Date of Graduation

5-2018

Document Type

UAF Access Only - Thesis

Degree Name

Bachelor of Science in Biological Engineering

Degree Level

Undergraduate

Department

Biological and Agricultural Engineering

Advisor

Haggard, Brian E.

Reader

Garcia, M. Elena

Second Reader

Zhu, Jun

Abstract

Increasing population and decreasing arable soil worldwide is placing pressure on farmers. To increase crop yield, these fertilizers improve soil nutrients for crops but can be carried into bodies of water, ultimately causing eutrophication. It is hypothesized that the application of fertilizer will increase nutrient concentrations in water relative to the control. The goal of this study is to show the concentrations and release rates of the nutrients from soils with fertilizer banded beneath the soil surface. The research uses twenty soil cores from a tomato plot and four different treatments. Two treatments were Class A bio-solids at different rates, one treatment was a generic fertilizer, and one treatment had no fertilizer. Sixteen soil cores had fertilizer applied in subsurface banding, except the control. Four cores without fertilizer were to have the fertilizer applied in broadcast. Overlying water was applied, then samples collected over seven hours to determine initial concentrations, final concentrations, and release rates of nutrients; leachate samples were also collected. The nutrient concentrations and release rates from the soil cores with the fertilizers banded subsurface were not different across treatments or relative to the broadcast simulation even though the broadcast simulation had the fertilizer applied at a third of the rate. The only concern was elevated concentrations of NO3-N in the leachate, which exceeded 10 mg L-1 for the fertilizer treatments. The use of bio-solids might be a sustainable option that does not increase nutrient loss relative to commercial fertilizers.

Keywords

Bio-solids, banding fertilizer, water runoff, nutrients, broadcasting fertilizer

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