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Title Biological potential and diffusion limitation of methane oxidation in no-till soils
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University/Publisher IUPUI
Abstract

Indiana University-Purdue University Indianapolis (IUPUI)

Long term no-till (NT) farming can improve the CH4 oxidation capacity of agricultural lands through creation of a favorable soil environment for methanotrophs and diffusive gas transport. However, limited data is available to evaluate the merit of that contention. Although the potential for biological CH4 oxidation may exist in NT soils, restricted diffusion could limit expression of that potential in fine-textured soils. A study was conducted to assess the CH4 oxidation potential and gaseous diffusivity of soils under plow till (PT) and NT for > 50 years. Intact cores and composite soils samples (0-10 and 10-20 cm) were collected from NT and PT plots located at a well-drained site (Wooster silt loam) and at a poorly-drained (Crosby silt loam) site in Ohio. Adjacent deciduous forest soils were also sampled to determine maximum rate expected in undisturbed soils in the region. Regardless of study sites and soil depth, CH4 oxidation rate (measured at near ambient CH4) and oxidation potential (Vmax, measured at elevated CH4) were 3-4 and 1.5 times higher in NT than in PT soils, respectively. Activity in the NT soils approached (66-80 %) that in the forest soils. Half saturation constants (Km) and threshold for CH4 oxidation (Th) were lower in NT (Km: 100.5 µL CH4 L-1; Th: 0.5 µL CH4 L-1) than in PT soils (Km: 134 µL CH4 L-1; Th: 2.8 µL CH4 L-1) suggesting a greater affinity of long-term NT soils for CH4, and a possible shift in methanotrophic community composition. CH4 oxidation rates were lower in intact soil cores compared to sieved soils, suggesting that CH4 oxidation was limited by diffusion, a factor that could lead to lower field-measured CH4 uptake than suggested by biological oxidation capacity measured in the laboratory. Regardless of soil drainage characteristic, long-term NT resulted in significantly higher (2-3 times) CH4 diffusivity (mean: 2.5 x 10-3 cm2 s-1) than PT (1.5 x 10-3 cm2 s-1), probably due to improved soil aggregation and greater macro-pores volume in NT soils. Overall, these results confirm the positive impact of NT on the restoration of the biological (Vmax, Km and Th) and physical (diffusivity) soil attributes essential for CH4 uptake in croplands. Long-term implementation of NT farming can therefore contribute to the mitigation of CH4 emission from agriculture.

Subjects/Keywords No-tillage  – Statistics  – Research  – Ohio  – Analysis; Conservation tillage  – Research  – Ohio  – Analysis; Methylotrophic bacteria  – Research; Biogeochemistry  – Research; Gases in microorganisms; Soils  – Nitrogen content  – Research  – Ohio  – Analysis  – Statistics; Soils  – Oxidation  – Research  – Analysis; Soil chemistry  – Analysis; Drainage; Soil texture; Soil physics; Methane  – Research  – Analysis; South Charleston (Ohio)  – Soils  – Sampling  – Research; Wooster (Ohio)  – Soils  – Sampling  – Research; Oxidation  – Environmental aspects  – Research; Soils  – Sampling  – Statistics  – Research  – Analysis
Contributors Wang, Xianzhong; Martin, Pamela; Jacinthe, Pierre-André
Language en
Country of Publication us
Record ID handle:1805/4446
Repository iupui
Date Retrieved
Date Indexed 2020-01-07

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…soils under long-term NT in comparison to soils under conventional tillage practices (PT). Soil samples for this study were from research plots that have been under NT for about 50 years - to our knowledge, this is the longest running…

…made using soils under NT for such a long period of time. Results of the proposed study will be a valuable contribution to society and agricultural sciences. Research questions and hypotheses 1. How does long term adoption of NT affect the methane…

…aggregation, gas diffusivity will be 10 significantly greater in NT compared to PT soils. However, due to increase in bulk density and higher moisture content, NT can lead to lower soil diffusivity in fine-textured and poorly-drained soils. Research

…objectives The specific objectives of this research study are as follows: 1. To characterize the methane oxidation potential of NT soils in comparison to PT. 2. To assess the significance of diffusion restriction on CH4 oxidation in NT soils. 11 MATERIAL…

…in Ohio (USA). These plots were established by the Ohio Agricultural Research and Development Center (OARDC) to study the effect of tillage practices on land productivity and soil properties. Tillage practices investigated include…

…same tillage practice for the same length of time but have contrasting soil drainage characteristics (moderately well drained in Wooster and somewhat poorly drained in South Charleston), they offer a 12 unique opportunity to evaluate the…

…effect of soil drainage on CH4 oxidation and associated soil properties. Table 1. Surface soil texture at the study sites Parameter Soil classification Slope Crosby silt loam (Aeric Ochraqualf) Wooster Wooster silt loam (Typic Fragiudalf…

…woodlots are treated as reference sites during data analysis and interpretation to represent the maximum oxidation potential of undisturbed soils in the region. 13 Fig 1. Location of the study sites in Ohio. Wooster site 14 Ohio South Charleston site…

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