Research

17 pages, 1687 KiB

Open AccessArticle

Soil Structure Stability under Different Land Uses in Association with Polyacrylamide Effects

by Amrakh I. Mamedov, Atsushi Tsunekawa, Nigussie Haregeweyn, Mitsuru Tsubo, Haruyuki Fujimaki, Takayuki Kawai, Birhanu Kebede, Temesgen Mulualem, Getu Abebe, Anteneh Wubet and Guy J. Levy

Sustainability 2021, 13(3), 1407; https://doi.org/10.3390/su13031407 - 29 Jan 2021

Cited by 12 | Viewed by 2790

Abstract

Soil structural stability is a vital aspect of soil quality and functions, and of maintaining sustainable land management. The objective of this study was to compare the contribution of four long-term land-use systems (crop, bush, grass, and forest) coupled with anionic polyacrylamide (PAM [...] Read more.

Soil structural stability is a vital aspect of soil quality and functions, and of maintaining sustainable land management. The objective of this study was to compare the contribution of four long-term land-use systems (crop, bush, grass, and forest) coupled with anionic polyacrylamide (PAM = 0, 25, and 200 mg L⁻¹) application on the structural stability of soils in three watersheds of Ethiopia varying in elevation. Effect of treatments on soil structural stability indices were assessed using the high energy moisture characteristic (HEMC, 0–50 hPa) method, which provides (i) water retention model parameters α and n, and (ii) soil structure index (SI). Soil (watershed), land use and PAM treatments had significant effects on the shape of the water retention curves (α, n) and SI, with diverse changes in the macropore sizes (60–250; >250 μm). Soil organic carbon (SOC) content and SI were strongly related to soil pH, CaCO₃ soil type-clay mineralogy, exchangeable Ca²⁺, and Na⁺ (negatively). The order of soil SI (0.013–0.064 hPa⁻¹) and SOC (1.4–8.1%) by land use was similar (forest > grass > bush > cropland). PAM effect on increasing soil SI (1.2–2.0 times), was inversely related to SOC content, being also pronounced in soils from watersheds of low (Vertisol) and medium (Luvisol) elevation, and the cropland soil from high (Acrisol) elevation. Treating cropland soils with a high PAM rate yielded greater SI (0.028–0.042 hPa⁻¹) than untreated bush- and grassland soils (0.021–0.033 hPa⁻¹). For sustainable management and faster improvement in soil physical quality, soil properties, and land-use history should be considered together with PAM application. Full article

(This article belongs to the Special Issue Soil Erosion and Sustainable Land Management (SLM))

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14 pages, 3163 KiB

Open AccessArticle

Constructability Criteria for Farmland Reclamation and Vegetable Cultivation Using Micro-Dam Sediments in Tigray, Ethiopia

by Kazuhisa Koda, Gebreyohannes Girmay and Tesfay Berihu

Sustainability 2020, 12(16), 6388; https://doi.org/10.3390/su12166388 - 07 Aug 2020

Cited by 2 | Viewed by 2127

Abstract

The Ethiopian agriculture sector is characterized by rain-fed smallholder systems. The Ethiopian Government has promoted micro-dam construction in micro-watershed in Tigray for the past two decades. The lack of proper conservation measures to control severe soil erosion at the micro-watershed level, however, has [...] Read more.

The Ethiopian agriculture sector is characterized by rain-fed smallholder systems. The Ethiopian Government has promoted micro-dam construction in micro-watershed in Tigray for the past two decades. The lack of proper conservation measures to control severe soil erosion at the micro-watershed level, however, has often filled downstream micro-dams in with sediments. Sedimentation has affected the irrigation performance of micro-dams due to their bottom pipes becoming clogged with nutrient-rich soils eroded from upstream farmlands. While there is a growing need for adequate resource management to mitigate severe soil erosion at the watershed-level, it is urgent that methods to make use of the sediments deposited in micro-dam reservoirs to facilitate rural agricultural development are discovered. One practical solution is to use sediments to rehabilitate the bare land excavated for micro-dam embankment construction and turn it into reclaimed farmland. The purpose of this paper is to relate the constructability criteria to the farmland reclamation to solve sedimentation problems. This case study reports the yield of vegetable cultivation on farmland reclaimed using sediments from a micro-dam reservoir in Tigray. This case study highlights the practical potential of such a method to contribute to the livelihoods of farmers through the production of vegetable cash crops. The future research needs cost reduction factors on durability, safety or other related aspects to improve our “Constructability Criteria” approach. Full article

(This article belongs to the Special Issue Soil Erosion and Sustainable Land Management (SLM))

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21 pages, 13026 KiB

Open AccessArticle

Evaluation of the SEdiment Delivery Distributed (SEDD) Model in the Shihmen Reservoir Watershed

by Kent Thomas, Walter Chen, Bor-Shiun Lin and Uma Seeboonruang

Sustainability 2020, 12(15), 6221; https://doi.org/10.3390/su12156221 - 02 Aug 2020

Cited by 5 | Viewed by 4254

Abstract

The sediment delivery ratio (SDR) connects the weight of sediments eroded and transported from slopes of a watershed to the weight that eventually enters streams and rivers ending at the watershed outlet. For watershed management agencies, the estimation of annual sediment yield (SY) [...] Read more.

The sediment delivery ratio (SDR) connects the weight of sediments eroded and transported from slopes of a watershed to the weight that eventually enters streams and rivers ending at the watershed outlet. For watershed management agencies, the estimation of annual sediment yield (SY) and the sediment delivery has been a top priority due to the influence that sedimentation has on the holding capacity of reservoirs and the annual economic cost of sediment-related disasters. This study establishes the SEdiment Delivery Distributed (SEDD) model for the Shihmen Reservoir watershed using watershed-wide SDR_w and determines the geospatial distribution of individual SDR_i and SY in its sub-watersheds. Furthermore, this research considers the statistical and geospatial distribution of SDR_i across the two discretizations of sub-watersheds in the study area. It shows the probability density function (PDF) of the SDR_i. The watershed-specific coefficient (β) of SDR_i is 0.00515 for the Shihmen Reservoir watershed using the recursive method. The SY mean of the entire watershed was determined to be 42.08 t/ha/year. Moreover, maps of the mean SY by 25 and 93 sub-watersheds were proposed for watershed prioritization for future research and remedial works. The outcomes of this study can ameliorate future watershed remediation planning and sediment control by the implementation of geospatial SDR_w/SDR_i and the inclusion of the sub-watershed prioritization in decision-making. Finally, it is essential to note that the sediment yield modeling can be improved by increased on-site validation and the use of aerial photogrammetry to deliver more updated data to better understand the field situations. Full article

(This article belongs to the Special Issue Soil Erosion and Sustainable Land Management (SLM))

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20 pages, 5803 KiB

Open AccessArticle

Effects of Landscape Changes on Soil Erosion in the Built Environment: Application of Geospatial-Based RUSLE Technique

by Bilal Aslam, Ahsen Maqsoom, Shahzaib, Zaheer Abbas Kazmi, Mahmoud Sodangi, Fahad Anwar, Muhammad Hassan Bakri, Rana Faisal Tufail and Danish Farooq

Sustainability 2020, 12(15), 5898; https://doi.org/10.3390/su12155898 - 22 Jul 2020

Cited by 15 | Viewed by 3908

Abstract

The world’s ecosystem is severely affected by the increase in the rate of soil erosion and sediment transport in the built environment and agricultural lands. Land use land cover changes (LULCC) are considered as the most significant cause of sediment transport. This study [...] Read more.

The world’s ecosystem is severely affected by the increase in the rate of soil erosion and sediment transport in the built environment and agricultural lands. Land use land cover changes (LULCC) are considered as the most significant cause of sediment transport. This study aims to estimate the effect of LULCC on soil erosion potential in the past 20 years (2000–2020) by using Revised Universal Soil Loss Equation (RUSLE) model based on Geographic Information System (GIS). Different factors were analyzed to study the effect of each factor including R factor, K factor, LS factor, and land cover factor on the erosion process. Maps generated in the study show the changes in the severity of soil loss in the Chitral district of Pakistan. It was found out that 4% of the area was under very high erosion risk in the year 2000 which increased to 8% in the year 2020. An increase in agricultural land (4%) was observed in the last 20 years which shows that human activities largely affected the study area. The outcomes of this study will help the stakeholders and regulatory decision makers to control deforestation and take other necessary actions to minimize the rate of soil erosion. Such an efficient planning will also be helpful to reduce the sedimentation in the reservoir of hydraulic dam(s) constructed on Chitral river, which drains through this watershed. Full article

(This article belongs to the Special Issue Soil Erosion and Sustainable Land Management (SLM))

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18 pages, 5284 KiB

Open AccessArticle

Farming Influence on Physical-Mechanical Properties and Microstructural Characteristics of Backfilled Loess Farmland in Yan’an, China

by Lina Ma, Shengwen Qi, Bowen Zheng, Songfeng Guo, Qiangbing Huang and Xinbao Yu

Sustainability 2020, 12(14), 5516; https://doi.org/10.3390/su12145516 - 08 Jul 2020

Cited by 3 | Viewed by 1929

Abstract

A gigantic project named Gully Land Consolidation (GLC) was launched in the hill-gully region of the Chinese Loess Plateau in 2011 to cope with land degradation and create new farmlands for cultivation. However, as a particular kind of remolded loess, the newly created [...] Read more.

A gigantic project named Gully Land Consolidation (GLC) was launched in the hill-gully region of the Chinese Loess Plateau in 2011 to cope with land degradation and create new farmlands for cultivation. However, as a particular kind of remolded loess, the newly created and backfilled farmland may bring new engineering and environmental problems because the soil structure was disturbed and destroyed. In this study, current situations and characteristics of GLC are introduced. Test results show that physical-mechanical properties and microstructural characteristics of backfilled loess of one-year and five-year farmland are significantly affected by the Gully Land Consolidation project. Compared to natural loess, the moisture content, density, and internal friction angle of backfilled loess increase. On the contrary, the porosity, plasticity index, particle size index, and cohesion index decrease. Through SEM tests, it is observed that the particles of backfilled loess are rounded, with large pores filled with crushed fine particles, which results in skeleton strength weakness among particles and pores. The pore size distribution (PSD) of the four types of loess (Q₃ loess, Q₂ loess, one-year farmland, and five-year farmland) was measured using mercury intrusion porosimetry (MIP) tests, showing that the pore size of Q₃ loess is mainly mesopores 4000–20,000 nm in size, accounting for 67.5%. The Q₂, five-year, and one-year farmland loess have mainly small pores 100–4000 nm in size, accounting for 52.5%, 51.7%, and 71.7%, respectively. The microscopic analysis shows that backfill action degrades the macropores and mesopores into small pores and micropores, leading to weak connection strength among soil particles, which further affects the physical-mechanical properties of loess. The disturbance of backfilled loess leads to an obvious decrease in cohesion and a slight increase in internal friction compared to natural loess. The farming effect becomes prominent with increased backfill time, while the loess soil moisture content increases gradually. Both the cohesion and internal friction of the backfilled loess soil decrease to different degrees. This study is helpful to investigate sustainable land use in the Chinese Loess Plateau and similar areas. Full article

(This article belongs to the Special Issue Soil Erosion and Sustainable Land Management (SLM))

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20 pages, 2283 KiB

Open AccessArticle

Effect of Soil Microbiome from Church Forest in the Northwest Ethiopian Highlands on the Growth of Olea europaea and Albizia gummifera Seedlings under Glasshouse Conditions

by Getu Abebe, Atsushi Tsunekawa, Nigussie Haregeweyn, Takeshi Taniguchi, Menale Wondie, Enyew Adgo, Tsugiyuki Masunaga, Mitsuru Tsubo, Kindiye Ebabu, Amrakh Mamedov and Derege Tsegaye Meshesha

Sustainability 2020, 12(12), 4976; https://doi.org/10.3390/su12124976 - 18 Jun 2020

Cited by 5 | Viewed by 2344

Abstract

Loss of beneficial microbes and lack of native inoculum have hindered reforestation efforts in the severely-degraded lands worldwide. This is a particularly pressing problem for Ethiopia owing to centuries-old unsustainable agricultural practices. This study aimed to evaluate the inoculum potential of soils from [...] Read more.

Loss of beneficial microbes and lack of native inoculum have hindered reforestation efforts in the severely-degraded lands worldwide. This is a particularly pressing problem for Ethiopia owing to centuries-old unsustainable agricultural practices. This study aimed to evaluate the inoculum potential of soils from church forest in the northwest highlands of Ethiopia and its effect on seedling growth of two selected native tree species (Olea europaea and Albizia gummifera) under a glasshouse environment. Seedlings germinated in a seed chamber were transplanted into pots containing sterilized and/or non-sterilized soils collected from under the canopy of three dominant church forest trees: Albizia gummifera (AG), Croton macrostachyus (CM), and Juniperus procera (JP) as well as from adjacent degraded land (DL). A total of 128 pots (2 plant species × 4 soil origins × 2 soil treatments × 8 replicates) were arranged in a factorial design. Overall, seedlings grown in AG, CM, and JP soils showed a higher plant performance and survival rate, as a result of higher soil microbial abundance and diversity, than those grown in DL soils. The results showed significantly higher plant height, root collar diameter, shoot, and total mass for seedlings grown in non-sterilized forest soils than those grown in sterilized soils. Furthermore, the bacterial relative abundance of Acidobacteria, Actinobacteria, and Nitrospirae was significantly higher in the non-sterilized forest soils AG, CM, and JP (r² = 0.6–0.8, p < 0.001). Soil pH had a strong effect on abundance of the bacterial community in the church forest soils. More specifically, this study further demonstrated that the effect of soil microbiome was noticeable on the performance of Olea seedlings grown in the soil from CM. This suggests that the soils from remnant church forests, particularly from the canopy under CM, can serve as a good soil origin, which possibly would promote the native tree seedling growth and survival in degraded lands. Full article

(This article belongs to the Special Issue Soil Erosion and Sustainable Land Management (SLM))

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18 pages, 3329 KiB

Open AccessArticle

New Soil, Old Plants, and Ubiquitous Microbes: Evaluating the Potential of Incipient Basaltic Soil to Support Native Plant Growth and Influence Belowground Soil Microbial Community Composition

by Aditi Sengupta, Priyanka Kushwaha, Antonia Jim, Peter A. Troch and Raina Maier

Sustainability 2020, 12(10), 4209; https://doi.org/10.3390/su12104209 - 21 May 2020

Cited by 2 | Viewed by 3628

Abstract

The plant–microbe–soil nexus is critical in maintaining biogeochemical balance of the biosphere. However, soil loss and land degradation are occurring at alarmingly high rates, with soil loss exceeding soil formation rates. This necessitates evaluating marginal soils for their capacity to support and sustain [...] Read more.

The plant–microbe–soil nexus is critical in maintaining biogeochemical balance of the biosphere. However, soil loss and land degradation are occurring at alarmingly high rates, with soil loss exceeding soil formation rates. This necessitates evaluating marginal soils for their capacity to support and sustain plant growth. In a greenhouse study, we evaluated the capacity of marginal incipient basaltic parent material to support native plant growth and the associated variation in soil microbial community dynamics. Three plant species, native to the Southwestern Arizona-Sonora region, were tested with three soil treatments, including basaltic parent material, parent material amended with 20% compost, and potting soil. The parent material with and without compost supported 15%, 40%, and 70% germination of Common Bean (Phaseolus vulgaris L. ‘Tarahumara Norteño’), Mesquite (Prosopis pubescens Benth), and Panic Grass (Panicum Sonorum Beal), respectively, though germination was lower than in the potting soil. Plant growth was also sustained over the 30 day period, with plants in parent material (with and without amendment) reaching 50% height compared to those in the potting soil. A 16S rRNA gene amplicon sequencing approach showed Proteobacteria to be the most abundant phyla in both parent material and potting soil, followed by Actinobacteria. The potting soil showed Gammaproteobacteria (19.6%) to be the second most abundant class, but its abundance was reduced in the soil + plants treatment (5.6%–9.6%). Within the basalt soil type, Alphaproteobacteria (42.7%) and Actinobacteria (16.3%) had a higher abundance in the evaluated bean plant species. Microbial community composition had strong correlations with soil characteristics, but not plant attributes within a given soil material. Predictive functional potential capacity of the communities revealed chemoheterotrophy as the most abundant metabolism within the parent material, while photoheterotrophy and anoxygenic photoautotrophy were prevalent in the potting soil. These results show that marginal incipient basaltic soil, both with and without compost amendments, can support native plant species growth, and non-linear associations may exist between plant–marginal soil–microbial interactions. Full article

(This article belongs to the Special Issue Soil Erosion and Sustainable Land Management (SLM))

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18 pages, 2916 KiB

Open AccessArticle

Effects of Land Use and Topographic Position on Soil Organic Carbon and Total Nitrogen Stocks in Different Agro-Ecosystems of the Upper Blue Nile Basin

by Getu Abebe, Atsushi Tsunekawa, Nigussie Haregeweyn, Taniguchi Takeshi, Menale Wondie, Enyew Adgo, Tsugiyuki Masunaga, Mitsuru Tsubo, Kindiye Ebabu, Mulatu Liyew Berihun and Asaminew Tassew

Sustainability 2020, 12(6), 2425; https://doi.org/10.3390/su12062425 - 19 Mar 2020

Cited by 33 | Viewed by 3867

Abstract

Soil organic carbon (SOC) and total nitrogen (TN) are key ecological indicators of soil quality in a given landscape. Their status, especially in drought-prone landscapes, is associated mainly with the land-use type and topographic position. This study aimed to clarify the effect of [...] Read more.

Soil organic carbon (SOC) and total nitrogen (TN) are key ecological indicators of soil quality in a given landscape. Their status, especially in drought-prone landscapes, is associated mainly with the land-use type and topographic position. This study aimed to clarify the effect of land use and topographic position on SOC and TN stocks to further clarify the ecological processes occurring in the landscape. To analyze the status of SOC and TN, we collected 352 composite soil samples from three depths in the uppermost soil (0–50 cm) in four major land-use types (bushland, cropland, grazing land, and plantation) and three topographic positions (upper, middle, and lower) at three sites: Dibatie (lowland), Aba Gerima (midland), and Guder (highland). Both SOC and TN stocks varied significantly across the land uses, topographic positions, and agro-ecosystems. SOC and TN stocks were significantly higher in bushland (166.22 Mg ha⁻¹) and grazing lands (13.11 Mg ha⁻¹) at Guder. The lowest SOC and TN stocks were observed in cropland (25.97 and 2.14 Mg ha⁻¹) at Aba Gerima, which was mainly attributed to frequent and unmanaged plowing and extensive biomass removal. Compared to other land uses, plantations exhibited lower SOC and TN stocks due to poor undergrowth and overexploitation for charcoal and firewood production. Each of the three sites showed distinct characteristics in both stocks, as indicated by variations in the C/N ratios (11–13 at Guder, 10–21 at Aba Gerima, and 15–18 at Dibatie). Overall, land use was shown to be an important factor influencing the SOC and TN stocks, both within and across agro-ecosystems, whereas the effect of topographic position was more pronounced across agro-ecosystems than within them. Specifically, Aba Gerima had lower SOC and TN stocks due to prolonged cultivation and unsustainable human activities, thus revealing the need for immediate land management interventions, particularly targeting croplands. In a heterogeneous environment such as the Upper Blue Nile basin, proper understanding of the interactions between land use and topographic position and their effect on SOC and TN stock is needed to design proper soil management practices. Full article

(This article belongs to the Special Issue Soil Erosion and Sustainable Land Management (SLM))

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16 pages, 4970 KiB

Open AccessArticle

Using Machine Learning-Based Algorithms to Analyze Erosion Rates of a Watershed in Northern Taiwan

by Kieu Anh Nguyen, Walter Chen, Bor-Shiun Lin and Uma Seeboonruang

Sustainability 2020, 12(5), 2022; https://doi.org/10.3390/su12052022 - 06 Mar 2020

Cited by 19 | Viewed by 3846

Abstract

This study continues a previous study with further analysis of watershed-scale erosion pin measurements. Three machine learning (ML) algorithms—Support Vector Machine (SVM), Adaptive Neuro-Fuzzy Inference System (ANFIS), and Artificial Neural Network (ANN)—were used to analyze depth of erosion of a watershed (Shihmen reservoir) [...] Read more.

This study continues a previous study with further analysis of watershed-scale erosion pin measurements. Three machine learning (ML) algorithms—Support Vector Machine (SVM), Adaptive Neuro-Fuzzy Inference System (ANFIS), and Artificial Neural Network (ANN)—were used to analyze depth of erosion of a watershed (Shihmen reservoir) in northern Taiwan. In addition to three previously used statistical indexes (Mean Absolute Error, Root Mean Square of Error, and R-squared), Nash–Sutcliffe Efficiency (NSE) was calculated to compare the predictive performances of the three models. To see if there was a statistical difference between the three models, the Wilcoxon signed-rank test was used. The research utilized 14 environmental attributes as the input predictors of the ML algorithms. They are distance to river, distance to road, type of slope, sub-watershed, slope direction, elevation, slope class, rainfall, epoch, lithology, and the amount of organic content, clay, sand, and silt in the soil. Additionally, measurements of a total of 550 erosion pins installed on 55 slopes were used as the target variable of the model prediction. The dataset was divided into a training set (70%) and a testing set (30%) using the stratified random sampling with sub-watershed as the stratification variable. The results showed that the ANFIS model outperforms the other two algorithms in predicting the erosion rates of the study area. The average RMSE of the test data is 2.05 mm/yr for ANFIS, compared to 2.36 mm/yr and 2.61 mm/yr for ANN and SVM, respectively. Finally, the results of this study (ANN, ANFIS, and SVM) were compared with the previous study (Random Forest, Decision Tree, and multiple regression). It was found that Random Forest remains the best predictive model, and ANFIS is the second-best among the six ML algorithms. Full article

(This article belongs to the Special Issue Soil Erosion and Sustainable Land Management (SLM))

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18 pages, 3063 KiB

Open AccessArticle

Effectiveness of Polyacrylamide in Reducing Runoff and Soil Loss under Consecutive Rainfall Storms

by Birhanu Kebede, Atsushi Tsunekawa, Nigussie Haregeweyn, Amrakh I. Mamedov, Mitsuru Tsubo, Ayele Almaw Fenta, Derege Tsegaye Meshesha, Tsugiyuki Masunaga, Enyew Adgo, Getu Abebe and Mulatu Liyew Berihun

Sustainability 2020, 12(4), 1597; https://doi.org/10.3390/su12041597 - 20 Feb 2020

Cited by 21 | Viewed by 2911

Abstract

The use of anionic polyacrylamide (PAM) as a soil conditioner could help prevent soil loss by water. In this study, we determined the effective granular PAM rate that best reduces runoff and soil loss from Oxisols. Furthermore, the effectiveness of the selected PAM [...] Read more.

The use of anionic polyacrylamide (PAM) as a soil conditioner could help prevent soil loss by water. In this study, we determined the effective granular PAM rate that best reduces runoff and soil loss from Oxisols. Furthermore, the effectiveness of the selected PAM rate was tested by applying it in a mixture with gypsum (G) or lime (L). The study was conducted in two phases: (i) Dry PAM rates of 0 (C), 20 kg ha⁻¹ (P20), 40 kg ha⁻¹ (P40), and 60 kg ha⁻¹ (P60) were applied onto soil surface and run for six consecutive rainfall storms of 70 mm h⁻¹ intensity for 1 h duration, and the effective PAM rate was selected; and (ii) G (4 t ha⁻¹) or L (2 t ha⁻¹) were applied alone or mixed with the selected PAM rate. The P20 was found to be effective in reducing runoff in the beginning while P40 and P60 were more effective starting from the third storm through the end of the consecutive storms, but with no statistically significant difference between P40 and P60. Hence, P40 was selected as the most suitable rate for the given test soil and rainfall pattern. On the other hand, the mixed application of P40 with G or L increased infiltration rate (IR) in the first two storms through improving soil solution viscosity. However, effectiveness of the mixtures had diminished by various degrees as rain progressed, as compared to P40 alone, which could be attributed to the rate and properties of G and L. In conclusion, the variation in effectiveness of PAM rates in reducing runoff with storm duration could indicate that the effective rates shall be selected based on the climatic region in that lower rates for the short rains or higher rates for elongated rains. Moreover, combined application of PAM with L could offer a good option to both fairly reduce soil erosion and improve land productivity especially in acidic soils like Oxisols, which requires further field verification. Full article

(This article belongs to the Special Issue Soil Erosion and Sustainable Land Management (SLM))

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12 pages, 2076 KiB

Open AccessArticle

Experimental Setup for Splash Erosion Monitoring—Study of Silty Loam Splash Characteristics

by David Zumr, Danilo Vítor Mützenberg, Martin Neumann, Jakub Jeřábek, Tomáš Laburda, Petr Kavka, Lisbeth Lolk Johannsen, Nives Zambon, Andreas Klik, Peter Strauss and Tomáš Dostál

Sustainability 2020, 12(1), 157; https://doi.org/10.3390/su12010157 - 24 Dec 2019

Cited by 22 | Viewed by 3983

Abstract

An experimental laboratory setup was developed and evaluated in order to investigate detachment of soil particles by raindrop splash impact. The soil under investigation was a silty loam Cambisol, which is typical for agricultural fields in Central Europe. The setup consisted of a [...] Read more.

An experimental laboratory setup was developed and evaluated in order to investigate detachment of soil particles by raindrop splash impact. The soil under investigation was a silty loam Cambisol, which is typical for agricultural fields in Central Europe. The setup consisted of a rainfall simulator and soil samples packed into splash cups (a plastic cylinder with a surface area of 78.5 cm²) positioned in the center of sediment collectors with an outer diameter of 45 cm. A laboratory rainfall simulator was used to simulate rainfall with a prescribed intensity and kinetic energy. Photographs of the soil’s surface before and after the experiments were taken to create digital models of relief and to calculate changes in surface roughness and the rate of soil compaction. The corresponding amount of splashed soil ranged between 10 and 1500 g m⁻² h⁻¹. We observed a linear relationship between the rainfall kinetic energy and the amount of the detached soil particles. The threshold kinetic energy necessary to initiate the detachment process was 354 J m⁻² h⁻¹. No significant relationship between rainfall kinetic energy and splashed sediment particle-size distribution was observed. The splash erosion process exhibited high variability within each repetition, suggesting a sensitivity of the process to the actual soil surface microtopography. Full article

(This article belongs to the Special Issue Soil Erosion and Sustainable Land Management (SLM))

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22 pages, 2356 KiB

Open AccessArticle

Communities’ Livelihood Vulnerability to Climate Variability in Ethiopia

by Misganaw Teshager Abeje, Atsushi Tsunekawa, Nigussie Haregeweyn, Zerihun Nigussie, Enyew Adgo, Zemen Ayalew, Mitsuru Tsubo, Asres Elias, Daregot Berihun, Amy Quandt, Mulatu Liyew Berihun and Tsugiyuki Masunaga

Sustainability 2019, 11(22), 6302; https://doi.org/10.3390/su11226302 - 09 Nov 2019

Cited by 29 | Viewed by 4908

Abstract

Ethiopia has experienced more than 10 major drought episodes since the 1970s. Evidence has shown that climate change exacerbates the situation and presents a daunting challenge to predominantly rain-fed agricultural livelihoods. The aim of this study was to analyze the extent and sources [...] Read more.

Ethiopia has experienced more than 10 major drought episodes since the 1970s. Evidence has shown that climate change exacerbates the situation and presents a daunting challenge to predominantly rain-fed agricultural livelihoods. The aim of this study was to analyze the extent and sources of smallholder famers’ livelihood vulnerability to climate change/variability in the Upper Blue Nile basin. We conducted a household survey (n = 391) across three distinct agroecological communities and a formative composite index of livelihood vulnerability (LVI) was constructed. The Mann–Kendall test and the standard precipitation index (SPI) were employed to analyze trends of rainfall, temperature, and drought prevalence for the period from 1982 to 2016. The communities across watersheds showed a relative difference in the overall livelihood vulnerability index. Aba Gerima (midland) was found to be more vulnerable, with a score of 0.37, while Guder (highland) had a relatively lower LVI with a 0.34 index score. Given similar exposure to climate variability and drought episodes, communities’ livelihood vulnerability was mainly attributed to their low adaptive capacity and higher sensitivity indicators. Adaptive capacity was largely constrained by a lack of participation in community-based organizations and a lack of income diversification. This study will have practical implications for policy development in heterogeneous agroecological regions for sustainable livelihood development and climate change adaptation programs. Full article

(This article belongs to the Special Issue Soil Erosion and Sustainable Land Management (SLM))

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13 pages, 6476 KiB

Open AccessArticle

The Recent Sediment Record as an Indicator of Past Soil-Erosion Dynamics. Study in Dehesa Areas in the Province of Cáceres (Spain)

by María Teresa de Tena Rey, Agustín Domínguez Álvarez and Lorenzo García-Moruno

Sustainability 2019, 11(21), 6102; https://doi.org/10.3390/su11216102 - 02 Nov 2019

Viewed by 2050

Abstract

The work presented is a study of the recent sediment deposits in a pilot basin in dehesa areas in the province of Cáceres (Spain) through analysis of the sediment record, radiocarbon dating and correlation with historic data to assess the factors that conditioned [...] Read more.

The work presented is a study of the recent sediment deposits in a pilot basin in dehesa areas in the province of Cáceres (Spain) through analysis of the sediment record, radiocarbon dating and correlation with historic data to assess the factors that conditioned the deposit in these areas over time. It is a qualitative study based on the important role of sediments as recorders of history, given that sediment facies and their architecture provide one of the best records of past processes and environmental factors. For the study, sediment profile surveys were used to determine the configuration and characteristics of the infill and its chronology. The sediment model of the facies studied is associated with a context of slope water erosion that led to the infill of the watercourse areas, mainly sand and fine gravel, where alterations in the normal rate were detected due to the insertion of a thicker level of materials (soil stoniness) that was able to be dated. The sediment and chronological results obtained can be used to determine the historical events in the area that could have affected the erosion and deposit processes in the basin for the estimated period, from the late 18th to the early 19th century. During this period, pastureland that maintained the ecological balance of the dehesa, with a balanced, stable displacement of soil particles, was converted to cropland, in most cases resulting in soil with a limited profile, overuse and the consequent loss of structure and texture, making it more vulnerable to erosion. Greater remobilisation would have carried thicker material to the watercourses than the material deposited as a result of limited ploughing. This study provides data for the dehesa areas studied with regard to their hydrogeomorphological dynamics, from which past environmental impacts due to tillage can be inferred. Full article

(This article belongs to the Special Issue Soil Erosion and Sustainable Land Management (SLM))

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23 pages, 2068 KiB

Open AccessArticle

Exploring Drivers of Livelihood Diversification and Its Effect on Adoption of Sustainable Land Management Practices in the Upper Blue Nile Basin, Ethiopia

by Misganaw Teshager Abeje, Atsushi Tsunekawa, Enyew Adgo, Nigussie Haregeweyn, Zerihun Nigussie, Zemen Ayalew, Asres Elias, Dessalegn Molla and Daregot Berihun

Sustainability 2019, 11(10), 2991; https://doi.org/10.3390/su11102991 - 27 May 2019

Cited by 40 | Viewed by 6275

Abstract

Land degradation poses a major threat to agricultural production and food security in Ethiopia, and sustainable land management (SLM) is key in dealing with its adverse impacts. This paper examines the covariates that shape rural livelihood diversification and examines their effects on the [...] Read more.

Land degradation poses a major threat to agricultural production and food security in Ethiopia, and sustainable land management (SLM) is key in dealing with its adverse impacts. This paper examines the covariates that shape rural livelihood diversification and examines their effects on the intensity of adoption of SLM practices. Household-level data were collected in 2017 from 270 households in three drought-prone watersheds located in northwestern Ethiopia. We used the Herfindahl–Simpson diversity index to explore the extent of livelihood diversification. A stochastic dominance ordering was also employed to identify remunerative livelihood activities. A multivariate probit model was employed to estimate the probability of choosing simultaneous livelihood strategies, and an ordered probit model was estimated to examine the effect of livelihood diversification on the adoption intensity of SLM practices. In addition to mixed cropping and livestock production, the production of emerging cash crops (e.g., Acacia decurrens for charcoal, and khat) dominated the overall income generation of the majority of farmers. Stress/shock experience, extent of agricultural intensification, and agro-ecology significantly affected the probability of choosing certain livelihood strategies. Livelihood diversification at the household level was significantly associated with the dependency ratio, market distance, credit access, extension services, membership in community organizations, level of income, and livestock ownership. A greater extent of livelihood diversification had a significant negative effect on adopting a greater number of SLM practices, whereas it had a positive effect on lower SLM adoption intensity. Overall, we found evidence that having greater livelihood diversification could prompt households not to adopt more SLM practices. Livelihood initiatives that focus on increasing shock resilience, access to financial support mechanisms, improving livestock production, and providing quality extension services, while also considering agro-ecological differences, are needed. In addition, development planners should take into account the livelihood portfolios of rural households when trying to implement SLM policies and programs. Full article

(This article belongs to the Special Issue Soil Erosion and Sustainable Land Management (SLM))

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