Comparing Soil Erosion Rates on Terraced and Sloping Cultivated Land in Palestine Using FRN <sup>137</sup>Cs Trace

Houshia, Orwa; Benmansour, Moncef; Mabit, Lionel; Fulajtár, Emil; Abu-Jabal, Saber; Hroub, Ismail; Odeh, Rafat

doi:https://doi.org/10.1155/2022/2933661

International Journal of Analytical Chemistry

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Abstract Introduction Results and Discussion Conclusions Data Availability Conflicts of Interest Authors’ Contributions Acknowledgments References Copyright Related Articles

Research Article | Open Access

Volume 2022 | Article ID 2933661 | https://doi.org/10.1155/2022/2933661

Comparing Soil Erosion Rates on Terraced and Sloping Cultivated Land in Palestine Using FRN ¹³⁷Cs Trace

Orwa Houshia,¹Moncef Benmansour,²Lionel Mabit,³Emil Fulajtár,⁴Saber Abu-Jabal,⁵Ismail Hroub,⁶and Rafat Odeh⁶

Academic Editor: Ammar AL-Farga

Received25 Jul 2022

Revised01 Sept 2022

Accepted12 Sept 2022

Published30 Sept 2022

Abstract

Soil erosion is a serious problem in Palestine. It is enhanced mainly by poor farming practices used in upland agricultural areas occupying the Central Highland of Palestine. The objective of this study is to assess the impact of terracing on soil erosion and deposition rates in the Al-Yamoun area (the Northern West Bank) using the fallout radionuclides cesium -137 (FRN ¹³⁷Cs). The FRN ¹³⁷Cs technique, which has proved its efficiency in estimating erosion rates over the last 50–60 years, was used for the first time in Palestine to measure rates of erosion and deposition. The activity of ¹³⁷Cs was measured by gamma spectrometry using an HPGe detector. For the reference site, the ¹³⁷Cs inventories ranged between 2499 and 4086 Bq/m2. The average value of the reference site is 3315 ± 410 Bq/m2, which corresponds to a coefficient of variance of 12%, suggesting that the reference site is well representative for estimating 137Cs fallout. This ¹³⁷Cs amount is too high for bomb-derived fallout and indicates that a significant part of the deposition is from the Chernobyl accident. The ¹³⁷Cs inventories at both studied sites (terrace site and foot slope site) are significantly lower than those of the reference site. For the terrace site, the inventories are found between 1707 and 2749 Bq/m2, while for the slope site they are between 1050 and 2617 Bq/m2. The lower ¹³⁷Cs values at both studied sites than values at the reference site indicate that the entire areas of both study sites are eroded and no depositional activity occurs.

1. Introduction

Agriculture is an important cultural tradition vital to the economy of the West Bank, Palestine. Also, agriculture plays a vital role in the region’s future. Palestinians are coping in creative ways [1] every day despite the challenges of establishing a livelihood or any sustainable economic activity based on agriculture. Whether the challenge lies in water scarcity, soil degradation [2], or blockade restrictions, Palestinian families implement innovative and collaborative approaches to living off the land [3]. However, the land suitable for agriculture in Palestine is shrinking due to soil erosion, land degradation, and water erosion, which in turn affect soil properties and functions [4–7] and cause the loss of soil, which is not renewable on the human timescale. Consequently, these factors represent a major threat to the soil and water resources the country needs to ensure sustainable agricultural production.

Within this context, and in order to provide a comprehensive assessment of the magnitude of these problems and to support the selection of effective soil conservation measures, quantitative data on the extent and rates of soil erosion under various agroecological conditions and land use systems were needed [8]. Integrated land and water management practices improve agricultural production and enhance soil productivity and its resilience against desertification and other impacts of climate change and variability. Radionuclide and stable isotopic techniques can be used to study soil erosion and land degradation problems [9]. Data on soil erosion acquired by conventional methods takes several years to obtain and is time consuming. Furthermore, it is labor-intensive, and these conventional methods do not provide for the spatial distribution of soil erosion. On the other hand, the 137Cs isotope tracer fills the deficits of the conventional methods and facilitates the investigation of soil erosion on a much better timescale, so there is no need for costly, labor-intensive long-term monitoring.

2. Methodology

2.1. Study Area

The study area is located in the Central Highland in the Jenin Province, which receives annual precipitation of about 300 mm (Figure 1). The sampling sites were selected to acquire soil samples within the Jenin Province. The reference site at an elevation of 293 m above sea level was covered with shrub vegetation and had a slope of about 2%. The other two sites were labeled Terrace Site, which at an elevation of 246 m above sea level, cultivated land on a terrace with a slope of 2%, and foot slope site, which at an elevation of 140 m above sea level, cultivated land on a foot slope that was not terraced and had a slope of 3%. The difference in slope inclination is very small, but the important difference is the slope length (field length), which is very short on the terrace (10–15 m) and several folds longer at the foot slope field (60 m).

2.2. Field Sampling

The sampling design is as follows:

2.2.1. Reference Site

Grid samplingof 1.5 m (24 samples) (3 × 8), bulk samples, 30 m depth, and a distance between two points is of 1.5 m.

2.2.2. Terrace site

Sampling along 3 transects containing 8 points in each transect (24 soil samples), bulk samples, 30 cm depth, and a distance of 1.5 m between two points.

2.2.3. Foot slope site

Sampling along 3 transects containing 8 points in each transect (24 soil samples), bulk samples, 30 cm depth, and a distance of 1.5 m between two points.

3. Sample Preparation and ¹³⁷Cs Analysis

Physical preparation of the soil samples was performed at the Palestine National Agricultural Center (NARC) including drying and light grinding. Then, samples were oven dried at 105 degrees Celsius, grinded, sieved (<2 mm), and homogenized. Radionuclide analysis of ¹³⁷Cs was performed by gamma spectrometry using an HPGe detector (45 efficiencies) by the Centre National de l’Energie des Sciences et des Technique Nucleaires (CNESTEN), Morocco. Tennelec/Nucleus HPGe (184 cc) planar-type coaxial intrinsic germanium detector was used. The ¹³⁷Cs activity was measured by its gamma emission at 662 keV. Background counts were made at regular intervals to ensure the maintenance of low background characteristics. Each soil sample was counted for 20000 s. The Cs inventory A (Bq·m⁻²) was calculated using the following equation:where C is the ¹³⁷Cs activity concentration of the sample (in Bq·kg⁻¹), M is the total dry mass of the collected soil core (in kg) and S is the cross-section of the sampling tube (in m²)

4. Results and Discussion

Numerous models were established to analyze soil erosion [10]. The main postulates and necessities of the ¹³⁷Cs approaches have been reported in several papers [11]. The calculation of soil erosion and deposition rates at the undisturbed site is based on ¹³⁷Cs inventories and the ¹³⁷Cs depth distribution. Two methods are used. The simpler method considers the fixed ¹³⁷Cs fallout input and stable ¹³⁷Cs profile distribution. The depth distribution over the soil profile is mathematically described [12]. If this distribution is considered by a simple mathematical function, then the soil loss can be estimated by the proportion of the ¹³⁷Cs reference value removed at the examined site [13]. This method is used for the Profile Distribution Model (PDM). A more widespread method takes into consideration the time-variant processes of: (1) the ¹³⁷Cs fallout and (2) the gradual postdepositional redistribution of ¹³⁷Cs within the soil profile, which is caused predominantly by bioturbation and several other processes. This approach is used by the Diffusion and Migration Model (DMM) [14]. The calculation of soil loss in cultivated land can be based on two theoretical concepts. The first one called, the proportional concept, is very simple and it presumes that the removal of soil and ¹³⁷Cs are directly proportional. Models based on this concept are called the Proportional Model (PM). More complex approaches involve a mass balance concept, which considers the temporal dynamics of ¹³⁷Cs inputs and outputs resulting in the time-variant concentration of ¹³⁷Cs in soil [12]. These changes in concentration affect considerably the relation between the ¹³⁷Cs loss and soil loss caused by erosion. The ¹³⁷Cs concentration in soil is controlled by several processes [13, 15–17]. Most important are (1) time-variable 137Cs fallout, (2) radioactive decay of ¹³⁷Cs (i.e., 30.17 years), (3) removal of freshly deposited ¹³⁷Cs by erosion prior to its incorporation into the plough horizon by tillage, and (4) incorporation of subsoil material free of ¹³⁷Cs or having low ¹³⁷Cs content into the eroded ploughed horizon by tillage [18].

The Mass Balance Models (MBM) were developed in the mid-1980s. Different models use different approaches to handle the ¹³⁷Cs time-variant concentration in soil and consider some but not all processes and factors controlling it [12, 19, 20]. Moreover, three Mass Balance Models that were initially developed by Walling and He [10] are used, e.g., Mass Balance Model 1 (MBM1), Mass Balance Model 2 (MBM2), and Mass Balance Model 3 (MBM3).

In order to convert inventories or areal activities (in Bq/m²) into soil erosion or deposition rates (in t/ha/yr), conversion models were used. First, the Proportional Model (PM) was used to have preliminary results about soil erosion, in accordance with equations (2), (3), and (4) obtained from references [12, 21].

The basic equation (2) of the Proportional Model [10] can, therefore, be represented as follows:where X is the percentage reduction in total ¹³⁷Cs inventory (defined as (A_ref -A)/A 100), d is the depth of the plough or cultivation layer (m), B is the bulk density of the soil (kg·m⁻³), T the time elapsed since the start of ¹³⁷ Cs accumulation (yr), A_ref, represents the local reference inventory (Bq·m⁻²), and A is the total inventory measured at the sampling point (Bq m⁻²). P represents the particle size correction factor for erosion. This model does not require many parameters, but it is not realistic as he neglected some processes or phenomena related to ¹³⁷Cs behavior and erosion processes in cultivated sites.

In addition, the Chernobyl contribution was not included when applying this model. In this case, Mass Balance Models were used (equation (3)) and, more specifically, the Mass Balance Model 2, which can describe suitably the real situation and therefore was also applied (equation (4)). It has to be noted that the file for the annual deposition of ¹³⁷Cs was modified to take the Chernobyl contribution into account. The results given by both models for both sites 1 and 2 are reported in Table1 and Table 2.where t represents the time since 1963, B is the bulk density of the soil (kg·m⁻³), and d is the depth of the plough or cultivation layer (m). X is the percentage reduction in total 137 Cs inventory (defined as (A_ref -A)/A 100) where A (t) = cumulative ¹³⁷Cs activity per unit area (Bq/m²); R = erosion rate (kg/m². yr) d = cumulative mass depth, representing the average plough depth (kg/m⁻²) λ = decay constant for ¹³⁷Cs (yr⁻¹); I (t) = annual ¹³⁷Cs deposition flux (Bq/m² yr); Γ = percentage of the freshly deposited ¹³⁷Cs fallout removed by erosion before being mixed into the plough layer; P = particle size correction factor.

The inventories of the samples were calculated from the ¹³⁷Cs concentration (in Bq/kg), the bulk density of the sample, and the depth of the core. An average bulk density was calculated for each type of site. There are about 1160 kg/m³, 1240 kg/m³, and 1190 kg/m³ for a reference site, site 1, and site 2, respectively.

The results of all inventories (Bq/m²) are given in Table 3. For the reference site, the inventories ranged between 2927 and 4086 Bq/m². The average value of the reference site is 3315 ± 410 Bq/m², which corresponds to a coefficient of variance of about 12%. This coefficient of variance can be considered as low, confirming the low variability and low disturbance of the selected reference site. The high inventory associated with the reference site suggests that the fallout ¹³⁷Cs deposited in this region is the result of both old nuclear weapon tests conducted in the 1950s–1960s and the Chernobyl disaster that occurred in 1986. Taking into account the average rainfall in this region (Jenin Province) of about 300 mm, the inventory estimated by prediction using conversion models is about 897 Bq/m². It means that the contribution of Chernobyl is about 2418 Bq/m², which represents around 73% of the total reference inventory. Concerning study site 1 and site 2, the inventories are significantly lower than those of the reference site (see Table 1), especially for site 2, indicating that these sites are eroded. Figure 2 shows the distribution of ¹³⁷Cs inventory along 3 transects for each site and the mean reference inventory value. For site 1, inventories are found between 1707 and 2749 Bq/m², while for the site 2, inventories are found between 1050 and 26117 Bq/m². In comparison, all the inventories obtained are lower than the reference value (Figure 1), indicating that there is no depositional area at both sites.

(a)

(b)

As previously reported by Nouira et al. [19], the Proportional Model does not take into account the dilution of ¹³⁷ Cs concentrations in the soil within the cultivated layer, resulting from the assimilation of soil from below the originally cultivated depth due to surface lowering by erosion; thus, the results obtained by this model in the present study likely underestimate the actual rates of soil loss. The Mass Balance approach that takes into account the effect of mixing the subsoil containing no ¹³⁷Cs from below the plough depth into the plough layer gave higher values for soil loss rate, as is observed in some other reports [19, 22].

5. Conclusions

¹³⁷Cs distribution at the sites confirmed that the ¹³⁷Cs tracking procedure can be effectively used to assess soil erosion and deposition rates. The application of the ¹³⁷Cs tracking system enabled us to quantify the extent of soil erosion in the Northern Palestine region. For the reference site, the inventories ranged between 2927 and 4086 Bq/m². The average value of the reference site is 3315 ± 410 Bq/m², which corresponds to a coefficient of variance of about 12%, suggesting that the fallout 137Cs deposited in this region is a result of both old nuclear weapon tests conducted in 1950s–1960s and the Chernobyl disaster that occurred in 1986.

Finally, the ¹³⁷ Cs tracking technique is a useful erosion model for the Northern Palestine region. This data can be used to refine erosion control guidelines influencing the selection of a vast array of management practices by an agricultural producer, such as tillage, fertilizer application, crop rotation, plant population, and structures. Thus, the future work, which will be carried out in phase–II of the project, highly recommends the selection of more locations in Gaza and the West Bank in order to generate a soil erosion map of Palestine. This result will also be presented to legislators and decision makers within the government to implement appropriate soil erosion solutions.

Data Availability

All data has been included.

Conflicts of Interest

The authors declare that there are no conflicts of interest.

Authors’ Contributions

Orwa Houshia is the project P.I. and coordinator who oversees the project and is responsible for grant and funding acquisition from the IAEA. Also, Orwa Houshia wrote the draft of the manuscript and is the corresponding author of the article. Benmansour Moncef ran samples and interpreted data using Gamma HPGeD spectroscopy. Lionel Mabit, the IAEA Technical Officer, helped to revise the proposal for phase-1 and also edited manuscripts and facilitated funding. Emil Fulajtár, IAEA Technical Officer, helped in revising the manuscript, specifically the abstract and title, and facilitated a scientific visit. Sample collection and preparation were done by Saber Abu-Jabal. Ismail Hroub carried out the sample preservation, shipping and handling, and logistics. Procurement and sample analysis follow-ups were done by Rafat Odeh.

Acknowledgments

This research has been made possible through the generous donation and support from the IAEA. The authors also express their gratitude to NARC for providing transportation, especially Dr. M. AbuEid (former DG of NARC), Mr. Motasem Zaid, and Mr. Oday Zaid.

References

A. A. Hammad, L. E. Haugen, and T. Børresen, “Effects of stonewalled terracing techniques on soil-water conservation and wheat production under mediterranean conditions,” Environmental Management, vol. 34, no. 5, pp. 701–710, 2004.
View at: Publisher Site | Google Scholar
S. Alkhouri, Monitoring of Land Condition in the Occupied Palestinian Territory, Applied Research Institute—Jerusalem/Society | ARIJ|, Bethlehem, State of Palestinian, 2010.
A. A. Hammad and T. Børresen, “Socioeconomic factors affecting farmers’ perceptions of land degradation and stonewall terraces in Central Palestine,” Environmental Management, vol. 37, no. 3, pp. 380–394, 2006.
View at: Publisher Site | Google Scholar
H. A. Elwell, “Sheet erosion from arable land in Zimbabwe: prediction and control,” Challenges in African Hydrology and Water Resources, IAHS Press, Wallingford, UK, pp. 429–438, 1984.
View at: Google Scholar
R. Lal, “Soil erosion and the global carbon budget,” Environment International, vol. 29, no. 4, pp. 437–450, 2003.
View at: Publisher Site | Google Scholar
L. Mabit, M. R. Laverdière, and S. Wicherek, Césium-137 et érosion des sols Cah, Agric, vol. 7, no. 3, 1998.
M. Ben Mansour, M. Ibn Majah, H. Marah, T. Marfak, and D. Walling, “Use of the Cesium 137 technique in soil erosion investigation in Morocco-case study of the Zitouna basin in the north,” in Proceeding of the International Symposium on Nuclear Techniques in Integrated Plant Nutrient, Water and Soil Management, AIEA/FAO, pp. 308–315, Vienna, Austria, October 2000.
View at: Google Scholar
L. Ivan, Q. Laura, P. Leticia, G. Leticia, and N. Ana, “Enhancing connectivity index to assess the effects of land use changes in a Mediterranean catchment,” Land Degradation & Development, vol. 29, no. 3, pp. 663–675, 2018.
View at: Publisher Site | Google Scholar
L. Mabit, K. Meusburger, E. Fulajtar, and C. Alewell, “The usefulness of 137Cs as a tracer for soil erosion assessment: a critical reply to Parsons and Foster (2011),” Earth-Science Reviews, vol. 127, pp. 300–307, 2013.
View at: Publisher Site | Google Scholar
D. E. Walling and Q. He, “Improved models for estimating soil erosion rates from 137Cs measurements,” Journal of Environmental Quality, vol. 28, Article ID 611e622, 1999.
View at: Publisher Site | Google Scholar
A. Navas, J. Machín, and J. Soto, “Assessing soil erosion in a Pyrenean mountain catchment using GIS and fallout 137Cs,” Agriculture, Ecosystems & Environment, vol. 105, no. 3, pp. 493–506, 2005.
View at: Publisher Site | Google Scholar
A. Navas and D. E. Walling, “Using caesium-137 to assess sediment movement on slopes in a semiarid upland environment in Spain,” Erosion, Debris Flows and Environment in Mountain Regions, IAHS Press, Wallingford, UK, pp. 129–138, 1992.
View at: Google Scholar
A. Navas, L. Gaspar, M. López-Vicente, and J. Machín, “Spatial distribution of natural and artificial radionuclides at the catchment scale (South Central Pyrenees),” Radiation Measurements, vol. 46, no. 2, pp. 261–269, 2011.
View at: Publisher Site | Google Scholar
A. Navas, T. A. Quine, D. E. Walling, L. Gaspar, L. Quijano, and I. Lizaga, “Relating intensity of soil redistribution to land use changes in abandoned pyrenean fields using fallout caesium‐137,” Land Degradation & Development, vol. 28, no. 7, pp. 2017–2029, 2017.
View at: Publisher Site | Google Scholar
E. Fulajtar, “Assessment of soil erosion through the use of 137Cs at jaslovske bohunice, western Slovakia,” Acta Geologica Hispanica, vol. 35/3, pp. 291–300, 2000.
View at: Google Scholar
A. Navas, M. López Vicente, L. Gaspar, and J. Machín, “Assessing soil redistribution in a complex karst catchment using fallout 137Cs and GIS,” Geomorphology, vol. 196, pp. 231–241, 2013.
View at: Publisher Site | Google Scholar
A. Navas, M. López-Vicente, L. Gaspar, L. Palazón, and L. Quijano, “Establishing a tracer-based sediment budget to preserve wetlands in Mediterranean mountain agroecosystems (NE Spain),” Science of the Total Environment, vol. 496, pp. 132–143, 2014.
View at: Publisher Site | Google Scholar
L. Mabit, C. Bernard, and M. R. Laverdiere, “Quantification of soil redistribution and sediment budget in a Canadian watershed from fallout cesium?137 (137Cs) data,” Canadian Journal of Soil Science, vol. 82, 2002.
View at: Google Scholar
A. Nouira, E. H. Sayouty, and M. Benmansour, “Use of Cs technique for soil erosion study in the agricultural region of casablanca in Morocco,” Journal of Environmental Radioactivity, vol. 68, pp. 11e26–137, 2003.
View at: Publisher Site | Google Scholar
A. Navas, D. E. Walling, T. Quine et al., “Variability in 137Cs inventories and potential climatic and lithological controls in the central Ebro valley, Spain,” Journal of Radioanalytical and Nuclear Chemistry, vol. 274, no. 2, pp. 331–339, 2007.
View at: Publisher Site | Google Scholar
E. Fulajtar, L. Mabit, and C. S. Renschler, “Use of 137Cs for soil erosion assessment,” 2017, https://www.fao.org/3/I8211EN/i8211en.pdf.
View at: Google Scholar
X. B. Zhang, D. L. Higgitt, and D. E. Walling, “A preliminary assessment of the potential for using caesium-137to estimaterates of soil erosion in the Loess plateau of China,” Hydrological Sciences Journal, vol. 35, Article ID 267e276, 1990.
View at: Google Scholar

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Copyright © 2022 Orwa Houshia et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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