Document Type

Paper- Restricted to Campus Access

Publication Date

Fall 2022

Faculty Mentor

Denise Finney

Abstract

Understanding the way that soil processes nutrient inputs is critical for understanding soil’s contribution to an eco-friendly future. A critical understanding in this puzzle is the way that nutrients flow through soils and factors that impact this. Nutrient ratios are a key factor in microbial interactions with litter inputs. Higher nitrogen litter would be expected to decompose at a faster rate and allow better accumulation of carbon and nitrogen in the soils based on the Microbial Efficiency-Matrix Stabilization framework. To test this, a controlled environment soil study was established to investigate the effects of crop legacy on carbon and nitrogen cycling from newly added litters of varying quality. In the twenty-week incubation study, destructive harvests were conducted at weeks 6, 14, and 20. During the incubation period, the respiration rate of each sample was measured weekly. At destructive harvest points, the overall remaining litter biomass was measured. The fresh soil was used to extract inorganic nitrogen for later sampling. Finally, soils were dried for POX-C analysis at destructive harvest points. The change in carbon to nitrogen ratios of litter and soils were measured using combustion analysis. These data accompanied by the respiration data give a comprehensive picture of the flow of carbon in the soil and gives comprehensive understanding of the way carbon flows through soils by comparing carbon composition of litter and whole soils over time. The nitrogen extracts were then chemically processed to measure both nitrate and ammonium levels in the soils comparing levels before and after incubation to develop a similar understanding of nitrogen flux in the systems. To look at impacts on labile carbon pools POX-C analysis was performed to understand decomposition in the system. All the data allows nutrient pools to be indirectly tracked in soils and develop an understanding of how nutrient pools cycle through soil.

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