Soil And Water Conservation Measures Research Articles

Impact of participation in collective action on farmers’ decisions and waiting time to adopt soil and water conservation measures

Purpose This study aims to analyze the influence of farmers’ degree of participation in collective action on their adoption decisions and waiting time regarding soil and water conservation (SWC) measures. Design/methodology/approach The Probit model and Generalized Propensity Score Match method are used to assess the effect of the degree of participation in collective action on farmers’ adoption decisions and waiting time for implementing SWC measures. Findings The findings reveal that farmers’ engagement in collective action positively influences the decision-making process regarding terrace construction, water-saving irrigation and afforestation measures. However, it does not significantly impact the decision-making process for plastic film and ridge-furrow tillage practices. Notably, collective action has the strongest influence on farmers’ adoption decisions regarding water-saving irrigation technology, with a relatively smaller influence on the adoption of afforestation and terrace measures. Moreover, the results suggest that participating in collective action effectively reduces the waiting time for terrace construction and expedites the adoption of afforestation and water-saving irrigation technology. Specifically, collective action has a significantly negative effect on the waiting time for terrace construction, followed by water-saving irrigation technology and afforestation measures. Practical implications The results of this study underscore the significance of fostering mutual assistance and cooperation mechanisms among farmers, as they can pave the way for raising funds and labor, cultivating elite farmers, attracting skilled labor to rural areas, enhancing the adoption rate and expediting the implementation of terraces, water-saving irrigation technology and afforestation measures. Originality/value Drawing on an evaluation of farmers’ degree of participation in collective action, this paper investigates the effect of participation on their SWC adoption decisions and waiting times, thereby offering theoretical and practical insights into soil erosion control in the Loess Plateau.

Effectiveness of physical soil and water conservation measures under simulated and observed dataset in Ethiopia: Meta‐analysis

AbstractTo combat land degradation through conserving soil and water resources, Ethiopia has undergone vigorous implementation of soil and water conservation (SWC) measures, predominantly physical structures. To evaluate the effectiveness of these implemented structures, various researches have been conducted through using both measured and simulated approaches. This study was initiated to analyze the reliability of SWAT‐based simulated studies results on the effectiveness of SWC measures toward erosion reduction potential against the measured dataset using unpaired t‐test statistical analysis. In this study, 123 published papers were downloaded, of which 70 were found to be more related to the objective of the review. After applying four refining criteria, only 43 were found more compatible with the study objective and used for data analysis. Studies conducted by different scholars show up to 98% and 93.50% soil loss reduction effectiveness by SWC measures in measured and simulated approaches, respectively. The simulated SWC measure efficiency output was also evaluated with respect to the ground‐measured data of the same structure within the same agroecology class. Finally, the unpaired t‐test results indicated that the grass strip in the mid‐highland agroecology showed a significant difference from the measured one at a 95% significance level. However, none of the other measures showed significant differences between the measured and simulated datasets. Hence, the SWAT model can effectively simulate the effectiveness of physical SWC measures on soil loss reduction if it is well‐calibrated and validated with sediment yield data. Refining model parameters that can be sufficiently captured and represent biological measures (grass strip), incorporating additional field data for calibration and validation coupled with exploring alternative modeling approaches that efficiently simulate biological SWC was set as a recommendation to obtain an effective biological measure simulation.

Evaluating effects of physical soil and water conservation measures using farmers’ perception and soil analysis in southern Ethiopia

Context Soil and water conservation (SWC) measures have been widely practiced on cultivated lands across regions but evidence on their effects is inadequate. Aims To examine the effects of variously aged SWC measures on cultivated land. Methods A total of 122 farm households were interviewed. At the 0–20 cm layer, soil samples (n = 59) were collected from soil bunds of <5 years, 5–10 years, and 10–15 years old, and no-bund adjacent fields and analysed in the laboratory. Key results Approximately 40% of respondents perceived soil erosion as a severe problem in their area. The respondents (70%) practiced the introduced SWC measures such as soil bunds. The introduced SWC measures are beneficial in improving soil fertility (78%) and thus 96% of the respondents were interested in repairing and sustaining it. The soil pH, soil organic carbon, total nitrogen, and available phosphorous were significantly (P < 0.05) greater in the fields with bunds of 10–15 years old than the fields with bunds of less than 10 years. The 10–15 year old bund showed greater soil organic carbon (37%), total nitrogen (40%), and available phosphorous (27%) than adjacent no-bund fields, implying that SWC can show effects on soil in the long term. Conclusions The results of the study revealed that the effects of physical SWC measures on soil properties can be observed after a decade of managing them. Implications Farmers are advised to repair and retain bunds if the erosion-prone areas are used for cultivating annual crop.

Response of Floods to the Underlying Surface Changes in the Taojiang River Basin Using the Hydrologic Engineering Center’s Hydrologic Modeling System

Due to underlying surface changes (USCs), the changes in the Taojiang River Basin’s flood generation conditions could impact the flooding process in the basin. However, most studies have typically focused on either land-use changes (LUCs) or soil and water conservation measures (SWCMs) to assess the impact of the USCs on floods, which may not provide a more comprehensive understanding of the response of floods to the USCs. To investigate how the USCs have altered the floods in the Taojiang River Basin, located upstream of Poyang Lake, China, the HEC-HMS model, which incorporates the influence of the USCs into the parameter calibration, is established in this study to investigate the flood processes on an hourly scale. The flood peak and the maximum 72 h flood volume are selected as two indexes and are applied to analyze the changes in floods caused by the USCs. The 1981–2020 period is divided into three sub-periods (i.e., 1981–1992, 1993–2007, and 2008–2020) based on the conditions of the USCs. It is found that the two indexes have exhibited decreasing trends, mainly due to the USCs during 1981–2020. Benchmarked against the baseline period of 1981–1992, the two indexes decreased by 3.06% (the flood peak) and 4.00% (the maximum 72 h flood volume) during 1993–2007 and by 5.92% and 7.58% during 2008–2020. Moreover, the impacts of the LUCs and SWCMs are separated through parameter adjustments in the model, revealing that the SWCMs played a dominant role in the USCs in the Taojiang River Basin. The quantification and assessment of the impact of the USCs on floods of different magnitudes revealed that the influence decreases with increasing flood magnitude. The results of this study improve our understanding of how USCs affect the flooding process and therefore provide support for flood control management under changing environments.

Response of Runoff Change to Soil and Water Conservation Measures in the Jing River Catchment of China

Soil and water conservation measures (SWCMs) are vital in reducing runoff and ultimately affect water security and regional development. However, previous studies have mainly focused on the impact of a single SWCM, neglecting to distinguish between the effects of different SWCMs on runoff reduction. A Soil and Water Assessment Tool (SWAT) model was established in the Jing River catchment to identify the responses to runoff changes resulting from climate change and human activities. The model was used to quantitatively analyse the impact of different SWCMs on runoff reduction. The results indicated that human activities contributed significantly more to runoff reduction than climate change. The reduction benefits of different unit area changes for each SWCM on discharge, surface runoff and water yield at the outlet were ranked as follows: changing cultivated land to forest land > changing cultivated land to grassland > building terraces on a 5–15° slope > building terraces on a 5–25° slope > building terraces on a 15–25° slope. Regional authorities should comprehensively consider the effects of various SWCMs on water reduction, and optimise the layout of vegetation and terracing measures, to support the efficient utilization of water resources in the Jing River catchment.

Precipitation, topography, and soil conservation measures determine the spatiotemporal pattern of sediment yield at the regional scale

Exploring the driving effects of control factors on changes in sediment yield from a watershed perspective is of paramount importance for refined watershed management. The objective of this research is to unveil the spatiotemporal variation of sediment yield in the Coarse Sandy Hilly Catchments (CSHC) region from 1956 to 2019 and further investigate the relationship between sediment yield and driving factors. The findings revealed that the mutation years of sediment load (SL) at Toudaoguai and Longmen stations were 1986 and 1996, respectively, with annual SL declining by 66.75 % and 79.04 % after the mutation. Water and sediment discharge at Toudaoguai station exhibited more consistent fluctuations over time, while water and sediment discharge at Longmen station remained relatively consistent before 1967, followed by an entirely inconsistent trend. The spatial pattern of the annual average specific sediment yield (SSY) indicated that the northwest watersheds had a relatively higher erosion rate compared to the southeast. Over time, the SSY of each watershed exhibited a decreasing trend. The SSY showed significant negative correlations with terrace, afforestation, topographic position index (TPI), grass planting (GP), and elevation, while demonstrating significant positive correlations with rainfall indicators and runoff depth. Changes in precipitation, topography, vegetation and engineering measures accounted for 58.5 % of the variance in SSY. The total impact of precipitation on SSY change was positive (standard path coefficient (SPC) = 0.567, P < 0.01), whereas the total impact of topography, vegetation measures, and engineering measures on SSY change was negative (SPC = -0.282, −0.231, and −0.087, respectively). This study quantified the impact of different types of controlling factors on sediment yield at the watershed level. The insights provided by these results can contribute to sustainable watershed management and the optimal allocation of soil and water conservation measures (SWCMs).

Effect of Staggered Contour Trenches and Hillside Ditches on surface runoff and soil loss on steep slopes in shaded coffee (Coffea arabica), Costa Rica

Soil erosion is one of the main causes of soil degradation and an important environmental problem, often accelerated by human activities. Different types of soil and water conservation measures (SWCM) have been implemented in worldwide to control soil loss, such as Staggered Contour Trenches (SCT) and Hillside ditches (HD) which are recommended in topographies up to 40 % slope. This study measured the effects of STC and HD, on surface runoff, soil loss, exposed of organic matter and soil moisture content, in a shaded coffee crop with steep slopes in an Entisol soil. Nine runoff plots were installed in Llano Brenes, Costa Rica, in the upper basin of the Jesús María River in a study area with slopes between 50 and 71 ± 7.92 %. We conclude that this study could make an important contribution to research on the use of SWCM on tropical soils with slopes greater than 50 %. Due to the non-compliance of assumptions, a logarithmic transformation of the data was used, and they were evaluated using the Kruskal-Wallis one-way nonparametric test. Spearman correlation and linear regressions were used to assess the effect of the precipitation and intensity in the soil loss and runoff in each treatment. The amount of organic matter exposed by soil removal was not statistically different between HD and SCT, but both were different to the control (R2 = 0.81, P < 0.05). Spearman correlation analysis showed the rainfall depth contributed more to runoff depth (HD R = 0.62; SCT R = 0.62; Control R = 0.60; P < 0.001) and soil loss (HD R = 0.50; STC R = 0.53; Control R = 0.50; P < 0.001) than other variables. Regression analysis showed that runoff and soil loss were significant (P < 0.05) and positively correlated with rainfall depth for each treatment. In this study, HD was shown to be efficient in erosion control on steeper slopes. HD helped reduce soil loss compared to the control, by 88 % in 2018 and 83 % in 2019. HD also reduced runoff generation by 55 % in 2018 and 60 % in 2019 compared to the control. While SCT was not statistically different in the generation of surface runoff and soil loss compared to the control.

How Can Drones Uncover Land Degradation Hotspots and Restoration Hopespots? An Integrated Approach in the Mount Elgon Region with Community Perceptions

Human-induced land degradation in biodiverse regions like Mount Elgon threatens vital ecosystems. This study employs drone mapping and community insights to assess land use changes, degradation, and restoration in Mount Elgon, Uganda. Drone monitoring (2020–2023) covered six sites, complemented by household surveys (n = 499), Focus Group Discussions (FDGs), and interviews. Drone imagery shows agriculture and planted forest as dominant land use types, gradually replacing tropical high forest, bushland, and grassland. Drone image results showed that smallholder subsistence farming is leading to and enhancing degradation. Landslides and encroachment into the park were detected in three of the six sites. Trenches were the most adopted Soil and Water Conservation (SWC) measure. The trench adoption varied by location and crop type, creating restoration potential, notably in Elgon, Nabyoko, and Shiteka. Interviews and FGDs revealed adoption of trenches, grass strips, and afforestation as remedies to land degradation. Complex interactions exists among land use, degradation, and SWC measures in the upper Manafwa watershed, underscoring the urgency of addressing landslides and encroachment into the forest. Community-based initiatives are vital for hands-on SWC training, emphasizing long-term benefits. Collaboration among government, local communities, and NGOs is crucial to enforce conservation and restore Mt. Elgon National Park, while encouraging diversified income sources can reduce land dependency and mitigate degradation risks.

Soil and water conservation measures and rainfed agriculture in Telangana, India: Role of community and neighborhood conservation measures

Soil erosion is a significant problem in rain-fed areas in India. This study attempts to evaluate the causal effects of on-farm soil and water conservation (SWC) measures on farm profit and yield. The study uses the inverse-probability-weighted regression adjustment (IPWRA) method to assess the causal impact of SWC measures on agriculture output while controlling socioeconomic, institutional, and village-level characteristics. The results suggest a significant difference in overall agricultural profit, crop-wise profit, and crop-wise yields among the adopters and non-adopters of the SWC measures. The study highlights that there is a complementarity between the causal impact of community-level SWC measures and individual SWC measures on agricultural outcomes. Further, the neighbor’s adoption of SWC measures plays a pivotal role on farmer’s agricultural profits. The study highlights that farmer’s profit for rainfed crops such as maize further increases if their adjacent neighbors also undertake SWC measures. Such complementary effects, however, are not observed in case of irrigated crops such as paddy.

Effects of different soil and water conservation measures on plant diversity and productivity in Loess Plateau

Many soil and water conservation measures (SWCM) have been implemented in the Loess Plateau of China, and they have an impact on ecosystems all levels and involve complicated mechanisms. Previously, studies typically focused on a single factor's effect on diversity or productivity. With this background, the current investigation embarked on an extensive study, with vegetation survey conducted in the no measure plots (NM), vegetation measure plots (VM) and engineering measure plots (EM) in the Loess Plateau of China. We used structural equation models (SEM) to explain the mechanism by which SWCM affects plant productivity and diversity. VM have direct effects on plant diversity, and EM have direct effects on soil properties and community structure. The two measures also had indirect effects on plant functional traits and community structure. The results show that the changes in plant functional traits and community structure by SWCM decreased plant diversity, whereas the increase of productivity was primarily dominated by improvements in community structure, and we conclude that variability in plant diversity and productivity across different measures on the Loess Plateau was primarily due to the responses of different plants to variable soil properties and the community responses. It was also emphasized that vegetation measures were beneficial to the increase of biomass per plant, while engineering measures were more beneficial to the growth of dominant species. These findings provide a theoretical foundation for vegetation management and restoration after the application of different SWCM.

Impact Assessment of Soil and Water Conservation Measures at Gharat Watershed in Pindwara, Sirohi, India

The study was carried out 2020-2021 at the Gharat watershed is located in Pindwara district. To evaluate the impact of various biological and physical soil and water conservation (SWC) measures, implemented in the Gharat watershed during 2011-12 in combating minimal land resource use, land degradation caused by soil erosion, and lack of implementation of agriculture technology. Therefore, evaluation is required to determine the success or failure of conservation measures and to alter future planning appropriately. Due to the implementation of the watershed program, arable area increased by 16.56 percent, irrigated area by 53 percent, and additional farm income increased by approximately 17 lakhs, according to data collected through field observation, survey, semi-structured interviews, and field measurements. SWC measures applied in this watershed, cropping intensity and irrigated area increased from 122.12 percent to 137.08 percent, 51ha to 78ha respectively. The understanding and adaption of soil and water conservation strategies has a favorable influence on the overall development of the watershed. Existing SWC measures should be improved for continuing monitoring and extended as part of an integrated strategy to restore damaged regions to their full potential. It provides project planners and managers, programme leaders, and policymakers with details about actual project accomplishments in the format they need.

Effects of soil and water conservation measures of slope surfaces on flood peaks of small watersheds: A study based on three extreme rainstorm events in northern China

Flash floods resulting from extreme rainstorms seriously threaten regional socioeconomic development. However, few studies have explored the general impacts of soil and water conservation measures (SWCMs) on flood peaks during extreme rainstorms through multiple field investigations. On the basis of field surveys of three rainstorm events in Shaanxi, Shandong, and Henan provinces, the effects of vegetation and agricultural terraces on flood peaks were investigated in 75 small watersheds in northern China. Compared with watersheds dominated by sloping cropland, the flood peak modulus of watersheds dominated by forest land, grass land, and agricultural terraces decreased by 54.75%, 47.80%, and 53.65%, respectively; the peak shaving effects (PSEs) of SWCMs were stronger during minor floods. Soil and water conservation measures reduced the flood magnitudes of small watersheds and their sensitivities to rainstorm events; the PSEs were positively correlated with the area of SWCMs. In earth-rocky mountainous areas, the PSEs of forest land were stronger than those of grassland and agricultural terraces, while in the loess hilly-gully areas, the PSEs of agricultural terraces were stronger than those of other SWCMs. In loess hilly-gully areas, the flash floods demonstrated a phenomenon of small rainfall amounts but substantial flood peaks. Besides the reasonable installation of SWCMs on slopes, appropriate channel measures (e.g., check dams) are warranted to cope with extreme rainstorm events. In northern earth-rocky mountainous areas, intercropping management should be promoted to cover bare soil on orchard agricultural terraces. Our results provide a theoretical basis for combating extreme rainstorm disasters.

Simulating the hydrological impacts of intensive soil and water conservation measures in the Yellow River basin using a distributed physically-based model

Intensive Soil and Water Conservation (SWC) has been conducted in the Yellow River basin (YRB) since the 1950s, which has greatly altered the eco-hydrological processes and particularly led to the runoff reduction. However, previous hydrological models performed in the YRB rarely simulated the SWC explicitly to quantify its spatiotemporal impacts. This study developed a SWC parameterization scheme based on the distributed physically-based model named Geomorphology-Based Ecohydrological Model (GBEHM). The hillslope SWC (HSWC) was parameterized as an additional surface storage capacity and simulated together with hillslope hydrological processes. The check dams along the river networks (i.e., river-networks SWC, RSWC) were parameterized as reservoirs and simulated together with the flow routing. The enhanced model (GBEHM-SWC) was first calibrated and validated using natural streamflow and remote sensing-based evapotranspiration. Then it was applied to analyze the hydrological changes from 1982 to 2019 in the YRB. Our simulation showed that, compared with the first period (1982–2000), the climatic factors (especially an increase of annual precipitation by 27.3 mm) would cause an increase of annual natural runoff by 2.9 mm (2.17 billion m3) in the second period (2001–2019). But in fact, the observed annual natural runoff decreased by 4.3 mm in the second period, which was caused by the reduction effects of the HSWC and RSWC by 3.8 and 3.7 mm (2.84 and 2.74 billion m3), respectively. Regarding the spatial distribution, the simulated natural runoff increased above Lanzhou and decreased on the Loess Plateau. The SWC impacts showed high spatial heterogeneity over the YRB, which offered useful information to evaluate the SWC measures.

Effects of soil and water conservation practices and landscape position on soil physicochemical properties in Anuwa watershed, Southern Ethiopia

Ethiopia's main environmental problem has been soil erosion. To control and reverse the problem, soil and water conservation (SWC) techniques have been deployed over the past two to three decades. The purpose of this study is to evaluate the effect of implemented soil and water conservation measures on soil physicochemical properties in the Anuwa watershed, southern Ethiopia, under various conservation structures (Soil bund, Fanya Juu, Stone bund and Micro Basin) and topographic positions (upper, middle and lower) of conserved plots. The soil samples were collected from 45 locations to analyze topsoil texture, bulk density (ρd), pH, soil organic carbon (SOC), total nitrogen (TN), available phosphorus (AP), CEC, exchangeable Na+, K+, Ca2+, and Mg2+. All soil samples were analyzed using standard and recommended methods. Using the SPSS computer program 21, the effect of independent variables (SWC practices and landscape position) on the dependent variables (soil properties) was statistically tested. The significance test was performed using two-way ANOVA. The findings indicated that the SWC measure significantly decreases the percent values of sandy soil texture, while it increased the mean values of organic carbon, available phosphorus, exchangeable Na+, K+, Ca2+, Mg2+, and CEC (P < 0.05). The sand content, the bulk density, the SOC, and the total nitrogen showed statistically significant variations between the conserved and non-conserved upper topography (P < 0.05). The effects of conservation measures were significant in almost all soil physicochemical properties at P < 0.01 except for the silt content, bulk density, and Ca2+ in the lower topography. The study findings revealed that Fanya Juu SWC measures are by far the most efficient, and recommended method to minimizing soil erosion, and improving selected soil physical and chemical quality in the Anuwa watershed. Local governments and other stakeholders should work cooperatively to strengthen and sustain the implementation process.

Impacts of soil and water conservation measures on soil physicochemical properties in the Jibgedel Watershed, Ethiopia.

Soil erosion significantly affects agricultural production. Soil and Water Conservation (SWC) measures have been constructed to reduce soil loss. However, the impact of SWC measures on physicochemical soil properties has rarely been investigated in most parts of Ethiopia. Therefore, this study was designed to evaluate the effects of SWC measures on selected soil physicochemical properties in the Jibgedel watershed, West Gojjam zone, Ethiopia. The study also assessed the farmers' perception of the benefits and impacts of SWC measures. Composite and core soil samples were taken at a depth of 0 to 20cm from four farmlands with SWC measures (soil bund, stone bund, and soil bund with sesbania tree) and without SWC measures in three replications. Results have shown that employing SWC measures in the farmland significantly improved most of the physicochemical properties of the soil compared to farmland without SWC measures. Bulk density from soil bund with and without sesbania trees was significantly lower than stone bund and untreated farmland. Soil organic carbon, total nitrogen, electrical conductivity, and available phosphorus from soil bund with sesbania tree were significantly higher than other treatments. The result also revealed that most farmers perceived that the implemented SWC measures improved soil fertility and crop yield. SWC measures are easier to adopt for integrated watershed management when farmers are well-versed in them.

Sediment yield estimation in GIS environment using RUSLE and SDR model in Southern Ethiopia

Soil erosion and sediment yields are the current limitations and future threats to agriculture, water resources and hydropower projects particularly in developing countries. Estimating the extent and comprehending the spatial distribution of hotspot area is crucial to implement evidence-based soil and water conservation (SWC) measures with limited resources. The study used RUSLE and SDR models in ArcGIS 10.8 environment. The RUSLE model was found to be highly sensitive to C factor followed by LS factor. The result indicated that the annual soil loss varies from 0 to 359.99 t ha−1 yr−1 with 22.31 t ha−1 yr−1 as a mean annual. Besides, the estimated sediment yield ranged from 0 to 42.5 t ha−1 yr−1 with a mean value of 12.02 t ha−1 yr−1. The finding revealed that the central west (SW_5) and northeast (SW_4) parts of the watershed yield higher sediment. The result also signified that about 52.9% of the eroded materials including soil and nutrients are transferred to the outlet. The outcome of our finding undoubtedly aids in the identification of hotspot areas for the adoption of appropriate SWC measures. Hence, adopting RUSLE and SDR for Gununo watershed and another watershed having similar biophysical and environmental factors is suggested.

Soil and water conservation measures reduce erosion but result in carbon and nitrogen accumulation of red soil in Southern China

Soil erosion is continually overlooked in the hilly red soil region of southern China, and there is a substantial lack of knowledge about the effects of soil and water conservation measures (SWCMs) on erosion prevention and soil carbon and nitrogen accumulation for the eroded sloping arable land in this region. Herein, based on a long-term experiment in the red soil hilly region in China, we investigated the effects of 17 years of SWCMs on soil organic carbon (SOC), total nitrogen (TN), microbial biomass carbon and nitrogen (MBC and MBN, respectively) as well as soil erodibility (K factor) at soil depths of 0–100 cm in the top, middle and bottom parts of the slope. The SWCMs included straw mulching (SM), downslope ridge cultivation (DC), downslope ridge cultivation + contour hedgerow planting (DCH), and contour ridge cultivation tillage (CC). A bare land treatment without any crops was used as a control (CK). We found that SWCMs increased SOC, TN, MBC, and MBN by 8–57%, 1–14%, 25–68%, and 17–35%, respectively, with greater increases in these variables in the CC and SM treatments and smaller increase in the DC treatment. Additionally, the effects of the SWCMs were greater at the top and middle of the slope than at the bottom of the slope, and the effects varied with soil depth. Moreover, the SWCMs decreased soil erodibility, with a lower K factor in the SWCMs treatments (0.018–0.049 t ha h ha−1 MJ−1 mm−1) than in the CK (0.042–0.068 t ha h ha−1 MJ−1 mm−1) and a greater decrease in the CC treatment. The effects of the SWCMs on soil erodibility mainly occurred through the regulation of SOC according to structural equation modeling. Overall, this study suggested that straw mulching and contour ridge cultivation tillage were the most effective strategies for restoring soil carbon and nitrogen and preventing soil erosion.

Downward Trends in Streamflow and Sediment Yield Associated with Soil and Water Conservation in the Tingjiang River Watershed, Southeast China

Soil erosion is one of the most serious environment problems in China. Soil and water conservation (SWC) measures play an important role in reducing streamflow and sediment yields. A nested watershed approach, together with the Mann–Kendall trend test, double mass curve, and path analysis were used to quantitatively explore hydrological effects of SWC measures in the Tingjiang River Watershed. Results showed the annual streamflow and sediment yields tended toward a remarkable downward trend since the implementation of SWC measures during 1982–2014, indicating that SWC measures produced significant hydrological effects. The contribution of precipitation to annual streamflow increased from 71% to 79% from the periods 1982–2000 to 2000–2014, indicating decreases in annual precipitation after 2003 and stronger impacts on streamflow than that of SWC measures. However, the contribution of SWC measures to sediment yields increased from 11% to 64% from 1982 to 2014 and gradually dominated contributions to the sediment yields in the watershed. An ecological threshold was established at which the proportion of the cumulative afforestation area due to SWC reaches 10% of the whole watershed, and the remarkable improvements of hydrological effects in the watershed can be observed. These findings could be used to evaluate performance of SWC measures in watersheds.

Assessment of implemented physical designs and determinant factors of soil and water conservation measures: Wenago district, southern Ethiopia

Soil erosion and its consequences is one of the major serious problems in Ethiopia. Even though adoption of soil and water conservation (SWC) measures has been underway for the past three decades, the implementation and use of introduced technologies were below the expectation and the problem is still has continued in the country. The study was aimed at assessing the implemented physical designs of soil and water conservation structures in respect to the standards and identifying the major adoption determinant factors in Wenago district, southern Ethiopia. The data for this studywas collected from a survey of 262 total household farmers selected through simple random sampling techniques in the year 2020/21 and the datawas analyzed using descriptive statistics, chi-square and logistic regression model via SPSS and Stata soft wares. Focus group discussion, key informant interview and personal observation were also undertaken to gather data having qualitative nature. (i) About 55.6% of the implemented physical design failed to meet the standards (ii) Adoption of SWC measures were determined by 47.4% of the tested variables (iii) 55.5% of the variables were significantly associated at 5% probability level between adopters and non-adopters in terms of adoption of SWC measures in the study area. Overall, we conclude that construction of conservation structures should be focused on minimizing the observed mismatch of the implemented physical designs against the standards. This study is expected to contribute in achieving sustainable land management schemes, agricultural productivity and smallholder farmers livelihood improvement in international, national, regional and local level and it is strongly recommended that policy makers and technical institutions should address SWC related issues to ensure rural farmers food security.

SOIL EROSION ASSESSMENT WITH INVEST MODEL: CASE STUDY IN WEE-OYA WATERSHED IN SRI LANKA

Human-induced soil erosion is one of the most significant types of land degradation in the Wee Oya watershed in Sri Lanka. The high intensity of rainfall, steep slopes, and inappropriate land use practices are strongly associated with soil erosion in the area. The prime aim of the study was to estimate soil erosion in the watershed and its seven sub-watersheds using the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST), Sediment Delivery Ratio (SDR) model. Furthermore, a comprehensive household (HH) questionnaire survey (n=30) was conducted to ascertain key socio-economic information such as the farmer’s age, gender, education level, the extent of land for cultivation, and the degree of practicing soil and water conservation (SWC) measures. Then, the multiple regression analysis was applied to determine the significant socio-economic determinants of erosion in the watershed. The results of the assessment disclosed that the present average annual rate of human-induced soil erosion of the watershed is 167 t/ha/yr. Moreover, the most significant (p&lt;0.05) socio-economic determinants of the soil erosion of the study area are the farmer’s age and family size. Furthermore, the study revealed that more than 50% of the farmers do have not a substantial perception of existing government policies’ implications concerning human-induced soil erosion. Finally, the outcome of the assessment has highlighted the necessity of human intervention for effective SWC measures in the study area.