Date of Graduation

5-2021

Document Type

Thesis

Degree Name

Master of Science in Agricultural Economics (MS)

Degree Level

Graduate

Department

Agricultural Economics and Agribusiness

Advisor/Mentor

Michael P. Popp

Committee Member

Nathan P. Kemper

Second Committee Member

John D. Anderson

Keywords

Broadcast litter, Commercial fertilizer, Decision support, Sub-surfaced litter

Abstract

Livestock producers routinely spread fertilizer or broadcast poultry litter to improve forage production. With poultry litter widely available across the Southeastern United States and a cheaper source of plant nutrition than fertilizer when proximal to application sites, the novel application of litter below the soil surface, while costly, allows for greater nutrient retention than broadcasting. Since quantifying costs and benefits of sub-surface litter application (SSLA) is complex, we develop and present a spreadsheet tool for automated comparison between SSLA, fertilizer, and broadcasted litter for user-specific scenarios involving equipment choices (new, used, custom), desired nutrient needs for crops grown, litter nutrient concentration, and interval between litter application given the slow-release nature of litter compared to fertilizer. Results showed that SSLA can compete with fertilizer on a cost/return basis and especially so in situations where organic farming practices are targeted. With a longer interval between litter application, enhanced annual capacity utilization of the applicator, and a good match between nutrient needs of crops fertilized and litter nutrient content, the tool demonstrated cost savings with SSLA over fertilizer while more-or-less cost neutral with broadcasting. Given the latter, the tool lends itself to estimating operation-specific subsidies needed for SSLA adoption to reduce nutrient runoff and odor externalities or, alternatively, modify the litter drill to enhance speed of application by changing the implement’s width.

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