Changes In Soil Properties Research Articles

Effects of Land uses on Soils Quality in Rwandan Central Plateau Agro-Ecological Zone

Conversion of land use from forest to agricultural uses modifies soil quality through physiochemical soil properties changes. This study was conducted in Rwanda’s central plateau agro-ecological zone to evaluate the effect of forest and agricultural land uses on soil quality. The study was conducted in 2020. Soil samples were collected at the top, middle and bottom positions of each of the two land uses. We analyzed soil bulk density, soil moisture content, soil pH, soil organic matter (SOM), total nitrogen (TN), available phosphorus (Av P), and CEC for each position of the land uses. Data were analyzed using ANOVA in GENSTAT version 13. The results revealed that soil properties were significantly affected by land use change. Analysis of variances (LSD<0.05) results showed, however, that treatments were not significantly different within the same land use. The results showed that treatments from top position of forest lands had the highest mean values for soil organic matter and total N parameters with the respective mean values of 6.58 %, and 0.37 %. Treatments from middle position of forest lands had the highest mean values for soil moisture content and Av P parameters respectively with 23.60 % and 29.56 ppm. But, soil bulk density was high on top position of agricultural land with a mean value of 1.49 g/cm3. Land users are advised to apply crop and soil management techniques which maintain soil quality and productivity on agricultural lands.

Long‐term soil change in the US Great Plains: An evaluation of the Haas Soil Archive

AbstractDiverse patterns of climate and edaphic factors challenge detection of soil property change in the US Great Plains. Because detectable soil change can take decades, insights into the trajectory of soil properties frequently require long‐term site monitoring and, where available, associated soil archives to enable comparisons with initial or baseline states. Unfortunately, few multi‐decadal soil change investigations have been conducted in this region. Here, we document effects of dryland cropping on a suite of soil properties by comparing matched historic (1947) and contemporary (2018) soil samples from the Haas Soil Archive at three sites in the US Great Plains: Moccasin, MT, Akron, CO, and Big Spring, TX. Current analytical methods were used to provide insight into changes in soil texture, pH, carbon, and micronutrients at 0‐ to 15.2‐cm and 15.2‐ to 30.5‐cm depths. Changes in direction and magnitude of soil properties over 71 years were site specific. Changes in textural class occurred at all sites, with Moccasin and Akron transitioning from loam to clay loam and Big Spring from sandy clay loam to sandy loam. The soil pH reaction class changed from slightly alkaline to moderately acid at Akron and slightly alkaline to moderately alkaline at Big Spring. At 0–15.2 cm, soil organic carbon decreased by 15% and 36% at Moccasin and Big Spring, respectively, but increased by 15% at Akron. Soil micronutrients generally declined at all sites. Weather‐related variables derived from air temperature and precipitation records were not correlated with soil change. Inferred factors contributing to soil change included on‐site management, inherent soil features, weather metrics not evaluated, or a combination thereof.

Effect of freeze‒thaw cycles on root-Soil composite mechanical properties and slope stability.

Natural disasters such as landslides often occur on soil slopes in seasonally frozen areas that undergo freeze‒thaw cycling. Ecological slope protection is an effective way to prevent such disasters. To explore the change in the mechanical properties of soil under the influence of both root reinforcement and freeze‒thaw cycles and its influence on slope stability, the Baijiabao landslide in the Three Gorges Reservoir area was taken as an example. The mechanical properties of soil under different confining pressures, vegetation coverages (VCs) and numbers of freeze‒thaw cycles were studied via mechanical tests, such as triaxial compression tests, wave velocity tests and FLAC3D simulations. The results show that the shear strength of a root-soil composite increases with increasing confining pressure and VC and decreases with increasing number of freeze‒thaw cycles. Bermuda grass roots and confining pressure jointly improve the durability of soil under freeze‒thaw conditions. However, with an increase in the number of freeze‒thaw cycles, the resistance of root reinforcement to freeze‒thaw action gradually decreases. The observed effect of freeze‒thaw cycles on soil degradation was divided into three stages: a significant decrease in strength, a slight decrease in strength and strength stability. Freeze‒thaw cycles and VC mainly affect the cohesion of the soil and have little effect on the internal friction angle. Compared with that of a bare soil slope, the safety factor of a slope covered with plants is larger, the maximum displacement of a landslide is smaller, and it is less affected by freezing and thawing. These findings can provide a reference for research on ecological slope protection technology.

Challenges in Sustainable Agriculture—The Role of Organic Amendments

Soil degradation threatens global food security and environmental sustainability, necessitating effective soil management strategies. This review comprehensively examines the impact of organic soil amendments on soil quality and productivity across various soil types and climatic conditions. A review of significant research related to organic amendments was performed using encompassed data from online search engines for studies published up until 31 December 2023. Despite their heterogeneity and use of varying methodologies, the data were narratively synthesized, providing a comprehensive understanding of amendment-induced changes in the chemical and physical properties of soil and the effectiveness of restoration on soil degradation. Organic amendments, including compost, vermicompost, biochar, and pomace, are pivotal in enhancing soil quality by increasing soil organic matter content, fostering aggregate formation, and improving soil structure in the short term. They positively influence water retention capacity, pH levels, nutrient availability, and carbon sequestration. In several studies, amendment-induced changes were absent, indicating that the effects of amendments vary depending on soil texture, application rates, and cropping systems, which emphasizes the need for tailored, sustainable soil management practices. This study concludes that organic amendments are a promising option for structure improvement and organic matter accumulation. It further suggests that an approach that integrates various methods is essential in order to meet desirable soil quality and retain agricultural productivity and offers valuable insights and recommendations for policymakers, practitioners, and researchers. Organic amendments can improve soil ecosystem services and contribute to climate change adaptation. In the future, more attention should be directed to tillage management and soil amendment interaction, as well as their effectiveness over specific periods of time.

Comparative Assessment of Inorganic Fertilizer and Farm Yard Manure Application on Yield, Sustainable Yield Index and Soil Physico-Chemical Properties in Cauliflower-Capsicum Cropping Sequence in Northern- Western Himalayas

ABSTRACT Continuous addition of inorganic fertilizer and farm yard manure (FYM) alone or in combination is necessary to assess the changes in yield and soil properties. Therefore, a study was conducted for consecutive two years on nutrient management with nine treatments viz. T1- control, T2-100% FYM (N equivalent basis), T3-100% N, T4-NP, T5-NK, T6-PK, T7-NPK, T8-100% NPK+ FYM (recommended Practice) and T9- 150% NPK+ FYM to assess the influence of different treatments on yield, sustainable yield index, soil physic-chemical properties and soil carbon stock and sequestration rate in cauliflower and capsicum cropping sequence. Results showed that the addition of farm yard manure alone or in a combination with chemical fertilizers contributed to higher soil organic stock and soil carbon sequestration rate. Application of 150% NPK + FYM improved the SYI of system by 49.4% over a control. This treatment increases soil carbon stock by 12.5% from 25.9 Mg ha−1 to 29.6 Mg ha−1 and recorded with maximum soil carbon sequestration rate, i.e. 2.21 Mg C m−3 year−1 over the 2 years. Thus, balanced fertilization of NPK and FYM is beneficial for the maintenance of soil physical health, improving CEC and macro and micronutrient levels.

Microplastics change soil properties, plant performance, and bacterial communities in salt-affected soils

Microplastics (MPs) are emerging contaminants found globally. However, their effects on soil-plant systems in salt-affected habitats remain unknown. Here, we examined the effects of polyethylene (PE) and polylactic acid (PLA) on soil properties, maize performance, and bacterial communities in soils with different salinity levels. Overall, MPs decreased soil electrical conductivity and increased NH4+-N and NO3−-N contents. Adding NaCl alone had promoting and inhibitive effects on plant growth in a concentration-dependent manner. Overall, the addition of 0.2% PLA increased shoot biomass, while 2% PLA decreased it. Salinity increased Na content and decreased K/Na ratio in plant tissues (particularly roots), which were further modified by MPs. NaCl and MPs singly and jointly regulated the expression of functional genes related to salt tolerance in leaves, including ZMSOS1, ZMHKT1, and ZMHAK1. Exposure to NaCl alone had a slight effect on soil bacterial α-diversity, but in most cases, MPs increased ACE, Chao1, and Shannon indexes. Both MPs and NaCl altered bacterial community composition, although the specific effects varied depending on the type and concentration of MPs and the salinity level. Overall, PLA had more pronounced effects on soil-plant systems compared to PE. These findings bridge knowledge gaps in the risks of MPs in salt-affected habitats.

Untargeted metabolomics to study changes in soil microbial community in response to tillage practices

Soil microbes are the main drivers of nutrient turnover in agro-ecosystems. The series of biochemical processes involved by these microorganisms are inseparable from the regulation of metabolites in the root-zone soils. Therefore, understanding the evolution of microbial communities driven by root-zone soil metabolites will help optimize agricultural management practices. Based on a field experiment, we explore the changes in soil properties, microbes, and metabolites under three tillage practices such as no-tillage with straw mulching (NTS), rotary tillage, and plough tillage with straw returning (RTS and PTS) based on untargeted metabolomics. We found that NTS helped to enhance nutrient contents and enzyme activities in the 0–20 cm soil layer. Specifically, compared with RTS and PTS, NTS increased grain yield by 6.4 % and 8.5 %, and SOC by 13.3 % and 5.7 %, respectively, but decreased pH by 2.8 % and 1.1 %. In addition, compared with NTS, RTS and PTS decreased the fungal richness by 16.5 % and 8.1 %, and decreased the fungal shannon index by 16.4 % and 9.2 %. However, tillage practices did not result in substantial differences in the alpha diversity of bacterial community. Both bacterial and fungal community composition were substantially affected by tillage practices and they were both significantly correlated with soil metabolites. In the symbiotic networks, NTS significantly increased the abundance of microorganisms with high connectivity, while RTS significantly increased the concentration of metabolites with high connectivity. Amino acids, as the main drivers, were significantly and positively associated with bacterial and fungal community composition, mainly enriched in the metabolic pathways of D − glutamine and D − glutamate metabolism and arginine and proline metabolism, and correlated with soil properties negatively and carbohydrates positively, directly or indirectly affecting soil microbial community composition. Our findings would provide new insight into metabolomics for the in-depth understanding of the metabolic mechanism for soil microbial community changes in dryland wheat fields under different tillage practices.

Response of Soil Physicochemical Properties and Microbial Community Composition in Larix olgensis Plantations to Disturbance by a Large Outbreak of Bark Beetle

Forests are affected by a wide range of disturbances globally, resulting in the decline or death of large areas of them. There is a lack of comparative studies on how soil properties change in forests that die under the influence of disturbances, especially considering different levels of disturbance. For this study, we took Larix olgensis—a major plantation forest species in northeast China—as the research object, one in which a large outbreak of bark beetle led to large-scale forest death, and set up fixed sample plots characterized by different disturbance intensities. We investigated the responses of soil physicochemical properties and microbial community compositions to different disturbance intensities through the determination of soil nutrient indices and high-throughput sequencing. The results show that there were significant differences (p < 0.05) in the effects of different disturbance intensities on soil physicochemical properties, where the soil moisture content, total nitrogen, total carbon, and total phosphorus in the control group were significantly higher than those in the disturbed groups. The soil pH was highest under low-intensity disturbance and the soil total potassium content was highest under high-intensity disturbance. At different disturbance intensities, the highest soil moisture content was found in the high-intensity group. Proteobacteria, Actinobacteria, Verrucomicrobia, Acidobacteria, Candidatus_Rokubacteria, Chloroflexi, Gemmatimonadetes, and Thaumarchaeota were the dominant populations with higher abundances; meanwhile, the relative abundance of Bacteroidetes, Tenericutes, and a tentatively unclassified fungus differed significantly (p < 0.05) across disturbance intensities. Among the dominant microbial populations, Acidobacteria showed a significant negative correlation with soil pH and a significant positive correlation with total potassium content, Thaumarchaeota showed significant positive correlations with soil moisture content and total nitrogen content, and Firmicutes and Gemmatimonadetes showed significant negative correlations with total carbon content in the soil. Furthermore, soil total nitrogen content was the key factor driving changes in microbial communities. The results of this study provide a scientific basis for the study of the long-term effects of tree mortality caused by insect pests on soil microbial communities and their response mechanisms, which is of great theoretical value for the establishment of scientific and effective methods for woodland restoration.

Response of Vegetation and Soil Property Changes by Photovoltaic Established Stations Based on a Comprehensive Meta-Analysis

Since the commencement of Sustainable Development Goals (SDGs), renewable energy has faced many challenges in reaching the target of SDGs, while the potential ecological impact on the environment cannot be ignored. The expansion of photovoltaic (PV) networks is raising concerns regarding the potential impact of large-scale PV power stations on local ecosystems. However, a comprehensive understanding of the specific responses of vegetation and soil factors to PV con-struction across different study locations is still lacking. To address this knowledge gap, we con-ducted a comprehensive meta-analysis of 28 studies internationally representing 31 observational points that evaluated 432 different vegetation and soil factor responses to the installation of PV power stations. We used piecewiseSEM to explore the responses of predictors/factors to the eco-logical environment. This study investigated the geographical and environmental conditions associated with PV construction and their responses to vegetation and soil factors, considering the advantages and disadvantages of PV power station construction in different ecosystems. The results indicate that (1) the response of the ecosystems to PV power station construction increased by 58.89%. Among these, the most significant improvement is in the desert, which accounts for 77.26%. Im-provement in temperate regions is 59.62%, while there is a decrease of 19.78% in boreal regions. Improvement in arid regions is 84.45%, while improvement in humid regions is 9.84%. (2) PV construction promotes SWC, vegetation diversity, vegetation coverage, and vegetation biomass, significantly enhancing vegetation productivity. (3) Among the different ecosystems, PV power station effects were most significant in deserts, while showing negative impacts on croplands. (4) Compared to below-panel treatments, between-panel treatments were more effective in improving ecological conditions. The study contributes to mitigating adverse effects associated with photovoltaic site development, offering insights into site selection planning for solar power stations and the advancement of the renewable energy sector.

Изменения дерново-подзолистой почвы в лесных культурах лиственницы европейской за длительный период

The research has been carried out in European larch forest plantations (Larix decidua Mill.) with the recording of changes in their silvicultural effect and the properties of sodpodzolic soil under the canopy of plantations over a period of more than 40 years. The aim of this work is to determine the nature of changes in the morphological and physicochemical properties of soils under the canopy of European larch forest plantations over a long period (45 years) in the conditions of the north-eastern Moscow Region. The research has covered 2 sample plots located in the B2 type of site conditions (simple fresh subor), which corresponds to fresh blueberry pine forests. The first sample plot (permanent sample plot 46) is located in an artificial plantation created in 1871 by planting. As for the second one (permanent sample plot B-2), it is located in forest plantations created in 1870 by sowing. Throughout the entire period of the research, the forest plantations have been growing according to the Ia quality class and have significantly increased the stock of stem wood. In forest plantations of the sample plot 46, the stock increased by 470 m3/ha (the current increase over 42 years of observation has equaled to 11.2 m3/ha per year), and in forest plantations of the sample plot B-2 – by 417 m3/ha (the current increase over 41 years of observations has equaled to 10.2 m3/ha per year). This indicates that there is currently no decay in the cultivated stands: they function successfully up to a century and a half old. Over 45 years, there have been changes in the morphological and physicochemical properties of the soil. A decrease in the content of the clay fraction has been established, especially in the upper part of the soil profile. The actual, exchange and hydrolytic acidity of the soil have increased as indicators of the ongoing process of podzolization. At the same time, the thicknesses of the forest floor and the humus content in the humus-eluvial layer have risen. The absorption capacity, the content of the exchange bases and the degree of saturation with the bases have increased, especially in the upper horizons of the soil, and the hydrolytic acidity has risen. In general, over a 45-year period, there has been no significant deterioration in the properties of sod-podzolic soils under the canopy of European larch forest plantations, and there are even trends of improvement in some indicators.

Micro and nanoplastics pollution: A review on global concern and its impacts on ecosystems

AbstractIn recent decades, the ubiquity of micro and nanoplastics (MNPs) pollution has emerged as a global concern due to its potential risks to both ecological and human health. The detrimental effects of MNPs have resulted in significant changes in the physicochemical and biological properties of terrestrial soil and benthic sediment. These alterations have led to a disrupted nutrient cycle, potential future climate hazards, and further impacts on ecosystem services. This review aims to discuss the possible origins, composition, abundance, life cycle, and transport processes of MNPs in aquatic and terrestrial ecosystems. It seeks to understand the potential ecological and human health risks associated with MNPs pollution and explores their implications for biodiversity conservation and ecosystem services. Moreover, this review highlights the advanced analytical techniques used to detect and quantify MNPs. It further suggests policy frameworks to combat this pollution in natural environments. The findings of this review are intended to assist environmentalists, microbiologists, hydrologists, and policymakers in identifying scientific gaps and pragmatic solutions to reduce MNPs pollution. Future research should investigate the intake mechanism and impact of MNPs on plants in different ecosystems, as well as their effects on food chains and human health. This will ensure that the ecological and human health risks associated with MNPs pollution can be timely mitigated.

Changes in properties of reclaimed-mine soil, plant growth, and metal accumulation in plants with application of coal fly ash and empty fruit bunches of oil palm

Reclaimed-mining soil (RMS) is characterized by low fertility, acidic pH, and high heavy metal contents. As a result, adding amendments becomes essential to support plant growth. Therefore, this research measured alterations in the characteristics of RMS, plant growth, and metal accumulation in plants with the co-application of coal fly ash (CFA) and empty fruit bunches of oil palm (EFBOP). In the first experiment, various levels of CFA (0, 75, and 150 Mg ha-1) and EFBOP (0, 25, and 50 Mg ha-1) were added to the RMS and then incubated at 70% water holding capacity for 45 days to determine their effect on changes in soil properties. In the second experiment, four treatments: control, CFA, EFBOP, and CFA+EFBOP were tested in the greenhouse to quantify their effects on the growth and metal accumulation of plants. Results of the study showed that the co-application of CFA and EFBOP significantly affected bulk density, pH, mineral nitrogen (NH4+ and NO3-), available phosphorus, and exchangeable Ca and Mg in RMS. CFA application increased exchangeable Al by 82-160%, while EFBOP resulted in a decrease of 24-119%. CEC decreased with CFA application and increased with the use of EFBOP. Plant growth increased with the co-application of CFA and EFBOP. The addition of CFA to soils results in increasing metal contents in plant tissue; however, the presence of EFBOP reduced the concentrations of metal in plant tissue. These results highlight the potential of CFA and EFBOP, which are industrial and agricultural wastes, as valuable soil amendments.

An agrogeophysical modelling framework for the detection of soil compaction spatial variability due to grazing using field‐scale electromagnetic induction data

AbstractSoil compaction is a regarded as a major environmental and economical hazard, degrading soils across the world. Changes in soil properties due to compaction are known to lead to decrease in biomass and increase in greenhouse gas emissions, nutrient leaching and soil erosion. Quantifying adverse impacts of soil compaction and developing strategies for amelioration relies on an understanding of soil compaction extent and temporal variability. The main indicators of soil compaction (i.e., reduction of pore space, increase in bulk density and decrease in soil transport properties) are relatively easy to quantify in laboratory conditions but such traditional point‐based methods offer little information on soil compaction extent at the field scale. Recently, geophysical methods have been proposed to provide non‐invasive information about soil compaction. In this work, we developed an agrogeophysical modelling framework to help address the challenges of characterizing soil compaction across grazing paddocks using electromagnetic induction (EMI) data. By integrative modelling of grazing, soil compaction, soil processes and EMI resistivity anomalies, we demonstrate how spatial patterns of EMI observations can be linked to management leading to soil compaction and concurrent modifications of soil functions. The model was tested in a dairy farm in the midlands of Ireland that has been grazed for decades and shows clear signatures of grazing‐induced compaction. EMI data were collected in the summer of 2021 and autumn of 2022 under dry and wet soil moisture conditions, respectively. For both years, we observed decreases of apparent electrical resistivity at locations that with visible signatures of compaction such as decreased vegetation and water ponding (e.g., near the water troughs and gates). A machine learning algorithm was used to cluster EMI data with three unique cluster signatures assumed to be representative of heavy, moderately, and non‐compacted field zones. We conducted 1D process‐based simulations corresponding to non‐compacted and compacted soils. The modelled EMI signatures agree qualitatively and quantitatively with the measured EMI data, linking decreased electrical resistivities to zones that were visibly compacted. By providing a theoretical framework based on mechanistic modelling of soil management and compaction, our work may provide a strategy for utilizing EMI data for detection of soil degradation due to compaction.

Understanding Salinity-Driven Modulation of Microbial Interactions: Rhizosphere versus Edaphic Microbiome Dynamics.

Soil salinization poses a global threat to terrestrial ecosystems. Soil microorganisms, crucial for maintaining ecosystem services, are sensitive to changes in soil structure and properties, particularly salinity. In this study, contrasting dynamics within the rhizosphere and bulk soil were focused on exploring the effects of heightened salinity on soil microbial communities, evaluating the influences shaping their composition in saline environments. This study observed a general decrease in bacterial alpha diversity with increasing salinity, along with shifts in community structure in terms of taxa relative abundance. The size and stability of bacterial co-occurrence networks declined under salt stress, indicating functional and resilience losses. An increased proportion of heterogeneous selection in bacterial community assembly suggested salinity's critical role in shaping bacterial communities. Stochasticity dominated fungal community assembly, suggesting their relatively lower sensitivity to soil salinity. However, bipartite network analysis revealed that fungi played a more significant role than bacteria in intensified microbial interactions in the rhizosphere under salinity stress compared to the bulk soil. Therefore, microbial cross-domain interactions might play a key role in bacterial resilience under salt stress in the rhizosphere.

Urea fertilization increased CO2 and CH4 emissions by enhancing C-cycling genes in semi-arid grasslands

Global climate change is predicted to increase exogenous N input into terrestrial ecosystems, leading to significant changes in soil C-cycling. However, it remains largely unknown how these changes affect soil C-cycling, especially in semi-arid grasslands, which are one of the most vulnerable ecosystems. Here, based on a 3-year field study involving N additions (0, 25, 50, and 100 kg ha−1 yr−1 of urea) in a semi-arid grassland on the Loess Plateau, we investigated the impact of urea fertilization on plant characteristics, soil properties, CO2 and CH4 emissions, and microbial C cycling genes. The compositions of genes involved in C cycling, including C fixation, degradation, methanogenesis, and methane oxidation, were determined using metagenomics analysis. We found that N enrichment increased both above- and belowground biomasses and soil organic C content, but this positive effect was weakened when excessive N was input (N100). N enrichment also altered the C-cycling processes by modifying C-cycle-related genes, specifically stimulating the Calvin cycle C-fixation process, which led to an increase in the relative abundance of cbbS, prkB, and cbbL genes. However, it had no significant effect on the Reductive citrate cycle and 3-hydroxypropionate bi-cycle. N enrichment led to higher soil CO2 and CH4 emissions compared to treatments without added N. This increase showed significant correlations with C degradation genes (bglA, per, and lpo), methanogenesis genes (mch, ftr, and mcr), methane oxidation genes (pmoA, pmoB, and pmoC), and the abundance of microbial taxa harboring these genes. Microbial C-cycling genes were primarily influenced by N-induced changes in soil properties. Specifically, reduced soil pH largely explained the alterations in methane metabolism, while elevated available N levels were mainly responsible for the shift in C fixation and C degradation genes. Our results suggest that soil N enrichment enhances microbial C-cycling processes and soil CO2 and CH4 emissions in semi-arid ecosystems, which contributes to more accurate predictions of ecosystem C-cycling under future climate change.

Meta-analysis shows the impacts of ecological restoration on greenhouse gas emissions

International initiatives set ambitious targets for ecological restoration, which is considered a promising greenhouse gas mitigation strategy. Here, we conduct a meta-analysis to quantify the impacts of ecological restoration on greenhouse gas emissions using a dataset compiled from 253 articles. Our findings reveal that forest and grassland restoration increase CH4 uptake by 90.0% and 30.8%, respectively, mainly due to changes in soil properties. Conversely, wetland restoration increases CH4 emissions by 544.4%, primarily attributable to elevated water table depth. Forest and grassland restoration have no significant effect on N2O emissions, while wetland restoration reduces N2O emissions by 68.6%. Wetland restoration enhances net CO2 uptake, and the transition from net CO2 sources to net sinks takes approximately 4 years following restoration. The net ecosystem CO2 exchange of the restored forests decreases with restoration age, and the transition from net CO2 sources to net sinks takes about 3-5 years for afforestation and reforestation sites, and 6-13 years for clear-cutting and post-fire sites. Overall, forest, grassland and wetland restoration decrease the global warming potentials by 327.7%, 157.7% and 62.0% compared with their paired control ecosystems, respectively. Our findings suggest that afforestation, reforestation, rewetting drained wetlands, and restoring degraded grasslands through grazing exclusion, reducing grazing intensity, or converting croplands to grasslands can effectively mitigate greenhouse gas emissions.

Effect of various biochar on selected soil properties and agronomical parameters of okra (Abelmoschus esculentus L.) at Rupandehi, Nepal

Biochar is rich in carbon and obtained by carbonization of biomass heated at 300-1000°C under limited oxygen which improves the soil properties and yield of various crops. This study aimed to determine the changes in soil properties and agronomical characteristics of okra by biochar prepared from different feedstock. The research was conducted in randomized blocks and replicated thrice, with treatments; control, wood ash (WA), rice husk biochar (RHB), bamboo biochar (BB), Ashoka leaves biochar (ALB), coconut husk biochar (CHB), and sawdust biochar (SB), applied at 18 t/ha. Biochar-incorporated soil and the biochar were analyzed for pH, electrical conductivity, nitrogen, P2O5, K2O, and organic matter, and the soil for bulk density, particle density, and porosity. Agronomical parameters like plant height, fruit size, and yield were also recorded. The biochar incorporation modified the soil's chemical properties and significantly decreased bulk and particle density. The highest reduction of 10.9% in bulk density (1.22gm/cm3), and 4.4% in particle density (2.39gm/cm3) were observed in ALB and SB incorporated soil respectively. ALB (50%) followed by BB (49%) showed a significant increase in soil porosity compared to the control (45.18%). BB (15.7cm) significantly increased the fruit size compared to the control (14.06cm) followed by ALB (15.5cm). ALB (8.16t/ha) significantly increased the yield of okra relative to control (7.82t/ha). The findings suggest the use of ALB and BB to improve soil properties and yield in the long run.

Влияние молотой серы на альгоцианофлору щелочных засолённых почв

The paper considers the impact of ground sulphur (S 0 ) used as a chemical ameliorant for alkali-saline soils, as well as of sulphur with mineral and organic fertilizers, on species diversity and abundance of soil phototrophic microorganisms – algae and cyanobacteria. The research was carried out in laboratory conditions through the example of alkali soil. The alkali type is automorphic, its subtype is brown semiarid. Application of ground sulphur, as well as sulphur with mineral and organic fertilizer additives to alkali-saline soil caused considerable change in its chemical and physical-chemical properties: рН decrease, and increase in conductivity and phosphorus, potassium, magnesium, and calcium content in soil extract. Soluble carbonates and hydrocarbonates content decreased. Changes in soil properties and chemical composition effected species composition and abundance of soil algocyanoflora. 16 species, including Cyanobacteria – 10, Bacillariophyta – 4, Chlorophyta – 2, were found in the control soil. 25 species of soil microphototrophs, such as Cyanobacteria – 14, Chlorophyta – 4, Bacillariophyta – 7, were found in the soil of experiment variants. Algocyanoflora species composition of control and experiment variants remains mostly the same (64%). Application of mineral and organic additives caused growth of algocyanoflora species diversity in soil. Sulphur application contributed to microphototrophs cells increasing in number. The highest species diversity of microphototrophs found in the variant with sulfur and a complex of mineral and organic fertilizers.

The physical and chemical properties of the technosols in the pot experiment with waste and groundwater irrigation


 
 
 Mediterranean areas are characterized by a strong spatial variability that makes the soil hydrogeological logical response highly complicated. Some seasons provoke dramatic changes in soil properties determining the runoff rates, such as soil water content or soil water repellency. In recent years, important progress has been made in adapting water needs to local conditions through the use of various parameters to assess soil water status. Estimation of the water status of the soil has been widely used in soil science as a tool for quantitative analysis. The main objective of this case study was to analyze technosol and irrigation water physical and chemical properties in the pot experiment with lysimeters. A pot experiment with Avocado rootstocks was equipped with lysimeters in the facilites of the «La Mayora Experimental Field site» of the Higher Council for Scientific Research (Spain). The scheme of the pot experiment included three sources of irrigation: a) groundwater; b) regenerated municipal wastewater (100%); c) a mix of ground and regenerated municipal wastewater (50 / 50%). Chemical analysis data indicate that the reclaimed wastewater does not meet irrigation requirements in terms of pH, EC and due to the significant content of sodium and chlorine. Even groundwater satisfies irrigation water qualitative requirements partially. The suitability of irrigation water on pH level can be characterized mainly as unsuitable and doubtful. Diluting regenerated wastewater with groundwater following the 50% principle led to a decrease in the potential risks for salinization of groundwater connected with leaching of the leachate. The dynamics of the change in the volume of leachate are related to precipitation, the frequency of irrigation, and different manifestations of the physical, mineralogical, and chemical properties of technosols.
 
 

Effect of Eucalyptus globulus Plantations on Soil Physicochemical Properties in the Upper Blue Nile, Ethiopia

In recent years, there has been a substantial conversion of croplands and grasslands to short rotation Eucalyptus globulus plantations in the northern highlands of Ethiopia. This has raised concerns among researchers, policymakers, and environmentalists regarding potential adverse effects on soil fertility. To address these concerns, a study was conducted to evaluate the impact of Eucalyptus globulus plantations on selected soil physicochemical properties in the region. The study involved four land-use types, comprising two age groups of Eucalyptus globulus plantations (4-year-old and 9-year-old), as well as areas designated for grasslands and croplands. Soil sampling was carried out in 10 m × 10 m subplots within each experimental plot, and standard methods were employed for soil analysis. The soil laboratory results were statistically analyzed using Two-way ANOVA and Pearson’s correlation coefficients in R software version 4.1.0. The findings revealed significant variations (p<0.05) in soil bulk density, soil organic carbon, and soil pH between the 4-year-old and 9-year-old Eucalyptus globulus plantations and the grasslands. A notable difference (p<0.05) in exchangeable acidity was observed between the 4-year-old and 9-year-old E. globulus plantations, with the latter exhibiting the highest mean exchangeable acidity (6.20 ± 0.76). However, no significant differences (p<0.05) were observed between the Eucalyptus plantations and the grasslands in available phosphorus (Av.P), exchangeable calcium (Ca2+), sodium (Na+), and magnesium (Mg2+) concentrations, as well as cation exchange capacity (CEC). The study results has, therefore, implied that Eucalyptus globulus plantations induced changes in specific soil properties with varying stand ages in the study area. Nonetheless, it was emphasized that further long-term research is necessary to comprehend the effects of these plantations on soil properties.