Dry Sieving Research Articles

Soil aggregate stability index independent from pre-stress aggregate size distribution: A test from soils affected by the water level fluctuation in the Three Gorges Reservoir, China

Soil aggregate stability measurement is essential to determine soil health status under various conditions. The Mean Weight Diameter (MWD) is the most applied index to express aggregate stability particularly for wet and dry sieving. However, the MWD could generally present results affected by pre-stress aggregate size distribution when remained aggregates after stress are considered for calculation. Therefore, the objective of the present study was to eliminate the similarities between the MWD results and pre-stress aggregate size distribution, which largely affects treatments differentiation. Samples from 145-160 m (lower), 160–169 m (middle), and 169–175 m (upper) elevations differently affected by the Water Level Fluctuation in Three Gorges Reservoir (TGR) and control (>175 m) were exposed to wet shaking stress. Aggregates remained at each sieve opening, aggregates disintegrated/passed through the sieve opening, and small macroaggregates and microaggregates accumulated were recorded. These aggregates were used to determine and compare two indexes (1) using remained aggregates (MWD) and (2) using disintegrated/accumulated aggregates (MWDd/a) based on the differences among treatments. The results for both pre-stress aggregates and remained aggregates after stress were showed consistent significant differences (p < 0.05) between upper and control elevations. This gives indication that aggregates remained after stress strongly depend on pre-stress aggregate size distribution. As the MWD was calculated from remained aggregates, the identified difference between upper and control elevations for this index could also confirm its dependence to pre-stress aggregates distribution. Contrary, disintegrated and accumulated aggregates showed non-significant differences between upper and control elevations. This non-significant and significant differences between upper and control elevations for disintegrated and pre-stress aggregates suggest a non-dependence condition. Similarly, the upper and control elevations showed no significant differences in MWDd/a. This substantially informs that this index is independent from pre-stress aggregates distribution because it was entirely calculated from disintegrated aggregates. Higher aggregate stability was indicated by high MWD, with values ranging from 1.41 to 6.24 mm. On the other hand, higher stability was expressed by lower values of the MWDd/a, with the values varying between 3.87 and 0.5 mm. Overall, the present study evidenced the major advantage of considering the disintegrated/accumulated than remained aggregates in calculating unbiased MWD index for aggregate stability.

Regularity of zinc, copper, and lead distribution in different size fractions of Rostov-on-Don urban soil aggregates

: The article is devoted to the study of zinc, copper, and lead content in the soils of Rostov-on-Don. Soil samples were collected from full-profile sections located in different districts of the city and suburbs of Rostov-on-Don. The group of anthropogenically disturbed soils included Urbic Technosol urbanstratozems and replantozems, as well as urbanized chernozems Calcic Chernozems (Technic). Natural soils of recreational areas are represented by migration-segregation chernozems Calcic Chernozems (Pachic). The study was carried out using atomic absorption spectrometry and X-ray fluorescence analysis to determine metal content. Soil structure was determined by the Savvinov method (dry sieving) (&lt;0.25; 1–2; 3–5; 5–7; &gt;10 mm). Statistical analysis of the Wilcoxon criterion for related samples was performed to identify relationships. The main objective of the study was to assess the heavy metal content in different size fractions of aggregates and the ability of structural fractions to accumulate zinc, copper, and lead. Structural aggregates of different sizes differ in their ability to accumulate zinc, copper and lead. Zinc, including its mobile compounds, is predominantly accumulated in microaggregates. The content of gross copper and especially lead is confined to larger aggregates. At the same time, mobile copper compounds are concentrated in microaggregates and in fractions larger than 10 mm. Mobile lead compounds are distributed in fractions of different sizes quite uniformly in all studied soils.

Influence of Water Erosion on Soil Aggregates and Organic Matter in Arable Chernozems: Case Study

Since Chernozems are among the most fertile soils in the world, the study of their degradation is of great interest. However, the microstructure and composition of the soil organic matter (SOM) in eroded Chernozems have not yet been sufficiently studied. We studied the SOM and aggregate states of eroded Chernozems using the example of two catenas with arable Haplic Chernozems in the Kursk region of Russia. In the plow horizons (the part of the soil most susceptible to water erosion), we determined the mean-weighted aggregate diameter (MWD), structure and water stability coefficients (SC and WS; dry and wet sieving, respectively), soil organic carbon (SOC) content, and SOM composition and content (qualitative and quantitative micromorphological analyses, respectively). It was shown that with an increase in the degree of erosion, the content of SOC decreased significantly, according to both chemical and micromorphological methods of evaluation. No significant relationships were found between the degree of erosion and the indicators of the structure (except for WS, which was significantly lower in non-eroded Chernozem than in slightly and moderately eroded soils). With the increasing degree of erosion, the humus state of these soils deteriorates at the microlevel, the intensity of humification decreases, the depth of the appearance of assimilated biogenic aggregates with finely dispersed calcite in the profile increases, the structure is destroyed, lumpy aggregates form, and the proportion of planar voids increases. The downslope transport of the soil solid phase under the impact of erosion is accompanied by the accumulation of the transformation products of carbohydrates, phenolic compounds, and black carbon in the passive pool of SOM in the Chernozems in the lower part of the catena. In the Chernozems located in the transit position of the slope, the composition of SOM is characterized by the predominance of lipids and nitrogen-containing compounds. Our unique results contribute to a deeper understanding of the formation of structure and water resistance in eroded soils.

Research on the enhancement material and culture method of soil aggregates composed of feldspathic sandstone and sand

The Mu Us Sandy Land is a region characterized by wind-blown sand and soil erosion in northern China. To enhance the soil quality of this area, various organic materials were incorporated into the mixed soil at a volume ratio of 1:2 for feldspathic sandstone to sand. Culture was conducted in the field and under constant temperature conditions in laboratory culture chambers. Four treatments were established in the experiment, each calculated based on weight ratio and controlled (with no organic material added, CK); single application of straw (5% straw, P1); single application of biochar (5% biochar, P2); combined application of biochar and straw (5% biochar + 5% straw, P3). After 90 days of culture, soil samples were collected for analysis of various indicators such as soil aggregate particle size distribution, water stability of soil aggregates, mean weight diameter, mean geometric diameter, and fractal dimension using dry sieving and wet sieving methods. The objective is to establish a scientific basis and provide technical support for addressing the challenges associated with compound soil and implementing rational fertilization measures. The research results indicate that: (1) The quantity of aggregates > 0.25 mm under different treatments follows the order CK < P1 < P2 < P3, and the differences between treatments are significant (P < 0.05); (2) Soil water stability, mean weight diameter (MWD), mean geometric diameter (GMD), and fractal dimension of soil aggregates in compound soil with different organic material additions are superior to the control, and the effect of biochar on improving soil aggregates is better than that of corn straw. The combined application of both significantly improves the effect compared to single applications. In both culture modes, under wet sieving, the P3 treatment shows the highest MWD and GMD of soil aggregates, with an increase ranging from 3.45% to 85% and 4.55% to 38.46%, respectively, compared to other treatments. (3) The trend of fractal dimension among treatments is consistent: P3 < P2 < P1 < CK, and the differences between treatments are significant (P < 0.05). Moreover, there is a good negative correlation linear equation relationship between the fractal dimension (y) and WR > 0.25 (x) of compound soil, with a correlation coefficient of up to 0.9851. In conclusion, the incorporation of organic materials can effectively enhance the proportion of macroaggregates in compound soil consisting of Feldspathic sandstone and sand, thereby improving soil stability and erosion resistance. The optimal outcome is achieved through the combined application of biochar and straw. Indoor culture proves to be more effective than field culture, while wet sieving accurately reflects the structural characteristics of compound soil under both dry and wet sieving treatments.

Grain Size Distribution and Provenance of Holocene Sand from the Sava River (Zagreb, Croatia)

This study involves an investigation into the grain size distribution and provenance of the sand deposited near Zagreb (Croatia) in the riverbed of the regionally important, almost 1000 km long Sava River, which connects several SE European countries. Recent research in the study area has mainly focused on the deposits forming the Zagreb alluvial aquifer system, rather on the Sava River sediment deposited in its riverbed, which is the focus of this study. The grain size distribution results obtained by dry sieving and laser granulometry showed a predominately fine and medium sand deposition at riverbanks and sand point bars. Medium sand increased downstream towards the east, within the artificially more channelized riverbed in the urban area. Fine sand prevailed 50 km further downstream in a more meandering low-relief area, near the city of Sisak and Lonjsko Polje Nature Park. Provenance analysis showed predominately carbonate sand in the western part of the city of Zagreb, originating from distant (Alpine) and local (Medvednica Mt. and Samobor Hills) sources. More siliciclastic sand was deposited in the Sava riverbed in the middle and eastern parts of Zagreb, originating mainly from the Medvednica Mt. The prevailing siliciclastic sand further downstream of the Sava River is probably sourced from the Kupa River tributary. Although various studies of the Zagreb alluvial aquifer system have been conducted so far, this study represents a novelty in its investigation into the grain size distribution of the Sava riverbed sand itself, setting the foundations for investigations in the future.

Detecting differences in starch digestibility using in vitro methods among corn hybrids harvested at silage maturities

The objectives were to 1) determine whether genetic differences can be detected for carbohydrate fermentability among corn hybrids at silage maturities when the effects of drying and grinding are eliminated and 2) determine if in vitro starch digestibility (IVSD), a routine laboratory method used by commercial laboratories for hybrid evaluation, can detect differences when DM is controlled. Samples of whole corn plants from 3 hybrids (Brevant): B99B79SX (BMR, n = 7), B96T79SX, standard (STAN, n = 6), and B95U78SXE, floury-BMR (FL, n = 7), that had similar range of DM were selected. Sets of 8 ears were harvested concurrently and kernels removed from the ears by hand. Samples of undried kernels were quartered (QKERN) and in vitro gas production (IVGP) was measured for 120 h. More gas was produced by QKERN of FL than of STAN and BMR from 9 to 18 h (P < 0.05), and QKERN of FL produced more gas than BMR through 21 h (P < 0.05). The QKERN of FL had a shorter lag than STAN or BMR (P < 0.001) and a faster rate of gas production than BMR (P < 0.01), establishing that genetic differences are present at silage maturities. To determine whether the routine laboratory method can detect these differences, kernels (GKERN) and whole corn plants (GWP) were dried and ground to pass a 4-mm screen to measure IVSD after 3, 8, and 24 h. Particle size of GKERN was determined by dry sieving using a set of 13 sieves. For both GKERN and GWP, IVSD was lowest for BMR and highest for FL after 8 h. The IVSD8h of GKERN decreased as particle size increased at a similar rate for the 3 hybrids but the intercepts were different, with BMR being lowest and FL highest. Similarly, the IVSD8h of both GKERN and GWP decreased with increasing whole plant DM at a similar rate for the 3 hybrids and the magnitude of difference for IVSD8h was larger for the range in DM than the range in intercepts for the hybrids (0.123 vs 0.071 and 0.117 vs. 0.100, for GKERN and GWP, respectively). Plant maturity, or DM, has a larger effect on IVSD than hybrid type, and should therefore be controlled when evaluating genetic differences.

The Effect of Sediment Texture on the Composition and Abundance of Microplastics in Banjaran River, Banyumas Regency, Indonesia

Plastic waste is a serious environmental problem for all countries in the world, including Indonesia. Plastic waste of various sizes can have a negative impact, especially microplastics. Microplastic contamination can be found in aquatic sediments. One of the waters potentially polluted by microplastics is the Banjaran River, Banyumas Regency. This research was conducted to determine the composition and abundance of microplastics as well as the effect of sediment texture on the composition and abundance of microplastics in the sediments of Banjaran River, Banyumas Regency. The research location was determined using purposive sampling at four stations. At each station, samples were taken randomly at three different places with three repetitions. Analysis of the composition and abundance of microplastics in sediments was done in a laboratory using microscope observation. Sediment texture analysis was done using a dry sieve and pipetting method. Five types of microplastics were found in all sediment samples with a predominance of fiber (35%), followed by fragments (29%), films (19%), pellets (10%) and foam (7%). The abundance of microplastics in sediments ranged from 2.3 to 4.86 particles/50 grams of dry sediment. The sediment texture that dominated the four stations was sand, with an average fraction proportion value of 86.62%. Sediment texture had the strongest effect on the composition of fragment-type microplastic at 50.2% and had the same impact on the overall abundance at 56%, which indicated that the sediment texture had a significant effect on these two variables.

Aggregate stability and carbon and N dymamics in macroaggregate size fractions with different soil texture

Soil nutrient cycling, the distribution of soil aggregates, and their stability are directly influenced by soil texture. Different sizes of soil aggregates provide microhabitats for microorganisms and therefore influence soil carbon (C) and nitrogen (N) mineralization. The purpose of the present study was to assess the aggregate stability and dynamics of carbon and nitrogen in macroaggregate size fractions (1-8 mm) with different clay content from meadow soils. Surface soil samples (0-15 cm) were collected from 4- to 5-year-old forage crops. Four macroaggregate size classes were isolated by dry sieving and analyzed for their mass proportions: fine macroaggregates (FM) (less than 1 mm), medium-fine macroaggregates (MFM) (1-2 mm), medium-coarse macroaggregates (MCM) (2-4 mm), and large-coarse macroaggregates (LCM) (4-8 mm). The dry mean weight diameter (MWD), organic carbon (OC), total nitrogen (TN), carbon and nitrogen of microbial biomass (C-MB, N-MB) were determined. CO2 emission and net nitrogen mineralized (NM) were measured after 14 weeks of incubation. The amounts of FM were significantly lower than those of intermediate macroaggregates (MCM and MFM) and decreased markedly with increasing clay content within soil macroaggregates. In general, the amounts of macroaggregate size fractions were lowest in soils with high clay content. MWD exhibited a significant correlation with particle size distribution, OC, and MB-C. OC, TN, MB-C, and MB-N contents within macroaggregates increased with decreasing macroaggregate size and increasing clay content of macroaggregate fractions. The CO2 emission and NM content increased with increasing macroaggregate size, indicating higher organic C and N mineralization activity in larger macroaggregates. Mineralization of OC was lowest in macroaggregate fractions with the highest clay content. We conclude that clay content can increase the protection of microbial biomass in meadow soils. Small macroaggregates tend to contain more recalcitrant organic matter compared to larger macroaggregates.

Regional metakaolin particle size reduction for higher strength geopolymer

AbstractThe objective of this project was to further develop new composites and a testing program for the performance‐based specification for natural Amazonian geopolymer (GP) for use in ceramics and construction. While fly ash‐based alkali activated materials are now an established technology, metakaolin‐based GPs still need to be developed and optimized regarding the knowledge of the specific characteristics and properties of local resources. Amazonian kaolin was calcined into metakaolin (AMK). AMK particle size reduction for better reactive material was evaluated by means of dry and wet ball milling and sieving. Three types of metakaolin were analyzed for particle size distribution, and their size d50 ranged from 7.9 to 2.8 µm. Further GP characterization followed physical and mechanical properties in flexural strength tests. In addition, scanning electron microscopy and energy dispersive spectroscopy were used to investigate the microstructure of the materials. Energy dispersive X‐ray fluorescence was used to measure the GP material composition. Analysis of the results revealed that the strength and stiffness of sodium–metakaolin‐based GP were inversely proportional to particle size. All distinct particle size GPs showed, in general, some increase in strength and stiffness within curing times ranging from 3 to 28 days.

Analysis of Sediment Characteristics and Depositional Environment of Beach Sediment along the Pulmoddai Mineral Sand Deposit in Eastern Coast of Sri Lanka

Abstract Pulmoddai mineral sand deposit which extends about 800,000m2 is located in the Northeast coastal zone of Sri Lanka. It is the largest and well known heavy mineral sand deposit in Sri Lanka. High-quality Zirconium-bearing minerals like Rutile, Zircon, and Ilmenite are concentrated in this deposit. This study focuses to analyse the spatial distribution of the heavy minerals abundance and sedimentlogical characteristics of the deposit. Five miles (8 km) long stretch along the coast of this deposit was selected as the study area. Ten traverses representing two traverses within each mile are demarcated across the coastline and are running from inshore to backshore. Forty sand samples representing inshore, swash zone, berm, and backshore region were collected. These samples were analysed using a dry sieve and heavy liquid separation methods. According to statistical analysis, sediments in the Pulmoddai mineral sand deposit are mostly fine-grained, moderately to moderately well sorted. Also, these are negatively skewed to nearly symmetrical and mesokurtic in nature. According to the linear discrimination function, these sediments are shallow marine agitated depositions controlled by aeolian, fluvial and marine depositional environments under the high impact of turbidity currents. The average heavy mineral concentration at the inshore, swash zone, berm region, and backshore (dune) region is 5.95%, 10.87%, 12.82%, and 23.5% respectively. The concentration of the heavy minerals increases towards the backshore and also increases towards the southern part of the study area.

Variables related to the stability of soil macro and microaggregates of a toposequence in the Brazil south region

Soil aggregates are the basic components of soil structure, being important to its environmental properties and functions. The objective of this study was to investigate the variables related to the aggregates stability, measured by the method of dry and wet sieving and by applying ultrasound energy, in three different soils of a toposequence in southern Brazil. The study was performed in three soils sampled in the city of Pinhais / PR: i) Oxisol (top slope); Ii) Inceptisol (medium third) and; Iii) Gleisol (floodplain). The aggregates stability was determined measured by the method of dry and wet sieving (macroaggregates), as well as by applying ultrasound energy (microaggregate). The results were correlated with soil chemical, physical and mineralogical attributes. The organic matter, the low crystallinity Fe oxides and kaolinite were the most important variables for the profile structural stability. In turn, the soil texture did not show a direct relation with soil aggregation. The Gleisol show highest structural stability, followed by Oxisol and Inceptisol.

Event-scale suspended sediment fluxes in a dryland environment valley-bottom wetland: Implications for downstream sediment and phosphorous fluxes

Suspended fine sediment in rivers and small streams contributes to fluvial pollution loads because of its association with anthropogenically introduced heavy metals, pesticides / herbicides, and nutrients, including phosphorous (P). By acting as sinks for suspended sediment, wetlands located along drainage lines have considerable potential in reducing downstream sediment and nutrient fluxes. The aim of this research was to document downstream sediment fluxes within a single valley-bottom wetland to establish the effectiveness of this common wetland type in retaining P attached to sediment. The study was accomplished by conducting a topographic survey (dGPS and 0.5 m Lidar-derived DEM) with surface and sub-surface sediment sampling to establish long-term (decades to centuries) processes of erosion and deposition within the wetland, as well as consider storage of P. This was paired with event-based suspended sediment sampling at eight positions within the wetland over a wet season, as well as time-averaged suspended sediment sampling at a seasonal-scale at the wetland inlet and outlet. Sediment samples were characterised in terms of organic content, total phosphorous and particle size, which were determined using loss-on-ignition, ICP-AES following aqua regia extraction, and a combination of dry sieving and settling, respectively.Over the wet season, average suspended sediment concentrations increased to a maximum value of 0.26 g.L−1 and then declined, potentially because of the exhaustion of locally available sediment. The total P concentration of incoming sediment was 2174 mg/kg compared to 800 mg/kg at the wetland outlet. However, when considering the seasonal flux for the single year sampled, it was found that the wetland was a net downstream contributor of sediment (11 g of sample were retained at the inlet, relative to 19 g at the outlet). Despite this, the wetland retained ∼37 % of the total P supplied to it from upstream sources, with the remainder passing through the wetland as a result of sediment reworking in reforming channels. Thus, while wetlands may be effective at retaining some sediment and nutrients, they are not an alternative to more formal water treatment works.

Study of Some Physical Properties of Soil in Immature Oil Palm Plant at Different Slopes

The physical properties of the soil will influence plant growth and development. This research aims to examine the physical properties of soil in various slope classes of oil palm plantations inPTPN III KebunAekNabara Utara, BilahHulu District, Labuhanbatu Regency. This research uses survey and descriptive methods by analyzing the parameters of the physical properties of the soil, namely:Bulk Density (g/cm3) Total Pore Space (%) Soil Structure, Soil Water Content (%), Soil Texture (%). The tools used are a Global Positioning System (GPS), sample ring, hoe, soil drill, penetrometer, oven, permeameter, dry sieve, wet sieve, and pressure plate apparatus. The materials used are soil samples and work maps. The research results show that several soil physical properties showBulk Density value 1.30 – 1.51 g/cm3, Total Pore Space 0.17-0.58%, water content 0.20-0.27%, while the texture is dominantly clayey, and the structure is dominantly angular blocky. The physical properties of soil require a long time to change, because the physical properties of soil are difficult to change.

Evaluation of the effects of long‐term maize–peanut intercropping on soil aggregate stability based on different methods

AbstractIntercropping is an effective measure to increase crop yield and improve soil structure. The soil aggregate is the basic unit of soil structure, and its stability is affected by intercropping system. To study the effects of intercropping system on soil aggregate stability, the particle size distribution and stability characteristics of soil aggregates under three planting patterns of maize only (SM), peanut only (SP) and maize intercropped with peanut (M‐P) were evaluated by dry sieving (mainly used to determine the mechanical stability of soil aggregates), wet sieving (mainly used to determine the water stability of soil aggregates) and Le Bissonnais (mainly used to distinguish different decomposition mechanisms of soil aggregates) (including slow wetting (SW), wet stirring (WS) and fast wetting (FW) tests) methods. The results showed that the particle size distribution of soil aggregates was mainly the &gt;2 mm fraction in the dry sieving test, the 1–0.5 mm and &lt;0.053 mm fractions in the wet sieving test, the &gt;2 mm fraction in the SW test, the &gt;2 mm and 2–1 mm fractions in the WS test and the 1–0.5 mm and 0.5–0.25 mm fractions in the FW test. The mean weight diameter (MWD), geometric mean diameter (GMD) and R0.25 of soil aggregates in the three determination methods were all ranked as SP &lt; SM &lt; M‐P, indicating that intercropping could increase the proportion of large aggregates and improve the stability of soil aggregates. In the three tests using the Le Bissonnais method, the MWD order was FW &lt; WS &lt; SW, indicating that the soil aggregates in this area were the most sensitive to slaking effects and the least sensitive to mechanical breakdown, and intercropping could reduce the sensitivity of soil aggregates to slaking effects and mechanical breakdown. In addition, the MWD of dry sieving was significantly positively correlated with the MWD of SW and WS, and the MWD of wet sieving was significantly positively correlated with the MWD of FW. The results of this study could provide a reference for better understanding of farmland soil structure and aggregate stability under intercropping system in the North China Plain.

Effects of aftercrop tomato and maize on the soil microenvironment and microbial diversity in a long-term cotton continuous cropping field.

Long-term continuous cropping affects the soil microecological community and leads to nutrient imbalances, which reduces crop yields, and crop rotation can increase soil productivity. To study the effects of the cultivation of tomato (Solanum lycopersicum) and corn (Zea mays) on the microbial community, physical and chemical factors and the structure of aggregates in cotton (Gossypium hirsutum) long-term continuous cropping soils were examined. Four cropping patterns were established, including one continuous cropping pattern and three crop rotation patterns, and the diversity of the soil microecological community was measured using high-throughput sequencing. The physical and chemical properties of different models of soil were measured, and the soil aggregate structure was determined by dry and wet sieving. Planting of aftercrop tomato and corn altered the bacterial community of the cotton continuous soil to a lesser extent and the fungal community to a greater extent. In addition, continuous cropping reduced the diversity and richness of the soil fungal community. Different aftercrop planting patterns showed that there were very high contents of soil organic carbon and organic matter in the cotton-maize rotation model, while the soil aggregate structure was the most stable in the corn-cotton rotation model. Planting tomato in continuous cropping cotton fields has a greater effect on the soil microbial community than planting maize. Therefore, according to the characteristics of different succeeding crop planting patterns, the damage of continuous cropping of cotton to the soil microenvironment can be alleviated directionally, which will enable the sustainable development of cotton production.

Microplastic in Beach Sediment of Nasi Island, Aceh Besar Regency, Indonesia

Microplastic might be a small size of plastic that is directly released into the environment or the result of larger in size of plastic degradations. The presence and effect of microplastic have been reported globally. However, the existence of microplastic trapped in beach sediment of Nasi Island is limited. This research was conducted to analyse the type of sediment, abundance and type of microplastic polymer found in beach sediments in Nasi Island, Aceh Besar Regency, Aceh Province, Indonesia. Sampling was carried out in April 2022 at Nipah Beach and Alue Riyeung Beach in Nasi Island, Aceh Besar Regency. Sediment type was analysed by dry sieve method, using a stratified sieve shaker while the observation of microplastic and its polymer were identified by microscope and Fourier Transform Infrared Spectroscopy (FTIR), respectively. The results showed that the types of sediment at both beaches belonged to the sand type. There were three types of microplastics found, namely fragments, films, and fibres. The highest abundance of microplastics was found in a 0.063mm filter at Nipah Beach with an amount of 2651 Particles/Kg while the lowest was found in a 0.125mm filter with an amount of 8 Particles/Kg at Alue Riyeung Beach. As the polymer types, it is found that fragment type microplastics are likely to have PETE (Polyethylene Terephthalate) polymers, film type microplastics are likely to have PS (Polystyrene) polymer types and Fibre microplastics are likely to have LDPE (Low-Density Polyethylene) polymers.

Environmental assessment of the state of fallow drained meadow-soddy-gley and brown mountain-forest soils to involve them into a new agricultural turnover (on the example of the Jewish autonomous region)

Relevance. In the context of ever-increasing anthropogenic influence, the importance of agricultural land reclamation increases and becomes more complicated. Involvement of new virgin soils in agricultural circulation requires large financial investments and huge labor resources, which the local administration does not have. The secondary return to agricultural circulation of fallow reclaimed lands that are not used in agriculture may be a less costly method of increasing the area of agricultural arable land. Aim. To analyze the changes in vegetation and aggregate composition on drained fallow soils of different ages. Object. Drained fallow meadow-soddy-gley and brown mountain-forest soils of different ages. Methods. Standard geobotanical methods were used to describe the vegetation of the polygons. The granulometric analysis of soils was carried out by the method of dry sieving. Soil density was determined by the cutting cylinder method. Results. The study showed that reclaimed arable land, after being withdrawn from agricultural use, enters into a long process of self-recovery. In the course of a long-term transformation, a noticeable accumulation of humus is observed in fallow brown mountain-forest soils in comparison with adjacent arable lands. In the 20-year-old deposit, the highest content of humus is noted, while there is a decrease in saline and hydrolytic acidity. In fallows, the density of the upper soil horizon decreases, which favorably affects the structure of soils. On brown mountain-forest soils, in a 20-year-old fallow, there is a noticeable increase in the proportion of mesoaggregates (0,25–10 mm), including agronomically valuable ones. The number of micro- (&lt;0,25 mm) and macro-aggregates (&gt;10 mm) decreases, which indicates an improvement in the agronomic properties of fallow soils. The results of dry screening indicate that the fallow period of drained meadow-soddy-gley soils adversely affects their structure.

Spectral reflectance of atmospheric dust as an indirect indicator of its soil origin

Atmospheric dust affects both human health and climate change. Therefore, the study of atmospheric dust is one of the important tasks of many scientific fields. The aim of our research was to indirectly assess the relation of atmospheric dust over arable lands of two test sites in Tver and Tula regions of Russia with soils. Dust was analyzed on aspirator filters after pumping specified volumes of air at the level of 20–30 cm above the arable surface. Its spectral reflectance was used as a criterion of soil origin of dust, which was compared with the reflectance of the size fraction (50–200 nm) of soils isolated by dry sieving of a sample of arable soil horizon. The spectral reflectance of dust was calculated based on approaches of linear separation of spectral mixture, taking into account the projective coverage of dust particles on filters, which was determined by analyzing microscope photographs of the filters in GIS. As a result, it was found that the recovered dust spectra on the filters correlate well with the spectra of the same size soil fraction separated by dry sieving, which indirectly confirms the predominance of specifically soil dust on the filters. Spearman correlation coefficient is within the range of 0.84–0.90, Kendall's Tau correlation coefficient varies within 0.70–0.79 (at significance level p &lt; 0.05). Under the conditions of insignificant atmospheric dust load and when collecting a sufficient amount of dust for direct analysis is time and labour consuming, the approach used may serve as an alternative for indirect confirmation of the soil origin of dust in the near ground layer of the atmosphere. In the future, this approach can be used as a basis for monitoring of arable soils deflation.

Effects of precision irrigation on water regime and productivity of winter wheat

The aim of the research was to establish the effect of precision irrigation with varying mineral fertilizer availability on winter wheat productivity. Studies were carried out on irrigated arable land in the Rostov region. The test scheme included 3 replications. The climate of the research area is arid but not hot enough. The sum of temperatures for growing period is in the range of 30003200 C, the average annual precipitation is 470 mm, for the growing period - 285 mm. The soil cover of the experimental site is chernozem. According to the granulometric composition of the soil, the entire profile is represented mainly by heavy loam, turning into medium loam at a depth of 130-160 cm. The structural state in dry sieving and the water resistance of the aggregates are characterized as excellent. The lowest water-holding capacity for 0-60-centimeter layer is 28.3 %, which is good according to the existing classification. Soil density in 0.6 m layer is 1.27 t/m3, and in 1.0 m layer - 1.33 t/m3. Differentiated doses of fertilizers against the background of irrigation technologies studied in variants had a significant impact on productivity of winter wheat. Thus, in the variants with no irrigation, water consumption coefficient of winter wheat was 890.8 to 1343.6 m3/t; using the recommended irrigation system reduced its value to 725.91327.3 m3/t, and the precision irrigation technology provided a reduction in the value of water consumption coefficient to 681.61147.6 m3/t. The conducted studies revealed advantage of precision irrigation technology and mineral fertilizers, the use of which in different years provided higher winter crop yield by an average of 0.55 t/ha in comparison with the recommended technology, and, in comparison with variants without irrigation - by 3.49 t/ha. The introduction of modern high-precision irrigation technologies will make agricultural products produced on irrigated land more competitive.

Mechanical Analysis of Sand Ripples Deposits in the Lower Basin of Wadi Tilal "Geomorphological study"

The current study is set to determine the volumes of sand ripple deposits in the lower basin of Wadi Tilal in micro depositional environments by mechanical analysis. To do so, the present study analyzed samples of sediment in the laboratory using an electric sieve and the dry sieving method. The results were then calculated in the Phi unit to be processed using the Fraction V.3 program combined with the Folk &amp; Ward equations in order to find out an estimation of the volume coefficients, and categories of statistical coefficients for the volumes of sediment sand. The study’s main findings was that the medium-sized sand category (1-2ø) constitutes about 44.75% of the weight of the ripple sand samples, and that the average sand size is about (1.698ø) and it falls within the medium-sized sand category. Moreover, the average value of the sorting coefficient was (0.873ø), which falls within the medium sorting category. In addition, most of the distribution curves fell within the high positive skewness category with an average of (0.336ø), and the value of the flattening coefficient was (1.265ø). The shape of the distribution curve falls within the category of flattened and sharpen end.