Erosion Degradation Research Articles

Investigation of Cavitation Bubble Dynamics Considering Pressure Fluctuation Induced by Slap Forces

Cavitation erosion is induced by the penetrating pressure from implosion of cavitation bubbles nearby solid boundary. The bubble evolution and the subsequent collapse pressure are especially important to evaluate the erosion degradation of solid boundary materials. The bubble dynamics equation taking into account the influence of distance between bubble and solid boundary is formulated to investigate the effect of boundary wall on bubble evolution process. The pressure fluctuation induced by slapping forces is adopted to evaluate the bubble dynamic characteristics. Negative pressure period which reflects the effect of vibration velocity and gap clearance also has large influence on bubble dynamics. The effects of standoff distance, initial radius and negative pressure period on bubble evolution and collapsing shock pressure are discussed. Maximum bubble radius increases with standoff distance and initial radius, while shock pressure increases with distance and decreases with bubble initial radius, and both of them increase with negative pressure period.

Resource characteristics of post-agrogenic chernozems in multiple-aged fallow lands of the Belgorod Region

As a result of anthropogenic degradation, chernozems often lose their ability to provide an economically acceptable crop and, therefore, are removed from use, passing into a state of fallow. In this state, a certain restoration of the resource characteristics of chernozems is possible, but this process should be investigated using an extensive empirical base. The purpose of this work was the accumulation and primary analysis of data on the natural reproduction of forest-steppe chernozems. The authors have studied the structure and properties of regenerative (post-agrogenic) soils of abandoned arable land in the Belgorod Region which were taken out of use due to severe erosion degradation. For comparison, we have examined the arable soils located in the same agricultural landscapes. Depending on the abandoning age, the soils are characterized by different degrees of recovery in terms of humus horizon’s morphological structure and agrochemical properties. The most obvious regenerative feature of bedding rocks is the thickness of a newly formed humus horizon. For 30 years of recovery, it is 12 – 14 cm and can reach 18 cm in the 80-year-old fallow soils. Post-agrogenic soils demonstrate an accumulation of carbon and nitrogen as well as restoration of soil absorbing complex. The soil organic matter in the recent fallow lands is characterized by a narrower C/N ratio as compared to the middle-aged fallow soils. As compared to arable soils, post-agrogenic soils have less acidic solutions reaction. An intensity degree of progressive changes in post-agrogenic soils tends to decrease with age, which is an indicator of a slowdown in their recovery.

Controllable Degradation of Poly (trimethylene carbonate) via Self-blending with Different Molecular Weights

Blend films of Poly (trimethylene carbonate) (PTMC) homopolymers with different molecular weights were prepared. The in vitro enzymatic degradation tests were carried out in lipase solutions to investigate the effect of self-blending on the degradation performance of PTMC. It was observed that the mass loss decreased as the proportion of low molecular weight PTMC in the blend film increased. And the sample's mass loss with the mass ratio of PTMC334/PTMC57=1/16 reached almost 30% after seven weeks, which corresponded to the minimum degradation rate constant k value of 5.219. It is also indicated by the changes in weight as well as the macroscopic and microscopic morphology. Furthermore, during the degradation cycle, the thickness of the film also became thinner with the mass loss, confirming the surface erosion degradation mechanism of the PTMC blend films. The conclusion that PTMC does not produce acidic degradation products has also been confirmed. Finally, decreases in glass transition temperature (Tg) and thermal stability were found along with the film degraded, attributing to the accumulation of low molecular weight degradation products on the surface. In brief, the long-acting application of PTMC in biomedical fields could be satisfied by precisely tailoring the degradation properties via its self-blending with different molecular weights.

INFLUENCE OF THE RELIEF ON THE EROSION DEGRADATION CHERNOZEMS OF THE PRYDNISTERSKA UPLAND

This publication deals with the erosive degradation of chernozem soils in the context of the the Prydnisterska Upland relief. The structure of the soil coverage of the studied area is represented by two subzonal subtypes of chernozem soils. Precisely: typical and podzolic, with a total area of 4 060 km2 (62% of the territory). The major part of these are flat interfluve: flat interfluve, wavy interfluves dissected by beam and valley forms, high fragmentary terrace complexes with insignificant horizontal dismemberment. The background surfaces of the intensity of erosion chernozem soils degradation are slopes of different steepness, exposure and morphometry. With the help of the geoinformational program ArcGIS, the distribution of slopes with the corresponding parameters of steepness and total area is determined. Inclined slopes with the steepness of 1–3° (1 700 km2) are dominant. The area with a steepness of 5° or less is approximately 87% of the total area of chernozem soils. However are of slightly inclined relief with only mere erosion occurant. The steep surfaces expositional distribution indicates the predominance of the southern, southwestern exposure slopes of an average length of 500–1 500 m. The results of the field morphological studies show that in the 5–6° – incline surfaces of inflection areas chernozem podzolic and strongly washed away. The degree of typical chernozem soils erosion is mostly associated with transversely convex and slightly convex slopes. In accordance with the degree of erosion, slightly washed typical chernozem soils formed on the same slopes of 2–3°, medium washed on 3–5°, strongly washed 8° incline. However, on the oblique slopes with an incline of 3–5° of complex shapes, typical chernozem soils the entire humus line is washed away. Particularly critical degree of chernozem soils erosion is observed within the complex slopes of river meanders and beam girder systems. In addition to the listed morphometric parameters of slope surfaces, the development of erosion degradation is influenced by the local unreasonable placement of linear boundaries. Thus, roads laid perpendicularly to river valleys and watersheds or along the plane of individual slopes form artificial bases of erosion, accelerating degradation processes. The formation of natural quarries leads to the active development of linear erosion of regressive nature. Key words: podzolic chernozem; typical chernozem; Prydnisterska Upland; GIS-analysis; erosive degradation; slope morphology; relief.

The ways to regulate environmental security in land management

The distribution of the share of agricultural and arable lands owned and used by agricultural enterprises and farms across the regions of Ukraine and in the developed countries of Europe and America is analyzed. The paper determines that sixteen regions of Ukraine have extremely and very high share of agricultural lands in the total area of the region. The share of agricultural lands in the mentioned regions is 75.6 % of their area in Ukraine or 53.5 % of the total area of Ukraine. Thirteen oblasts have extremely and very high share of arable lands. The share of arable lands in these oblasts is 67.6 % of their area in Ukraine, 85.3 % of the total area of farmlands, 49.2 % of the total area of agricultural lands, and 34.8 % of the total are of Ukraine. The paper reveals that soils with high bio productivity within especially valuable lands of forest-steppe and steppe agrolandscapes are the most agriculturally developed and ploughed, while the least – the lands of physical and geographical area of mixed forests and mountain areas of Carpathians and Crimea. Main factors of intensive development of surface water and wind erosion are outlined. According to the research results, the ranges of areas of erosion degradation are singled out and classified, and maps-schemes are developed. Extremely high, very high, high, and significant share of eroded soils covered by combined impact of water and wind were recorded for thirteen oblasts. The total share of eroded soils in the researched agricultural farmlands of these regions is 82.1 % of their total share in the country. The zonal patterns of expansion and development of soil erosion are revealed. The legal framework of activity directions and measures directed at prevention of soil erosion is presented. The ways to introduce economic measures to achieve environmental security in land management are suggested. The issues of extending the list of environmental taxes provided by the Tax Code of Ukraine with inclusion of chemical pollution, depletion, and reduction of natural land fertility tax are addressed.

Strength modeling for degradation of bioresorbable polyesters based on phase image pattern recognition

Biomedical degradable polymer materials are widely used in medicine because of their excellent mechanical properties and degradation properties. The matching of strength change and degradation rate in the degradation process is a crucial consideration in the design of polymer devices. Establishing a strength model of the polymer degradation process can quantify the intensity evolution during the degradation process. In this research, the structural changes in the process of polymer erosion degradation are taken as the primary consideration, and the evolution of the phases of strength are reflected by the changes of structure. The concept of strength phase images is proposed. The images of the strength phase diagram are identified by the image processing method. The Near Neighbor-Boundary Enlargement Algorithm (NNBE) is put forward to identify features with the hole(block) and crack(strip) shape patterns. The strength model for different phase patterns is established. The model calculation is compared with the experimental data, and the model simulation value and the experimental value are well fitted, which indicates that the strength model and phase diagram feature extraction algorithm are feasible.

Comparative Study on the Cavitation Erosion and Sliding Wear of Cold-Sprayed Al/Al2O3 and Cu/Al2O3 Coatings, and Stainless Steel, Aluminium Alloy, Copper and Brass

The paper investigates the cavitation erosion (CE) and sliding wear (SW) resistance of cold-sprayed Al/Al2O3 and Cu/Al2O3 composites and studies them in relation to a set of metallic materials such as aluminium alloy (AlCu4Mg1), pure copper (Cu110), brass (CuZn40Pb2) and stainless steel (AISI 304). The coatings were deposited on stainless steel by low-pressure cold spray (LPCS) using Al (40 wt.%) and Cu (50 wt.%) blended with Al2O3 (60 and 50 wt.%, respectively) feedstocks. CE resistance was estimated by the stationary sample method according to the ASTM G32 standard. The SW test was conducted using a ball-on-disc tester with compliance to the ASTM G99 standard. Results obtained for the LPCS coatings show that the Cu/Al2O3 coating exhibits a denser structure but lower adhesion and microhardness than Al/Al2O3. The Al/Al2O3 and Cu/Al2O3 resistance to cavitation is lower than for bulk alloys; however, composites present higher sliding wear resistance to that of AlCu4Mg1, CuZn40Pb2 and stainless steel. The CE wear mechanisms of LPCS composites start at the structural discontinuities and non-uniformities. The cavitation erosion degradation mechanism of Al/Al2O3 relies on chunk material detachment while that of Cu/Al2O3 initiates by alumina removal and continues as layer-like Cu-metallic material removal. CE damage of metal alloys relies on the fatigue-induced removal of deformed material. The SW mechanism of bulk alloys has a dominant adhesive mode. The addition of Al2O3 successfully reduces the material loss of LPCS composites but increases the friction coefficient. Coatings’ wear mechanism has an adhesive-abrasive mode. In both CE and SW environment, the behaviour of the cold-sprayed Cu/Al2O3 composite is much more promising than that of the Al/Al2O3.

Assessment of Soil Erosion and Climate Variability on Kerio Valley Basin, Kenya

This study was aimed at assessing soil erosion, climate variation and how climate has affected both the agro climatic and agro-ological zones of Kerio Valley basin. The basin faces challenges especially soil loss, due to the massive degradation that takes place in Kerio valley. Due to the increase in rainfall recently experienced in the area, most of the top soil has been carried away leading to excessive degradation of the valley, causing soil loss in the basin and subsequent deposition of the sediments in Lake Kamnarok which is an oxbow lake posing it to the threat of extinction. All these aforementioned factors, i.e. soil erosion, climate variation and land degradation have contributed to reduction of water storage capacity of the Lake. The main objective of this study was to assess the effects of soil erosion, climate variation on the basin and climate effect on agro-climatic and agro-ecological zones of the basin. Agro-climatic zones show how climate variability shapes agricultural landscape of an area while agro-ological zones show how agriculture affects the ecology of the basin. This includes the reduction of the lake size that has led to the disruption of the ecology of Lake Kamnarok and its environs, the major implications being the lake size reduction as the lake is proved to be a home for reptiles especially crocodiles. All these factors were finally assessed to determine their effect on water reduction capacity of Lake Kamnarok. The results depicted that the major factors that have caused changes in the basin and the Lake include heavy rainfall that has resulted in soil erosion and subsequent land degradation. These factors have eventually affected the agroclimatic and agroecological zones of the basin. This study integrated the use of Geographic Information System (GIS) and Remote Sensing (RS) to assess the areas with massive degradation and to quantify the amount of soil loss using Revised Universal Soil Loss Equation (RUSLE) model. It was concluded that the main factor that caused the changes in the agroclimatic and the agroecological zones was soil erosion which was influenced by climatic factors, i.e. rainfall and temperature.

Effect of no tillage on the physico-chemical properties of soils of the El Koudia region, Rabat (Morocco)

In Morocco, agriculture is an important sector of the economy, accounting for 15 to 20% of Gross Domestic Product. However, it has faced several challenges: intensive tillage of land that has accelerated water erosion, seriously threatening water and soil potential, low plant cover density and misuse of traditional agricultural practices, causing a decrease in organic matter levels and destroying aggregate stability. Climate change is making water and soil management in agriculture more and more complicated. The major challenge for Moroccan agriculture is to increase agricultural production while preserving natural resources. The objective of our study is to evaluate the effect of no tillage (NT) on the physico- chemical properties of soil in the El Koudia experimental station, Rabat, Morocco. The crop is durum wheat, Arrehane variety. Soil samples are pre-dried, ground and screened to 0.2mm for organic matter (OM) analysis and 2mm for the remainder of the analyses. Plugs, canned, are then sintered, screened and dried for structural stability tests. The results show that no tillage (NT) favours the accumulation of surface OM, particularly at the 0-5cm horizon unlike conventional tillage (CT). The NT promotes structural stability, with a mean weight diameter (MWD) = 0.94mm for the NT compared to 0.83mm for the CT. These results show that soils ploughed in CT are more exposed to erosion degradation than soils not ploughed (NT). In addition, NT preserves soil moisture and promotes additional water retention of 5 to 10%.

Темно-сірі опідзолені ґрунти Чижиківського пасма: проблеми деградації та охорони

The results of the research of degradation of dark gray podzolized soils (Luvis Greyzemic Phaeozems) of the Chyzhykiv ridge are presented. The causes and consequences of this dangerous natural and anthropogenic phenomenon are analyzed. It has been established that the intensive agricultural use of soils caused the activation of water erosion processes, the development of physical degradation processes, which lead to soil compaction, deterioration of their general physical properties, and loss of humus. Degradation processes lead to a decrease in soil fertility and unprofitability of agriculture, worsen the ecological state of the environment. In the study of degradation processes and their consequences in dark gray podzolized soils, the following methods were used: comparative-geographical, comparative-profile, catena method, analytical, statistical. Soil field explorations were carried out after the growing season. The most dangerous among the degradation processes are erosion degradation, which leads to a decrease in the capacity of the soil profile and deterioration of the soil agrophysical properties. The results of the studies demonstrated that the capacity of the profile of poorly eroded soils decreased on average by 14.5 cm compared to the standard, in medium-eroded – by 28.3 cm, in highly-eroded – by 50.8 cm. Soils underwent erosion from low to very high (crisis) degree. Degradation processes of anthropogenic genesis caused a deterioration of the structural and aggregate state of the soils, which is manifested in a decrease in the content of agronomically valuable soil aggregates and the dominance of the sloping fraction. According to the research results, the content of agronomically valuable aggregates with a size of 10–0.25 mm in the arable soil layer is 18.65–33.86 %, which indicates a high and very high (crisis) level of degradation. Soils also undergo degradation due to re-compaction, which is manifested in an increase in the density of the structure and a decrease in the overall porosity of the soil. Long anthropogenic pressure on soils and erosion degradation processes have led to a decrease in humus content. In particular, in poorly eroded soils the humus content is 2.03 %, in medium-eroded soils – 1.45 %, in highly eroded – 1.06 %, which is 16.9–64.6 % less than the standard. Measures are proposed to minimize the degradation of the dark gray podzolized soils of the Chyzhykiv ridge, which consist in the application of anti-erosion measures and soil-protective methods of soil processing, conservation of heavily degraded lands. The introduction of basic and crisis monitoring of the state of soils in the research area is recommended. Key words: the Chyzhykiv ridge, dark gray podzolized soils, erosion, degradation, soil protection.

Spatially distributed GIS-realized mathematical model of rainstorm erosion losses of soil

In connection with the wide and ever increasing spread of erosion degradation of agricultural lands in Ukraine, the task of developing mathematical models and methods for calculating water erosion of soils corresponding to the current level of erosion study and the demands of soil protection practices is becoming increasingly important. The article is devoted to the development of a spatially distributed GIS-implemented mathematical model of rainstorm soil erosion, which accounts for most of the annual soil losses (in the Steppe zone, for example, about 90 %). The development of the model is based on the most theoretically and informationally grounded model for the Steppe and Forest-Steppe of Ukraine , “the logical-mathematical model of rainstorm soil outwash” developed by H. I. Shvebs (1974, 1981), as well as the results of theoretical and field studies and mathematical modeling of the slope runoff and water erosion of soil, carried out at the Department of Physical Geography and Environmental Management of Odessa I. I. Mechnikov National University in the 1990s - 2010s, and also the possibilities of modern geoinformation technologies. For the spatial implementation of the model, a raster model of spatial data and operators of the PCRaster GIS-package (University of Utrecht, the Netherlands) were used, integrated with the Basic programming language into a single system that provides an implementation of the computational algorithm. The developed physical-statistical model of soil erosion-sedimentation takes into account the peculiarities of the formation of slope runoff and soil outwash in conditions of excessive nonstationarity of heavy rainfall, as well as spatial heterogeneity of all major natural and economic factors of water erosion on a slope, including slope steepness, exposure, longitudinal and transverse forms of slopes, soil erodibility, structure of sown areas and anti-erosion measures. Checking the adequacy of the mathematical model was performed using observational data of four experimental catchments ; two runoff plots of the Moldavan water-balance station with total area of 0.08 ha, the Ploska catchment with area of 8.5 ha (Boguslav field experimental base of Ukrainian Hydrometeorological Institute) and the Sukha catchment with area of 63 ha (Veliko-Anadol water-balance station) with observation periods of 17-31 years. Comparison of the calculated average over the catchment area of mean annual values of rainstorm soil losses, with the corresponding values obtained from measurements on these catchments, made on the basis of Nash-Sutcliff efficiency criterion (NS), allowed us to evaluate the quality of the model as good (NS = 0.72).

Theoretical analysis of engine coolant cavitation with different additives based on ultrasonic induced bubble dynamics

Cavitation, the process of formation and collapsing of vapor cavities is of great importance to material erosion degradation and enhanced physicochemical process by ultrasound. Commonly the ultrasonic cavitation bench test is utilized to study the cavitation correlate properties of different materials or coolants, which is time consuming and costly compared to numerical tests and lack of micro perspective analysis. Therefore, a mathematical model is needed to study cavitation bubble dynamics under different circumstances beforehand. Different types of ultrasonic waves are used to identify their ability to control bubble evolution and collapse intensity. Rectangular wave is found to be the most efficient to produce large radius and bubble wall speed compared with triangular and harmonic wave. As a potential mechanism to damage rigid wall, shock pressure is evaluated with variations of viscosity and surface tension. It is found that both decreased surface tension and increased viscosity can reduce shock pressure and thereby the cavitation potential, while viscosity shows less effect. Testing is achieved by comparing effects of typical coolants with different percentage of ethylene glycol (EG), propylene glycol (PG) and glycerin. PG is found to be the most efficient to suppress shock pressure followed by EG and glycerin the worst.

Effect of Sulfide Concentration on the Corrosion and Cavitation Erosion Behavior of a Manganese-Aluminum Bronze in 3.5% NaCl Solution

The effect of sulfide concentration on the corrosion and cavitation erosion behavior of a cast manganese-aluminum bronze (MAB) alloy in 3.5% NaCl solution was investigated. The electrochemical results showed that when the sulfide concentration exceeded 50 ppm, hydrogen evolution reaction dominated the cathodic process because of the very negative corrosion potential of MAB, and the formation of a copper sulfide film on MAB was a diffusion-controlled process. The mass loss rate of MAB after longer-term immersion was ordered by the sulfide concentration as: 20/50 ppm > 100 ppm > zero > 200 ppm. In the 200 ppm sulfide solution, the mass loss rate of MAB was the lowest, because of the formation of a thin and homogeneous copper sulfide film. In the other sulfide solutions, the formation of a less-protective film with both oxides and sulfides resulted in higher mass loss rate of MAB. Moreover, selective phase corrosion occurred at the β and κ phases in solutions with sulfide addition less than 100 ppm. For all solutions, it was the mechanical attack that dominated cavitation erosion degradation. The cavitation erosion–corrosion synergy was lower in high sulfide solutions, because the corrosion products on MAB could reduce the mechanical impact under cavitation erosion.

Dynamic study of infiltration rate for soils with varying degrees of degradation by water erosion

Ultisols, widely distributed in tropical and subtropical areas of south China, are suffering from serious water erosion, however, slope hydrological process for Ultisols under different erosional degradation levels in field condition has been scarcely investigated. Field rainfall simulation at two rainfall intensities (120 and 60 mm/h) were performed on pre-wetted Ultisols with four erosion degrees (non, moderate, severe and very-severe), and the hydrological processes of these soils were determined. The variation of soil infiltration was contributed by the interaction of erosion degree and rainfall intensity (p < 0.05). In most cases, time to incipient runoff, the decay coefficient, steady state infiltration rate, and their variability were larger at the high rainfall intensity, accelerating by the increasing erosion severity. Despite rainfall intensity, the infiltration process of Ultisols was also significantly influenced by mean weight diameter of aggregates at the field moisture content, soil organic carbon and particle size distribution (R2 > 30%, p < 0.05). The temporal erodibility of surface soil and soil detachment rate were significantly and negatively correlated with infiltration rate (r < -0.32, p < 0.05), but less significant correlation was observed between sediment concentration and infiltration rate for most soils, especially at the high rainfall intensity. The variation of surface texture and soil compactness generated by erosion degradation was the intrinsic predominant factors for the change of infiltration process of Ultisols. The obtained results will facilitate the understanding of hydrological process for degraded lands, and provide useful knowledge in managing crop irrigation and soil erosion.

Comparison and characterization of different polyester nano/micro fibres for use in tissue engineering applications

The study focuses on a comparison of the electrospinning of various polylactide and polycaprolactone (PLCL) copolymers and poly-L-lactide (PLLA) and polycaprolactone (PCL) homopolymers. The chemical characterisation, electrospinnability, fibrous morphology, degradation rate and interactions with fibroblasts were assessed with respect to copolymers and homopolymers with both lower (around 50,000) and higher (around 95,000) molecular weights. The research investigated commercially available as well as synthesised copolymers. The results revealed that the electrospinnability of polymeric solutions depends on both the molecular weight and the PLA/PCL ratio in the final copolymer. It was determined that PLCL copolymers with a higher content of PCL (≥20%) were not spinnable via the electrospinning process. With the exception of PCL, the resulting fibrous materials were found to be homogeneous and with fibre diameters of slightly more than 1 µm with respect to both the tested molecular weights. The degradation rate was tested under simulation conditions via the utilisation of the lipase and Proteinase K enzymes. The degree of degradation was found to depend on the molecular weight, the crystallinity of the polymer and the specificity of the enzyme applied. While lipase was responsible for the degradation of the PCL polymer, it exerted a minor impact on the PLLA and the copolymers. Proteinase K degraded all the tested polymers with a higher specificity towards PLLA and the PLCL copolymers. All the tested polymers were affected by the surface erosion degradation process via fibrous morphology changes and mass loss with no accompanying shift in the molar mass. The electrospun PLLA materials supported both fibroblast adhesion and proliferation. All the tested materials were determined to be cytocompatible with 3T3 mouse fibroblasts.

Effects of Soil and Water Conservation on Selected Soil Physicochemical Properties and Its Implication on Soil Productivity in Ethiopia. A Review

Soil erosion and land degradation have been a severe problem in the Ethiopian highlands due to dense population, high livestock density and intensive crop production in the area. Soil and water conservation practice is one the mechanism used to reduce soil and associated nutrient loss; thus, reduce the risk of production. Efforts were started through soil and water conservation strategy at a large scale on farmland since the mid-1970 and 1980’s. However, its effectiveness depends on specific site conditions. Therefore, reviewing the effects and implication of the soil and water conservation practices on selected soil physicochemical properties and soil productivity is essential. The study conducted in various part of the country showed that the implemented soil bund reduced annual runoff and soil loss at different rates. Soil and water conservation have improved the soil physicochemical properties on conserved cropland (BD, SMC, infiltration rate, clay content, pH, CEC, av. K, av. P, SOC and TN) than in the adjacent cropland without soil and water conservation measures. In contrast, the constructed soil and water conservation has shown no significant variations as compared to adjacent cropland in a study conducted at Dawuro zone, Southern Ethiopia. Soil and water conservation, reduce the removal of fertile topsoil and improves soil moisture, which favors crop growth as a result grain yield of the crops were increased at various rates based on agro ecology, crop type and local management practices. In general, the effect of constructed soil and water conservation had clearly showed positive impact on selected soil physicochemical properties and crop yields. Therefore, maintenance of the existing soil and water conservation structures is highly recommended to sustain its benefit, productivity and production; hence, improve the livelihood of the community. Keywords : land degradation, soil and water conservation, soil properties, soil productivity. DOI : 10.7176/JEES/9-5-02 Publication date :May 31 st 2019

Satellite agroecological monitoring within the system of sustainable environmental management

Satellite data are a relevant part of information, required for sustainable environmental management, assessment of the impact of economic activity of ecosystems, determination of risks, related to global climate changes, desertifi cation processes, loss of landscape and biotic diversity. Aim. To substantiate the reasonability and prove the effi ciency of using satellite data in the agroecologic monitoring system regarding the impact of climate changes on vegetation, processes of soil erosion degradation, and assessment of landscape diversity. Methods. The study was conducted in the territory of Ukraine. It involved the application of SWOT and Gap-analysis methodology, materials of NOAA satellite observa- tions, Sentinel, different spatial resolution, methodological and regulatory provision of the Institute of Agroecology and Environmental Economics of the National Academy of Agrarian Sciences regarding satellite monitoring of the structure of agrolandscapes, norms of establishing a network of testing agrarian grounds, list of vegetation state indicators, in par- ticular, “Remote sensing of the Earth from space. Land data about controlling the condition of plantings and performance of agricultural crops. General requirements: DSTU 7307:2013”, “Remote sensing of the Earth from space. Ground in- spection of plantings. Classifi er of objects and functions: SUC 01.1-37-907:2011”, “Methodological recommendations on establishing the network of testing agrarian grounds in the system of monitoring of plantings using the materials of cosmic information”. The investigation on the impact of climate changes on vegetation state was conducted on the territory of three natural-climatic zones which were geographically represented by Chernihiv, Poltava and Zaporizhzhia regions re- spectively. The determination of the threat of erosion degradation of arable lands and landscape diversity was performed on the territory of two administrative districts with high level of ploughness of agrolandscapes, intense agrarian produc- tion and manifestation of erosion degradation of lands. Results. Inadequacy of the traditional system of agroecological monitoring was determined. It was proven that it was reasonable to have comprehensive application of satellite data regarding climate warming within the natural climatic zones and its impact on vegetation according to the normalized dif- ference vegetation index (NDVI), erosion degradation of soils and landscape diversity. According to satellite data of the National Oceanic and Atmospheric Administration (NOAA), the correlation analysis was performed on the connection between the dynamics of the sum of effective temperatures and the sum of NDVI values for the vegetation period. There was positive impact of climate warming on vegetation state according to NDVI index in the zone of Polissia and Forest- Steppe. The correlation coeffi cients were R = 0.64 and R = 0.77 respectively. In the Steppe zone the correlation coeffi cient dropped down to R = 0.35 which demonstrated the elevated risk of droughts. Conclusions. Satellite data of Sentinel-1 were used to determine critical zones of erosion degradation of arable lands, requiring preservation and their inclusion to the natural fi elds, which had a positive impact on the optimization of agrolandscape diversity.

Разработка мероприятий по снижению эрозионной деградации почв Левобережья Днестра

Разработка мероприятий по снижению эрозионной деградации почв Левобережья Днестра

Mapping and monitoring soil erosion in a watershed in western Algeria

Fergoug watershed is subject to severe water erosion and land degradation that threaten agricultural sustainability for local populations. Soil loss and degradation by water erosion were estimated using the universal soil loss equation (USLE). The spatial distribution of soil losses was determined using the following parameters: the erosivity factor (R), obtained using climatic data from 12 local stations over a period of 41 years; the land cover factor (C), obtained using LandSat-TM satellite imagery 7 and 8; the erodibility factor (K), estimated from soil particle size analyses; and the topographic factor (LS), obtained from a digital terrain model. The Fergoug watershed is characterized by complex topography, and the topographic factor reached a value of 14.29. The erodibility factor K ranged from 0.08 to 0.38, and high values were recorded for about 20% of the watershed. The rainfall erosivity factor R ranged between 212.32 and 146.73 from east to west. The plant cover factor varied inter- and intra-annually from 2.24 in May 2000 to 0.06 in May 2015. As a result, soil losses varied from 0.35 to 617.66 tons per hectare per year (t/ha/year) in a rainy year, and from 0.27 to 1188.92 t/ha/year in a dry year. The combined effects of the slope angle and the vegetation cover were shown to play a major role in soil losses in this area.

New degradable composite elastomers of POC/PCL fabricated via in-situ copolymerization blending strategy

Poly(1, 8-octanediol citrate) (POC) degradable elastomer have attracted much attention due to its good biological properties. However, there is a compromise, i.e. to improve its extendibility inevitably leads to a sticky feature that causes inconvenient handling. Poly(ε-caprolactone) (PCL) is a commonly used biodegradable, flexible polyester applied in a variety of FDA-approved products. Here, an in-situ copolymerization blending strategy, i.e. melt polycondensation of citric acid and 1, 8-octanediol in the presence of PCL was adopted to produce a POC/PCL composite elastomer, in which partial PCL took part in polycondensation reaction and chemically bonded into the POC network, and the rest physically traversed within the network structure, leading to a transparent, flexible composite elastomer. The wide angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC) analyses confirmed a full-amorphous structure and no crystallization of PCL occurring. Moreover, the introduction of PCL not only improved extendibility but avoided stickiness. Compared to the POC, the time for curing POC/PCL prepolymers was highly reduced; and the degradation of composite elastomers in PBS solution was accelerated despite the slow degradation of PCL incorporated; additionally, surface erosion degradation presumably happened for POC/PCL elastomers, which would allow the implant to retain inner strength for a longer time.