Estimate of soil erosion on cultivated soils using 137Cs measurements and calibration models: A case study from Nakhla watershed, Morocco

2006 ◽  
Vol 86 (1) ◽  
pp. 77-87 ◽  
Author(s):  
K. Hassouni ◽  
S. Bouhlassa
Keyword(s):  
Soil Erosion ◽  
Mass Balance ◽  
Balance Model ◽  
Mass Balance Model ◽  
Erosion And Deposition ◽  
Deposition Rates ◽  
Erosion Rates ◽  
Soil Redistribution ◽  
Calibration Models ◽  
Soil Erosion Rates

Despite the seriousness of the erosion problem in the Nakhla watershed, there are still only limited data on the rates of soil loss on cultivated land on steep slopes. Thus, there is a need for more information for optimizing strategies for soil conservation. Recent concern over problems of soil degradation and the off-site impacts of accelerated erosion has highlighted the need for improved methods of estimating rates and patterns of soil erosion by water. In this paper, soil erosion and deposition rates have been studied using the 137Cs technique in upstream part in the Nakhla watershed on cultivated soils (Larbaa Beni Hassan area), which is known to suffer soil erosion. Multiple transect sampling was established parallel to the slope, and 137Cs inventories were determined for the sampling points. After establishing the local reference inventory (3073 Bq m-2), soil erosion and deposition rates were estimated using the 137Cs inventories on all the transects with three calibration models: proportional model (PM), mass balance model 1 (MBM1) and mass balance model 2 (MBM2). The magnitude of the soil erosion rates depends on many factors, including the location of sampling, the local topography, and the soil properties. Estimated soil erosion rates for the study area varied from 0.4 to 28.9 t ha-1 yr-1 using PM; from 0.5 to 66.9 t ha-1 yr-1 using MBM1; and from 0.4 to 56.4 t ha-1 yr-1 using MBM2. The deposition ranged, respectively, from 0.3 to 8.0 t ha-1 yr-1 for PM, from 0.4 to 14.5 t ha-1 yr-1 for MBM1, and from 0.3 to 11.5 t ha-1 yr-1 for MBM2. The sediment delivery ratio is about 98%. For one selected plot, L11, the erosion rates show a clear relationship with the range of slopes in its three different horizontal parts. Estimates of soil redistribution rates were interpolated by means of kriging, using Surfer 7.0 software. Two representative transects were selected to identify the contribution of tillage on 137Cs redistribution by using mass balance model 3. It is observed that the pattern of 137Cs redistribution is dominated by water erosion and that the contribution of tillage redistribution remain is smaller. Key words: 137Cs method, soil erosion, erosion rate, soil redistribution, conversion models

Soil erosion rates under intensive vegetable production on clay loam, strongly structured soils at Pukekohe, New Zealand

Soil Research ◽  
2002 ◽  
Vol 40 (6) ◽  
pp. 947 ◽  
Author(s):  
L. R. Basher ◽  
C. W. Ross
Keyword(s):  
New Zealand ◽  
Vegetable Production ◽  
Clay Loam ◽  
Erosion And Deposition ◽  
Deposition Rates ◽  
Erosion Rates ◽  
Soil Redistribution ◽  
Structured Soils ◽  
Soil Erosion Rates ◽  
Tillage Erosion

Rates of soil redistribution by water and tillage erosion were determined in 3 fields under long-term continuous vegetable production on clay loam, strongly structured soils derived from volcanic ash at Pukekohe, South Auckland, New Zealand. Erosion and deposition rates were estimated using a mass balance model to convert variation in 137Cs areal activity within the fields to estimates of erosion and deposition. Caesium-137 areal activity in cropped fields ranged from 171 to 2144 Bq/m2, compared with a reference value under permanent pasture of 774 Bq/m2. There was a characteristic pattern of 137Cs distribution within each field, with differences between the fields related to variation in topography. Lowest values of 137Cs were found in the upper parts of each field and highest values towards the base of each field. In all 3 fields there was a net loss of 137Cs, ranging from 13 to 32%, with an average over the 3 fields of 18%. Net rates of soil loss from the fields were 30, 11, and 7 t/ha.year. However, within the fields there was a much wider range of both erosion (up to 92 t/ha.year) and deposition (up to 100 t/ha.year) rates. Most of the soil redistribution is caused by water erosion, with tillage erosion accounting for 10-20% of the soil redistribution. The soil redistribution rates were 2 orders of magnitude higher than sediment export measured at small catchment scale. Soil erosion rates are not reflected in variation in topsoil depth, because frequent tillage and incorporation of organic residues maintains a uniform topsoil depth, but soil deposition rates are closely related to topsoil depth.

scholarly journals Estimating the soil erosion and deposition rate using 137Cs tracer method in the catchment of Drenova reservoir (B&H)

2012 ◽  
Vol 27 (3) ◽  
pp. 247-253 ◽  
Author(s):  
Radislav Tosic ◽  
Slavoljub Dragicevic ◽  
Istvan Bikit ◽  
Sofija Forkapic ◽  
Dusan Mrdja ◽  
...  
Keyword(s):  
Soil Erosion ◽  
Balance Model ◽  
Soil Profiles ◽  
Mass Balance Model ◽  
Tracer Method ◽  
Erosion And Deposition ◽  
Deposition Rates ◽  
The Mean ◽  
Traditional Approaches ◽  
Empirical Methodology

There are many limitations associated with traditional approaches to estimation of soil erosion and deposition rates. Recently attention has been focused on 137Cs and successful usage of this isotope in soil erosion studies. This paper presents the results of measurements of 137Cs in soil profiles which were sampled within catchments of Drenova reservoir. The proportional model and a simplified version of the mass balance model were used to estimate the mean soil loss or deposition redistributions rates. The aim of this study is to estimate the soil erosion and deposition rates using 137Cs tracer model, as a support for the results obtained by empirical methodology.

scholarly journals THE INFLUENCE OF CONVERSION MODEL CHOICE FOR EROSION RATE ESTIMATION AND THE SENSITIVITY OF THE RESULTS TO CHANGES IN THE MODEL PARAMETER

2010 ◽  
Vol 6 (2) ◽  
pp. 199-204
Author(s):  
Nita Suhartini
Keyword(s):  
Soil Erosion ◽  
Mass Balance ◽  
Erosion Rate ◽  
Balance Model ◽  
Mass Balance Model ◽  
Small Catchment ◽  
Distributed Information ◽  
Model Parameter ◽  
Conversion Model ◽  
137Cs Technique

A study of soil erosion rates had been done on a slightly and long slope of cultivated area in Ciawi - Bogor, using 137Cs technique. The objective of the present study was to evaluate the applicability of the 137Cs technique in obtaining spatially distributed information of soil redistribution at small catchment. This paper reports the result of the choice of conversion model for erosion rate estimates and the sensitive of the changes in the model parameter. For this purpose, small site was selected, namely landuse I (LU-I). The top of a slope was chosen as a reference site. The erosion/deposit rate of individual sampling points was estimated using the conversion models, namely Proportional Model (PM), Mass Balance Model 1 (MBM1) and Mass Balance Model 2 (MBM2). A comparison of the conversion models showed that the lowest value is obtained by the PM. The MBM1 gave values closer to MBM2, but MBM2 gave a reliable values. In this study, a sensitivity analysis suggest that the conversion models are sensitive to changes in parameters that depend on the site conditions, but insensitive to changes in  parameters that interact to the onset of 137Cs fallout input.   Keywords: soil erosion, environmental radioisotope, cesium

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