Soil loss estimation and severity mapping using RUSLE model and GIS: a case study in Megech Watershed, Ethiopia

AbstractBackground: Soil erosion is the most serious problem that affects economic development, food security, and ecosystem services which is the main concern in Ethiopia. This study focused on quantifying soil erosion rate and severity mapping of the Megech watershed for effective planning and decision-making processes to implement protection measures. The RUSLE model integrated with ArcGIS software was used to conduct the present study. The six RUSLE model parameters: erosivity, erodibility, slope length and steepness, cover management, and erosion control practices were used as input parameters to predict the average annual soil loss and identify erosion hotspots in the watershed. Results: The RUSLE estimated 1,399,210 tons yr-1 total soil loss from the watershed with a mean annual soil loss of 32.84 tons ha-1yr-1. The soil erosion rate was varied from 0.08 to greater than 500 tons ha-1yr-1. A severity map with seven severity classes was created for 27 sub-watersheds: low (below 10), moderate (10-20), high (20-30), very high (30-35), severe (35-40), very severe (40-45) and extremely severe (above 45) in which the values are in tons ha-1yr-1. The area coverage was 6.5%, 11.1%, 8.7%, 22%, 30.9%, 13.4%, and 7.4% for low, moderate, high, very high, severe, very severe, and extremely severe erosion classes respectively. Conclusion: About 82 % of the watershed was found in more than the high-risk category which reflects the need for immediate land management action. This paper could be important for decision-makers to prioritize critical erosion hotspot areas for comprehensive and sustainable management of the watershed.

Assessing the Effect of Landuse/Land Cover (1986-2020) on Soil Loss in Alluvium Geologic Formation Using Geospatial Technology in Southern Nigeria

The occurrence of soil loss is a continuous process and occurs spatially across the earth’s surface. The study of soil loss is a necessity for proper understanding of the processes and the rate of soil loss for conservational purpose. Landsat Thematic Mapper (TM)/Enhanced Thematic Mapper Plus (ETM+)/Operational Land Imager (OLI) image data was acquired for 1986, 2003 and 2020 were used to derive the C factor of the RUSLE model while other factors of the model were kept fixed for the years considering their inability to change easily. The RUSLE model was used to determine the trend of the soil loss on the alluvium geologic formation considering their land use/land cover changes for 1986, 2003 and 2020. The rainfall erosivity of the study area had an average of 8201.45MJmmha-1h-1yr-1. The soil erodibility index of the soils obtained from Alluvium had an average of 0.150tons MJ-1 hmm-1. The slope length and steepness factor of the study area range from 0 to 2.574. the crop cover factor of for 1986 range from 0.52 to 0.87, 2003 range from 0.52 to 0.87 and 2020 range from 0.62 to 0.92. No active field conservation was found out within the study area as described by Wischmeier and Smith. The results obtained show that 1986, 2003 and 2020 had a soil loss of 1966.3, 2167.85 and 3361.14 tonha-1yr-1 respectively. The results show that the study area is experiencing an increased trend of soil loss. This result can serve as guide into understanding the past and current rate of soil loss for soil resource planning and management

Retraction: Temporary ditches are effective in reducing soil erosion in hilly areas. An evaluation with the RUSLE model

To: Pier Paolo Roggero, Editor-in-Chief, Italian Journal of Agronomy, and Michele Moscato, PAGEPress Publications, Publisher We take note of your communication following the report by Dr. Paolo Bazzoffi regarding the copyright infringement of the paper ‘Effectiveness of the GAEC cross-compliance standard short-term measures for runoff water control on sloping land (temporary ditches and grass strips) in controlling soil erosion’ (Authors: Bazzoffi, Ciancaglini, Laruccia), that can be found at the following address: https://www.agronomy.it/index.php/agro/ article/view/ija.2011.6.s1.e3. The title of the retracted publication is: ‘Temporary ditches are effective in reducing soil erosion in hilly areas. An evaluation with the RUSLE model’ (Authors: Francaviglia, Neri), that can be found at the following address: https://www.agronomy.it/index. php/agro/article/view/1762). The undersigned authors thoroughly agree with the points raised by Dr. Paolo Bazzoffi in relation to the copyright infringement. In particular, we agree that the original paper ‘Effectiveness of the GAEC cross compliance standard short-term measures for runoff water control on sloping land (temporary ditches and grass strips) in controlling soil erosion’ was not clearly indicated as original data source in the paper ‘Temporary ditches are effective in reducing soil erosion in hilly areas. An evaluation with the RUSLE model’. We also recognize that we did not give credit to Dr. Paolo Bazzoffi of the original methodology, particularly: i) the original materials and methods; ii) the GIS elaboration; and iii) the original data and results. The authors declare that: - they considered the opportunity to review the data published by Dr. Bazzoffi et al. shown in Table 7 of their original publication after a data re-elaboration, as shown in Table 3 of the publication to be retracted, with the aim to provide a statistical comparison of erosion in hilly agricultural land among the Italian Regions, as well as introducing an evaluation of the weight of the parameters implemented in the RUSLE model using a multiple regression technique; - they are aware of not having adequately recognized the copyrights of Dr. Bazzoffi and co-authors Ciancaglini and Laruccia. For these reasons, and as requested, we retract the paper ‘Temporary ditches are effective in reducing soil erosion in hilly areas. An evaluation with the RUSLE model’ from publication. We apologize to Dr. Bazzoffi, Dr. Ciancaglini and Dr. Laruccia for the unpleasant inconvenience caused. We also take the opportunity to thank Dr. Paolo Bazzoffi for coordinating the EFFICOND and MONACO projects, in which we participated in various work packages, offering the possibility of a valuable and constructive work experience. Sincerely, Rosa Francaviglia and Ulderico Neri