Soil Content Research Articles

A rapid detection method for diesel content in diesel-contaminated soil based on dielectric measurement and oven-drying tests

Geophysical testing techniques have been successfully applied to identify light non-aqueous phase liquids in soils, but challenges remain in rapidly detecting contaminant content. Detection of contaminants in soil using geophysical testing techniques relies on sensors sensitive to electrical and electromagnetic parameter changes. In this study, the complex permittivity of silty clay contaminated with 0# diesel was measured using an open-ended coaxial probe at frequencies from 200–3000 MHz, and the four-phase dielectric mixing models were evaluated. The measurement results showed that the complex refractive index method (CRIM) model provided a better match with the real permittivity of the four-phase system between 500–3000 MHz with relative errors within an acceptable range of 4%. To eliminate the unknown variable in the CRIM model, an improved equation for the relationship between water content and diesel content of the watery diesel-contaminated silty clay was established by the oven-drying method. Thus, a method for the rapid quantitative detection of the diesel content in contaminated soil has been developed based on dielectric measurement and oven-drying tests. The relative error between the calculated and actual set diesel content for ten manually configured diesel-contaminated soil samples was within 10%, with a maximum error of 15.75%.

Numerical simulation of the uplift bearing behavior of pile foundations for transmission towers in expansive soil area

Piles are commonly used as foundations for power transmission towers located in expansive soil areas. The strength of expansive soil is highly sensitive to the changing water content, which complicates the pile–soil interaction. In this study, a 3D elastoplastic finite element analysis of a typical pile foundation for a transmission tower in an expansive soil area was conducted to understand the effect of water content in expansive soil on the uplift bearing capacity of the pile foundation. The results that the failure mode of the pile foundation is almost unaffected by the water content. Shear failure was observed at the pile–soil interface, and, when the pile was pulled out, it lost its uplift bearing capacity. With the increasing water content of the soil, the ultimate uplift bearing capacity of the pile foundation exhibited a significant decreasing trend, whereas the displacement of soil around the pile became remarkable. The distribution of pile axial force and lateral frictional resistance during the uplift process was also evaluated. The pile axial force decreased gradually and at a higher rate with increasing depth. Once the pile reached the ultimate uplift bearing state, the pile lateral friction increased almost linearly with depth.

Mitigative translocation of Singleton Mint Bush (Prostanthera cineolifera) on the NSW North Coast: Effects of soil texture, horticultural practice and bushfire on the translocation outcome

SummaryTranslocation of the threatened species Singelton Mint Bush (Prostanthera cineolifera R.T.Baker & H.G.Sm.) was carried out for a highway project on the New South Wales North Coast to mitigate development impact on this species. The translocation aimed to augment an existing population with propagated plants to compensate for cleared plants and conduct field research to better understand the effects of soil properties, horticultural practices and a wildfire on translocation results. A novel soil seedbank and fire method applied ex‐situ was used to propagate plants for introduction. After an initial attempt at site‐wide introduction resulted in widespread mortality of seedlings from a wilt disease, three plot‐based experiments were carried out to examine how disease incidence was related to spatial variation in soil properties and horticultural practices. The experiments showed that relatively subtle changes in the clay and sand content of soil strongly affected susceptibility of Singelton Mint Bush seedlings to wilt disease; 12 month old seedlings performed much better than 6 month old seedlings; plants propagated from seed performed better than cuttings, and most of the recipient site represented unsuitable habitat for Singelton Mint Bush. Sufficient Singelton Mint Bush seedlings were established after 3 years, but after a bushfire, the translocated cohort recruited poorly from seed, so that after 6 years, <10% of the total Singelton Mint Bush population in the recipient site was of translocated origin and >90% of in‐situ (pre‐translocation) origin. Lessons learnt from the translocation project were that: (i) microhabitat is as important as macrohabitat in selecting a translocation recipient site; (ii) short‐term survival may not be a reliable indicator of a self‐sustaining population; (iii) translocation incorporating designed experiments can greatly improve understanding of how certain factors influence species performance and (iv) horticultural practices can be as important as ecology in determining the translocation outcome.

Effect of fertilizer treatments on sugar beet cultivars: A comprehensive study on crop yield and nutrient contents of soil and plant in chestnut soil of Kazakhstan

This study aimed to investigate the effects of different fertilizer treatments on the growth, yield, and nutrient content of two sugar beet cultivars, Aksu (Kazakhstan) and Yampol (Poland), cultivated in the Almaty region of Kazakhstan. The experiment was conducted using a complete randomized block design with three replicates, comprising six treatments: control (without fertilizer), N120P120K90, and N130P130K130 for both cultivars. The soil's physical and chemical properties were analyzed, revealing a foothill light chestnut soil with favorable nutrient levels. Results indicated that the N130P130K130 treatment significantly increased soil available nitrogen, phosphorus, and potassium contents, leading to enhanced sugar beet growth, nutrient uptake, and yield. Both cultivars responded positively to the increased nutrient levels, with the N130P130K130 treatment showing the highest yield of 785.6 tons/ha for Aksu and 802.5 tons/ha for Yampol. Furthermore, nutrient content in tubers and leaves was significantly higher in the N130P130K130 treatment compared to other treatments. These findings underscore the importance of balanced nutrient management tailored to specific cultivars for optimizing sugar beet productivity and soil fertility in diverse agro-climatic conditions. Adopting balanced mineral nutrient management approaches could offer promising solutions to enhance sugar beet productivity and sustainability. Future research should focus on exploring long-term effects and integrated nutrient management strategies for sustainable sugar beet cultivation.

R3 strain and Fe-Mn modified biochar reduce Cd absorption capacity of roots and available Cd content of soil by affecting rice rhizosphere and endosphere key flora

Microorganisms have a significant role in regulating the absorption and transportation of Cd in the soil-plant system. However, the mechanism by which key microbial taxa play a part in response to the absorption and transportation of Cd in rice under Cd stress requires further exploration. In this study, the cadmium-tolerant endophytic bacterium Herbaspirillum sp. R3 (R3) and Fe-Mn-modified biochar (Fe-Mn) were, respectively, applied to cadmium-contaminated rice paddies to investigate the effects of key bacterial taxa in the soil-rice system on the absorption and transportation of Cd in rice under different treatments. The results showed that both R3 and Fe-Mn treatments considerably decreased the content of cadmium in roots, stems and leaves of rice at the peak tillering stage by 17.24–49.28% in comparison to the control (CK). The cadmium content reduction effect of R3 treatment is better than that of Fe-Mn treatment. Further analysis revealed that the key bacterial taxa in rice roots under R3 treatment were Sideroxydans and Actinobacteria, and that their abundance showed a substantial positive correlation and a significant negative correlation with the capacity of rice roots to assimilate Cd from the surroundings, respectively. The significant increase in soil pH under Fe-Mn treatment, significant reduction in the relative abundances of Acidobacteria, Verrucomicrobia, Subdivision3 genera incertae sedis, Sideroxydans, Geobacter, Gp1, and Gp3, and the significant increase in the relative abundance of Thiobacillus among the soil bacterial taxa may be the main reasons for the decrease in available Cd content of the soil. In addition, both the R3 and Fe-Mn treatments showed some growth-promoting effects on rice, which may be related to their promotion of transformations of soil available nutrients. This paper describes the possible microbial mechanisms by which strain R3 and Fe-Mn biochar reduce Cd uptake in rice, providing a theoretical basis for the remediation of Cd contamination in rice and soil by utilizing key microbial taxa.

Biochar and Azolla Effects on Soil Chemical Properties, Lead Content and Growth of Paddy

The objective of the study was to determine the influences of biochar amendments and Azolla sp application on soil chemical value, lead (Pb) content, and growth of paddy. The research was conducted in Growth Centre LLDIKTI I, Medan, Sumatera Utara, Indonesia, from April to July 2014. The research design used a factorial randomized block design with three replications. The first factor was Azolla sp application: without Azolla (A0); Azolla pinnata (A1); Azolla mikropilla (A2)] and the second factor was biochar amendment without biochar (B0); RSB-Rice straw biochar (B1), RHB-Rice husk biochar (B2), CPB-coconut peat biochar (B3), OPB-Oil Palm Empty Bunch biochar (B4)]. The result showed that the biochar amendment treatments had significant differences (P<0.05) in all soil chemical values and growth parameters of paddy. The Azolla application showed significant differences (P<0.05) in plant height, number of tillers, shoot dry weight, root dry weight, and Pb content in the root. The interaction among the Azolla sp and the biochar amendments showed significant differences (P<0.05) in a number of the tillers. It was concluded that the application of rice husk biochar and Azolla microphylla was able to increase soil chemical properties, increase the growth of paddy, and also increase the Pb content in soil, leaves, and roots.

Reforestation Will Lead to a Long-Term Downward Trend in the Water Content of the Surface Soil in a Semi-Arid Region

The spatial distribution of soil moisture is a critical determinant for the success of vegetation restoration initiatives in semi-arid and arid regions. The Qilian Mountains, situated within a semi-arid zone in China, have been subject to significant water-induced soil erosion, which has led to extensive restoration activities, predominantly utilizing the species P. crassifolia. However, the interconnections between soil moisture and various land cover types within this region remain unclear, presenting challenges to effective woodland rehabilitation. This study examines the surface soil moisture dynamics in afforested areas with varying ages of plantation to determine the influence of tree planting on the moisture content of the upper soil layer. It investigates the characteristics and temporal patterns of surface soil moisture as the age of the plantation increases. The findings indicate that: (1) soil moisture levels follow a descending sequence from natural forest, through shrubland and grassland, to planted forest and mixed forest, with statistically significant differences observed between natural and mixed forests (p < 0.05); (2) young afforested areas (less than 50 years old) have lower soil moisture levels compared to natural forests, shrublands, or grasslands, and the ecohydrological impacts of afforestation become apparent with a temporal delay; and (3) the analysis using Generalized Additive Mixed Models (GAMM) and the application of Kriging interpolation to determine the spatial distribution of soil moisture reveals that in semi-arid and arid regions, several factors have a pronounced a non-linear relationship with the moisture content of the surface soil. These factors include the duration of afforestation, the position on the lower slope, the presence of shade on the slope, and the scale at which the study is conducted. Therefore, a comprehensive understanding of the dynamics of soil water content is essential to prevent the potential failure of artificially established forests due to inadequate soil moisture in their later stages.

Heavy metal content in dumpsite soils and vegetables: A case study of Ondo Town, Nigeria

The investigation scrutinized the levels and distribution of five heavy metals (iron, cadmium, copper, lead, and nickel) at two dumpsites (Site A and Site B) and a control zone in Ondo Town, Nigeria. Moreover, the examination assessed the presence of these heavy metals in vegetable plants (Talinum triangulare and Chromolaena odorata) commonly encountered in these areas, employing atomic absorption spectrophotometry (Buck AAS 210 VGP). Conventional methodologies were utilized to evaluate specific soil physicochemical characteristics. In the control region, minimal levels of each metal were identified, with the exception of nickel. The quantities of metals varied, with lead at 0.02 mg/kg in the control area and iron at 3.54 mg/kg in Site A. The metal levels in both soil and vegetables investigated generally remained below the maximum thresholds established by the World Health Organization (WHO) for soil and vegetables, except for cadmium in Site A. The dumpsites and the associated vegetables displayed elevated levels of the heavy metals in comparison to the control area, suggesting a gradual accumulation of these metals in the vegetable flora. Hence, the consumption of vegetables cultivated near the examined sites and the use of these areas for agricultural activities should be discouraged.

Diagnosis of Crude Oil Impacted Soil in Eleme Local Government Area, Rivers State, Nigeria

This study assessed the potential effects of crude oil on soil quality in Eleme Local Government Area of Rivers State. Soil samples were collected from 10 geopolitical wards of the Eleme Local Government Area of Rivers State, Nigeria. The soil and water samples were subjected to physicochemical and microbial analyses to test for pH, heavy metal content (Cadmium, Iron, Lead, Copper, and Chromium), Total Petroleum Hydrocarbon (TPH), Benzene, Toluene, Ethylbenzene and Xylene (BTEX) contents and Total Viable Count (TVC). Parameters of the soil were determined and compared to the control site and the permissible World Health Organization (WHO) limits. The soil pH varied across location, ranging from 5.5-7. TPH varied in across the different communities studied, ranging from 1.275-4889.29 mg/kg, and exceeding the WHO limit of 10mg/kg in all polluted soils. The result for the heavy metals showed that the soil samples of the studied sites showed increases in all heavy metals, when compared to the control. Cd values ranged from 0.01 - 0.32 mg/kg; Fe from 1325.23 - 9364.76 mg/kg, Pb from 0.001 mg/kg to 0.93 mg/kg and Cr from 0.001 - 5.08 mg/kg, all with WHO limits. The result for the microbial showed increases in TVC content in polluted soil. Results indicate that crude oil spillage has led to significant contamination of soil in the study area which could affect soil fertility.

Phthalate ester (PAEs) accumulation in wheat tissues and dynamic changes of rhizosphere microorganisms in the field with plastic-film residue

Phthalates acid esters (PAEs) have accumulated in soil and crops like wheat as a result of the widespread usage of plastic films. It is yet unclear, nevertheless, how these dynamic variations in PAE accumulation in wheat tissues relate to rhizosphere bacteria in the field. In this work, a field root-bag experiment was conducted to examine the changes of PAEs accumulation in the rhizosphere soil and wheat tissues under film residue conditions at four different growth stages of wheat, and to clarify the roles played by the microbial community in the alterations. Results showed that the plastic film residues significantly increased the concentrations of PAEs in soils, wheat roots, straw and grains. The maximum ΣPAEs concentration in soils and different wheat tissues appeared at the maturity, with the ΣPAEs concentration of 1.57 mg kg−1, 4.77 mg kg−1, 5.21 mg kg−1, 1.81 mg kg−1 for rhizosphere soils, wheat roots, straw and grains, respectively. The plastic film residues significantly changed the functions and components of the bacterial community, increased the stochastic processes of the bacterial community assembly, and reduced the complexity and stability of the bacterial network. In addition, the present study identified some bacteria associated with plastic film residues and PAEs degradation in key-stone taxa, and their relative abundances were positive related to the ΣPAEs concentration in soils. The PAEs content and key-stone taxa in rhizosphere soil play a crucial role in the formation of rhizosphere soil bacterial communities. This field study provides valuable information for better understanding the role of microorganisms in the complex system consisting of film residue, soil and crops.

On the accuracy of saturation estimation from electrical measurements of soils with high swelling clay content

AbstractElectrical conductivity models have been widely used to estimate water content and petrophysical properties of soils in hydrogeophysical studies. However, these models are typically only valid for soils with non‐expandable matrices because they were originally developed for clean sandstone reservoir rocks. Soils containing swelling clays are characterized by matrices that expand/contract upon gaining/losing water. In this laboratory study, we demonstrate that soil matrix changes affect saturation estimation using Archie's laws. A sample of a soil containing a swelling clay was fully saturated with a potassium chloride solution, then left to dry evaporatively at room temperature for 8 days. The complex resistivity of the soil, along with its weight and volume shrinkage, were measured daily during the drying period, and the surface conductivity was calculated based on previous empirical findings. Over the course of the study, the simultaneous evaporation yielded a 33% decrease in volume and caused a nonlinear reduction in saturation with decreasing water content. Accounting for surface conductivity and correcting for saturation using the calculated volume reduction resulted in a power‐law relationship with high R2 values between resistivity and saturation along with reasonable saturation exponents. On the contrary, neglecting either surface conductivity or shrinkage caused similar underestimations of saturation exponents. These results indicate that the application of Archie's second law to soils with swelling clays leads to erroneous predictions of resistivity if saturation values are not corrected for changes in the volume of the soil and surface conductivity is neglected.

Effect of pH, Carbonate and Clay Content on Magnesium Measurement Methods on Hungarian Soils

More exact information on soil nutrient management is crucial due to environmental protection, nature conservation, decreasing sources for mining, general precaution, etc. Soil magnesium (Mg) analytical methods of potassium chloride (KCl), Mehlich 3 (M3), water (WA) and cobalt hexamine (CoHex) extractions are compared with an elemental analysis and X-ray fluorescence (XRF) analysis. The ratio of the available to the total Mg content was calculated and compared on the whole dataset. The results showed that the linear regressions between all the pairs of Mg content measurement methods were significant. The linear relationship between the KCl and CoHex methods has the highest determination coefficient (R2 = 0.96), followed by WA–M3 (R2 = 0.68), M3–CoHex (R2 = 0.66) and M3–KCl (R2 = 0.60). The M3 solution demonstrated a greater capacity for extracting Mg from the soil. The second part is the analysis of the influence of CaCO3, pH, soil texture and clay content on the measurable magnesium content of soils. It was established that the extraction methods, the soil and the classification method of the soil properties affect the evaluation. These results may help through the nutrient replenishment and the melioration of soils. These results can help the examination of mineral nutrients, especially the Mg uptake.

Effects of banqueting on water infiltration and physico-chemical properties of soil in semi-arid lands

Banqueting is a simple and cheap soil conservation practice in natural rangelands under dry climates. Little research exists about its impacts compared to other land uses, where agriculture and land abandonment may be important reasons for degradation. This study has evaluated water infiltration and key physico-chemical properties of soil in natural rangelands with banquets in West Azerbaijan (North-Western Iran) compared to: (i) undisturbed sites (assumed as reference condition) and (ii) cultivated or abandoned dry farmlands. Under these soil conditions, the texture, bulk density, porosity, water content, pH, electrical conductivity, organic carbon and carbonate contents of soil (using common physical-chemical methods) as well as the hydraulic conductivity (using a single-cylinder infiltrometer) were measured in the topsoil (0–20 cm). This data was further processed by applying the Principal Component Analysis and the Agglomerative Hierarchical Cluster Analysis. In areas with banquets, soil hydraulic conductivity was higher by 84% compared to dry farmlands (abandoned or not), where water infiltration was noticeably reduced (−44%) compared to the reference soil condition. Moreover, a noticeable increase in organic carbon content (+80%) and a lower salinity (−36%) of soil compared to cultivated areas was measured. These effects are important to enhance soil fertility on one side, and resistance to erosion on the other side. Therefore, in the experimental areas, banqueting may counteract the degradation of soil due to the agricultural activity as well as its abandonment, and restore the properties of the undisturbed soils that are typical of natural rangelands. The results of this study may be of help for landscape managers and agronomists for the pressing needs for soil conservation and productivity in semi-arid areas that are prone to degradation and abandonment.

Inversion of coastal cultivated soil salt content based on multi-source spectra and environmental variables

Soil salinization seriously hinders the development of efficient ecological agriculture in coastal areas. The use of Landsat, Sentinel series and hyperspectral data is an ideal way for assessing soil salinity indicators. However, environmental data (e.g. climate, terrain and parent material) are important factors for estimating such indicators. It is necessary to find the advantages and limitations of a combination of satellite images, hyperspectral data and environmental variables (ENVI) for assessing soil salinity accurately. Various data or their combinations ([I] remote sensing [RS], i.e. bands and salinity indices of Landsat 9 and Sentinel 2; [II] ENVI, including soil attributes, climate and topography; and [III] RS + ENVI) were used to construct the salinity inversion model using random forest (RF) and extremely randomized trees (ERT) for cultivated areas in the coastal plain of Dongtai City, China. The hyperspectral data were also resampled to match the range of the image bands. RF performed better than ERT for all types of analyzed data, and RS + ENVI exhibited the best performance for Sentinel 2 (R2 = 0.86). Compared with the RS data alone, Landsat 9 and Sentinel 2 provided higher salinity simulations (41% and 126%, respectively) after combination with ENVI, and salinity mapping was closer to the actual soil salinity measurements. The variables of slope, salinity index (SIT), difference index and SIT had the highest contribution in Landsat 9, Sentinel 2 and resampled hyperspectrum based on Landsat 9 and Sentinel 2, respectively. In conclusion, RS + ENVI based on Sentinel 2 data is the recommended approach for monitoring the salt content of coastal cultivated soil.

Rapid estimation of soil Mn content by machine learning and soil spectra in large-scale

Manganese (Mn) is an essential element in both plants and the human body; however, traditional methods for monitoring Mn in soil are costly and inefficient. As such, it is necessary to establish a model for environmental research uses that can accurately predict soil Mn content over large areas. This study aims to develop a multilayer perceptron (MLP) model capable of accurately predicting Mn content in diverse soils based on visible and near-infrared (VNIR) spectroscopy. A dataset containing 18,675 soil samples compiled from the Land Use and Coverage Area Frame Survey was used to train and adjust the model, following which the optimal model was applied globally. The correlation coefficient, root mean square error, and mean absolute error values for the optimal model on the test set were 0.76, 140.52, and 97.30, respectively. Feature importance analysis revealed crucial spectral bands at approximately 1400, 2200, 2300, and 2400–2500 nm, which enabled the Mn content to be estimated. The presence of these spectral bands indicates that clay minerals, H2O, and OH− groups had significant influence on Mn content. The MLP model developed can effectively identify regions with potentially high or low soil Mn content. With improvement of the spectral database, this model can provide effective assistance in evaluating soil Mn distribution at the global scale.

Degradation of pharmaceutical pollutants in different soils by photocatalytic treatment under solar irradiation

Pharmaceutical compounds are chemicals widely applied for the treatment and prevention of human/animal diseases. Wastewater treatment plants (WWTP) are identified as one of their main transfer pathways to aquatic environment since traditional wastewater treatments do not completely remove them. Agricultural irrigation with reclaimed water from WWTP effluents is a growing strategy in areas where water scarcity is a limiting issue. However, the residual presence of these compounds in wastewaters facilitates a new terrestrial route of environmental exposure, increasing the risks of soil pollution and giving rise to dangerous situations for human health and the environment. In this study we have evaluated the effectivity of TiO2 photocatalysis using solar irradiation for the degradation of four contaminants (diclofenac, ibuprofen, ketoprofen and sulfadiazine) in different soil matrices. Influential parameters of photocatalytic process (TiO2 dosage and soil moisture content) were optimized at laboratory scale using UV-LED lamps as light source. Solar remediation trial was performed exposing polluted soils to different treatments (in presence and absence of photocatalyst) during August 2023. After 50 h of solar exposure degradations of these pharmaceuticals reached 97.8–99.5 %, 99.7–100 % and 83.2–97.5 % for soils S1, S2 and S3 respectively. For all compounds, removal followed the order S2 > S1 > S3, in coincidence with the lesser organic matter content of soils. Results suggest that TiO2 photocatalysis under sunlight irradiation could be a useful tool for remediating soils polluted with pharmaceutical residues.

Oenothera biennis with strong copper toxicity resistance enriches trace copper in seeds under copper pollution soil

Excess copper (Cu) imparts negative effects on plant growth and productivity in soil. To develop the ability of O. biennis to govern pollution soil containing excessive Cu, we investigated seed germination, seedling growth, and seed yield. Furthermore, Cu content and the expression levels of Cu transport related genes in different tissues were measured under exogenous high concentration Cu. O. biennis seeds were sensitive to excess Cu, with an observed reduction in the germination rate, primary root length, fresh weight, and number of seeds germinated daily. Consecutive Cu stress did not cause fatal damage to evening primrose, yet it slowed down plant growth slightly by reducing the leaf water, chlorophyll, plant yield, and seed oil contents while increasing the soluble sugar, proline, malondialdehyde, and H2O2 contents. The Cu content in different organs of O. biennis was disrupted by excess Cu. In particular, the Cu content in O. biennis seeds and seed oil increased and subsequently decreased with the increase of exogenous Cu, reaching a peak under 600 mg·kg−1 consecutive Cu. Furthermore, the 4-month 900 mg·kg−1 Cu treatment did not induce the excessive accumulation of Cu in peels, seeds, and seed oil, maintaining the Cu content within the range required by the Chinese National Food Safety Standards. The treatment also resulted in an upregulation of Cu-uptake (ObCOPT5, ObZIP4, and ObYSL2) and vigorous efflux (ObHMA1) of transport genes, of which expression levels were significant positive correlation (p < 0.05) with the Cu content. Among all organs, the stem replaced the root as the organ exhibited the greatest ability to absorb and store Cu, and even the Cu transport genes could still function continuously in stem under excess Cu. This work identified a species that can tolerate high Cu content in soil while maintaining a high yield. Furthermore, the results revealed the enrichment of Cu to occur primarily in the O. biennis stem rather than the seeds and peel under excess Cu.

Effect of Quarry Dust in Compaction Characteristics of Loose Sandy Soil from a Local Paddy Field

Loose Soils found in locations such as paddy fields deemed as unsuitable for construction works in general. Loose sandy soil is characterized by its granular and non-cohesive structure, which results in a high porosity and low bulk density. In construction, achieving adequate compaction is essential for enhancing the load-bearing capacity and stability of the soil. Therefore, if the geotechnical properties of these soils can be improved using a waste material such as quarry dust, which is a byproduct of the construction aggregate crushing process, it can offer a significant advantage. This study aims to assess the effect of quarry dust in maximum dry density and optimum moisture content of sandy soils from a local paddy field. Quarry dust is mixed with the soil in proportions of 10%, 20%, 30%, 40% &amp; 50% by weight. Laboratory tests such as sieve analysis, specific gravity, Atterberg limit and proctor compaction tests were conducted on soil and soil – quarry dust. The results indicated that maximum dry density continues to increase with the addition of quarry dust while optimum water content reduces up to the addition of 30% quarry dust. The findings support that compaction characteristics can be improved using quarry dust which increases the suitability of the soil for construction purposes.

Size Effects of Copper Oxide Nanoparticles on Boosting Soybean Growth via Differentially Modulating Nitrogen Assimilation.

Nanoscale agrochemicals have been widely used in sustainable agriculture and may potentially affect the nitrogen fixation process in legume crops. The present study investigated the size-effects of copper oxide nanoparticles (CuO NPs) on nitrogen assimilation in soybean (G. max (L.) Merrill) plants, which were treated with different sizes (20 and 50 nm) of CuO NPs at low use doses (1 and 10 mg/kg) for 21 days under greenhouse conditions. The results showed that 50 nm CuO NPs significantly increased the fresh biomass more than 20 nm CuO NPs achieved at 10 mg/kg. The activities of N assimilation-associated enzymes and the contents of nitrogenous compounds, including nitrates, proteins, and amino acids, in soybean tissues were greatly increased across all the CuO NP treatments. The use doses of two sizes of CuO NPs had no impact on the Cu contents in shoots and roots but indeed increased the Cu contents in soils in a dose-dependent fashion. Overall, our findings demonstrated that both 20 and 50 nm CuO NPs could positively alter soybean growth and boost N assimilation, furthering our understanding that the application of nanoscale micro-nutrient-related agrochemicals at an optimal size and dose will greatly contribute to increasing the yield and quality of crops.

Productivity of crop rotations with different types of fallow and their effect on the humus content in sod-podzolic soil the Middle Urals

The research was carried out in the conditions of the Perm Region on sod-podzolic heavy loamy soils in a long stationary plot trial, laid down in 1977. The purpose of the research is to study the effect of various types of fallow on crop rotation productivity and humus content in the soil. The data are given for two rotations (2009–2022) of fallow-grain–grass crop rotations with various types of fallow – with manurial, sown with clover, sown with melilot, sideral with clover and sideral with melilot – without mineral fertilizers and with fertilizers (N60P30K60). It was found that in the sown fallows, the mass of root and mowing plant residues of meadow clover and yellow melilot, depending on the nutrition background, reaches 4.08–4.36 t/ha with a nitrogen content of 41.8–46.9 kg/ha, phosphorus 16.7–18.6 kg/ha and potassium 42.7–69.6 kg/ha. In sideral fallow with clover and clover biomass, 6.99–9.04 t/ha and 6.83–8.53 t/ha of dry matter with a content of 133.5–148.1 kg/ha of nitrogen, 34.3–41.2 phosphorus and 121.2–148.9 potassium were supplied to the soil, respectively. The application of organic fertilizers in the fallow field contributed to an increase in the humus content by 0.19 abs.% to the initial (2.04 %) in the variant without mineral fertilizers and by 0.69 abs.% in the variant with the introduction of mineral fertilizers to the initial (2.08 %) Clover sideral fallow also contributed to an increase in the humus content in the soil by – 0.38–0.52 abs.%. There was an increased productivity of crop rotation with sideral melilot fallow (2.22–2.25 t/ha of grain units per year) relative to the traditional crop rotation with pure fallow (2.08–2.11 t/ha of grain units per year). Cultivation of crops in all studied crop rotations was energetically efficient, the energy efficiency coefficient was 3.63...4.48 in the variants without mineral fertilizers, against the background of NRK – 2.38...3.21.