Date of Award

10-7-2016

Document Type

Thesis and Dissertation

Degree Name

Master of Science (MS)

Department

Department of Agriculture

First Advisor

Robert Rhykerd

Abstract

It has been estimated that nitrate (NO3-N) leaching from artificially drained agricultural fields in the Upper Mississippi River Basin accounts for approximately 65% of nitrogen (N) delivered annually to the Gulf of Mexico. Therefore, the objectives of this study were to investigate the impact fertilizer application timing and cover crops (CC) adoption on the load and concentration of nutrients in subsurface drainage leachate. This experiment was conducted at the Illinois State University Nitrogen Management Field Station, in Lexington, IL. Treatments include a zero control (no N fertilizer and no cover crop), fall dominated N application (70% fall, 30% spring) with and without CC, and a spring dominated N application (20% fall, 80% spring) with and without CC. A total rate of 224 kg N ha-1 was applied to all treatments, except the zero control. Spring cover crop sampling revealed an average biomass of 1165 kg ha-1 and an average N uptake of 42.5 kg N ha-1. Soil samples were collected in the spring at four separate depths and were analyzed for inorganic N. Regardless of N fertilizer application system, cover crops demonstrated the ability to decrease the concentration of NO3- N 33-62% within the soil profile across the study. The addition of cover crops also reduced the amount of NO3- N within at the lower depths of the soil profile by 17% in the fall system and 37% in the spring system. The Illinois Nutrient Loss Reduction Strategy presents a target reduction in NO3-N losses by 15% by 2025. This data demonstrates that CC have the potential to significantly reduce NO3-N losses in both spring and fall dominated N management systems.

Comments

Imported from ProQuest Ruffatti_ilstu_0092N_10855.pdf

Page Count

136

Included in

Agriculture Commons

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