Sediment trap efficiency of paddy fields at the watershed scale in a mountainous catchment in northwest Vietnam
Composite agricultural systems with permanent maize cultivation in the uplands and irrigated rice in the valleys are very common in mountainous southeast Asia. The soil loss and fertility decline of the upland fields is well documented, but little is known about reallocation of these sediments withi...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2016-06-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/13/3267/2016/bg-13-3267-2016.pdf |
| _version_ | 1811278210666594304 |
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| author | J. I. F. Slaets P. Schmitter T. Hilger T. D. Vien G. Cadisch |
| author_facet | J. I. F. Slaets P. Schmitter T. Hilger T. D. Vien G. Cadisch |
| author_sort | J. I. F. Slaets |
| collection | DOAJ |
| description | Composite agricultural systems with permanent maize cultivation in the
uplands and irrigated rice in the valleys are very common in mountainous
southeast Asia. The soil loss and fertility decline of the upland fields is
well documented, but little is known about reallocation of these sediments
within the landscape. In this study, a turbidity-based linear mixed model
was used to quantify sediment inputs, from surface reservoir irrigation
water and from direct overland flow, into a paddy area of 13 ha.
Simultaneously, the sediment load exported from the rice fields was
determined. Mid-infrared spectroscopy was applied to analyze sediment
particle size. Our results showed that per year, 64 Mg ha<sup>−1</sup> of
sediments were imported into paddy fields, of which around 75 % were
delivered by irrigation water and the remainder by direct overland flow
during rainfall events. Overland flow contributed one-third of the received
sandy fraction, while irrigated sediments were predominantly silty. Overall,
rice fields were a net sink for sediments, trapping 28 Mg ha<sup>−1</sup> a<sup>−1</sup>
or almost half of total sediment inputs. As paddy outflow consisted almost
exclusively of silt- and clay-sized material, 24 Mg ha<sup>−1</sup> a<sup>−1</sup> of
the trapped amount of sediment was estimated to be sandy. Under continued
intensive upland maize cultivation, such a sustained input of coarse
material could jeopardize paddy soil fertility, puddling capacity and
ultimately food security of the inhabitants of these mountainous areas.
Preventing direct overland flow from entering the paddy fields, however,
could reduce sand inputs by up to 34 %. |
| first_indexed | 2024-04-13T00:31:47Z |
| format | Article |
| id | doaj.art-f7b31d9a0a0142fab55d3557095527af |
| institution | Directory Open Access Journal |
| issn | 1726-4170 1726-4189 |
| language | English |
| last_indexed | 2024-04-13T00:31:47Z |
| publishDate | 2016-06-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Biogeosciences |
| spelling | doaj.art-f7b31d9a0a0142fab55d3557095527af2022-12-22T03:10:28ZengCopernicus PublicationsBiogeosciences1726-41701726-41892016-06-0113113267328110.5194/bg-13-3267-2016Sediment trap efficiency of paddy fields at the watershed scale in a mountainous catchment in northwest VietnamJ. I. F. Slaets0P. Schmitter1T. Hilger2T. D. Vien3G. Cadisch4Institute of Plant Production and Agroecology in the Tropics and Subtropics, University of Hohenheim, Garbenstrasse 13, Stuttgart, GermanyThe International Water Management Institute, Nile Basin and East Africa Office, Addis Ababa, EthiopiaInstitute of Plant Production and Agroecology in the Tropics and Subtropics, University of Hohenheim, Garbenstrasse 13, Stuttgart, GermanyCentre for Agricultural Research and Ecological Studies (CARES), Vietnam National University of Agriculture, Hanoi, VietnamInstitute of Plant Production and Agroecology in the Tropics and Subtropics, University of Hohenheim, Garbenstrasse 13, Stuttgart, GermanyComposite agricultural systems with permanent maize cultivation in the uplands and irrigated rice in the valleys are very common in mountainous southeast Asia. The soil loss and fertility decline of the upland fields is well documented, but little is known about reallocation of these sediments within the landscape. In this study, a turbidity-based linear mixed model was used to quantify sediment inputs, from surface reservoir irrigation water and from direct overland flow, into a paddy area of 13 ha. Simultaneously, the sediment load exported from the rice fields was determined. Mid-infrared spectroscopy was applied to analyze sediment particle size. Our results showed that per year, 64 Mg ha<sup>−1</sup> of sediments were imported into paddy fields, of which around 75 % were delivered by irrigation water and the remainder by direct overland flow during rainfall events. Overland flow contributed one-third of the received sandy fraction, while irrigated sediments were predominantly silty. Overall, rice fields were a net sink for sediments, trapping 28 Mg ha<sup>−1</sup> a<sup>−1</sup> or almost half of total sediment inputs. As paddy outflow consisted almost exclusively of silt- and clay-sized material, 24 Mg ha<sup>−1</sup> a<sup>−1</sup> of the trapped amount of sediment was estimated to be sandy. Under continued intensive upland maize cultivation, such a sustained input of coarse material could jeopardize paddy soil fertility, puddling capacity and ultimately food security of the inhabitants of these mountainous areas. Preventing direct overland flow from entering the paddy fields, however, could reduce sand inputs by up to 34 %.http://www.biogeosciences.net/13/3267/2016/bg-13-3267-2016.pdf |
| spellingShingle | J. I. F. Slaets P. Schmitter T. Hilger T. D. Vien G. Cadisch Sediment trap efficiency of paddy fields at the watershed scale in a mountainous catchment in northwest Vietnam Biogeosciences |
| title | Sediment trap efficiency of paddy fields at the watershed scale in a mountainous catchment in northwest Vietnam |
| title_full | Sediment trap efficiency of paddy fields at the watershed scale in a mountainous catchment in northwest Vietnam |
| title_fullStr | Sediment trap efficiency of paddy fields at the watershed scale in a mountainous catchment in northwest Vietnam |
| title_full_unstemmed | Sediment trap efficiency of paddy fields at the watershed scale in a mountainous catchment in northwest Vietnam |
| title_short | Sediment trap efficiency of paddy fields at the watershed scale in a mountainous catchment in northwest Vietnam |
| title_sort | sediment trap efficiency of paddy fields at the watershed scale in a mountainous catchment in northwest vietnam |
| url | http://www.biogeosciences.net/13/3267/2016/bg-13-3267-2016.pdf |
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