Assessing potassium environmental losses from a dairy farming watershed with the modified SWAT model

Chunying Wang, Rui Jiang, Laurie Boithias, Sabine Sauvage, José-Miguel Sánchez-Pérez, Xiaomin Mao, Yuping Han, Atsushi Hayakawa, Kanta Kuramochi and Ryusuke Hatano

Agricultural Water Management, 2016, vol. 175, issue C, 91-104

Abstract: Potassium (K) was intensively used to optimize agricultural crop yield. Potassium losses should be accurately quantified for efficient nutrient management. However, no hydrologic model had been developed yet to quantify daily K losses at watershed scale. The Soil and Water Assessment Tool (SWAT) model was modified (named SWAT-K) by including the main K dynamic processes (solid–liquid distribution in soil and stream, plant uptake, and transportation with water flow and soil erosion) to simulate stream K load and K budget at the watershed scale. The SWAT-K was tested on the dairy farming Shibetsu River Watershed (672km2), Eastern Hokkaido, Japan. The solid–liquid distribution coefficient for K in suspended sediment was 10mlg−1. Langmuir equation was fitted to describe the solid–liquid distribution of K in soil, which derived an affinity constant of 0.046LmgK−1 and was used directly in SWAT-K. The fitted Langmuir equation also derived an adsorption maximum for K in soil. The adsorption maximum for K in soil normalized for clay content ranged from 4 to 20gKkg−1, and the fitted value of 15.5g Kkg−1 was used in SWAT-K. The SWAT-K satisfactorily predicted the daily dissolved K load at watershed outlet, and estimated an annual dissolved K load of 27.3kgKha−1year−1. The simulated pasture K yield of 36.1 (±2.5) kgKha−1year−1 was close to the observed data of 38.0 (±3.1) kgKha−1year−1. Then the model was used to quantify K budget at watershed scale. The simulated dissolved K leaching was 15.1kgKha−1year−1, and simulated soil K surplus of 75.1kgKha−1year−1 was much higher than plant uptake of 28.4kgKha−1year−1. The large amount of leaching and soil storage indicated that agricultural K input might be excessive and reducing the K application was recommended.

Keywords: Potassium; Solid–liquid distribution; Stream load; Plant uptake; Potassium budget; SWAT-K (search for similar items in EconPapers)
Date: 2016
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0378377416300452
Full text for ScienceDirect subscribers only

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:agiwat:v:175:y:2016:i:c:p:91-104

DOI: 10.1016/j.agwat.2016.02.007

Access Statistics for this article

Agricultural Water Management is currently edited by B.E. Clothier, W. Dierickx, J. Oster and D. Wichelns

More articles in Agricultural Water Management from Elsevier
Bibliographic data for series maintained by Catherine Liu ().