Levels Of Organic Matter Research Articles

Metagenomic Analysis of Microbial Diversity in the Moroccan Coastal Water of the Gibraltar Strait

Coastal waters are known for higher productivity and organic matter levels, which support a high diversity and abundance of microorganisms compared to some aquatic environments. The characterization of marine microbiomes can provide valuable information for evaluating the sustainability of coastal waters that are increasingly subjected to environmental and human impacts. Our study is the first metagenomic study realized on Moroccan Mediterranean coastal seawater. We analyzed and described the Gibraltar Detroit marine microbiome taxonomic and functional profiling using MG-RAST software. Shotgun sequencing revealed a predominance of bacterial taxa, particularly the Proteobacteria (57.29%) and Bacteroidetes (27.06%) phyla, alongside notable populations of eukaryotes, viruses, and archaea. Alphaproteobacteria and Gammaproteobacteria emerged as the dominant bacterial classes, while Flavobacteria represented a significant portion of Bacteroidetes. Functional profiling of the microbial community highlighted a wide array of metabolic pathways, emphasizing genes related to carbohydrate metabolism, amino acid synthesis, and protein processing. The marine microbiome exhibited essential biogeochemical activities, particularly in nitrogen, sulfur, and carbon cycles, with notable pathways including denitrification, thiosulfate oxidation, and carbon fixation. This functional diversity underlines the microbiome’s role in sustaining ecosystem health through nutrient cycling and organic matter degradation. Our findings offer a crucial baseline for understanding microbial community structure and resilience in Mediterranean coastal ecosystems, with implications for assessing future environmental and anthropogenic impacts on these microbial dynamics.

Comparison of Hollow Fiber and Flat Sheet Membranes for Removing TDS and Turbidity of Palm Oil Mill Effluent Wastewater

The most significant pollutant produced from agricultural industry in Kalimantan, Indonesia is Palm Oil Mill Effluent (POME). Due to the high levels of suspended particles and organic matter, POME has become a brownish color with high turbidity, color, chemical oxygen demand, and oil and grease content. To recycle the POME wastewater as clean water, these pollutants must be eliminated. In this study, we compare the effectiveness of hollow fiber (HF) and flat sheet (FS) membrane to remove total dissolved solid (TDS) and turbidity from POME with varied filtration pressure. HF and FS membrane were prepared from PVDF and nylon66 polymer, respectively. The PVDF HF membrane was modified using TiO2 and SBE (spent bleaching earth) to improve HF membrane properties to maintaining fouling. Meanwhile, FS membrane was added by pectin to increase the hydrophilic properties. Overall membrane’s morphology was determined by Scanning Electron Microscopy (SEM) to investigate the membrane structure. Both of HF and FS membrane were operated via ultrafiltration (UF) under cross flow system. The filtration pressures were varied at 1-3 bar and followed by flux and rejection evaluation. The results show both HF and FS membranes has stability flux. In addition, TDS rejection up to 25% while turbidity is excellent high over 95% for all membranes. The fabrication HF membrane has finger like-sponge structure and FS membrane exhibits sponge asymmetric structure. Overall, all membranes perform highest water flux (FS membrane) while highest rejection conducted by HF membrane for POME wastewater treatment.

The Multifaceted Soils of Himachal Pradesh, India: Types and Characteristics

The soils of Himachal Pradesh face a multitude of pressing issues that threaten their health and agricultural productivity. The diverse geographical features, temperature regimes and biological zones of Himachal Pradesh have resulted into a vast range of soil types in the state. Alpine, forest, alluvial and sub-mountain soils are the four major soil categories into which the state's soils can be generally divided. Only a particular species and adapted plants can thrive in the extreme weather circumstances of alpine soils, which are located at higher elevations and possess soils having thin, stony and acidic in reaction. The mid-hill areas are dominated by forest soils which are distinguished by their high levels of organic matter and nutrients. These soils support luxuriant vegetation and make effective agricultural methods possible. Alluvial soils, which are mostly found in river valleys and are deposited by ravine systems are extremely rich and perfect in fertility and suitable for growing a range of crops including vegetables, rice and maize. Located in the foothills, sub-mountain soil exhibits a blend of traits from alluvial and forest soils, thus providing a range of uses for horticulture and agriculture. In addition to supporting a diverse array of plant and animal life, Himachal Pradesh's varied soil types are vital to the region's agricultural economy. One of the biggest problems is soil erosion, which is made worse by the steep terrain and abundant rainfall in the area. This results in the loss of topsoil and decreased fertility. Deforestation, overgrazing, and unsustainable farming methods all contribute to land degradation, which further reduces biodiversity and soil quality. Furthermore, crop development is impacted by soil acidity in high-altitude regions, which restricts nutrient availability. However, these issues need efficient conservation measures and soil management techniques. In order to maintain Himachal Pradesh's rich biodiversity and agricultural potential for future generations, sustainable agricultural development and environmental protection in this ecologically sensitive area depend on an understanding of the complex soil dynamics. Addressing these interconnected issues requires a comprehensive approach, emphasizing sustainable land management practices, community engagement, and restoration efforts to preserve the vital soil resources of this ecologically sensitive region.

Land Suitability Assessment and Crop Water Requirements for Twenty Selected Crops in an Arid Land Environment

Expanding projects to reclaim marginal land is the most effective way to reduce land use pressures in densely populated areas, such as Egypt’s Nile Valley and Delta; however, this requires careful, sustainable land use planning. This study assessed the agricultural potential of the El-Dabaa area in the northern region of the Western Desert, Egypt. It focused on assessing land capability, evaluating crop suitability, mapping soil variability, and calculating crop water requirements for twenty different crops. In this work, we evaluated land capability using the modified Storie index model and assessed soil suitability using the land use suitability evaluation tool (LUSET). We also calculated crop water requirements (CWRs) utilizing the FAO-CROPWAT 8.0 model. Additionally, we employed ArcGIS 10.8 to create spatial variability maps of soil properties, land capability classes, and suitability classes. Using a systematic sampling grid, 100 soil profiles were excavated to represent the spatial variability of the soil in the study area, and the physicochemical parameters of the soil samples were analyzed. The results indicated that the study area is primarily characterized by flat to gently sloping surfaces with deep soils. Furthermore, there are no restrictions on soil salinity or alkalinity, no sodicity hazards, and low CaCO3 levels. On the other hand, the soils in the study area are coarse textured and have low levels of CEC and organic matter (OM), which are the major soil limiting factors. As a result, the land with fair capability (Grade 3) accounted for the vast majority of the study area (87.3%), covering 30599.4 ha. Land with poor capability (Grade 4) accounted for 6.5% of the total area, while non-agricultural land (Grade 5) accounted for less than 1%. These findings revealed that S2 and S3 are the dominant soil suitability classes for all the studied crops, indicating moderate and marginal soil suitabilities. Furthermore, there were only a few soil proportions classified as unsuitable (N class) for fruit crops, maize, and groundnuts. Among the crops studied, barley, wheat, sorghum, alfalfa, olives, citrus, potatoes, onions, tomatoes, sunflowers, safflowers, and soybeans are the most suitable for cultivation in the study area. The reference evapotranspiration (ETo) varied between 2.6 and 5.9 mm day−1, with higher rates observed in the summer months and lower rates in the winter months. Therefore, the increase in summer ETo rates and the decrease in winter ones result in higher CWRs during the summer season and lower ones during the winter season. The CWRs for the crops we studied ranged from 183.9 to 1644.8 mm season−1. These research findings suggest that the study area is suitable for cultivating a variety of crops. Crop production in the study area can be improved by adding organic matter to the soil, choosing drought-resistant crop varieties, employing effective irrigation systems, and implementing proper management practices. This study also provides valuable information for land managers to identify physical constraints and management needs for sustainable crop production. Furthermore, it offers valuable insights to aid investors, farmers, and governments in making informed decisions for agricultural development in the study region and similar arid and semiarid regions worldwide.

Using pack animals instead of tractors in Central Italy's protected areas: No evidence of reduced soil disturbance

In thinning operations in Mediterranean beech forests, pack animals are often used when topographic conditions do not allow for the use of mechanisation to perform logging operations. Otherwise, mechanised extraction is the primary choice. In an effort to reduce soil disturbance caused by mechanised ground-based logging, the forest authorities who guard protected areas have been mandating animal logging at all logging sites in recent years. Since no comparative scientific trials of soil disturbance of these two extraction systems have ever been conducted in the target setting, there is no scientific evidence to sustain this approach. On this basis, we chose two study areas where the forest authorities mandated animal logging. Each study area consists of three sub-compartments, one unharvested, one harvested by animals, and one harvested by tractor in the same year (2021). We examined soil compaction, soil organic matter, and soil microarthropod biodiversity in animal skid trails, tractor skid trails, soil unaffected by extraction methods, and unharvested control sites in each study areas. We used linear mixed-effects models, indicating the study area as random intercept, to investigate the effect of the experimental treatments on the target soil features, and to check the relationship among soil physico-chemical parameters and soil microarthropod biodiversity. We discovered that only the animal and tractor skid trails showed signs of disturbance in terms of soil compaction and organic matter loss. Additionally, there was a significant decline in the biodiversity of soil microarthropods in both the skid trail types, with values of the QBS-ar index which were practically halved in comparison to the control area. We did not find any significant difference in the values in the tractor and animal skid trails for any of the examined soil characteristics. Low soil microarthropod biodiversity was found to be correlated with high soil compaction in terms of penetration resistance and low soil organic matter levels, according to linear mixed-effects models. Despite our preliminary findings, we made it clear that the short wood system by a tractor fitted with forwarding bins is unquestionably a very soil-disturbing extraction system, that ought to be avoided when conducting logging operations in protected areas. However, pack animals are not a suitable solution to reduce soil disturbance. Other extraction systems such as chute, small-scale cable yarders, as well as combination of animals and machine avoiding extensive traffic on the forest soil, are better solutions to the fundamental issue of low-impact logging in protected areas.

Analysis of Physicochemical Properties, Enzyme Activity, Microbial Diversity in Rhizosphere Soil of Coconut (Cocos nucifera L.) Under Organic and Chemical Fertilizers, Irrigation Conditions

The application of chemical fertilizers and organic fertilizers, as well as irrigation, is an important agricultural practice that can increase crop yields and affect soil biogeochemical cycles. This study conducted coconut field experiments to investigate the effects of conventional fertilization (NCF), optimized fertilization (MCF), conventional fertilization + organic fertilizer (NOF), optimized fertilization + organic fertilizer (MOF), conventional fertilization + organic fertilizer + irrigation (NOFW), and optimized fertilization + organic fertilizer + irrigation (MOFW) treatments on soil physicochemical properties, soil enzyme activity, bacterial and fungal community structure and diversity, and compared the controls (CK, non-fertilizer and non-irrigation). The results showed that MOFW significantly increased soil electrical conductivity (EC), organic matter (OM), alkaline nitrogen (AN), available phosphorus (AP), available potassium (AK), available calcium (ACa), and available magnesium (AMg) levels. At the same time, it also significantly enhanced the activities of soil catalase (CE), polyphenol oxidase (POE), sucrase (SE), urease (UE), acid protease (APE), and acid phosphatase (APPE) (p < 0.05). The PCA analysis of soil microorganisms in the coconut rhizosphere soil showed indicated significant changes in bacteria and fungi community structure under fertilization treatments. The fertilization application leaded to an increase in the relative abundance and diversity of bacteria, but a decrease in fungi. Acidobacteriota, Proteobacteria, and Actinobacterota were the dominant bacterial phyla, and Ascomycota, Basidiomycota, Rozellomycota, and Mortierellomycota were the significant fungal phyla. Compared with CK, MOFW significantly increased the abundance of Acidobacteriota, Proteobacteria, Basidiomycota, and Mortierellomycota. Redundancy analysis (CCA) and Mantel test further revealed that pH, EC, OM, and AP were the main soil fertility factors driving changes in microbial communities. CE, SE, UE, APE, APPE were significantly correlated with microbial communities. Compared with NOFW, MOFW has a lower proportion of N, P, and K fertilizers in its fertilizer composition. The results indicated that MOFW can better improve the nutrient and enzyme status of the soil, which is a promising method for maintaining the balance of soil microorganisms in coconut orchards, and accordingly, reducing chemical fertilizers within a certain range can not only ensure consistency with conventional fertilizers, but also effectively improve soil conditions.

Study of the effect of five growing media used for the nursery production of Bombax costatum Pellegr. et Vuillet: A multipurpose tree in Côte d'Ivoire

Bombax costatum Pellegr. et Vuillet is a species frequently recommended for reforestation in West Africa. Mass production of vigorous seedlings of this species in nurseries is necessary for the reconstitution of colonies. The effect of five growing media on the growth parameters and dry matter production of Bombax costatum was studied in a completely randomised design. The Soil substrate was compared with a mixture of three (3) portions of Soil + one (1) portion of organic matter based on poultry droppings, rice straw compost, cocoa pod husks compost and wood chips compost, respectively. The growing media enriched with organic matter had pH values close to neutral and high levels of organic matter and nitrogen. The Soil + Poultry droppings substrate favored the production of plants with the highest values of stem height (87.84 cm; p ≤ 0.042), collar diameter (13.72 mm; p ≤ 0.004), number of leaves (19.34; p ≤ 0.025) and total dry matter (20 g.plant-1; p ≤ 0.036). Since the quality of transplant affects plant establishment and initial growth, the substrate Soil + Poultry droppings must be recommended for the nursery production of Bombax costatum, followed by the substrates Soil + Rice straw and Soil + Cocoa pod husks compost.

Soil bacterial community characteristics and influencing factors in different types of farmland shelterbelts in the Alaer reclamation area

To investigate the effects of various types of farmland shelterbelts on soil quality and soil bacterial community diversity, this study focused on soil samples from four different shelterbelt types in the Alaer reclamation area, including Populus euphratica Oliv.- Populus tomentosa Carrière (PP), Elaeagnus angustifolia L.- Populus euphratica Oliv. (EP), Populus alba var. pyramidalis Bunge (P), and Salix babylonica L. (S). We analyzed their physical, chemical, biological properties as well as the differences in bacterial community structure, and explored the influencing factors on soil microbial community characteristics through microbial correlation network analysis. The results showed that: (1) There were significant differences in soil properties among the four types of farmland shelterbelts (p < 0.05), with P soils exhibiting the highest levels of organic matter, total nitrogen, and total phosphorus contents. (2) The Alpha diversity indices of soil bacteria showed significant differences among the four types of farmland shelterbelts (p < 0.05), with the P soils displayed the highest Chao1 and Shannon indices. (3) There were differences in the composition and abundance of dominant soil bacterial communities among different farmland shelterbelts, notably, the abundances of Verrucomicrobia, Acidobacteria, and Planctomycetes were significantly higher in P soils compared to the other three types. (4) The complexity of the correlation network between microbial species and environmental factors was highest in EP soils, soil microbial biomass nitrogen and available phosphorus were the main influencing factors. These findings indicated that different types of farmland shelterbelts had significant impacts on soil properties and soil bacterial communities. Soil bacterial communities were regulated by soil properties, their changes reflected a combined effect of soil characteristics and tree species.

Effect of Some Ecological Factors on Earthworms (Lumbercus terrestris) in Wasit Governorate

Monthly earthworm samples were collected from two locations in Suwairah City‎ of Wasit Governorate. where the first location was northwest of the district and is characterized by an abundance of citrus trees such as orange, lemon and Punica granatum as well as many palm trees of different types, the second area is characterized by an abundance of vegetable plants like Cauliflower, Allium cepa, and Brassica oleracea. Soil temperature, moisture, pH, texture and organic matter levels were measured at all sample sites. Soil temperature ranged between 11C° to 50C° as recorded during February and August respectively. The values of PH have ranged between 6.8 to 8.0. Soil moisture and Organic matter content were highest in Region (B) samples, 40% and 6.6% respectively. However, lowest organic matter and soil moisture percentage were 17% and 3.13% recorded at in Region (A) samples respectively. All sites were characterized by loamy acidic reactive soils.

Different characteristics of the soil in marmot habitats might be one of the factors that influcting Yersinia pestis prevalent in which than pikas.

Marmots are recognized as host animals for plague caused by Yersinia pestis infection. It is unclear that why plague prevalent in marmot rather than other rodents like pikas in the same habitats. This study aims to analyze the differences of the soil characteristics around marmots and pikas burrows to explore the soils factors impacting on different epidemic intensities of Yersinia pestis in these two rodents. Soil samples were collected from within and around marmot and pika burrows, as well as from the nearby areas not inhabited by them and Chinese baseline soil properties as control groups, in the Qilian Mountains of Gansu Province, China. The physicochemical properties and the bacterial 16S rRNA were measured to analyze the characteristics of soils from different groups. Subsequently, the data were analyzed using R studio. The analysis revealed that marmot habitats exhibited distinct soil characteristics, including lower organic matter and alkaline hydrolyzed nitrogen, but higher electrical conductivity and total soluble salts. And soil in marmot areas tended to have higher concentrations of nickel, chromium, and iron, also lower levels of zinc and selenium. Additionally, the alpha diversity of soil microorganisms in marmot habitats was significantly low. Simultaneously, redundancy analysis was conducted, which showed that the low alpha diversity of marmot-soil was influenced by its physicochemical properties. The alpha diversity of the soil was positively correlated with EC, TSS, Na, and Cr, etc., while it was negatively correlated with AHN, OM, Se, Zn, and Fe, etc. These characteristics in marmot habitats, including low levels of organic matter, alkaline hydrolyzed nitrogen, zinc, selenium, and bacterial alpha diversity, as well as high levels of electrical conductivity, total soluble salts, iron, and nickel, played a crucial role in the spread of plague. It was discovered that the unique characteristics of marmot-soils provided essential elements necessary for the survival of Yersinia pestis, including high levels of Fe and Ca, or facilitated the spread of plague. Thus, the transmission of the plague was facilitated.

An overview of soil and plant assessment for predicting site quality and recovery strategies of one the largest tailings dam failures worldwide.

Brazil's Fundão dam collapse is one of the world's largest disasters of tailing dam failures. Previous research has evaluated toxic metals and non-metals (Cd, Cr, Ni, Pb, As, Hg) in the same soil samples used in this study, and results have indicated that only Fe and Mn concentrations increased above the original baseline (Melo et al., 2023). Consequently, the present study's focus has shifted towards assessing and integrating changes in soil quality regarding chemical fertility and morphological, physical, and mineralogical attributes in the floodplains post-dam collapse. Soil samples from 0 to 0.2 and 0.2-0.4m depths, and samples of Urochloa sp. were collected along ten transects, spanning 100km perpendicular to the Doce River channel. This sampling strategy targeted specific landscape positions including areas affected by deposited iron tailings (DIT), soil tailing mixture (STM), and control soil (CS) devoid of iron tailing interference. Results showed no discernible alterations in Ca, Mg, K, and P concentrations in Urochloa sp., and the most severe negative impacts observed regarded the replacement of kaolinitic pre-disaster matrix for hematitic matrix, reduction in organic carbon, and the prevalence of sand and silt particles. These factors collectively contributed to triggering: (i) decrease in chemical fertility and cation exchange capacity and (ii) significant decline in physical quality, evidenced by increased density and reduced total porosity and macroporosity. Addressing these adverse effects would require the augment of organic matter levels and offset the dominance of the hematitic matrix in the DIT. Furthermore, it is imperative to decompact the DIT by mechanized or plant cultivation means.

Characteristics of organic carbon in tobacco-growing soils with different pH

This paper deal with the analysis of the relationship between acidity and alkalinity with organic carbon structure and humus components of tobacco-growing soils in Tengchong city. Under the same level of organic matter and nutrient content, soils with different pH values in Tengchong city were selected for the investigation. Results showed that the HA/FA values of the soil with low organic matter content gradually decreased with increasing pH, indicating a higher content of active carbon components and a lower content of stable carbon components in the soils. In soils with high organic matter content, pH value showed a highly significant negative correlation with HA/FA and PQ values. With increasing acidity, HA/FA became higher, and humus components with high stability increased. At the same level of organic matter content, the infrared A2920/A1630 ratio gradually increased with increasing pH. It indicates that at a certain pH range and the same level of organic matter content, the stable humus component increases, and the soil pH value decreases. Bangladesh J. Bot. 53(3): 745-755, 2024 (September) Special

Effects of Compost Application of Green Waste on Soil Properties: A Meta-Analysis

Objective: With the accelerating urbanization process, the garden area is gradually expanding, and the production of green waste is also increasing. Composting green waste can not only reduce environmental pollution caused by incineration and landfill and improve the utilization efficiency of resources but also improve the soil and increase soil productivity. The study aims to investigate the comprehensive impact of green waste compost (GWC) application on soil nutrient conditions. Through comprehensive data analysis, the impact of compost application of green waste on soil properties was revealed as a reference for compost application and fertilizer reduction. Methods: Based on meta-analysis, we quantitatively investigated the response of soil properties to the application of green waste, collected published experimental data, and integrated 25 domestic and international literature to analyze the effects of different soil properties on soil nutrients. Literature was used to analyze the impact of different application rates of GWC on the physicochemical properties of soils with varying pH levels. The results were compared to control conditions with no GWC application. Results: The application of significantly improved soil quality by reducing soil bulk density and increasing the levels of soil organic matter, organic carbon, total nitrogen, available phosphorus, available potassium, and dehydrogenase activity. The increases in available potassium and soil organic carbon were consistently significant across all subgroups. However, the effects on available phosphorus and organic matter varied in significance depending on initial soil pH. Soil bulk density was influenced by the GWC content, while dehydrogenase activity showed significant effects only when initial soil pH was ≥8. Total nitrogen levels were significantly impacted by GWC application in soil with an initial pH of <8 and at GWC contents of ≥50%. Conclusion: The application of green waste compost demonstrates a positive effect on soil improvement. This study provides a comprehensive database that supports the use of GWC in enhancing soil quality and reducing the need for chemical fertilizers.

Effects of aerial liming on soil chemical and biological properties in metal contaminated and inaccessible lands in Ontario (Canada).

The manual addition of lime to soil, in addition to tree planting and fertilization have been the dominant strategy described in restoration protocols for ecosystems damaged by acid rain and metal contamination. Investigations on aerial-limed soils in inaccessible lands are limited. The objective of this study was to assess the effects of aerial liming on soil pH, organic matter, microbial biomass, and enzymatic activities, and aboveground plant population quality in metal-contaminated lands in northern Ontario, Canada. Soil samples were collected from three sites around the City of Greater Sudbury with each pair being composed of a reclaimed (areal-limed) site and an adjacent undisturbed (unlimed) area. Soil physico-chemistry, microbial biomass (assessed by Phospholipid fatty acid analysis) and enzymatic activities were analyzed. Soil pH was higher in limed sites compared to unlimed at recently restored sites (Baby Lake and Wahnapitae) but not at the oldest reclaimed site (HWY 80 N). Organic matter was higher in limed areas compared to the unlimed reference site only at most recently reclaimed site at Baby Lake. Aboveground plant population health was visibly improved in limed sites compared to unlimed areas. Metal concentrations of iron (Fe) and arsenic (As), total microbial biomasses, gram-negative bacterial, fungal, and eukaryotic biomasses were all significantly increased in the limed soils compared to the unlimed samples. The same trend was observed for the activities of three of the enzymes tested, β-N-acetylglucosaminidase (BG), aryl sulfatase (AS), and glycine aminopeptidase (GAP). Interestingly, strong positive correlations between the levels of soil organic matter, microbial biomasses, and NAGase and ALP activities were observed. Although expensive, aerial liming is effective in restoring inaccessible sites impacted by smelting operations where other methods cannot easily be used.

Effects of soil amendments and coverings on the kenaf yield and soil physicochemical properties in saline-alkali land

In order to investigate the effects of various treatments on the growth of kenaf in saline soil, this study employed a comprehensive experimental design incorporating a dual approach of soil amendment and mulching techniques. Soil treatment of saline and alkaline land, as well as biological material mulching treatment after sowing kenaf, were conducted. The growth dynamics of kenaf were assessed before the mid-term investigation, and the harvest period was examined. Soil physicochemical properties were measured and analysed at different periods. The results show that in the analysis of red sesame yield traits, the differences mainly appeared between soil treatments. There is no significant difference between the different mulching treatments within each soil treatment. In the mid-term study, significant differences were observed in kenaf plant height. Plant height was the most affected by soil conditioners, while other yield traits did not show significant variations. During harvest, only stem thickness and dry weight of a single plant did not show significant differences, whereas other yield traits did. The application of soil conditioners resulted in a 58.15% increase in dry hull yield compared to organic fertilizers and a 22.66% increase compared to regular fertilizers. Soil conditioners also led to higher levels of effective phosphorus, quick-acting potassium, organic matter, and total nitrogen throughout the kenaf growth period compared to organic and regular fertilizers. This is beneficial for enhancing soil quality and reducing soil alkalinity. Combined with the results of kenaf yield and soil physical and chemical properties analysis, it has been proven that the application of soil conditioner has the best effect, followed by the application of compound fertilizer, with organic fertilizer treatment being the least effective.

Modulation of fecal microbiota and reductions in fecal antibiotic resistance genes (ARGs) driven by Weissella-fermented feed in growing pigs

Probiotics-induced feed fermentation can improve the composition of microbiota, leading to benefits in pig production. However, the influence of probiotics-driven feed fermentation on pollution reduction is limited. This study aimed to analyze the impact of Weissella-based feed fermentation on the chemical characteristics, changes in microbial abundance, and antibiotic resistance genes (ARGs). Moreover, the possible mechanism and the association among them was also analyzed. First, pigs reared on fermented feed exhibited improved growth performance. The fermentation group showed a significant reduction in emissions of total phosphorus (TP), total carbon (TC), organic matter (OM), copper (Cu), and zinc (Zn) levels in feces compared to the control group. The fermentation group also showed a significant decrease in the ARGs, especially for the tetX, tetW, tetQ, tetL, tetO, tet32, tet44, ermG, ermF, CfxA2, CfxA3, aph3-III, aadA, and ant9-I, compared to the control group. The primary functional microbiota, characterized by increased levels of Bifidobacterium, Megasphaera, and Mitsuokella, and decreased levels of Methanosphaera, and Ruminiclostridium, displayed both negative and positive correlations with ARGs, TC, TP, OM, Cu, and Zn. Furthermore, a significant association was observed between the alterations in microbiota and ARGs and the lactic acid concentration in the fermented feed. The molecular docking results showed a good fit between lactate dehydrogenase and three antibiotics, particularly tetracycline. In conclusion, these results offer novel targets and strategies to address environmental pollutants associated with pig farming.

Late Holocene geochemical signature of inter reef mixed sediments on the northeastern Brazilian outer shelf

The northeastern outer shelf in Brazil is a complex ecotone that holds significant information on Holocene sedimentary processes and evolution. X-ray diffraction (XRD), X-ray fluorescence (XRF), and scanning electron microscopy/energy dispersive spectrometry (SEM/EDS) were employed to investigate bioclastic sedimentary facies and patches of relict siliciclastic sands. Radiocarbon dating (AMS) indicates that the carbonate sediments and corals formed in the past millennium. The sediment samples were divided into two groups using a multivariate analysis of XRD and XRF. The first group consists of siliciclastic materials, characterized by Si, Al, Fe, K, Zr, and Ti, and has low levels of carbonate and organic matter. The second, bioclastic and mixed facies, has a high carbonate content and exhibits elevated concentrations of Ca, Sr, and Mg, indicating authigenic processes. The EDS data revealed that the shells predominantly consisted of Cl, Cu, Al, Fe, and Ca. The terrigenous sites are detached from the coastal sources and are mainly located within the reef areas of the outer shelf. The erosion processes in these areas were inefficient to eliminate the siliciclastic sediments. This deposit trapped in inter reef sediments holds the key to understanding the timing and interactions between past coastal processes, shelf valley incision, and reef evolution during the Late Holocene transgression.

Outburst floods and their impact on Chinese Neolithic cultures during the 4.2 ka BP event: Evidence from Dayeze Lake in the lower reaches of the Yellow River

Abrupt climate fluctuations between 4.2 and 3.5 ka BP, and in particular the 4.2 ka BP event, exerted a profound impact on the global ancient civilizations. However, hydroclimatic conditions within the Asian Summer Monsoon (ASM) regions during this event remain uncertain. Here we report a multi-proxy analysis of a sediment core obtained from Dayeze Lake in the lower reaches of the Yellow River in monsoonal China, to elucidate the hydroclimatic variabilities over the past 4.2 ka. Core intervals (4.2–3.5, 1.1–0.6 cal ka BP) containing high levels of sand fraction, low-frequency magnetic susceptibility and zirconium, and low levels of organic matter and calcium oxide, reflect outburst floods from the Yellow River. This is supported by the widespread fluvial deposits and slackwater deposits preserved in archaeological sites and loess-paleosol profiles from the middle and lower reaches of the Yellow River. In contrast, various climate records, such as lake level, pollen, and tree ring data, from the marginal regions of the ASM reflect widespread droughts during the same time period. This finding highlights the significant spatial heterogeneity of hydroclimate within ASM regions associated with the 4.2 ka BP event, which may be related to migrations of the monsoonal rain belt and the West Pacific subtropical high, as well as frequent El Niño–Southern Oscillation events. Referring to archaeological data, we conclude that the decline and collapse of Chinese Neolithic cultures were related to a pattern of droughts in the marginal regions of the ASM and floods in the middle and lower reaches of the Yellow River.

Green manure (Ophiopogon japonicus) cover promotes tea plant growth by regulating soil carbon cycling.

In mountainous tea plantations, which are the primary mode of tea cultivation in China, issues such as soil erosion and declining soil fertility are particularly severe. Although green manure cover is an effective agricultural measure for restoring soil fertility, its application in mountainous tea plantations has been relatively understudied. This study investigated the effects of continuous green manure cover using the slope-protecting plant Ophiopogon japonicus on tea plant growth and soil microbial community structure. We implemented three treatments: 1 year of green manure coverage, 2 years of coverage, and a control, to study their effects on tea plant growth, soil physicochemical properties, and soil bacterial and fungal communities. Results demonstrate that green manure coverage significantly promote the growth of tea plants, enhanced organic matter and pH levels in soil, and various enzyme activities, including peroxidases and cellulases. Further functional prediction results indicate that green manure coverage markedly promoted several carbon cycling functions in soil microbes, including xylanolysis, cellulolysis, degradation of aromatic compounds, and saprotrophic processes. LEfSe analysis indicated that under green manure cover, the soil tends to enrich more beneficial microbial communities with degradation functions, such as Sphingomonas, Sinomonas, and Haliangium (bacteria), and Penicillium, Apiotrichum, and Talaromyce (fungi). In addition. Random forest and structural equation models indicated that carbon cycling, as a significant differentiating factor, has a significant promoting effect on tea plant growth. In the management practices of mountainous tea plantations, further utilizing slope-protecting plants as green manure can significantly influence the soil microbial community structure and function, enriching microbes involved in the degradation of organic matter and aromatic compounds, thereby positively impacting tea tree growth and soil nutrient levels.

Influence of Eucalyptus globulus plantations on soil characteristics at different altitudinal levels

This study evaluated the influence of Eucalyptus globulus L. plantations on the physical, chemical and biological properties of the soil in three districts: Magdalena, Tingo and San Isidro del Maino. The evaluation was carried out in six plots, three with eucalyptus and three with natural forests. In each plot with eucalyptus, 10 specimens were selected to measure their dasometric characteristics. Ten soil samples were taken at the base of each specimen to evaluate the bulk density and soil characterization, replicating the sampling in the natural forest plots. Additionally, biological sampling was carried out in each plot using the Rapid Soil Sampling Protocol, with a total of five quadrats per plot. The results showed significant differences in diameter at breast height (DBH), tree height and dry biomass among the districts evaluated. Trees in Magdalena presented the highest DBH and height, with an average biomass of 934.22 kg/tree, while those in Tingo showed the lowest values, with an average biomass of 230.00 kg/tree. Diverse flora species associated with both eucalyptus and natural forests were identified, reflecting a rich biodiversity in each district. Soils with eucalyptus in Tingo showed a predominantly clay texture, while in Magdalena and San Isidro del Maino a sandy loam texture predominated. In the natural forests, the soils in Tingo were also clayey, with more varied textures in the other districts. Bulk density was higher in forest soils in Tingo and in eucalyptus soils in San Isidro del Maino. Soils under eucalyptus had lower pH and lower electrical conductivity compared to natural forest soils. In terms of nutrients, the eucalyptus soils in Tingo and Magdalena showed higher phosphorus and potassium contents, while in San Isidro del Maino, the forest soils had higher levels. In general, eucalyptus soils showed higher levels of organic carbon, organic matter and nitrogen in Tingo and Magdalena, but lower in San Isidro del Maino. Biologically, natural forest soils exhibited a higher diversity and quantity of organisms compared to eucalyptus soils, especially in San Isidro del Maino. Detritivore indices were higher in natural forests, suggesting greater soil biodiversity. This higher diversity could be associated with better soil quality in these systems, highlighting the importance of natural forests in maintaining healthy soils.