Estimation of Soil Erosion as a Function of Land Use and Rainfall Using rMMF Model on Amukura Hills, Busia County
DOI:
https://doi.org/10.2200/aerj.v5i1.33Keywords:
Soil Erosion, Morgan Finney Model, rMMF Model, Rainfall, Rainfall IntensityAbstract
Soil erosion by water is considered as the most critical problem on cultivated steeply sloping lands in Kenya. On the Amukura hills in Busia County, Kenya, there have been increased farming activities and indiscriminate infrastructural expansions which are affecting the biophysical environment of the area. The aim of this study was to estimate the amount of soil loss as a synergistic action of rainfall and land use on the hills using the revised Morgan Finney model and compare model generated soil erosion with that obtained from field measurements. One topo-sequence was selected for validating the model. Current soil loss was determined by measuring the dimensions of rills and multiplying the average width, depth and length to get actual volume of soil moved. The model was chosen because of its simplicity in structure, low input requirements semi-empirical basis and distributed application. The equations comprising the model were translated into Microsoft excel spread and the input parameters measured from the field and weather station used. The model calculations were based on daily rainfall time steps and the results presented here were a sum of individual rainfall events. While any amount of Hortonian flow is erosive, it was found that all the detached soil particles go into transport at a rainfall intensity of 7mm/hr in this watershed. The model estimated soil loss was 17 t/ha to 50 t/ha while that from field measurement was 11 t/ha to 107 t/ha for the period studied. There was a positive correlation between field measured and model generated soil loss. The model continuously generated soil erosion data and can be applied to other areas with steep slopes and can be used to extrapolate past and future soil erosion rates based on rainfall, land use and soil properties. On the steep slopes where cultivation has taken place mechanical soil erosion control measures such as terraces and contour stone bunds along with orchard trees should be undertaken.
References
Akhtar‐Schuster, M., Thomas, R. J., Stringer, L. C., Chasek, P., & Seely, M. (2011). Improving the enabling environment to combat land degradation: Institutional, financial, legal and science‐policy challenges and solutions. Land Degradation & Development, 22(2), 299-312.ater. Transactions of the ASAE, 12(6), 754-0758.methods (pp. 127-158). Routledge.
Angassa, A. (2014). Effects of grazing intensity and bush encroachment on herbaceous species and rangeland condition in southern Ethiopia. Land Degradation & Development, 25(5), 438-451.
Bednar, M., & Sarapatka, B. (2018). Relationships between physical–geographical factors and soil degradation on agricultural land. Environmental research, 164, 660-668.
Eswaran, H., Lal, R., & Reich, P. F. (2019). Land degradation: an overview. Response to land degradation, 20-35.
González-Pelayo, O., Andreu, V., Gimeno-García, E., Campo, J., & Rubio, J. L. (2010). Rainfall influence on plot-scale runoff and soil loss from repeated burning in a Mediterranean-shrub ecosystem, Valencia, Spain. Geomorphology, 118(3-4), 444-452.
Hari Eswaran, Ratan Lal., Reich P.F Land Degradation: an overview. Retrieved from http://www.scholar.google.com
Hossain, A., Krupnik, T. J., Timsina, J., Mahboob, M. G., Chaki, A. K., Farooq, M., & Hasanuzzaman, M. (2020). Agricultural land degradation: processes and problems undermining future food security. In Environment, Climate, Plant and Vegetation Growth (pp. 17-61). Springer, Cham.
Kayet, N., Pathak, K., Chakrabarty, A., & Sahoo, S. (2018). Evaluation of soil loss estimation using the RUSLE model and SCS-CN method in hillslope mining areas. International Soil and Water Conservation Research, 6(1), 31-42.
Li, L., Wang, Y., & Liu, C. (2014). Effects of land use changes on soil erosion in a fast developing area.International Journal of Environmental Science and Technology, 11(6), 1549-1562.
Martínez‐Casasnovas, J. A., Ramos, M. C., & Benites, G. (2016). Soil and Water Assessment Tool Soil Loss Simulation at the Sub‐Basin Scale in the Alt Penedès–Anoia Vineyard Region (Ne Spain) in the 2000s. Land Degradation & Development, 27(2), 160-170.
Martín‐Moreno, C., Martín Duque, J. F., Nicolau Ibarra, J. M., Hernando Rodríguez, N., Sanz Santos, M.A., & Sánchez Castillo, L. (2016). Effects of topography and surface soil cover on erosion for mining reclamation: the experimental spoil heap at El Machorro Mine (Central Spain). Land Degradation & Development, 27(2), 145-159.
Meyer, L. D., & Wischmeier, W. H. (1969). Mathematical simulation of the process of soil erosion by water. Transactions of the ASAE, 12(6), 754-0758.
Morgan, R. P. C., & Duzant, J. H. (2008). Modified MMF (Morgan–Morgan–Finney) model for evaluating effects of crops and vegetation cover on soil erosion. Earth Surface Processes and Landforms: The Journal of the British Geomorphological Research Group, 33(1), 90-106.
Nearing, M. A., Lane, L. J., & Lopes, V. L. (2017). Modeling soil erosion. In Soil erosion research
Sadeghi, S. H. R. (2017). Soil erosion in Iran: state of the art, tendency and solutions. Poljoprivreda i Sumarstvo, 63(3), 33-37.
Syahli, F. (2015).The impact of land use change on soil erosion in Serayu watershed: case study Merawu watershed, Banjarnegara, Central Java (Master's thesis, University of Twente).
Taguas, E. V., Guzmán, E., Guzmán, G., Vanwalleghem, T., & Gómez, J. A. (2015). Characteristics and importance of rill and gully erosion: a case study in a small catchment of a marginal olive grove. Cuadernos de investigación geográfica, 41(1), 107-126.
Tarolli, P., Preti, F., & Romano, N. (2014). Terraced landscapes: From an old best practice to a potential hazard for soil degradation due to land abandonment. Anthropocene, 6, 10-25.
