Soil pH Research Articles

Understanding the influence of environmental factors on forest composition along the vertical gradient of Northwestern Himalaya

Temperate and alpine ecosystems are considered the most sensitive and vulnerable region towards climate change in the Indian Himalayan region. The current study investigates forest composition in relation to environmental and edaphic factors, which is critical for determining plant community patterns. The impact of climatic and soil properties was studied to better understand species diversity and composition over an elevational gradient (2500–4800 m) in Beas Valley, Northwestern Himalaya. A total of 181 species from 15 community types, representing 122 genera and 53 families (9 Trees, 13 shrubs, and 142 herbs) were recorded from the valley. Non-metric multidimensional scaling (NMDS) analysis revealed significant compositional dissimilarity (PseudoF = 10.16, R2 = 0.48, p < 0.001) among vegetation types. Structural equation modeling (SEM) results indicated that tree species diversity was significantly influenced by solar radiation (β=0.17, p = 0.001) and winter temperature (β=41.95, p = 0.017). It was observed that solar radiation and winter temperature shape the community types in high elevation temperate regions. In contrast, precipitation, solar radiation along with summer temperature determine the composition of sub-alpine communities, whereas solar radiation, winter temperature and soil pH determine the composition of alpine communities. This indicated that multiple environmental factors are responsible for this diversity. The research findings shed light on crucial factors influencing high elevation plant diversity, emphasizing the significance of understanding environmental correlations for effective conservation. This is pioneer study, which will act as a reference for future studies in Beas valley. This scientific foundation allows for prioritized conservation efforts, focusing on areas with specific environmental conditions influencing forest composition and plant diversity, ultimately contributing to better management and preservation of high elevation plant communities.

Castor Bean Meal Fertilizer Improves Peanut Yield and Quality by Regulating the Soil Physicochemical Environment and Soil Enzyme Activities

PurposeFertilization is important for improving crop yield and soil quality. Elucidation of the effects of castor bean meal (CBM) fertilizer on peanut yield and quality and soil fertility can lead to additional fertilization options for peanut and provide a theoretical reference for achieving a high-quality, high-yielding peanut.MethodsDuring 2022–2023, a two-year long-term field experiment was conducted in Tongliao city, Inner Mongolia, China. No fertilizer (CK) was used as the control, and the effects of different treatments, i.e., CBM fertilizer (B1: 2520 kg ha-1, B2: 5040 kg ha-1, and B3: 10,080 kg ha-1), chemical fertilizer alone (F1: 175 kg ha-1, F2: 350 kg ha-1, and F3: 700 kg ha-1), and cow manure alone (N1: 3724 kg ha-1, N2: 7448 kg ha-1, and N3: 14,896 kg ha-1) on peanut yield and quality and soil fertility were investigated.ResultsThe results showed that CBM fertilizer application improved soil ecology. Compared with other fertilization treatments, the soil pH of B3 treatment decreased by 8.5%, but significantly increased the contents of organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), total potassium (TK), alkali-hydrolyzed nitrogen (AN), basic phosphorus (AP) and rapidly available potassium (AK) in the soil, which increased by 86.4%, 64.6%, 70.5%, 11.3%, 75.8%, 150.1%, and 116.2%, respectively, compared with CK. Meanwhile, B1, B2, N1 and N2 treatments also led to the elevation of the above indexes. In addition, the activities of urease (URE), sucrase (SUC), phosphatase (PPL), catalase (CAT), amylase (AMY) and protease (PRO) in the B3 treatment were significantly greater than those in the other fertilization treatments, with increases of 256.4%, 248.4%, 68.2%, 96.8%, 267.3%, and 155.7%, respectively, compared with CK. The B3 treatment also significantly increased the rootlet length(PRL), number of branches(BN), plant height(PLH) and lateral branch length(LBL) of the peanut plants. Compared with the other treatments, the B3 treatment had a greater peanut yields, reaching 8059.5 kg ha-1 and 9935.7 kg ha-1 in 2022 and 2023, respectively. Compared with the other treatments, the B1 treatment significantly increased the contents of protein (Pro), fat (FAT), unsaturated fatty acid (UFA) and vitamin E (VE), which increased by 23.3%, 6.1%, 1.0%, 29.1%, respectively, compared with CK, but the total sugar (TS) content was reduced by 9.1%. Correlation analysis further confirmed that peanut yield and quality were significantly correlated with soil nutrients and enzyme activities.ConclusionsThis study showed that the application of CBM fertilizer has certain positive effects. For example, the B3 treatment has certain potential for increasing peanut yield, and the B1 treatment can be used for peanut quality improvement. Therefore, CBM fertilizer is recommended as a new type of organic fertilizer for improving the peanut quality and yield.

In vitro tungsten bioaccessibility in Chinese residential soils: Implications for human health risk assessments and soil screening level derivation

Tungsten (W) contamination presents emerging environmental challenges, necessitating the need to establish soil screening levels (SSLs), especially for residential soils. This study assessed the health exposure risk and derived national and regional residential SSLs for W in Chinese residential soils, incorporating machine-learning prediction of in-vitro soil W bioaccessibility. We analyzed 204 residential soil samples collected across 24 provinces, recording a wide range of W concentrations (0.01–3063.2 mg/kg). Synchrotron-based X-ray fluorescence spectroscopy, chemical extractions, and random forest modeling indicated that the key determinants of soil W bioaccessibility were soil pH, cation exchange capacity, organic matter, and clay contents. Monte Carlo simulations demonstrated that soil W contamination predominantly results in noncarcinogenic health risks to residents via oral exposure, especially in mining-affected regions. A national residential SSL (NRSSL) of 35.5 mg/kg and regional residential SSLs (RRSSLs) of 34.5–49.2 mg/kg were established. Incorporating predicted bioaccessibility increased the NRSSL to 73.8 mg/kg and the RRSSLs to 69.8–112.5 mg/kg. Southern China, which is rich in W ore, exhibited lower RRSSLs, underscoring a need for enhanced safety management. Our framework and findings provide a robust scientific foundation for future soil contamination risk assessment studies, and we present customized SSLs that can guide targeted W risk control strategies.

Ketersediaan Nitrogen dan Pertumbuhan Selada (Lactuca sativa L.) pada Tanah Podsolik yang Diaplikasikan Azola (Azolla pinnata)

Podzolic soil is marginal land for agriculture because low N availability and low lettuce plant growth production can be overcome by appropriate fertilization. This study aimed to determine the effect of fresh Azola application on nitrogen availability, number of leaves, and fresh weight of lettuce plants on Podzolic soil. This research employed a single factor of completely randomized design (CRD), in which the treatments were: A0= control, A1= fresh Azola 4 t ha-1, A2= fresh Azola 8 t ha-1, A3= fresh Azola 12 t ha-1, A4= fresh Azola 16 t ha-1. Soil chemical characteristics: soil pH, contents of total N, NH4+, NO3-, organic C, and cation exchangeable capacity were determined on the 21st after incubation, while plant height and plant fresh weight were observed at harvest. The research results showed that increasing the amount of fresh Azola applied to the soil resulted in a tendency to increase soil pH, total N-content, N-NH4+, N-NO3-, number of plant leaves, and fresh weight of lettuce plants.

Effect of long-term radish (Raphanus sativus var. sativus) monoculture practice on physiological variability of microorganisms in cultivated soil

Long-term monoculture may affect soil environment biodiversity. An example of such a plant is radish (Raphanus sativus var. sativus), an economically important crop in Poland, a quick-growing vegetable with intensified harvest throughout the season. The aim of this study was to determine changes in biodiversity of soil under radish cultivation and to compare the research methods applied. The monoculture practice affected soil pH, but the organic carbon content remained stable. 16S RNA-seq analysis revealed changes in soil microbial population, with the dominant phyla Proteobacteria (37.3%), Acidobacteria (19%), and Actinobacteria (16%), and the dominant taxa Gaiella (1.59%), Devosia (1.51%) and Nocardioides (1.43%). These changes have not fully expressed in the number of culturable microorganisms, where only fungal abundance changed significantly. However, the physiological state of microbial cells (λ) indicated that oligotrophs and copiotrophs were in a vegetative (λ > 3.0) state at the beginning of the season and fungi at the end of the year. Changes in the biodiversity of soil microorganisms were visualised using Community Level Physiological Profiling, where an oscillation in Average Well Colour Development (OD560 = 0.78–1.48) was observed in successive months of radish culture, with biodiversity indices (Shannon and Substance richness) remaining similar. The greatest variation in the influence of monoculture practice on soil factors was observed for the soil enzymes activities (for dehydrogenase and peroxidase activities – 0.5 μg TPF/h/g DW and 1.5 μmolPYGL/h/g DW respectively). Alkaline phosphatases predominated among this group of enzymes, and the activity of carbon metabolism enzymes decreased over the season, except for invertases, where an increase in activity of up to 50 μg Glc/h/g DW was observed. All the parameters studied indicated changes in the soil environment. Nevertheless the microbial community remains stable during the whole experiment returning to equilibrium in a quite short time after changing conditions.

Soil nutrients and enzyme activities based on millet continuous cropping obstacles

In order to evaluate the effects of continuous cropping of millet on soil nutrients and soil enzyme activities, the present study was based on four treatments of 2 years of continuous cropping (T1), 3 years of continuous cropping (T2), 4 years of continuous cropping (T3) and rotational cropping (CK), based on 4 years of no fertilizer positioning experiments, and the soil nutrients, soil enzyme activities and millets yields were determined, respectively. The results showed that with the increase of continuous cropping years, the millet yield decreased and was significantly lower than that of rotating with legume crops, and compared with CK, the yields of T1, T2 and T3 treatments were reduced by 8.92%, 13.73% and 37.60%, respectively; the soil nitrogen and phosphorus contents were reduced, the quick-acting potassium content did not change obviously, and the soil pH was increased; Soil urease, alkaline phosphatase, sucrase and catalase activities generally showed a decreasing trend and the decrease was more significant with the increase in the number of years of continuous cropping. Therefore, in order to maintain the soil fertility and increase the millet yield, it is necessary to practice crop rotation and stubble reversal between millets and leguminous crops such as kidney beans, and to apply certain fertilizers.

Transport characteristics of heavy metals in the soil-atmosphere-wheat system in farming areas and development of multiple linear regression predictive model

Heavy metal accumulation in agricultural products has become a major concern. Previous studies have focused on the transport of heavy metals from the soil and their accumulation in crops. However, recent studies revealed that wheat leaves, ears, and awns can also transport and accumulate heavy metals. Wheat grains can be influenced by two sources of heavy metals: soil contamination and atmospheric deposition. To comprehend the transport characteristics of heavy metals in soil, atmospheric deposition, and wheat, 37 samples each for wheat rhizosphere soil, wheat roots, stems, leaves, and grains were collected. Fifteen samples of atmospheric dry deposition and atmospheric wet deposition were collected from Linshu County (northern area), China. Based on the test data, the characteristics of heavy metals and their distribution in the study area were analyzed. Migration patterns of heavy metals in crops from different sources were investigated using Pearson correlation and redundancy analysis. Finally, a predictive model for heavy metals in wheat grains was developed using multiple linear regression analysis. Significant disparities in the distribution of heavy metals existed among wheat roots, stems, leaves, and grains. The coefficient of variation of heavy metals in atmospheric deposition was relatively high, indicating discernible spatial patterns influenced by human activities. Notably, a positive correlation was observed between the concentration of heavy metals in wheat grains and atmospheric deposition of Hg, Cd, and Pb. Conversely, Zn and Ni levels in wheat grains were significantly negatively associated with soil Zn, Ni, pH, and OM content. The contribution of heavy metal elements from different sources varied in their impact on the grain's heavy metal content. Specifically, atmospheric deposition was the primary source of Hg and Pb in wheat grains, while Cd, Ni, Cu, and Zn were predominantly derived from soil. Using a multiple linear regression model, we could accurately predict Hg, Pb, Cd, Ni, Zn, and As concentrations in crop grains. This model can facilitate quantitative evaluation of ecological risk of heavy metals accumulation in crops in the study area.

Soil pH and organic matter: Key edaphic factors in sustaining optimum yield and quality of pomelo fruit

Identifying the soil properties associated with crop yield and quality variation is crucial for developing sustainable agronomic strategies. However, such information on pomelo production is scarce. Hence, forty independent sites in the primary pomelo production areas of Pinghe County were selected to investigate the influence of soil properties on pomelo yield and quality, and to provide reference for future soil management strategies. The results showed positive correlations between pomelo yield and soil pH, along with exchangeable calcium and magnesium, but this comes at the expense of fruit flavor quality. Meanwhile, soil organic matter positively influenced fruit flavor quality. Furthermore, a significant positive effect on fruit nutritional quality was noted across various soil properties, except for organic matter and available phosphorus concentration. A random forest model was used to predict pomelo yield, flavor quality, and nutritional quality based on soil properties and yielded R2 values of 0.50, 0.60, and 0.50, respectively. Partial least squares regression and structural equation modeling identified soil pH and organic matter as pivotal pomelo yield and quality determinants. The categorization of samples into four groups based on differences in pH and organic matter highlighted that integrating soil acidification remediation with organic matter increased is essential for sustainable pomelo production. Overall, this study offers comprehensive insights into the effects of holistic soil management on achieving both high yield and quality in pomelo cultivation. Furthermore, these findings serve as valuable reference for advancing sustainable production practices across large fruit types beyond the pomelo.

Characterization and Source Analysis of Heavy Metal(loid)s Pollution in Soil of an Industrial Park in Kunming, China

This study investigated the characteristics and sources of heavy metal(loid) pollution in the soil of a key industrial park in Kunming, China. In total, 60 soil samples (40 from agricultural land and 20 from construction land) were collected from and around the park. The soil pH and contents of Arsenic (As), lead (Pb), copper (Cu), zinc (Zn), cadmium (Cd), mercury (Hg), nickel (Ni), and chromium (Cr) were measured. The contents of the eight heavy metal(loid)s were analyzed using the background values of heavy metal(loid)s in the Kunming soil. The pollution load, geoaccumulation, and Nemero Comprehensive Pollution Indices were used for environmental risk evaluation. Cluster and principal component analyses were used to resolve heavy metal(loid) sources. Cd was enriched in construction and agricultural soils. As, Hg, Cd, Pb, Cu, and Zn exhibited large spatial differentiation and were significantly affected by the external environment. A regional pollution load index of 3.02 indicated overall heavy pollution. The pollution load index for each heavy metal(loid) indicated light pollution. The geoaccumulation index indicated relatively severe As, Cd, Cu, Pb, and Zn pollution. The Nemero Composite Pollution Index value showed that the study area was heavily polluted, with construction land being mildly polluted by Cd, and agricultural land being moderately polluted. The results of the spatial distribution show that there were high levels of contamination in the center. Correlation and principal component analyses showed that the pollution sources of the eight heavy metal(loid)s varied. Hg, Cd, and Pb originate primarily from industrial and agricultural pollution. Traffic sources significantly impacted Cu, Pb, Cd, and Cr. Natural sources are the main sources of Cr, Ni, and Cd. Ni is also affected by industrial sources, whereas Zn and Cu are affected by agricultural pollution. The influences of As, Cd, and Pb on the surface soil in the study area were more serious. Cd is more widely polluted and should be a priority in controlling soil heavy metal(loid)s.

A trait-based ecological perspective on the soil microbial antibiotic-related genetic machinery

Antibiotic resistance crisis dictates the need for resistance monitoring and the search for new antibiotics. The development of monitoring protocols is hindered by the great diversity of resistance factors, while the “streetlight effect” denies the possibility of discovering novel drugs based on existing databases. In this study, we address these challenges using high-throughput environmental screening viewed from a trait-based ecological perspective. Through an in-depth analysis of the metagenomes of 658 topsoil samples spanning Europe, we explored the distribution of 241 prokaryotic and fungal genes responsible for producing metabolites with antibiotic properties and 485 antibiotic resistance genes. We analyzed the diversity of these gene collections at different levels and modeled the distribution of each gene across environmental gradients. Our analyses revealed several nonparallel distribution patterns of the genes encoding sequential steps of enzymatic pathways synthesizing large antibiotic groups, pointing to gaps in existing databases and suggesting potential for discovering new analogues of known antibiotics. We show that agricultural activity caused a continental-scale homogenization of microbial antibiotic-related machinery, emphasizing the importance of maintaining indigenous ecosystems within the landscape mosaic. Based on the relationships between the proportion of the genes in the metagenomes with the main predictors (soil pH, land cover type, climate temperature and humidity), we illustrate how the properties of chemical structures dictate the distribution of the genes responsible for their synthesis across environments. With this understanding, we propose general principles to facilitate the discovery of antibiotics, including principally new ones, establish abundance baselines for antibiotic resistance genes, and predict their dissemination.

Enhancing phosphorus availability in biochar: Comparing sulfuric acid treatment to biological acidification approaches

AbstractBackgroundThe use of sulfuric acid (SA) to acidify biochars is known to enhance their phosphorus (P) fertilizer value. Potentially, biological approaches such as lowering the pH of biochar by lactic acid co‐fermentation or applying biochar with a nitrification inhibitor (NI) to reduce rhizosphere pH are an alternative to SA.AimThis study aimed to evaluate the two methods for increasing plant P availability from two biochars and compare them with SA‐treated biochars (as a reference) in a pot experiment.MethodsMeat and bone meal biochar (MB‐C) and digestate solids biochar (DS‐C) were bio‐acidified (BA) by lactic acid fermentation with organic waste. The untreated, SA‐treated, BA biochars, and biochars co‐applied with a NI (3,4‐dimethylpyrazolephosphate) were tested in a pot experiment with maize.ResultsThe fermentation reduced the pH of the organic waste biochar mixtures to &lt;4.3 and increased water‐extractable P (WEP) to 30% of total P. The untreated biochars had a mineral fertilizer replacement value of &gt;50% and SA increased replacement values to ≈100%. The application of NI did not affect rhizosphere pH or P uptake. The BA MB‐C increased soil solution P concentration, but P uptake did not significantly increase. The application of the BA DS‐C raised soil pH and reduced plant P uptake and biomass.ConclusionThe untreated biochars showed considerable P fertilizer effectiveness, suggesting that acidification may not always be necessary. Rhizosphere acidification and the bio‐acidification of biochars were not effective in further increasing P uptake, despite higher levels of WEP.

Fungal necromass contribution to carbon sequestration in global croplands: A meta-analysis of driving factors and conservation practices

Fungal necromass carbon (FNC) contributes significantly to the build-up of soil organic carbon (SOC) by supplying abundant recalcitrant polymeric melanin present in the fungal cell wall. However, the influence of a wide range of conservation practices and associated factors on FNC accumulation and contribution to SOC in global croplands remains unexplored. Here, a meta-analysis was performed using 873 observations across three continents, together with structural equation modeling, to evaluate conservation practices and factors responsible for the enhancement of FNC and SOC. FNC content (8.39 g kg−1) of North American soils was highest compared to FNC content of Asian and European soils. The structural equation models showed a significant (p < 0.05) positive influence of microbial biomass carbon (MBC), soil pH, and clay contents on the accumulation of FNC. Soil C/N ratio and climate factors, however, had only minor influences on FNC accumulation. Notably, the main driver of FNC was MBC, which is mainly influenced by the soil total N and geographic factors in the study areas. Typical 5 cropland practices had significant effect size (p < 0.05) on FNC, leading to an increase of 12 % to 26 %, and the FNC content was greatest under straw amendment (26 %). Fungal necromass accumulation efficiency ranged from 23 % to 45 % depending on cropland practices: non- and reduced tillage was the most efficient (45 %), followed by crop coverage (32 %), straw amendment (30 %), and manure application (27 %), while N fertilization had the lowest efficiency (23 %). We conclude that FNC contributes to over a quarter of SOC, highlighting its major role in enhancing C sequestration worldwide. Conservation practices, particularly non-tillage or reduced tillage, are important to enhance C sequestration from FNC in croplands.

Biochar effects on crop yield variability

Context or ProblemNumerous studies have demonstrated that biochar application can increase crop yield by improving soil properties and health. Yet, these studies, however, neglected how biochar alters yield variability across years – reflecting the yield stability. Objective or Research questionThis study aimed to investigate the effects of biochar application on crop yield variability. MethodsPublished data from 38 experimental sites were collected from the Web-of-Science. Two-thirds of the data were originated from three main staple crops: maize, wheat, and rice. The remaining were from rapeseed, soybean, sweet potato, and peppermint. Biochar effects on crop yield and its variability as well as their driving factors were analyzed by linear mixed models depending on soil conditions, field management practices, and climate types. ResultsBiochar increased the crop yield globally by 14 %, especially in soils with low pH (< 5.5), low nitrogen (N) and phosphorus (P) inputs (≤ 120 kg N ha−1, < 35 kg P ha−1), with high biochar inputs (≥ 20 Mg ha−1), and under crop rotation. Biochar increased crop yields by 12 % in short-term (≤ 5 years) and 21 % in long-term (> 5 years) experiments. Biochar increased yield variability by 42 % in acidic soils (pH < 5.5) and by 24 % with low N inputs (≤ 120 kg N ha−1), mainly because its liming and fertilization effects were short-lasting within the first few years. The yield variability after biochar application decreased with the increase in mean annual temperature, inter-annual variabilities of temperature and precipitation, but with the decrease in mean annual precipitation in the growing season. Yield variability under biochar increased in short-term experiments by 27 %, but there was no change (0 %) in long-term experiments because of the higher yield gains and resistance to fluctuating weather conditions. Therefore, crop yield variability decreased with increasing yield in long-term experiments. ConclusionsBiochar application increased short-term variability of crop yields, but its long-term variability remained unaffected. Implications or SignificanceThis study highlights that biochar can support steadily future crop production in the long run.

Beyond the rootzone: Unveiling soil property and biota gradients around plants

Although the effects of plants on soil properties are well known, the effects of distance from plant roots to root-free soil on soil properties and associated soil organisms are much less studied. Previous research on the effects of distance from a plant explored specific soil organisms and properties, however, comparative studies across a wide range of plant-associated organisms and multiple model systems are lacking.We conducted a controlled greenhouse experiment using soil from two contrasting habitats. Within each soil type, we cultivated two plant species, individually and in combination, studying soil organisms and properties in the root centre, the root periphery, and the root-free zones.We showed that the distance from the cultivated plant (representing decreasing amount of plant roots) had a significant impact on the abiotic properties of the soil (pH and available P and N) and also on the composition of the fungal, bacterial, and nematode communities. The specific patterns, however, did not always match our expectations. For example, there was no significant relationship between the abundance of fungal pathogens and the distance from the cultivated plant compared to a strong decrease in the abundance of arbuscular mycorrhizal fungi. Changes in soil chemistry along the distance from the cultivated plant were probably one of the important drivers that affected bacterial communities. The abundance of nematodes also decreased with distance from the cultivated plant, and the rate of their responses reflected the distribution of their food sources.The patterns of soil changes along the gradient from plant to root-free soil were largely similar in two contrasting soil types and four plant species or their mixtures. This suggests that our results can be generalised to other systems and contribute to a better understanding of the mechanisms of soil legacy formation.

Post-fire Effects on Soil Properties in High altitude Mixed-conifer Forest of Nepal

Studies on the effects of wildfires on soil are common in mixed-conifer forests worldwide; however, such studies are less frequent in the context of high-altitude mixed-conifer forests. In this research, we analyzed the soil physicochemical properties 14 years after a high-intensity wildfire. Soil samples were collected from a depth of 0–10 cm across 100 composite samples, representing both control and burnt areas. Our findings revealed significant changes in soil characteristics in the burnt area compared to the control area. Specifically, the average soil pH, electrical conductivity, and available potassium increased by 3 %, 81 %, and 53 %, respectively, in the burnt area, while available phosphorus decreased by 6 %. Conversely, the average total nitrogen and organic matter showed non-significant decreases of 20 % and 12 % in the burnt area compared to the control area. No significant differences were found in slope aspects. Electrical conductivity and available potassium varied significantly among upper (3300–3500 m), middle (3100–3300 m), and lower (2900–3100 m) altitude ranges. Principal component analysis explained a total of 50.1 % of the variance, with approximately 27.4 % explained by the first axis and 22.7 % by the second axis. The control and burnt areas were closely clustered, indicating similar soil properties. Electrical conductivity, available potassium, and pH were more linked to the burnt forests, while nitrogen and organic matter were more associated with the control forests. Consequently, post-fire restoration efforts should consider potential changes in soil nutrient availability to facilitate successful vegetation recovery. This study enhances the formulation of more precise post-fire land management strategies, improves forest restoration initiatives, and promotes sustainable land-use practices by comparing unburnt natural forests.

Exploring the mitigation effect of microbial inoculants on the continuous cropping obstacle of capsicum

To alleviate continuous cropping challenges of capsicums in the mountainous region of southern Ningxia, this study centered on the effect of microbial inoculants on capsicums continuous cropping. Through pot experiment, the effects of spraying actinomyces (PF) and root application of five kinds of microbial inoculants (F: Actinomyces, E: Effective Microorganisms, D: Bacillus licheniformis, K: Bacillus subtilis, and H: Trichoderma harzii) on the growth, physiological characteristics, quality, and soil fertility characteristics properties of capsicum in different growth periods were investigated. The results showed that compared with CK, PF treatment increased the root activity by 116.04 % and 53.32 % at seedling stage and mature stage respectively. E treatment significantly increased the yield, VC content, root volume, root surface area and soil microbial biomass (p<0.05). K treatment significantly increased the soil microbial biomass carbon content by 206.21 % compared with CK treatment at seedling stage. D and H treatments also increased soil pH, available phosphorus, total phosphorus, organic matter content, alkaline phosphatase activity and microbial biomass P content at each stage. In terms of yield, E, D, K and H treatments were increased by 173.40 %, 158.99 %, 166.03 % and 148.83 % respectively compared with CK treatment. The analysis by membership function method showed that EM compound microbial inoculant had the best effect on reducing the continuous cropping obstacles of capsicum in the mountainous area of southern Ningxia. In conclusion, microbial inoculant can promote the growth of continuous cropping of capsicum, increase its antioxidant enzyme activity, improve the soil environment of continuous cropping, and reduce the obstacles of continuous cropping of capsicum. This study reduced the continuous cropping obstacles of capsicum by reasonable improvement measures, and provided technical support for the sustainable development of capsicum industry in southern Ningxia.

Systematic review assessing the effects of amendments on acidic soils pH in tea plantations.

Soil acidification has emerged as a critical limiting factor for the sustainable development of the tea industry. In this article, a comprehensive review of 63 original research articles focusing on the impact of amendments on the pH in tea plantations soil was conducted. Through meta-analysis, the effect of applying soil amendments to increase the pH of tea plantation soil and its influencing factors were investigated. The results revealed that lime had a significant impact, increasing the pH by 18% in tea plantation soil, while rapeseed cake had a minimal (2%) effect. It was observed that as the quantity of amendments and pH levels increased, so did their impact on the pH of tea plantation soil. Subgroup analysis within biochar showed varying effects, depending on soil pH, with an 11% increase in acidic soil. Among these amendments, biochar produced at pyrolysis temperature ranging from 501-600 °C and derived from animal waste demonstrated significant effect on increasing soil pH in tea plantations by 9% and 12%, respectively. This study offers valuable insights into improving and ensuring the health and sustainability of tea plantations.

Cadmium Minimization in Grains of Maize and Wheat Grown on Smelting-Impacted Land Ameliorated by Limestone.

Cadmium (Cd) contamination in agricultural soils has emerged as a significant concern, particularly due to its potential impact on plant-based food. Soil pH reductions can exacerbate Cd mobility, leading to excessive accumulation in crops. While liming has been demonstrated as an effective method to mitigate Cd accumulation in rice grains in acid soils of southern China, its efficacy in remediating acid soils in northern China remains unclear. In this study, a multi-year field experiment was conducted on farmland impacted by zinc ore smelting at coordinates of 33.92° N 112.46° E to investigate the use of limestone for controlling Cd accumulation in wheat and maize grains. The results indicated that applying 7.5 t ha-1 of limestone significantly raised the soil pH from 4.5 to 6.8 as anticipated. Different rates of limestone application (2.25, 4.45, and 7.50 t ha-1) reduced Cd bioavailability in the soil by 20-54%, and Cd accumulation in wheat grains by 5-38% and maize grains by 21-63%, without yield penalty. The remediation effects were sustained for at least 27 months, highlighting limestone as a promising ameliorant for smelting-affected farmland in northern China.

The impact of land-use changes and management intensification on bacterial communities in the last decade: a review.

In the last decade, advances in soil bacterial ecology have contributed to increasing agricultural production. Brazil is the world leading agriculture producer and leading soil biodiversity reservoir. Meanwhile, there is still a significant gap in the knowledge regarding the soil microscopic life and its interactions with agricultural practices, and the replacement of natural vegetation by agroecosystems is yet to be unfolded. Through high throughput DNA sequencing, scientists are now exploring the complexity of soil bacterial communities and their relationship with soil and environmental characteristics. This study aimed to investigate the progress of bacterial ecology studies in Brazil over the last 10 years, seeking to understand the effect of the conversion of natural vegetation in agricultural systems on the diversity and structure of the soil microbial communities. We conducted a systematic search for scientific publication databases. Our systematic search has matched 62 scientific articles from three different databases. Most of the studies were placed in southeastern and northern Brazil, with no records of studies about microbial ecology in 17 out of 27 Brazilian states. Out of the 26 studies that examined the effects of replacing natural vegetation with agroecosystems, most authors concluded that changes in soil pH and vegetation cover replacement were the primary drivers of shifts in microbial communities. Understanding the ecology of the bacteria inhabiting Brazilian soils in agroecosystems is paramount for developing more efficient soil management strategies and cleaner agricultural technologies.

Sand mining deteriorates soil fertility and farming livelihoods around Accra, Ghana

Urbanization in Sub-Saharan Africa requires vast quantities of sand to meet infrastructural demands. In Accra, Ghana, sand mining occurs predominantly on farmlands at the city’s periphery. We selected three study communities to assess the effects of sand mining on agriculture using interviews with local farmers and soil analyses of mined and unmined fields. The results underscore the profound repercussions of sand mining on farmers, characterized by substantial agricultural land loss, the destruction of food crops, and the absence of compensation payments or land reclamation. The study further reveals a significant decline in soil fertility of mined fields compared to unmined fields as evidenced by reduced levels of carbon (C, by 6.3 g kg-1) and macronutrients (nitrogen (N, by 0.6 g kg-1), phosphorus (P, 12.7 mg kg-1), potassium (K, 77 mg kg-1) and magnesium (Mg, 88 mg kg-1)), and an increase in soil compaction (bulk density by 0.13 g cm-3 and penetration resistance by 0.11 MPa). Soil texture and pH were altered and sodium (Na, by 16 mg kg-1) and soil moisture (by 4%) increased. On a communal level, sand mining adversely affected water availability, road infrastructure, and the health of residents. The study fills research gaps on the effects of sand mining on agricultural productivity, soil fertility and livelihoods, emphasizing the urgent need for effective regulation, law enforcement and collaboration as well as compensation and land reclamation mechanisms to limit the adverse impacts of sand mining on ecosystem services. Further, the use of more sustainable building materials should be fostered to reduce the demand for sand in Ghana.