Soil Erosion Potential Research Articles

KARAKTERISTIK FISIK DAN TINGKAT BAHAYA EROSI TANAH ULTISOL

Soil erosion is a major factor leading to cause land damage in the upstream region. Therefore, erosion control should be done in the preservation of land resources and the environment can be maintained and the welfare of farmers can be improved. Land Ultisol widespread in many Kalimatan Islands, ultisol soil types other than guilty of fertility, soil types have the property ultisol easy erosion. As a result of coal mining activities carried out by PT KPC lead to peeling layers of top soil to the depth of rock. This stripping has directly changed the soil condition. Ultisol soil physical conditions in Kalimanan (available water capacity, density lumps, texture, structure, pore space and permeability of the soil) are relatively low, so they need to improve theaddition of organic materials, and lime. The process of reclamation of former coal mining PT. KPC has been done very well. The analysis of fertility levels and the amount of potential soil erosion occurs indicates that the post-miningrehabilitation revegetation way to post-mining land with the procedure referred. It can be seen from the parameters of soil fertility and erosion rates of post-mining land have been rehabilitated (56.5614 erosion rates tons/hectare/year) with areas of pristine forests (erosion rates 52.175 tons/hectare/year) were not show significant changes.Keywords: ultisol, rehabilitation, physical soil, erosion

Modified E30 Model for assessing soil erosion potential in a highly precipitated hilly watershed of North-East India

The empirical E30 model is applied to estimate the soil erosion rate of a hilly, forested watershed for a period from 1999 to 2014. The average rainfall in the study area is 10,000 mm/ year. In most of the area, the average erosion rate varies within 0–40 mm/yr and is found to increase from the year 1999–2014. The study establishes a logarithmic relationship between normalized difference vegetation index (NDVI) and slope for this hilly terrain and it may be used for characterizing other similar areas. The E30 model is modified by replacing NDVI with the logarithmic function of slope. Results of both the E30 model and the proposed single-parameter model are verified using Revised Universal Soil Loss Equation (RUSLE) which provides a comparable result up to 50° slope. The advantage of the modified model is that it is cost effective and does not require multispectral imageries for the analysis of soil erosion. It is also useful for the areas where data are limited as it depends only on the slope of the area.

Rainfall erosivity and sediment load over the Poyang Lake Basin under variable climate and human activities since the 1960s

Accelerated soil erosion exerts adverse effects on water and soil resources. Rainfall erosivity reflects soil erosion potential driven by rainfall, which is essential for soil erosive risk assessment. This study investigated the spatiotemporal variation of rainfall erosivity and its impacts on sediment load over the largest freshwater lake basin of China (the Poyang Lake Basin, abbreviate to PYLB). The spatiotemporal variations of rainfall erosivity from 1961 to 2014 based on 57 meteorological stations were detected using the Mann–Kendall test, linear regression, and kriging interpolation method. The sequential t test analysis of regime shift (STARS) was employed to identify the abrupt changes of sediment load, and the modified double mass curve was used to assess the impacts of rainfall erosivity variability on sediment load. It was found that there was significant increase (P < 0.05) in rainfall erosivity in winter due to the significant increase in January over the last 54 years, whereas no trend in year and other seasons. Annual sediment load into the Poyang Lake (PYL) decreased significantly (P < 0.01) between 1961 and 2014, and the change-points were identified in both 1985 and 2003. It was found that take annual rainfall erosivity as the explanatory variables of the double mass curves is more reasonable than annual rainfall and erosive rainfall. The estimation via the modified double mass curve demonstrated that compared with the period before change-point (1961–1984), the changes of rainfall erosivity increased 8.0 and 2.1% of sediment load during 1985–2002 and 2003–2014, respectively. Human activities decreased 50.2 and 69.7% of sediment load during the last two periods, which indicated effects of human activities on sediment load change was much larger than that of rainfall erosivity variability in the PYLB.

Assessment of soil erosion in a monsoon-dominated mountain river basin in India using RUSLE-SDR and AHP

ABSTRACTThe long-term average annual soil loss (A) and sediment yield (SY) in a tropical monsoon-dominated river basin in the southern Western Ghats, India (Muthirapuzha River Basin, MRB; area: 271.75 km2), were predicted by coupling the Revised Universal Soil Loss Equation (RUSLE) and sediment delivery ratio (SDR) models. Moreover, the study also delineated soil erosion risk zones based on the soil erosion potential index (SEPI) using the analytic hierarchy process (AHP) technique. Mean A of the basin is 14.36 t ha−1 year−1, while mean SY is only 3.65 t ha−1 year−1. Although the land use/land cover types with human interference show relatively lower A compared to natural vegetation, their higher SDR values reflect the significance of anthropogenic activities in accelerated soil erosion. The soil erosion risk in the MRB is strongly controlled by slope, land use/land cover and relative relief, compared to geomorphology, drainage density, stream frequency and lineament frequency.

Object‐oriented soil erosion modelling: A possible paradigm shift from potential to actual risk assessments in agricultural environments

AbstractOver the last 2 decades, geospatial technologies such as Geographic Information System and spatial interpolation methods have facilitated the development of increasingly accurate spatially explicit assessments of soil erosion. Despite these advances, current modelling approaches rest on (a) an insufficient definition of the proportion of arable land that is exploited for crop production and (b) a neglect of the intra‐annual variability of soil cover conditions in arable land. To overcome these inaccuracies, this study introduces a novel spatio‐temporal approach to compute an enhanced cover‐management factor (C) for revised universal soil loss equation‐based models. It combines highly accurate agricultural parcel information contained in the Land Parcel Identification System with an object‐oriented Landsat imagery classification technique to assess spatial conditions and interannual variability of soil cover conditions at field scale. With its strong link to Land Parcel Identification System and Earth observation satellite data, the approach documents an unprecedented representation of farming operations. This opens the door for the transition from the currently used potential soil erosion risk assessments towards the assessment of the actual soil erosion risk. Testing this method in a medium‐size catchment located in the Swiss Plateau (Upper Enziwigger River Catchment), this study lays an important foundation for the application of the very same methods for large‐scale or even pan‐European applications. Soil loss rates modelled in this study were compared with the insights gained from emerging techniques to differentiate sediment source contribution through compound‐specific isotope analysis on river sediments. The presented technique is adaptable beyond revised universal soil loss equation‐type soil erosion models.

Linking biological soil crust attributes to the multifunctionality of vegetated patches and interspaces in a semiarid shrubland

AbstractUnderstanding the importance of biotic community structure on ecosystem functioning, and whether communities inhabiting different microhabitats in highly heterogeneous areas provide different ecological functions is a challenge in ecological research in the face of biodiversity and habitat loss. Biological soil crusts (BSCs) have been largely treated as unique entities, and have been mostly examined in interspaces between perennial plants, limiting current understanding of their role as drivers of ecosystem functioning and their relative contribution in comparison to vascular plants.We assessed the role ofBSCs on ecosystem functioning in vegetated patches and interspaces, and how individual soil functions and ecosystem multifunctionality are related to changes inBSCspecies‐ and community‐level attributes. We contemplated nine ecosystem functions associated with soil water dynamics, nutrient cycling and erosion potential.We found that vegetated patches improve infiltration rates, soil stability and net potential nitrogen (N) mineralization compared to interspaces, and thus dominate multifunctionality. However, well‐developedBSCs improve soil moisture and N pool in both microsites, and are multifunctional stabilizing soils and regulating soil moisture and infiltration in the interspaces.BSCsurface microstructure, including changes in total cover, species richness, morphological functional groups and surface discontinuities, has significant effects on soil moisture. Differences in soil N and phosphorous are mostly related to the presence ofBSC‐lichens. The effect ofBSCs on multifunctionality varies in dependence of the particular set of functions that are sought to simultaneously maximize.Our results suggest that vascular plants andBSCs have idiosyncratic effects on different key ecosystem functions and multifunction, andBSCs substitute vascular plants in stabilizing soils and regulating water dynamics in the interspaces.BSCs greatly contribute to small‐scale heterogeneity in the functioning of vegetated patches and interspaces, hence consideration ofBSCs in different microsites is essential for enhancing our understanding of their functional relevance at a regional scale. In addition, quantification ofBSCmicrostructure is crucial, owing to the contrasting effects ofBSCspecies‐ and community‐level attributes on different functions and multifunction.Aplain language summaryis available for this article.

Land use changes and their catchment-scale environmental impact in the Polish Western Carpathians during transition from centrally planned to free-market economics

Land use and land cover changes (LULC) and their impact on potential soil erosion, road density as transfer routes of material and water to channels as well as channel level changes were studied in three catchments (~20 km2 each) in the central part of the Polish Western Carpathians in 1975-2015. It was hypothesised that short-term LULC changes during transition from a centrally planned to a free-market economy are sufficient to modify selected elements of the environment and that these changes can be identified in a measurable way. The analysis of aerial photographs and socio-economic data indicates that during the investigated period, the forest area increased by 20-27%, with a continuous decrease of cultivated land by 89-93% in the three catchments. LULC changes were accompanied by continuous population density growth by 29-50% and a decrease of the population dependent only on agriculture to less than 5%. Analyses confirmed the hypothesis that the environment was significantly modified due to the LULC changes. Abandonment of cultivated land, forest succession and a decrease in used road density, have resulted in lower efficiency of slope wash and sediment transport within the 4th-order catchments. This has led to an interruption of aggradation and initiated channel deepening by approximately 1 cm∙year-1 after the introduction of a free-market economy in 1989.

Cropland physical disturbance intensity: plot-scale measurement and its application for soil erosion reduction in mountainous areas

Various kinds of human disturbances on cropland are the main reasons for soil erosion and land degradation. Farming practices in mountainous areas vary greatly among cropland plots because of the heterogeneity of biophysical conditions and differences in farmers' management behavior. The main purpose of this paper is to develop a composite index of cropland physical disturbance intensity (CLDI) to reflect the plot-scale discrepancy of potential soil erosion in mountainous areas. The study was based on both plot survey and household interview data, collected from six typical catchments in mountainous areas of southwestern China. Four kinds of physical disturbance practices and two kinds of conservation practices during one crop rotation period were synthesized to develop the CLDI index. The rough set theory was referenced to avoid subjectivity during weight allocation. The results show that conventional tillage, deep fertilization, and manual weeding are the main causes of cropland soil erosion, whereas manure application in combination with seasonal fallow reduces soil erosion. Different crop types as well as cropland location factors determine the spatial pattern of CLDI. Crop rotation modes with major crops of tobacco and maize resulted in a maximal CLDI, and cropland plots with a distance radius of 150 meters away from households received the most intensive physical disturbance. These results are critical to help better protect rural environments in mountainous areas. Based on the results, methods to reduce cropland soil erosion are suggested.

GIS-technologies application for calculation of potential soil loss of Marha River basin (Republic of Saha)

In the article the presentation of estimation methods of potential soil loss in the conditions of Siberia with application of geographical information systems is resulted. For the reference area of the Marha river basin, which is a part of the Lena river catchment, there was created a specialized geographic information database of potential soil erosion, with scale of 1: 1,000,000. Digital elevation model “GMTED2010” and the hydroset layer corresponding to the scale of 1: 1,000,000 are taken to calculate the soil loss values. The formation of the geobase data is considered in detail being constructed on the basis of the multiplicative structure which reflects the main parameters of the relief (slope steepness, exposition, slope length, erosion potential of the relief), soil, climatic characteristics and modern types of land cover. At the quantitative level with sufficiently high degree of spatial detail results were obtained for calculating the potential erosion of soils. The average value of potential soil loss in the basin without taking into account the factor of land cover types, was 12.6 t/ha/yr. The calculations carried out, taking into account the types of land cover obtained from remote sensing data from outer space resulted in an appreciable reduction of the soil loss values (0.04 t/ha/yr.).

An assessment of the global impact of 21st century land use change on soil erosion

Human activity and related land use change are the primary cause of accelerated soil erosion, which has substantial implications for nutrient and carbon cycling, land productivity and in turn, worldwide socio-economic conditions. Here we present an unprecedentedly high resolution (250 × 250 m) global potential soil erosion model, using a combination of remote sensing, GIS modelling and census data. We challenge the previous annual soil erosion reference values as our estimate, of 35.9 Pg yr−1 of soil eroded in 2012, is at least two times lower. Moreover, we estimate the spatial and temporal effects of land use change between 2001 and 2012 and the potential offset of the global application of conservation practices. Our findings indicate a potential overall increase in global soil erosion driven by cropland expansion. The greatest increases are predicted to occur in Sub-Saharan Africa, South America and Southeast Asia. The least developed economies have been found to experience the highest estimates of soil erosion rates.

Integration of geospatial technologies with RUSLE for analysis of land use/cover change impact on soil erosion: case study in Rib watershed, north-western highland Ethiopia

In recent times, soil erosion interlocked with land use and land cover (LULC) changes has become one of the most important environmental issues in developing countries. Evaluation of this complex interaction between LULC change and soil erosion is indispensable in land use planning and conservation works. This paper analysed the impact of LULC change on soil erosion in the north-western highland Ethiopia over the period 1986–2016. Rib watershed, the area with dynamic LULC change and severe soil erosion problem, was selected as a case study site. Integrated approach that combined geospatial technologies with revised universal soil loss equation model was utilized to evaluate the spatio-temporal dynamics of soil loss over the study period. Pixel-based overlay of soil erosion intensity maps with LULC maps was carried out to understand the change in soil loss due to LULC change. Results showed that the annual soil loss in the study area varied from 0 to 236.5 t ha−1 year−1 (tons per hectare per year) in 1986 and 0–807 t ha−1 year−1 in 2016. The average annual soil loss for the entire watershed was estimated about 40 t ha−1 year−1 in 1986 comparing with 68 t ha−1 year−1 in 2016, a formidable increase. Soil erosion potential that was estimated to exceed the average soil loss tolerance level increased from 34.5% in 1986 to 66.8% in 2016. Expansion of agricultural land at the expense of grassland and shrubland was the most detrimental factor for severe soil erosion in the watershed. The most noticeable change in soil erosion intensity was observed from cropland with mean annual soil loss amount increased to 41.38 t ha−1 year−1 in 2016 from 26.60 in 1986. Moreover, the most successive erosion problems were detected in eastern, south-eastern and northern parts of the watershed. Therefore, the results of this study can help identify the soil erosion hot spots and conservation priority areas at local and regional levels.

Torrential flood prevention in the Kolubara river basin

One of the most vulnerable parts to natural hazards in Serbia is Kolubara river basin. In the past, during the period from 1929 to 2013, 121 torrential flood events in the Kolubara river basin were recorded which show that this territory is extremely vulnerable to the torrential floods. The extreme event which occurred in May 2014 causing the catastrophic material damages and casualties was the latest and historical flood. The analysis of natural conditions in the Kolubara basin uniformly showed that this area is predisposed to a greater number of torrential floods due to its geomorphological, hydrological and land use properties. Torrential floods are closely related to the intensity and spatial distribution of erosive processes in the upper part of the Kolubara basin. The estimation of soil erosion potential is generally achieved by Erosion Potential Model (EPM). For the purposes of determining the degree of torrential properties in various water streams in the Kolubara basin, the calculation of susceptibility to torrential floods was assessed by Flash Flood Potential Index (FFPI). More than half of the basin area (57.2%) is located within the category of very weak and weak erosion (Zsr = 0.35), but the category of medium erosion is geospatially very common. Such a distribution of medium erosion category provides conditions for generating, i.e. production of sediment which would boost torrential properties of water streams. After the classification of the obtained FFPI values it was determined that 25% of the Kolubara basin is very susceptible to torrents and this data should be seriously taken into consideration. Based on the analyses, the best and most successful manner of defence is prevention which consists of the integrated river basin management system (integrated torrent control system) so that technical works in hydrographic networks of torrents and biological and biotechnical works on the slope of the basin would be the best solution. Permanent control of erosive and torrential processes in the river basin will be not only important for flood control but it can also protect the existing and future water reservoirs and retentions from siltation with erosion sediment which is of great significance to the water management, agriculture, energy sector, and the entire society.

Quantifying the controls on potential soil production rates: a case study of the San Gabriel Mountains, California

Abstract. The potential soil production rate, i.e., the upper limit at which bedrock can be converted into transportable material, limits how fast erosion can occur in mountain ranges in the absence of widespread landsliding in bedrock or intact regolith. Traditionally, the potential soil production rate has been considered to be solely dependent on climate and rock characteristics. Data from the San Gabriel Mountains of California, however, suggest that topographic steepness may also influence potential soil production rates. In this paper I test the hypothesis that topographically induced stress opening of preexisting fractures in the bedrock or intact regolith beneath hillslopes of the San Gabriel Mountains increases potential soil production rates in steep portions of the range. A mathematical model for this process predicts a relationship between potential soil production rates and average slope consistent with published data. Once the effects of average slope are accounted for, a small subset of the data suggests that cold temperatures may limit soil production rates at the highest elevations of the range due to the influence of temperature on vegetation growth. These results suggest that climate and rock characteristics may be the sole controls on potential soil production rates as traditionally assumed but that the porosity of bedrock or intact regolith may evolve with topographic steepness in a way that enhances the persistence of soil cover in compressive-stress environments. I develop an empirical equation that relates potential soil production rates in the San Gabriel Mountains to the average slope and a climatic index that accounts for temperature limitations on soil production rates at high elevations. Assuming a balance between soil production and erosion rates on the hillslope scale, I illustrate the interrelationships among potential soil production rates, soil thickness, erosion rates, and topographic steepness that result from the feedbacks among geomorphic, geophysical, and pedogenic processes in the San Gabriel Mountains.

Effects of Changing Weather, Oceanographic Conditions, and Land Uses on Spatio-Temporal Variation of Sedimentation Dynamics along Near-Shore Coral Reefs

Sedimentation is a critical threat to coral reefs worldwide. Major land use alteration at steep, highly erodible semi-arid islands accelerates the potential of soil erosion, runoff, and sedimentation stress to nearshore coral reefs during extreme rainfall events. The goal of this study was to assess spatio-temporal variation of sedimentation dynamics across nearshore coral reefs as a function of land use patterns, weather and oceanographic dynamics, to identify marine ecosystem conservation strategies. Sediment was collected at a distance gradient from shore at Bahia Tamarindo (BTA) and Punta Soldado (PSO) coral reefs at Culebra Island, Puerto Rico. Sediment texture and composition were analyzed by dry sieving and loss-on-ignition techniques, and were contrasted with environmental variables for the research period (February 2014 to April 2015). Rainfall and oceanographic data were analyzed to address their potential role on affecting sediment distribution with BEST BIO-ENV, RELATE correlation, and linear regression analysis. A significant difference in sedimentation rate was observed by time and distance from shore (PERMANOVA, p<0.0100), mostly attributed to higher sediment exposure at reef zones closer to shore due to strong relationships with coastal runoff. Sedimentation rate positively correlated with strong rainfall events (Rho= 0.301, p=0.0400) associated with storms and rainfall intensity exceeding 15 mm/hr. At BTA, sediment deposited were mostly composed of sand, suggesting a potential influence of resuspension produced by waves and swells. In contrast, PSO sediments were mostly composed of silt-clay and terrigenous material, mainly attributed to a deforestation event that occurred at adjacent steep sub-watershed during the study period. Spatial and temporal variation of sedimentation pulses and terrigenous sediment input implies that coral reefs exposure to sediment stress is determined by local land use patterns, weather, and oceanographic dynamics. Comprehensive understanding of sediment dynamics and coastal ecosystem interconnectivity is fundamental to implement integrated and adaptive management strategies aimed to promote sustainable development at watershed and island wide-scale to fully mitigate terrigenous sediment impact to marine ecosystems. Furthermore, decision-making processes and policy needs to address sedimentation stress in the context of future climate to reduce land-based threats and strengthen coral reef resilience.

Simulating the impacts of future land use change on soil erosion in the Kasilian watershed, Iran

Predicting soil erosion potential is important in watershed management. A rapidly growing Iranian population and climate change are expected to influence land use and soil sustainability. In recent years, northern Iran has experienced significant land use changes due to internal migration along the Caspian coast and conversion of forests and rangelands. Considering the effect of these changes in the future, the purpose of this study is to forecast land use patterns and investigate soil erosion scenarios using the Revised Universal Loss Equation and Markov Cellular Automata. Data from 1981 to 2011 were used as a baseline to estimate changes that might occur in 2030. The results reveal that the mean erosion potential will increase 45% from the estimated 104.52 t ha−1 year−1 in the baseline period. Moreover, the results indicate that land use change from forest area to settlements will be the most significant factor in erosion induced by land use change, showing the highest correlation among erosional factors. Projecting land use change and its effect on soil erosion indicate that conversion may be unsustainable if change occurs on land that is not suited to the use. The method predicts soil erosion under different scenarios and provides policymakers a basis for altering programs related to land use optimization and urban growth. Those results indicated the necessity of appropriate policies and regulations particularly for limiting land use changes and urban sprawl in areas of unfavorable soil erosion risk factors.

Aerial Interseeded Cover Crop and Corn Residue Harvest: Soil and Crop Impacts

Core Ideas Harvesting 71% of corn residue can increase wind erosion potential of a sandy loam soil. Corn residue harvest did not affect soil fertility and corn yields. Aerially interseeded winter rye cover crop tended to reduce wind erosion potential. Residue harvest can increase erosion potential but interseeded cover crop could partly offset this effect. Corn (Zea mays L.) residue is a forage source and a biofuel feedstock. Excessive residue harvest may, however, result in increased soil erosion risks and degraded soil properties. Aerial interseeding of a cover crop (CC) before harvesting corn may offset adverse effects of residue harvest. We studied the impacts of harvesting 71% of corn residue with and without aerially interseeded winter rye (Secale cereale L.) CC on wind and water erosion potential, soil organic carbon (SOC), nutrients, soil water content, and corn yields in a farmer's field under irrigated strip till continuous corn on a sandy loam in the western Corn Belt from 2013 to 2016. Interseeded CC biomass yield ranged from 0.2 to 3.4 Mg ha−1. Corn residue harvest reduced geometric mean diameter of dry soil aggregates and increased wind erodible fraction (&lt;0.84 mm aggregates) by 0, 27, and 37% in the first, second, and third year, respectively, indicating that residue harvest increased the soil's susceptibility to wind erosion. Cover crop had no effect on geometric mean diameter and erodible fraction. Residue harvest reduced near‐surface water content but CC had no effect. Treatments did not affect fertility properties and corn yield. In spring, surface cover was 24.7% in residue‐harvested plots without CC and 65.3% in residue‐harvested plots with CC, indicating that CC provided soil protective cover. Overall. interseeded grass CC may not rapidly improve soil properties, but the added soil cover provided by the interseeded CC could partly offset the effect of residue harvest on wind erosion potential in sandy loam soils.

Estimation of soil erosion rate in the Democratic People's Republic of Korea using the RUSLE model

ABSTRACTForests are well known to control soil erosion and severe flooding. In the Democratic People's Republic of Korea (North Korea), deforestation was estimated at 20% between 1997 and 2014. This decline was mainly reflective of improper land use practices on steep slopes. Intensive deforestation and inappropriate land management can lead to severe soil erosion. The objective of this study was to describe the regional soil erosion severity in North Korea using the Revised Universal Soil Loss Equation (RUSLE) model coupled with a GIS technique. This model is widely being used to assess the potential mean annual soil erosion under different rainfall, soil characteristics, slope, and land use conditions. The results showed that the average annual rate of soil loss was estimated to be 15.8 tonnes ha−1 yr−1. Regionally, Nampo city is the most vulnerable region to soil erosion (55.1 tonnes ha−1 yr−1), followed by Hwanghaebuk-do (30.5 tonnes ha−1 yr−1), due to rapid land development. Denuded lands, which are estimated at around 6.5% of the total area, are predicted to have contributed 192.1 million tonnes yr−1 to the country's soil erosion. Participatory agroforestry and reforestation were found to be practical solutions to reduce soil erosion, particularly on degraded landscapes, and improve people's farm-based livelihoods.

Integrated Use of Aerial Photographs and LiDAR Images for Landslide and Soil Erosion Analysis: A Case Study of Wakamow Valley, Moose Jaw, Canada

Urban parks and open spaces offer a unique setting that can play a vital role in improving health and quality of life in cities and towns, making cities more attractive places to live and work, and connecting residents to nature. Degradation of park facilities caused by natural processes or recreational activities requires continuous monitoring for efficient maintenance and management. Identification and continuous monitoring of areas prone to natural hazards such as landslides within an urban park are particularly important for public safety. Traditional techniques for identification and monitoring of such areas involving field surveys, being costly and time-consuming, cannot be used on a regular basis. This research explored the integrated use of aerial photographs and point cloud LiDAR data for identification of areas prone to landslide and soil erosion zones in an urban park and a conservation area known as Wakamow Valley, Moose Jaw, Saskatchewan, Canada. This study used the point cloud LiDAR of 2014 to develop a Digital Elevation Model (DEM) of the area. The accuracy of the DEM was validated through a series of well-distributed ground control points collected through a survey grade handheld GPS device. The areas prone to potential landslides and soil erosion were identified using slope analysis techniques. A typical criterion of areas having a slope greater than 35° was used for classification of potential hazardous zones. Geospatial information including land-cover, land-use, and trail system was extracted from a 2014 aerial photograph to create a base map. It has been estimated that 5.3 km along the banks of the Moose Jaw River and 8 km along the cliff of the canyon-shaped Wakamow Valley are under a possible threat of soil erosion and landslides. This portion of the valley was classified as high-risk for possible landslides and soil erosion.

Environmental impact assessment of double- and relay-cropping with winter camelina in the northern Great Plains, USA

Recent findings indicate that double- or relay-cropping winter camelina (Camelina sativa L. Crantz.) with, forage, or food crops can increase yield per area, improve energy balance, and provide several ecosystem services. Double-cropping can help balance food and energy production. The objective of this study was to determine the environmental impact of double- and relay-cropping systems as compared with monocultured maize (Zea mays L.) and soybean [Glycine max (L.) Merr.] in the Midwest, USA. Ten crop sequences composed of double- and relay-cropped forage sorghum [Sorghum bicolor (L.) Moench.] and soybean with winter camelina were evaluated and compared with their monoculture counterparts. The environmental aspects evaluated included global warming potential (GWP), abiotic depletion, acidification, eutrophication, ecotoxicity, and human toxicity. Additionally, provisioning and regulating ecosystem services were estimated, including: primary aboveground productivity, soil erosion, and biodiversity in each crop sequence. The analysis was conducted from ‘cradle-to-gate’, including only the agricultural phase. Global warming potential estimated by three different methods indicated that winter camelina as a monocrop had a GWP of 579 to 922kgCO2eha−1. Maize in monoculture had higher GWP than all other double- and relay-cropping systems studied. The higher emissions of double- and relay-cropping systems and maize can be explained by higher N fertilizer application, which led to greater field N2O emissions. Also, the additional sowing and harvesting of the double- or relay-crop increased CO2 emissions due to increased diesel use. Winter camelina as a monocrop had the lowest values in all impact categories, indicating camelina agricultural production phase has low environmental impact compared with maize and soybean in monoculture. Double- and relay- cropping systems increased primary productivity per unit area and biodiversity and reduced soil erosion potential. Increasing productivity with the additional environmental benefits of these systems may encourage more farmers to adopt sustainable agricultural practices.

Applicability of Stream Order Data for Morphometric Analysis and Sub-watershed Prioritization

Sub-Watershed management and planning is integration of both technical and social aspects. Physical assessment of sub-watershed includes among many other bio-physical parameters, the morphometric analysis. The current study examines the applicability of existing stream order digital data for morphometric analysis and sub-watershed prioritization of Kailash Khola watershed. The study is based on secondary data and desk study and uses GIS data produced by Survey Department of Nepal and GIS tool for the analysis. Three linear and three aerial/shape parameters are taken for the morphometric analysis and simple ranking method based on calculated value is applied for sub-watershed prioritization. Technological tools like GIS and Remote Sensing has aided for spatial analysis using morphometric method. The study show that variation is found in vulnerability of sub-watershed in terms of linear and aerial morphometric parameters. The finding show that western part of the watershed is relatively vulnerable in terms of potential soil erosion and flooding. The study concludes that the importance of readily available stream order digital data and GIS tool and technology in identifying and analyzing priority subwatershed is reasonable. However, it is realized that spatial data at more finer spatial scale will improve the analysis and provide better analysis result and exemplify local problems in the area of topographical variation. The study suggest that, introduction of stream order data set finer scale or will allow analysis to be performed at much greater so that more localized effect of drainage morphometry in varying topographical landscape of the country could be assessed.