A systematic review of the incorrect use of an empirical equation for the estimation of the rainfall erosivity around the globe

Chen, Walter (author), Huang, Yu-Chieh (author), Lebar, Klaudija (author), Bezak, Nejc (author)

Soil erosion is part of the erosion-sedimentation cycle and a type of land degradation that can be caused by poor land management. This is expected to be exacerbated by climate change. The rainfall erosivity factor (R) of the Universal Soil Loss Equation (USLE) family of soil erosion models is one of the most important parameters being studied because it is heavily influenced by climate change. The determination of the R factor necessitates high-frequency precipitation data, which are unavailable for a significant portion of the globe. For decades, researchers in data-sparse regions have estimated the R factor using empirical equations that required only monthly or annual rainfall data. Unfortunately, many of these equations are outdated and susceptible to misuse. This study presents an empirical R equation based on the Modified Fournier Index (MFI) that has caused probably one of the most widespread and unnoticed errors in soil erosion research for at least 33 years. Our exhaustive literature search and analysis uncovered 125 papers with 28 incorrect R equation formulations. We discovered that the earliest incorrect publication dates back to 1989, and most of the studies were conducted in Asia (China and India). The 125 published papers have similar citation characteristics (three citations per year per paper) as other papers in the field of soil erosion modelling, and many of the 125 papers were published in well-known scientific journals. Together, they have been cited over 3300 times by international researchers. In addition, the number of incorrect papers has increased dramatically over the past few years (2015–2021), indicating that the equation is spreading more frequently than the general publication trend. Since using an incorrect R equation can result in a significant bias in estimating the R factor and, consequently, soil erosion, the incorrect use could significantly bias numerous studies. The inaccuracy also hinders global efforts like the “Global Applications of Soil Erosion Modelling Tracker (GASEMT)” to synthesize soil erosion studies worldwide to shed light on the global problem of soil erosion and to promote environmental education. Consequently, the primary objective of this paper is to contribute to the recognition of the use of incorrect R equations, thereby reducing or even preventing their further spread and thus limiting the number of studies publishing biased results.

• Language: English
• Keywords: rainfall erosivity, soil erosion, climate change, Modified Fournier Index, incorrect equation, land degradation, environmental education, systematic review, global study
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FGG - Faculty of Civil and Geodetic Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2023
• Number of pages: 14 str.
• Numbering: Vol. 238, art. 104339
• PID: 20.500.12556/RUL-148691
• UDC: 556.1
• ISSN on article: 0012-8252
• DOI: 10.1016/j.earscirev.2023.104339
• COBISS.SI-ID: 140437507
• Publication date in RUL: 29.08.2023

Record is a part of a journal

• Title: Earth-science reviews
• Shortened title: Earth-sci. rev.
• Publisher: Elsevier
• ISSN: 0012-8252
• COBISS.SI-ID: 4493834

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: erozivnost padavin, erozija tal, podnebne spremembe, modificiran Fournierjev indeks, nepravilna enačba