Assessing hydrological connectivity inside a soil by fast-field-cycling nuclear magnetic resonance relaxometry and its link to sediment delivery processes
- 129 Downloads
Connectivity is a general concept used to represent the processes involving a transfer of matter among the elements of an environmental system. The expression “hydrological connectivity inside the soil” has been used here to indicate how spatial patterns inside the soil (i.e., the structural connectivity) interact with physical and chemical processes (i.e., the functional connectivity) in order to determine the subsurface flow (i.e., the water transfer), thereby explaining how sediment transport due to surface runoff (i.e., the soil particle transfer) can be affected. This paper explores the hydrological connectivity inside the soil (HCS) and its link to sediment delivery processes at the plot scale. Soils sampled at the upstream- and downstream-end of three different length plots were collected together with sediments from the storage tanks at the end of each plot. All the samples were analyzed by traditional soil analyses (i.e., texture, Fourier transform infrared spectroscopy with attenuated total reflectance, C and N elemental contents) and fast-field-cycling (FFC) nuclear magnetic resonance (NMR) relaxometry. Results revealed that selective erosion phenomena and sediment transport are responsible for the particle size homogeneity in the sediment samples as compared to the upstream- and downstream-end soils. Moreover, while structural connectivity is more efficient in the upstream-end soil samples, functional connectivity appeared more efficient in the downstream-end and sediment samples. Further studies are needed in order to quantitatively assess FFC NMR relaxometry for HCS evaluation.
KeywordsHydrological connectivity Sediment delivery processes Nuclear magnetic resonance Fast field cycling Relaxometry
All authors set up the research and equally contributed to both analyzing the data and writing the manuscript.
- Baartman EM, Masselink R, Keesstra SD, Temme AJAM (2013) Linking landscape morphological complexity and sediment connectivity. Earth Surf Proc Land 38:1457–1471Google Scholar
- Conte P, Alonzo G (2013) Environmental NMR: fast-field-cycling relaxometry. eMagRes 2:389–398Google Scholar
- Djomgoue P, Njopwouo D (2013) FT-IR spectroscopy applied for surface clays characterization. J Surf Eng Mater Adv Technol 3:275–282Google Scholar
- Gee GW, Bauder JW (1986) Particle-size analysis. In: Klute A (ed) Methods of soil analysis. Part 1, 2nd edn. ASA and SSSA, Madison, pp 383–411Google Scholar
- Morgan RPC, Nearing MA (2000) Soil erosion models: present and future. In: Rubio JL, Asins S, Andreu V, de Paz JM, Gimeno E (eds) Proceedings, third international congress of the European society for soil conservation, 28 March–1 April, Valencia, Key notes volume, pp 145–164Google Scholar
- Noburo H, Katsuya N (2008) Breakdown process of aggregates with non-swelling and swelling clays as affected by electrolyte concentration and air condition. Clay Sci 14:33–42Google Scholar
- Novotny V, Chesters G (1989) Delivery of sediment and pollutants from nonpoint sources: a water quality perspective. J Soil Water Conserv 44:568–576Google Scholar
- Stevenson FJ (1994) Humus chemistry: genesis, composition, reactions, 2nd edn. Wiley, HobokenGoogle Scholar
- Wischmeier WH, Smith DD (1978) Predicting rainfall-erosion losses—a guide to conservation farming. US Dept of Agric, Agr Handbook no. 537Google Scholar