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ndltd-OhioLink-oai-etd.ohiolink.edu-osu13146318782021-08-03T06:03:47Z Soil carbon dynamics and gaseous emissions in riparian zones in Coshocton, Ohio Tanzosh, Joyce K. <p>Riparian zones are the land boundaries that connect aquatic and terrestrial realms, consisting of either natural or planted vegetation. The high productivity and the unique soil and moisture characteristics typical of riparian systems enables them to store relatively large amounts of soil organic carbon (SOC). However, riparian areas may be net emitters of other greenhouse gases (GHGs) because certain environmental conditions such as saturated soils may accentuate the emission of GHGs through methanogenesis and denitrification. Landuse influences the SOC pool and the release of GHGs though its effect on soil properties, temperature and moisture regimes. The objective of this study was to assess the effect of landuse on SOC pool and GHG emissions in riparian zones in two agricultural watersheds in Coshocton, Ohio. In watershed A, the SOC pool (0-100 cm depth) was 251.1 ± 78.1, 193.0 ± 47.2 and 97.9 ± 4.7 Mg ha<sup>-1</sup> in riparian grass, riparian forest and cropland systems, respectively. Both riparian systems contained more SOC pool than the upland landuse. In watershed B, the SOC pool was 126.3 ± 3.3, 135.0 ± 29.3 and 95.7 ± 1.2 Mg ha<sup>-1</sup> in riparian grass, riparian forest and upland pasture landuses, respectively. No differences were observed among landuses. Likewise, no differences existed between the SOC pool in the grass and forest riparian systems in either watershed sampled. Differences in fine root mass and soil properties were frequently observed among landuses, and were generally linearly related to the SOC pool. Soil properties consistently differed among landuses, yet, the SOC pool did not. These data suggest that site history, land management and ecosystem age were stronger determinants of SOC pool than soil properties.</p><p>In watershed A, the carbon dioxide (CO<sub>2</sub>-C) flux (Mg C ha<sup>-1</sup> y<sup>-1</sup>) was 24.5 ± 2.7, 9.2 ± 1.4 and 19.0 ± 3.3 in the riparian grass, riparian forest and cropland landuses, respectively. In watershed B, CO<sub>2</sub>-C flux (Mg C ha<sup>-1</sup> y<sup>-1</sup>) was 15.7 ± 1.8, 9.8 ± 1.1 and 13.9 ± 2.2 in the riparian grass, riparian forest and upland pasture landuses, respectively. The CO<sub>2</sub>-C flux was positively correlated with both air and soil temperatures across all landuses. In watershed A, methane (CH<sub>4</sub>-C) flux (kg C ha<sup>-1</sup> y<sup>-1</sup>) was 44.1 ± 5.8, 32.1 ± 7.7 and 40.9 ± 6.8 in the riparian grass, riparian forest and cropland landuses, respectively. In watershed B, CH<sub>4</sub>-C flux (kg ha<sup>-1</sup> y<sup>-1</sup>) was 63.3 ± 5.5, 29.4 ± 4.2 and 60.3 ± 5.9 in the riparian grass, riparian forest and pasture landuses, respectively. The CH<sub>4</sub>-C flux was positively correlated with both air and soil temperatures across landuses. In watershed A, nitrous oxide (N<sub>2</sub>O-N) flux (kg ha<sup>-1</sup> y<sup>-1</sup>) was 27.4 ± 5.3, 16.0 ± 1.5 and 37.4 ± 8.9 in the riparian grass, riparian forest and cropland landuses, respectively. In watershed B, N<sub>2</sub>O-N flux (kg N ha<sup>-1</sup> y<sup>-1</sup>) was 20.7 ± 4.3, 12.6 ± 1.2 and 15.9 ± 4.8 in the riparian grass, riparian forest and pasture landuses, respectively. The N<sub>2</sub>O-N flux was positively correlated with precipitation and soil moisture content for several landuses. Land management activities (i.e., tillage, herbicide application, grazing) also influenced GHG emission. Overall, the riparian forests in this study emitted less GHGs and had less global warming potential (GWP) compared to the riparian grasses.</p> 2005 English text The Ohio State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=osu1314631878 http://rave.ohiolink.edu/etdc/view?acc_num=osu1314631878 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.
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