Thesis
Carbon and nutrient fluxes in organically amended soils
Washington State University
Master of Science (MS), Washington State University
2013
Handle:
https://hdl.handle.net/2376/102794
Abstract
Understanding C, N and other nutrient pools and fluxes from organic amendments is important for mitigating greenhouse gas emissions, increasing nutrient uptake efficiency and reducing nutrient losses to the environment. This study tracked C and nutrient fluxes from organic soil amendments in lab and field conditions in order to improve our ability to predict decomposition of these and other materials in soil. During a 57-d laboratory incubation, CO2 and N2O evolution, resistant C and N, microbial biomass, soluble C, and inorganic N were quantified in two soils (Puyallup fine sandy loam and Koehler loamy fine sand) with various fertility amendments. Treatments included spinach (SP), canola (CAN), wheat (WH), bean (BN), dried chicken manure (CH), dried dairy manure (DM), dairy manure-based compost (COM), NutriURich 8U2U4 (NR), (NH4)2SO4 (AMS) and an unamended control (CTL). The SP, CAN, WH, BN, CH and AMS were enriched with 15N to allow analysis of the origin of N. Nonlinear regression was used to estimate the active and slow C pools. Soil texture greatly affected C and N mineralization kinetics. More C was mineralized from amended Koehler soil than from amended Puyallup soil. All treatments produced similar N2O to CTL in the Puyallup soil, but NR, BN, and CAN produced more N2O than CTL in Koehler soil. By d 57, COM had more resistant C than CTL. Amending soil with compost may be a means for C sequestration without increasing N2O emissions. In field trials, ion exchange resins (IER) were used to measure nutrient fluxes for 5 wk in soils with no amendment (CTL) or amended with NutriURich (NR), dairy manure (DM), or green manure (GM). At all times nutrient fluxes in soil with GM behaved similarly to CTL. Nitrate flux was greatest at weeks 2U4. In 2012, there was a distinct peak in NO3U flux in wk 3. Nitrogen uptake by wheat correlated (p< 0.1) to N flux in both 24Uhr lab incubations and 5 week field IER burials, indicating that short lab incubations may be used to predict nutrient release from organic materials in the field.
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Details
- Title
- Carbon and nutrient fluxes in organically amended soils
- Creators
- Marina A. Heppenstall
- Contributors
- Lynne A. Carpenter-Boggs (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Environment, School of the (CAHNRS)
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525178101842
- Language
- English
- Resource Type
- Thesis