Erosion Status Research Articles

Comprehensive Assessment of Soil Erosion using USLE and Sustainable Management Strategies

Continuous soil erosion from all parts of world through water and winds have become a severe concerns for soil scientists and geologists due to its adverse effect on soil productivity, water bodies siltation and deterioration of water quality. Therefore, it becomes most important to locate erosion-prone regions of any landscape and take the best measures to solve the issues of erosion. USLE and its modified models i.e. RUSLE (Revised Universal Soil Loss Equation) versions and MUSLE (Modified Universal Soil Loss Equation) are most commonly used for estimation of soil erosion. In India, soil erosion is a major serious concern which varies in its intensity depending on the country's different agro-climatic zones. USLE as well known model for evaluating soil deterioration is used in this review to provide an understanding of its parameters and how this approach is useful in soil erosion assessment. In addition, an overview of the current situation of erosion status in India which is being altered by regional variations like climate and land uses. Literature also dictates and discusses the potential advantages of better erosion control approaches, such as increased agricultural output and long-term land sustainability and looks at what might be possible in the future if the things get managed. The study also looks at crop selection and land use systems, emphasizing how crucial it is to choose crops that are suitable for the land vulnerability to erosion in order to prevent the further deterioration. Lastly, it emphasize on a thorough explanation of the USLE's parameters which are essential for precise erosion prediction including slope factors, soil erodibility, rainfall erosivity and conservation techniques. The study summarizes the knowledge on soil erosion in India and the necessity of customized, area-specific soil conservation plans to guarantee long-term agricultural outputs and sustainable agricultural goals.

A hierarchical cluster analysis for clinical profiling of tofacitinib treatment response in patients with rheumatoid arthritis.

Tofacitinib is the first oral JAK inhibitor approved for treating rheumatoid arthritis (RA). To enhance our understanding of tofacitinib drug response, we used hierarchical clustering to analyse the profiles of patient who responded to the treatment in a real-world setting. Patients who commenced on tofacitinib treatment were selected from 12 major rheumatology centres in Malaysia. The aim was to assess their response to tofacitinib defined as achieving DAS28-CRP/ESR ≤ 3.2 and DAS28 improvement > 1.2 at 12weeks. A hierarchical clustering analysis was performed using sociodemographic and clinical parameters at baseline. All 163 RA patients were divided into three clusters (Clusters 1, 2 and 3) based on specific clinical factors at baseline including bone erosion, antibody positivity, disease activity and anaemia status. Cluster 1 consisted of RA patients without bone erosion, antibody negative, low baseline disease activity measure and absence of anaemia. Cluster 2 comprised of patients without bone erosion, RF positivity, anti-CCP negativity, moderate to high baseline disease activity score and absence of anaemia. Cluster 3 patients had bone erosion, antibody positivity, high baseline disease activity and anaemia. The response rates to tofacitinib varied among the clusters: Cluster 1 had a 79% response rate, Cluster 2 had a 66% response rate, and Cluster 3 had a 36% response rate. The differences in response rates between the three clusters were found to be statistically significant. This cluster analysis study indicates that patients who are seronegative and have low disease activity, absence of bone erosion and no signs of anaemia may have a higher likelihood of benefiting from tofacitinib therapy. By identifying clinical profiles that respond to tofacitinib treatment, we can improve treatment stratification yielding significant benefits and better health outcomes for individuals with RA.

An experimental study on the evolution of beach profiles under different beach nourishment methods

Due to the influence of storm surges, hard coastal protection structures may exacerbate beach erosion, hence beach nourishment methods are considered in coastal protection and restoration efforts. An experiment is conducted in a wave flume to compare the advantages and disadvantages of three types of beach nourishment methods (berm nourishment, profile nourishment, and bar nourishment) under non-storm and storm wave conditions. The experiment analyzes wave height distribution, beach morphology changes, net sediment transport, shoreline recession, beach width increase, and beach volume changes. The findings indicate that the implementation of bar nourishment strategies facilitates the pre-breaking of storm waves, thereby mitigating the disruption caused by wave breaking on water flow dynamics. Moreover, the application of berm and profile nourishment methods proves to be highly effective in expanding the width of the beach and bolstering its stability. However, it is worth noting that bar nourishment exhibits limited efficacy in terms of restoring beach berms and mitigating coastal erosion within the same duration of wave action. The study presents two equations incorporating hydrodynamic parameters to predict the erosion or accretion status of beaches, and compares the predicted results with experimental data, thereby refining the criteria and making the formulas more applicable to beach nourishment projects. These findings provide valuable insights into the strengths and weaknesses of different beach nourishment methods, which will contribute to the implementation of nourishment projects.

ASSESSING LOCAL PORE WATER VELOCITY ALONG PREFERENTIAL FLOW IN EARTHEN DAM USING SALT TRACER

The local pore water velocity along the preferential flow path signifies the hydraulic parameter responsible for erosion within an earthen dam. This study introduces an empirical approach to ascertain the local pore water velocity within the earth dam's leakage zones by monitoring the travel time of the salt tracer through the corresponding electric potential anomalies in the ground. The alignment of electric potential anomalies with the movement of the salt tracer plume over time was confirmed through experiments on a physical model coupled with numerical simulations. The pore water velocity, calculated based on the location of the maximum electric potential anomaly, demonstrated excellent agreement with the experimental value, with an error of under 6%. For illustrative purposes, a field-scale salt tracer test was conducted at a leaking earthen dam in Vietnam. The tracer breakthrough curve originating from the leakage point revealed that the seepage water's travel time is approximately 40 days. The results of electric potential anomalies over time indicate that the pathway of seepage flow from upstream to the leakage point forms a horizontal V-shape, with the local pore water velocity ranging from 1.7 to 9.9x10-5 m/s. These local pore water velocities are subsequently compared with the critical seepage velocity to assess in-situ information regarding the internal erosion status of the target dam.

Evaluation of water ecological health of Yanhe River based on benthic fauna integrity index.

Yanhe River Basin is located in the hilly gully area of the Loess Plateau with serious soil erosion. Strong human activities in the middle and lower reaches lead to fragile ecological environment. Soil erosion status varies among different geomorphic units within the watershed (loess liang hilly and gully region, loess mao hilly and gully region, and broken platform region). In this study, we surveyed the benthic community from the Yanhe River Basin in April (spring) and October (autumn) of 2021. To evaluate the water ecological health status of the watershed and investigate the effects of different geomorphic units on the benthic integrity of the benthos, we constructed the benthic-index of biotical integrity (B-IBI) based on the biological data. We identified a total of 113 species of 73 genera in 4 phyla of benthic fauna, with aquatic insects as the dominant taxa in both seasons. Through screening 26 candidate indicators, we found that the spring B-IBI consisted of three indicators: relative abundance of individuals of dominant taxonomic units, family biotic index (FBI), and relative abundance of predator individuals, and that autumn B-IBI was composed of the number of taxonomic units of Ephemeroptera, FBI value, and the relative abundance of predator individuals. Results of the B-IBI evaluation showed that 83.3% of the sampling sites in the upper mainstem and tributaries were at a healthy condition, while only 28.6% sampling sites in the middle and lower mainstem and tributaries were at a healthy condition. In addition, the health status of the watershed was better in spring than in autumn. The Kruskal-Wallis nonparametric tests showed that benthic density, species number, and B-IBI percentile scores in the fragmented loess area were significantly higher in spring than in autumn, and significantly lower in autumn than in the loess liang hilly and gully region and loess mao hilly and gully region, being mainly caused by the increasing erosion due to the concentrated rainfall in wet season. Results of the redundancy analysis showed that key environmental factors affecting benthic community structure in spring were boulder substrate, chlorophyll-a, oxidation reduction potential, turbidity, conductivity, and dissolved oxygen, and were nitrate-nitrogen, oxidation reduction potential, and pH in autumn.

The Role of Mangrove Forests in The Coast and Dykes West Sea Zone Protection: A Case Study in Kien Giang and Ca Mau Provinces

Purpose: The study aimed to provide a picture total of the forest and erosion status of the beach and dykes of Kien Giang and Ca Mau. Method: There are 18 sample plots for testing. The map also includes 68 survey plots that are predefined and used as a basis for positioning in the field. The measurement indicators include tree species identification. Results and conclusion: The level of erosion in Ha Tien’s forests varies based on tree density and environmental factors. The forest with no erosion has a thickness of 9,600 trees/ha and a stem diameter of 19 cm, while the extremely erosion forest has 2,000 trees/ha and a stem diameter of 6 cm. Topographically, Ha Tien has little erosion, while U Minh is a low-lying area with high erosion. Erosion levels are 1-2 in January-April, 4-5 in May-October and 3 in November-December. Currently, the section is divided into 28 sub-sections, with Kien Giang having 23. One sub-section is level 1, 11 sub-sections are level 2, 1 is level 3, 3 are level 4, and 3 are level 5. In Ca Mau, two sub-sections are level 4, and 3 are level 5. Implications of the research: With climate change and rising sea levels, erosion levels tend to increase one level in sub-section areas in the coming years. Originality/value: This study assesses forest and erosion status in Kien Giang and Ca Mau provinces, Vietnam, providing local insights into environmental challenges. It uses a rigorous methodology, analyzes erosion levels, and classifies the area into sub-sections. The study also highlights the potential impact of climate change on erosion, promoting proactive adaptation and mitigation efforts.

Participant approach model in a basin: A case study from Turkey

Abstract The Beyşehir Lake Basin, which is the study area, is the second largest sub-basin within the Konya province, located southwest of the Konya Closed Basin in terms of surface by 7,308 km2. Some basin characteristics such as slope, elevation classes, land use, aspect groups, land capability class, erosion status were examined by a Geographic Information System. The aims of the study were to determine the problems and the requests and suggestions of the people living in the basin, and to reveal the needs and deficiencies. For these purposes, the current and potential situation of the basin was evaluated using a holistic evaluation approach, which represents the most important of the watershed management principles, and the solutions were concluded in the light of the findings of the study. Migration, inadequacy of agricultural activities, lack of pasture areas for livestock activities, lack and neglect of irrigation water and irrigation infrastructure, lack of basic infrastructure such as village roads, and soil losses due to lack of erosion structures were the most obvious problems of the basin based on the results of the Ask–Find–Resolve analyses.

Understanding the linkages between land-use transitions and soil erosion/sediment deposition: A case study of the transboundary Sio-Malaba-Malakisi watershed in Kenya and Uganda

Soil erosion consequent of unsustainable land-use practices represents one of the world's most pressing environmental problems affecting many watersheds. An assessment of sediment sources and delivery paths is essential for the development of site-specific soil management strategies for curbing environmental degradation. The present study employed a physically-based lumped approach to estimate soil erosion and sediment deposition patterns across the transboundary Sio-Malaba-Malakisi (SMM) watershed. The Unit Stream Power-based Erosion Deposition (USPED) model was adopted for the study, and integrated with physically-based parameters derived in a Geographical Information System (GIS). A land-use map for 2017 was used for simulating the reference soil erosion and deposition status of the basin. Furthermore, the impacts of two land-use scenarios representing options for cropland expansion (Scenario-I), and land reclamation (Scenario-II), were evaluated for the period 2047, corresponding to a thirty-year period used in assessing catchment management planning for SMM. The annual soil erosion ranged between 0 and 460 t. ha−1yr−1, with a mean erosion rate of 160 t.ha−1yr−1 for the baseline condition. Deposition zones were mainly concentrated along stream banks and floodplain in low-lying sub-catchments. The mean soil erosion rate increased by 61 % and 16 % for scenarios I and II respectively. Overall, the modelled erosion/deposition values were correlated with available sediment data for the basin, realizing a coefficient determination (R2) value of 0.74. These results could serve as a benchmark against which future trends in land-use changes can be compared in the region and hence support the development of regional soil erosion conservation strategies.

Analyzing vegetation recovery and erosion status after a large Landslide at Mt. Hakusan, Central Japan

A large-scale landslide occurred in 2015 in Senninvalley, Mt. Hakusan, Central Japan, releasing large amounts of sediment. To mitigate continuous erosion in the landslide area and its downstream adverse effects, reforestation activities were implemented from 2016 to 2021. This study assessed the status of vegetation recovery and erosion condition after 7 years using aerial photographs, light detection and ranging data, satellite imagery, and published documents. The results show that the greenery (herbaceous and woody plants) is mainly recovering on the upper slope of the landslide area where reforestation works were implemented, while the lower slope, where no reforestation activities have been applied, still lacks greenery. The lower slope suffered nearly 1–4 m of continued erosion from 2016 to 2022, while upper slope has no significant erosion. Within this 7-year period, the vegetation coverage on the upper slope of the landslide, where artificial restoration was applied, increased significantly from 10 to 43%.

Latanoprostene Bunod 0.024% w/v Treatment of Open-anlge Glaucoma: Short-term Effects, Safety, and Changes in Ocular Blood

Purpose: To study the short-term intraocular pressure (IOP)-lowering effect and optic nerve head (ONH) blood flow improvement after switching from latanoprost 0.005% w/v to latanoprostene bunod 0.024% w/v.Methods: This prospective study ran from May 2022 to December 2022 and included 40 patients with open-angle glaucoma who switched from latanoprost 0.005% w/v to latanoprostene bunod 0.024% w/v. The IOP, ONH blood flow, and conjunctival hyperemia, corneal erosion, and eyelid pigmentation status were measured 3 months after switching. We recorded all possible side effects.Results: The baseline IOP significantly dropped from 17.53 ± 6.49 to 16.00 ± 8.06 mmHg at 3 months (p = 0.032). The best-corrected visual acuity did not significantly change (0.24 ± 0.19 to 0.23 ± 0.16); neither did eyelid pigmentation (1.16 ± 0.78 to 1.16 ± 0.82) nor the corneal erosion score (0.58 ± 0.85 to 0.39 ± 0.76). Conjunctival hyperemia significantly decreased from 2.00 ± 0.69 to 1.67 ± 0.63 (p = 0.010). Neither the whole-image vessel density nor the peripapillary vessel density significantly changed. However, pruritus became significantly worse after the change (p = 0.008).Conclusions: In the short term, latanoprostene bunod 0.024% w/v lowered the IOP more effectively than did latanoprost 0.005% w/v. However, there was no significant change in ONH blood flow after the switch.

Application of Geospatial Techniques in Soil Erosion Assessment in Sarbari Khad of Himachal Pradesh, India

The accurate measurement of geomorphometric parameters is crucial for assessing the condition of watersheds, particularly in mountain ecosystems and extensive areas where it can be challenging to obtain precise measurements. In this study, drainage density was used to evaluate soil erosion in the Sarbari Khad watershed located in the lesser Himalayan region of Himachal Pradesh, India, using Geographical Information System (GIS) and remotely sensed digital data. The analysis of drainage density indicated that the Sarbari Khad watershed is susceptible to surface erosion and soil degradation. The watershed was classified into low, moderate, severe, and very severe erosion categories based on the drainage density values, which revealed that about 60 percent of the area suffers from very severe erosion. The findings of this study suggest that drainage density can be used as an effective indicator for estimating erosion status of watersheds. This information can be used to prioritize watershed areas for soil and water conservation measures, which are critical for ensuring the sustainability of the watershed. Overall, this research work highlights the significance of using GIS and remotely sensed data along with direct survey-based topographical maps for assessing soil erosion in mountain ecosystems and extensive areas. The results of this study can be used to guide conservation efforts and inform policy decisions aimed at mitigating the negative impacts of soil erosion on the environment and local communities.

Accommodating uncertainty in soil erosion risk assessment: Integration of Bayesian belief networks and MPSIAC model

Accommodating uncertainty stands as one of the most salient challenges in the development of soil erosion assessment tools. We presented a novel approach integrating the Modified Pacific Southwest Inter-Agency Committee (MPSIAC) model and Bayesian Belief Networks (BBNs) to assess soil erosion in a region of western Iran. The soil erosion status was reckoned based on the nine factors of MPSIAC. We utilized BBNs to produce a causal model for soil erosion, with output probabilities being validated through re-evaluation and sensitivity analysis. We identified erosion types, geological formations, run-off, soil erodibility, soil permeability, soil characteristics, and precipitation intensity as the main determinants of soil erosion. A significant, positive correlation existed between the erosion rate derived from MPSIAC and BBNs model in all land-use/covers over the work units. Overall, this study highlighted the potential of BBNs as a supportive tool for soil erosion prediction as well as a relatively simple and updatable soil erosion model for dealing with the diagnostic, scenario, and sensitivity analysis. Considering the increasing incidence of soil erosion, the BBNs model proposed in this study can be extended to a variety of ecosystems that are subject to soil erosion and changes in the probability of its causal factors.

Quantification of Agricultural Terrace Degradation in the Loess Plateau Using UAV-Based Digital Elevation Model and Imagery

Agricultural terraces are important artificial landforms on the Loess Plateau of China and have many ecosystem services (e.g., agricultural production, soil and water conservation). Due to the loss of rural labor, a large number of agricultural terraces have been abandoned and then the degradation of terraces, caused by rainstorm and lack of management, threatens the sustainability of ecological services on terraces. Our previous study has found its geomorphological evidence (sinkhole and collapse). However, no quantitative indicators of terrace degradation are identified from the perspective of microtopography change. A framework for quantifying terrace degradation was established in this study based on unmanned aerial vehicle photogrammetry and digital topographic analysis. The Pujiawa terraces in the Loess Plateau were selected as study areas. Firstly, the terrace ridges were extracted by a Canny edge detector based on high-resolution digital elevation model (DEM) data. The adaptive method was used to calculate the low and high thresholds automatically. This method ensures the low complexity and high-edge continuity and accuracy of the Canny edge detector, which is superior to the manual setting and maximum inter-class variance (Otsu) method. Secondly, the DEMs of the terrace slope before degradation were rebuilt through the terrain analysis method based on the extracted terrace ridges and current DEM data. Finally, the degradation of terraces was quantified by the index series in the line, surface and volume aspects, which are the damage degrees of the terrace ridges, terrace surface and whole terrace. The damage degrees of the terrace ridges were calculated according to the extracted and generalised terrace ridges. The damage degrees of the terrace surface and whole terrace were calculated based on the differences of DEMs before and after degradation. The proposed indices and quantitative methods for evaluating agricultural terrace degradation reflect the erosion status of the terraces in topography. This work provides data and references for loess terrace landscape protection and its sustainable management.

Soil Erosion Status Prediction Using a Novel Random Forest Model Optimized by Random Search Method

Soil erosion, the degradation of the earth’s surface through the removal of soil particles, occurs in three phases: dislocation, transport, and deposition. Factors such as soil type, assembly, infiltration, and land cover influence the velocity of soil erosion. Soil erosion can result in soil loss in some areas and soil deposition in others. In this paper, we proposed the Random Search-Random Forest (RS-RF) model, which combines random search optimization with the Random Forest algorithm, for soil erosion prediction. This model helps to better understand and predict soil erosion dynamics, supporting informed decisions for soil conservation and land management practices. This study utilized a dataset comprising 236 instances with 11 features. The target feature’s class label indicates erosion (1) or non-erosion (−1). To assess the effectiveness of the classification techniques employed, six evaluation metrics, including accuracy, Matthews Correlation Coefficient (MCC), F1-score, precision, recall, and Area Under the Receiver Operating Characteristic Curve (AUC), were computed. The experimental findings illustrated that the RS-RF model achieved the best outcomes when compared with other machine learning techniques and previous studies using the same dataset with an accuracy rate of 97.4%.

A new attempt for modeling erosion risks using remote sensing-based mapping and the index of land susceptibility to wind erosion

Digital soil maps at proper scales can support sustainable land-use planning over large areas; however, applying this approach in erosion studies is still limited. Therefore, in this work, we adopted remote sensing-based mapping and fuzzy logic techniques to develop wind erosion risk maps with a spatial resolution of 30 m. These procedures were then conducted in a newly-reclaimed area in Matruh Governorate, the Egyptian western desert. Sixty surface soil samples (0–30 cm) were collected and analyzed for soil erodibility-related properties (sand, silt, clay, organic matter, and CaCO3). The relationships of these properties with the reflectance data of Landsat 8 multispectral bands were explored. Then, the spatial predictions were performed using the stepwise multiple linear regression models. The results showed that band reflectance in the shortwave infrared spectrum had higher correlations with soil properties than in the visible and near-infrared regions. The regression models achieved reliable precision and acceptable prediction abilities for all soil properties, except for the silt content. For validation datasets (30 % of the total data), the best-fitted models had coeffect of determination (R2) and residual prediction deviation of 0.61–0.92 and 1.42–2.67, respectively. The fuzzy memberships revealed various contributions of the five drivers (climate erosivity, soil erodibility, soil crust, vegetation, and terrain roughness) to potential soil loss. The success rate curves indicated the different performances of the applied fuzzy overlay operators (AND, OR, Sum, Product, and Gamma 0.9). The best-predictive model with an overall success rate of 85.7 % was obtained by overlaying the five fuzzified layers under the fuzzy algebraic Sum operator. This model delineated five hazard classes over the study area, including severe (79.5 %), high (12.6 %), moderate (5.7 %), slight (1.8 %), and very slight (0.4 %). The developed approach would improve the insight into large-scale monitoring of wind erosion status in desert ecosystems.

Active morphological factors determining the locations of sand mines in dry-river channels

In Kenya, most of the construction sand is derived from dry riverbeds. Due to rampant nature in which sand mining is carried out in these rivers, adverse environmental and social effects have been reported. In order to ensure sustainable sand mining activities, this study assessed active morphological factors determining sand abundance in the seasonal river Tyaa in Kitui, Kenya. The study adopted quantitative research design. Purposive sampling was used to select river Tyaa due to uncontrolled sand mining that was taking place there. Systematic sampling at 20 meter intervals was used while collecting data at the stretches of the river channel, thus constituting 2,000 meters in total. Data on independent variables, namely the river channel’s width, depth, slope angles, bank position, weathering status, vegetation status, and erosion status was collected using physical measurements and logic guided observation. Binary logistic regression analysis was used to analyze the data, giving marginal effects and respective p-values. The study established four statistically significant factors responsible for sand abundance in the dry river channel’s namely depth (p=0.001), width (p=0.001), slope angles (p=0.001) and bank position (p=0.001). The study concluded that these factors should be observed while siting sand mines along dry river channels to mitigate adverse environmental effects. The study recommended that National Environmental Management Authority of Kenya should apply the findings of this study in the establishment of the locations of sand mines and monitoring of the mining process in line with the existing guidelines and regulations.

Agricultural Land Use Changes as a Driving Force of Soil Erosion in the Velika Morava River Basin, Serbia

The erosion potential model was applied to estimate the soil erosion status of rural settlements during the years 1971 and 2011. We used univariate and bivariate local Moran’s I indices to detect and visualize the spatial clustering of settlements with respect to changes in erosion intensity and agricultural land use, as well as their mutual spatial correlation. The study area was differentiated into four statistically significant clusters using the calculated bivariate local Moran’s I indices. The statistical analysis examined the two largest clusters, i.e., the high–high and low–low clusters, and the results of the research indicate that the first four principal components explained 70.50% and 73.47% of the total variance, respectively. In the high–high cluster, the low rates of erosion reduction (average Index Z = 98) in the most significant types of rural settlements were determined according to demographic indicators (i.e., the higher population vitality and population density, the smaller share of the old population and the lower average age of the population) and the large proportion of arable land and Neogene sediments. In the low–low cluster, high erosion reduction rates were detected (average index Z = 64). In this cluster, the more statistically significant influence of natural conditions in combination with demographic–agrarian processes (i.e., the larger share of the old population, the higher average age of the population, the lower vitality index and deagrarization) were decisive factors in changing erosion intensity.

Soil erosion in the savanna biome national parks of South Africa

Soil erosion has become a common feature in certain national parks across the global biomes, and national parks in the Savanna biome of South Africa have not been spared. Given their prominence in hosting large land mammals that contribute significantly to the tourism sector, the vulnerability of the parks to soil erosion merits attention. This study examines soil erosion status in the Savanna biome national parks of South Africa to recommend management practices aligned with the degree of erosion susceptibility. The results show that erosion rates across the national parks range between 0 and 25 t/ha/yr, and only a few have soil loss rates above 25 t/ha/yr. The Kgalagadi National Park has the lowest erosion rates, with a water erosion severity index (ESI) of 0. The Kruger and Mokala National Parks have low erosion rates, with an ESI of 0.017 and 0.01, respectively. The Mapungubwe National Park has moderate rates of soil loss, with an ESI of 0.023, while Marakele has the highest rates of soil erosion, with an ESI of 0.39. Soil erosion by water action is generally a minor environmental threat for the Kgalagadi, Kruger and Mokala National Parks. However, for Mapungubwe, soil erosion has a moderate threat, while in Marakele, it imposes a very high threat level. The different rates of soil erosion are attributed to the heterogeneous biophysical conditions of the Savanna biome, as well as different historical land use patterns across the parks. Climate change could be exacerbating the susceptibility of national parks to soil erosion. Park-specific management strategies that consider historical land use patterns and biophysical conditions within a climate change context are recommended.

Similar strong impact of N fertilizer form and soil erosion state on N2O emissions from croplands

Soil erosion affects 20% of croplands worldwide. However, understanding the effect of soil erosion on N2O emissions, which is one of the most potent greenhouse gases, is still limited. This limitation is likely because the small-scale differences in soil properties and fertility induced by erosion (i.e. ranges of erosion states) have barely been considered in studies quantifying N2O emissions from croplands. There are, however, indications that the erosion state itself strongly impacts N2O emission, similar to the N fertilizer form. Therefore, our investigations aimed to further explore these indications.We measured N2O fluxes for three years and at five sites within an erosion affected field experiment. N2O emissions were quantified using a manual chamber system. Three sites were established on a summit position (Albic Luvisol; non-eroded) but differed in N fertilizer forms (organic biogas fermented residues, calcium ammonium nitrate and a mixture of both fertilizers). Two additional sites were established on an extremely eroded soil (Calcaric Regosol) and wet depositional soil in a depression (Endogleyic Colluvic Regosol) to measure the effect of soil erosion states on N2O emissions. Both additional sites were fertilized with calcium ammonium nitrate only.In case of the non-eroded soil (summit), organic fertilization resulted in the highest cumulative N2O emission (6.2 ± 0.21 kg N2O-N/ha y−1) compared to mixed (5.5 ± 0.18 kg N2O-N/ha y−1) and mineral (1.9 ± 0.17 kg N2O-N/ha y−1) fertilization. These high emissions were probably caused by soluble C and N substrates from organic fertilizer, resulting in microbial activities favoring high N2O emissions. Regarding the erosion status, we observed the highest N2O emissions in the depositional soil (2.8 ± 0.21 kg N2O-N/ha y−1), followed by the non-eroded (1.9 ± 0.17 kg N2O-N/ha y−1) and the extremely eroded soil (0.6 ± 0.03 kg N2O-N/ha y−1). These differences in N2O emissions were mainly due to the site-specific, erosion induced differences in soil properties such as soil texture, soil organic C and total N contents and stocks, water-filled pore space and soil pH. These results indicate that soil erosion state may indeed be of similar importance, as N fertilizer form, for the magnitude of N2O emissions from croplands.

Spatial Pattern of Soil Erosion in Relation to Land Use Change in a Rolling Hilly Region of Northeast China

The black soil region in Northeast China is one of the major grain-producing areas of China. Soil erosion in the black soil region caused by natural factors and anthropic activities has attracted much attention, especially in a rolling hilly region. Compared with natural factors, the land use factor of cropland encompasses the most easily optimized measures. Jiutai County of Changchun City, located in the hilly areas of Northeast China, was taken as an example to calculate the soil erosion modulus using the Revised Universal Soil Loss Equation model. The overall soil erosion status of cultivated land in the study area was mainly slight and light, the proportion of cultivated land affected by extremely intensive and severe erosion was relatively small, and the average soil erosion modulus was 7.09 t·hm−2·a−1 in 2019. In view of spatial distribution characteristics of soil erosion revealed by the spatial aggregation and hot spot analysis, the most serious soil erosion intensity was concentrated in the southeast and northeast sloping farmland over 8°. With the increase in elevation and topographic slope, the proportion of slight and light soil erosion gradually decreased, which was closely related to the increase in soil erodibility caused by the space–time migration of soil organic carbon caused by the interaction of hydraulic and tillage erosion in complex topographic areas. The Geographically Weighted Regression model was introduced to explore the driving factors and superposition mechanism of farmland soil erosion in the hilly region of Northeast China. Based on the relationship between soil erosion and landscape fragmentation, landscape fragmentation was an important driving force promoting soil erosion, sediment yield, and sediment transport. This paper is committed to providing a basis for accurately deploying regional soil and water conservation measures and formulating macro land management policies.