (QW) was developed to extract and recover phosphorus (P) from manure and municipal sludge (MS), producing an acidic by-product with adequate N:P ratio to meet crop N requirements. Yet, data on crop response (biomass production) to nitrogen (N) application using acidic QW by-products are lacking. We evaluated the response of annual rye-grass and potential N leaching in a sandy soil to N applications using raw wastes, their corresponding acidified QW by-products, and ammonium sulfate (AMS) fertilizer. Treatments included a control, raw and acid-washed chicken litter, dairy and swine manure, MS, and AMS at 100, 200 and 400 kg of N per hectare. We found no significant differences in annual rye-grass yield and N uptake between the raw and acidified QW by-products. However, rye-grass produced 4 to 30 percent more biomass with AMS than raw or acidified manures and MS. The total inorganic N concentration in soil leachate accounted for 5 to 17% of total N applied with AMS, but less than1% of the total N for all the raw or QW treated organic amendments. Furthermore, we found no differences in soil N leaching between raw and acid-washed forms. Our results indicated that QW acidic by-products can substantially reduce N leaching in agricultural soils with additional benefits of reducing environmental risks of excess soil P with no penalties for crop yield losses.

Technical Abstract: The Quick Wash (QW) treatment extracts phosphorus (P) from manure and municipal sludge (MS), producing an organic acidified by-product with adequate nitrogen (N):P ratio to meet crop N requirements. Yet, data on crop response to N using QW by-products are lacking. We evaluated the response of annual ryegrass (Lolium multiflorum Lam.) and potential N leaching in sandy soil to N applications using raw wastes, their corresponding QW by-products, and ammonium sulfate (AMS) fertilizer. Treatments included a control (no amendment added), raw and acid-washed chicken litter, dairy and swine manure, MS, and AMS at 100, 200, and 400 kg N ha-1. We found no significant differences in annual ryegrass yield and N uptake between the raw and acidified organic QW by-products. However, ryegrass produced 4–30% more biomass with AMS than organic amendments. The total residual soil inorganic N under AMS treatments ranged between 6.3 and 67.9 mg pot-1 and accounted for 5–17% of the total N applied, but it was <1% for all the organic amendments. We found no differences in soil N leaching between raw and acid-washed forms of each organic soil amendment. Our results indicated that acidified organic QW by-products can improve environmental quality by substantially reducing the amount of applied P with no penalties for crop yield losses compared to raw manure and MS.