Open Access
Dissolved solids and suspended sediment dynamics from five small agricultural watersheds in Navarre, Spain: a 10-year study
(Elsevier, 2019) Merchán Elena, Daniel; Luquin Oroz, Eduardo Adrián; Hernández García, Iker; Campo-Bescós, Miguel; Giménez Díaz, Rafael; Casalí Sarasíbar, Javier; Valle de Lersundi, Jokin del; Ingeniaritza; Institute on Innovation and Sustainable Development in Food Chain - ISFOOD; Ingeniería; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Dissolved solids (DS) and suspended sediment (SS) loads are considered relevant environmental problems. They are related to a wide range of on-site and off-site impacts, such as soil erosion or salinization of water bodies. In this study, the dynamics of DS and SS concentrations and loads were assessed in five small watersheds covering representative agricultural land uses in Navarre (Spain). To this end, discharge, DS and SS concentration data were collected during ten hydrological years at each watershed outlet, and loads were computed from discharge and concentration values. DS concentration followed a seasonal pattern imposed by the availability of water, with higher concentrations recorded in low-flow periods and lower concentration in the high-flow period. SS concentration was extremely variable, with a range of 2–4 orders of magnitude in concentration for any specific discharge. Temporal variations (both intra- and inter-annual) in DS loads were explained by differences in runoff, whereas those of SS were not, being the SS loads associated mainly with specific high flow events. These temporal patterns were observed for both agricultural (this study) and non-agricultural (literature) watersheds. From the data in the Navarrese watersheds and those available in the literature, we inferred that agricultural land use, in general, tends to increase the concentration of both DS and SS. Regarding DS and SS yields, the effects of agricultural land use on DS yields are controlled by the changes in runoff rather than the (small) changes in DS concentration. In this sense, land uses changes expected to increase runoff (i.e., a shift from forested to arable or from rainfed to irrigated agriculture) would increase DS yields. On the other hand, agricultural land use tends to increase SS yields, although the effect is highly variable depending on site-specific factors, both natural (e.g., watershed shape) and anthropogenic (e.g., degree of soil conservation practices). In the Navarrese watersheds, DS yields ranged from 1.1 to 2.2 Mg ha−1 year−1 whereas SS yields ranged from 0.3 to 4.3 Mg ha−1 year−1. DS yields seem to dominate under non-agricultural conditions and in most agricultural land uses at the small watershed scale. On the other hand, SS yields dominate in watersheds with increased soil erosion as a consequence of arable land use over erosion-prone watersheds.
Open Access
Assessment of the main factors affecting the dynamics of nutrients in two rainfed cereal watersheds
(Elsevier, 2020) Hernández García, Iker; Merchán Elena, Daniel; Aranguren Erice, Itxaso; Casalí Sarasíbar, Javier; Giménez Díaz, Rafael; Campo-Bescós, Miguel; Valle de Lersundi, Jokin del; Ingeniaritza; Institute on Innovation and Sustainable Development in Food Chain - ISFOOD; Ingeniería
Nutrient dynamics and factors that control nutrient exports were observed in two watersheds, namely Latxaga and La Tejería, with similar climatic and management characteristics throughout 10 years (2007–2016). Similar patterns were observed in intra-annual and inter-annual dynamics with higher NO3 − concentration and NO3 −-N yield during the humid seasons (i.e., winters and hydrological year 2013). Regarding concentration, Latxaga showed a higher decrease of nitrate due to a higher development of vegetated areas. High discharge events produced nitrate dilution due to the presence of tile-drainage at La Tejeria. At Latxaga, where tile-drainage was not observed, an increase in concentration occurred as a response to high discharge events. Comparing both watersheds, La Tejería presented ca. 73 ± 25 mg NO3 − L−1 while at Latxaga, the concentration observed was almost three times lower, with ca. 21 ± 15 mg NO3 − L−1 throughout the study period. Similar patterns were observed for the NO3 −-N yield, with 32 kg NO3 −-N ha−1 year−1 and 17 kg NO3 −-N ha−1 year−1 at La Tejería and Latxaga, respectively. Regarding phosphorous, the observed concentrations were 0.20 ± 0.72 mg PO4 3− L−1 and 0.06 ± 0.38 mg PO4 3− L−1 at La Tejería and Latxaga, respectively, with PO4 3−-P yields being 71 kg PO4 3−-P ha−1 year−1 and 33 kg PO4 3−-P ha−1 year−1. Annual phosphate-P yield distribution in both watersheds followed similar patterns to those observed for the nitrate-N yield, with higher yields in the humid season. Regarding concentration, highly erosive rainfall that occurred in summer, mobilizing sediments and probably generating desorption of phosphorous in the stream channel, increased phosphate concentration. This research adds to the knowledge base regarding the dynamics of nutrients and the controlling factors in complex agricultural systems with Mediterranean characteristics.

Campo-Bescós, Miguel

Email Address

person.page.identifierURI

Birth Date

Job Title

Last Name

First Name

person.page.departamento

person.page.instituteName

ORCID

person.page.observainves

person.page.upna

Name

Filters

Author

Subject

Date

Has files

Item Type

Type

Settings

Sort By

Results per page

Search Results