Impacts of measured soil hydraulic conductivity on the space-time simulations of water and nitrogen cycling

A - Papers appearing in refereed journals

Liu, C., Shan, Y., Wang, Q., Harris, P., Liu, Y. and Wu, L. 2023. Impacts of measured soil hydraulic conductivity on the space-time simulations of water and nitrogen cycling. Catena. 226, p. 107058. https://doi.org/10.1016/j.catena.2023.107058

AuthorsLiu, C., Shan, Y., Wang, Q., Harris, P., Liu, Y. and Wu, L.
Abstract

In agriculture, variation in a soil’s nutrients and water are driven by soil properties, topography and agronomic practice; factors that typically interact and change over space and time. Agroecosystem models need to capture these sources in variation, where this study’s first objective was to assess the potential of using measured saturated soil hydraulic conductivity (ksat) to improve the simulation accuracy of water and soil mineral nitrogen content from the SPACSYS model for a lowland UK grazed field (6.34 ha). As a second objective, SPACSYS was run at the field level and at the within-field level to provide a further comparison of simulation accuracy. For model calibration, ksat was measured at 27 points at 0 – 10, 10 – 20 and 20 – 30 cm soil depths on a 50 × 50 m grid. For model validation, moisture and mineral nitrogen content in the same three soil layers, at 10 adjacent points on a 25 × 25 m grid, were measured monthly from May 2018 to April 2019, together with in situ field level water flux measurement. Measured ksat coupled with the within-field setting allowed a novel spatial investigation of SPACSYS performance. Measured ksat (as opposed to unmeasured, default values) was found to improve water flux simulation, but only slightly so, which was considered in part due to a high positive skew in the measured ksat coupled with no clear spatial structure. Field level and within-field specifications simulated soil moisture with equal accuracy, while simulation accuracy of soil ammonium and nitrate improved via the within-field setting; for water flux simulation, the field level setting should be preferred. Results provide further evidence for when a field level setting should be preferred to a within-field setting and vice-versa.

KeywordsSPACSYS; Ksat; Grid-to-grid; Soil nutrients; Process-based modelling
Year of Publication2023
JournalCatena
Journal citation226, p. 107058
Digital Object Identifier (DOI)https://doi.org/10.1016/j.catena.2023.107058
Open accessPublished as ‘gold’ (paid) open access
FunderBiotechnology and Biological Sciences Research Council
Natural Environment Research Council
Funder project or codeS2N - Soil to Nutrition - Work package 2 (WP2) - Adaptive management systems for improved efficiency and nutritional quality
S2N - Soil to Nutrition - Work package 3 (WP3) - Sustainable intensification - optimisation at multiple scales
The North Wyke Farm Platform- National Capability [2017-22]
Modelling and managing critical zone relationships between soil, water and ecosystem processes across the Loess Plateau
Publisher's version
Accepted author manuscript
Output statusPublished
Publication dates
Online09 Mar 2023
Publication process dates
Accepted01 Mar 2023
PublisherElsevier Science Bv
ISSN0341-8162

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