Acid Soils Research Articles

Influence of crop management on stability rye yield and some grain quality traits

AbstractThe study explored the performance of hybrid and population rye (Secale cereale) cultivars under two different crop management intensities in Poland: moderate‐intensity and high‐intensity management. The focus was grain yield, grain quality, yield components, and variety stability in two growing seasons (2018/2019 and 2019/2020) at three locations. Hybrid cultivars consistently yielded higher grain yields (9.81 t ha−1) than population cultivars (7.90 t ha−1), with increase of 24.9%. However, hybrid cultivars had lower protein content (8.94%) than population cultivars (9.77%). Spike number was the most influential factor on yield, followed by 1000‐grain weight and grains per spike, regardless of cultivar type. Hybrid cultivars displayed a lower degree of stability as assessed using the ranking sum of the Shukla variance and the multi‐trait stability index. Hybrid cultivars were strongly dependent on resistance to fungal diseases, including Septoria (Mycosphaerella graminicola), and increased stability under moderate‐intensity management. Resistance to soil acidification became more important for cultivar stability under high‐intensity management.

Impact of Stress Induced by Unfavorable Soil Conditions on the Germination, Seedling Developmentand Stress Tolerance Indices of Browntop Millet (Brachiaria ramosa L.)

Background: Browntop millet, a traditionally cultivated yet underutilized millet, is abundant in iron, zincand fiber. It can thrive in diverse soils and climates, adapting well to a broad spectrum of ecological conditions. Assessing the performance of Brown top millet in various challenging soils prevalent across Tamil Nadu could provide valuable insights into its adaptability and potential for cultivation in different soil conditions. The evaluation focuses on its germination, seedling growthand stress tolerance indices in these diverse soil environments. Methods: The pot experiment was carried out in the Department of Agronomy, Tamil Nadu Agricultural University, Coimbatore during Kharif 2023 season. Six soil types were collected from different zones in Tamil Nadu and tested in a completely randomized design with four replications. Germination, seedling growth and stress tolerance indices were calculated by using standard formula. Result: Results of the investigation revealed that the treatment with sandy clay loam soils of Eastern Block 37B TNAU, Coimbatore (T1) recorded higher germination and seedling growth indices. The lowest values were recorded with the sodic soils of ADAC and RI, Trichy (T6). The higher stress tolerance indices were recorded with the heavy clay soils of Cotton Research Station (CRS), Veppanthattai, Perambalur district (T2)and acidic soils of Anaikatti, Coimbatore district (T3).

Effect of soil factors on flavonoid metabolites in Striga asiatica using LC–MS based on untargeted metabolomics

BackgroundStriga asiatica (L.) O. Kuntze is a traditional medicinal plant rich in flavonoids, which has various pharmacological effects such as anti-hepatitis and antioxidant activities. However, there is a scarcity of resources, and artificial cultivation has not yet been achieved. This study explored the association between flavonoid metabolites and soil physicochemical properties and trace elements in different habitats, with the aim of offering theoretical guidance for the high-quality artificial cultivation of S. asiatica.ResultsThe results showed that S. asiatica has low requirements for soil fertility and prefers to grow in acidic soil with high contents of potassium and available potassium, while low contents of phosphorus, nitrogen and alkali hydrolyzed nitrogen. Additionally, 1592 kinds of metabolites were identified from S. asiatica, including 78 flavonoids.ConclusionsThe flavonoid metabolites were strongly related to soil factors. Reasonable application of nitrogen and potassium fertilizers as well as controlling the contents of sodium, manganese and boron in the soil, can promote the synthesis of flavonoid metabolites in the plant. Moreover, kaempferide, glycitein, luteolin, apigenin and genistein may be the metabolic markers for identifying different regions.Graphical

Effectiveness and Duration of Action of Dolomite Screening Particles Used for Reclamation of Acidic Soils. Empirical Models of the Acidification Process of SodPodzolic Light Loamy Soil (according to Field Experience)

In a long-term 10-variant microfield experiment based on a mediumacidic sod-podzolic light loamy soil, a comparative study of the reclamation properties of the screening of dolomite crumbs stored in dumps, without separation into fractions (SIF), particles of 5–7 and 7–10 mm in size and dolomite flour (DF) prepared from the screening of dolomite when sifting dolomite crumbs with the diameter of the holes is 0/25 mm. The experiment lasts for 14 experimental years. It has been revealed that dolomite particles of 5–7 and 7–10 mm in size are valuable calcareous material. Their use leads to the neutralization of soil acidity already in the year of liming. The higher the dose of application, the greater the reclamation effect. There were no significant differences in the effect of granules of 5–7 and 7–10 mm in size, applied in equivalent doses, on the pH value. The positive effect of liming with meliorant in the amount of 3 and 5 doses of hydrolytic acidity (Ah) did not end after 14 experimental years after reclamation and allowed to postpone the period of repeated (maintenance) liming. The positive effect of using a natural mixture of chalk fractions (SIF) in a scientifically justified dose was inferior to dolomite flour. Clustering of individual variants of the experiment was carried out according to their effect on the рHKCl value for the entire period of the experiment. Linear trends of the averaged dependencies of the acidification process for meliorant particles of various sizes over the entire period of the experiment have been developed. The mechanisms of interaction of dolomite particles with soil in the process of land reclamation are considered.

Zinc Oxide Nanoparticles in the “Soil–Bacterial Community–Plant” System: Impact on the Stability of Soil Ecosystems

The use of man-made nanoparticles (NPs) has increased exponentially in recent years, many of which accumulate in significant quantities in soil, including through use in agriculture as nanofertilizers and nanopesticides. ZnO NPs are more environmentally friendly but have specific antimicrobial activity, which can affect soil microbiota, thereby influencing key microbial processes such as mineralization, nitrogen fixation and plant growth-promoting activities. Their behavior and persistence in soil depend on their chemical nature and soil characteristics. This review summarizes the applications of ZnO NPs in soil systems and their effects on various plants and soil microorganisms, particularly rhizobacteria that promote plant growth. A stimulating effect of ZnO NPs on the morphometric and biochemical characteristics of plants, as well as on soil microbiota and its activity at relatively low concentrations of up to 500 mg/mL and 250 mg/kg, respectively, is observed. As the concentration of ZnO NPs increases above these limits, toxic effects appear. The different effects of ZnO NPs are related to their size, dose, duration of exposure, solubility in water, as well as soil type, acidity and organic matter content. The review substantiates the need to study the behavior of ZnO NPs in the “soil-plant-microbiota” system for the possibility of using nanotechnologies in the agricultural industry and ensuring the safety of agricultural products.

Enhanced degradation of polylactic acid microplastics in acidic soils: Does the application of biochar matter?

Biodegradable plastics, as an alternative to petroleum plastics, are fiercely increasing, but their incomplete degradation under natural conditions may lead to the breakdown into microplastics (MPs). Here, we explored the impacts of chicken manure-derived (MBC) and wood waste-derived biochar (WBC) on the degradation of polylactic acid microplastics (PLA-MPs) during soil incubation for one year. Both biochars induced more pronounced degradation characteristics in PLA-MPs, including enhanced surface roughness, the proportion of MPs < 100 µm by 12.89 %−25.67 %, oxygen loading and O/C ratio to 71.74 %−75.87 % and 1.70–1.76, as well as accelerated carbon loss and the cleavage of ester group and C-C bond. Also, biochar increased soil pH, depleted inorganic nitrogen and available phosphorus, and changed enzymic activity in PLA-MP-polluted soils. We proposed that both biochars accelerated the PLA-MP degradation by inducing alkaline, aminolysis/ammonolysis, oxidative, and microbial degradation. Among these, MBC induced aminolysis/ammonolysis by NH4+ via Fe2+-driven NO3-/NO2- reduction and microbial nitrogen fixation, and oxidative degradation by radicals generated through Fenton/Fenton-like reaction. WBC caused aminolysis/ammonolysis and oxidative degradation mainly through dissimilatory nitrate reduction to ammonium and surface free radicals on biochar. These findings indicate that biochar has the potential to accelerate PLA-MP degradation, and its regulatory mechanism depends on the type of biochar.

Effect of Lime Source, Fineness and Granulation on Soil Permeation with Contrasting Textures under Simulated Mediterranean Climate Rainfall Conditions

ABSTRACT Granulated micro-fine limes have recently been introduced as liming materials which are purportedly more effective than conventional agricultural limes in terms of rapidly correcting subsoil acidity in no-tillage systems. Hydrated limes are known to react more quickly in soils than calcitic limes, yet their soil permeability has not been evaluated under Mediterranean climate growing conditions. Therefore, the aim of this controlled study was to compare soil permeation and pH neutralization of different liming materials (hydrated lime, calcitic agricultural lime, micro-fine lime and molasses-granulated micro-fine lime) in two contrasting (sand and sandy loam) acid (pHKCl < 4.1) topsoils under simulated Mediterranean climate conditions. Limes were surface applied to 40 cm soil columns and then rainfall (350 mm) was simulated. Subsequently, soil chemical properties (pH, exchangeable cations, available P) were measured in 5 cm increments. Application of all liming materials increased soil pH 1–2 pH units above target pHKCl of 5.5 in the top 5 cm of both soils. Only hydrated lime was able to increase soil pHKCl (5.7–6.8) below 5 cm up to a depth of 15 cm on the sand soil. Hydrated lime, however, resulted in substantial over-liming (pHKCl 7.3–8.7) of the top 5 cm of soil compared to the other materials. Granulated micro-fine lime reacted more slowly than the agricultural limes and is therefore not a suitable quick-fix for subsoil acidity in rain-fed no-till systems under Mediterranean climate rainfall conditions. Whereas hydrated lime showed potential in ameliorating subsoil acidity in the sand soil within one season of rainfall.

THE ROLE OF LIMING IN COPPER ADSORPTION OF ACIDIC SOILS

Investigate the impact of varying rates of liming on the availability and sorption properties of copper in a range of acid soils with differing physico-chemical futures. Soil samples with varying acidity levels were collected from different locations in the acidic Black Sea Region of Türkiye. Out of the nine soil samples collected, four were obtained from regions where hazelnuts are grown, while the other five were obtained from areas dedicated to tea growth. The sorption properties of soils limed at 0%, 50%, and 100% of lime requirement and incubated for 12 months, then the Langmuir and Freundlich adsorption isotherms were determined by batch sorption technique. The results showed that increasing the soil pH resulted in an increase in Cu adsorption. Experimental results of Cu adsorption were explained with high coefficients of determination (93.44-98.98%) of the Langmuir model. In the three experimental groups with full, half, and no lime application, pH increased significantly to 3.95, 4.46, and 5.89, respectively, while the maximum adsorption obtained from Langmuir adsorption curves, Qmax1 1553, Qmax2 2205, and Qmax3 3902 mg kg-1, respectively. While the maximum adsorption in the tea plantation areas varied between 1491 and 1514 mg kg-1, the maximum adsorption in hazelnut cultivation areas varied between 777 and 3333 mg kg-1. These findings suggest that liming or other methods to increase soil pH could be effective soil management in reducing Cu mobility in acidic soils.

Responses in species diversity in the Hulunbuir grassland to phosphorus addition under nitrogen-limiting and non-limiting conditions.

The phenomenon of nitrogen deposition resulting in species loss in terrestrial ecosystems has been demonstrated in several experiments. Nitrogen (N) and phosphorus (P), as major nutrients required for plant growth, exhibit ecological stoichiometric coupling in many ecosystems. The increased availability of nitrogen can exacerbate the ecological effects of phosphorus. To reveal the ecological effects of phosphorus under nitrogen-limiting and non-limiting conditions, we conducted a controlled N-P interaction experiment over 5 years in the Hulunbuir meadow steppe, where two nitrogen addition levels were implemented: 0g N·m-2·a-1 (nitrogen-limiting condition) and 10g N·m-2·a-1 (nitrogen-non-limiting condition), together with six levels of phosphorus addition (0, 2, 4, 6, 8, and 10g P·m-2·a-1). The results showed that nitrogen addition (under nitrogen-non-limiting conditions) significantly decreased species diversity in the steppe community, which was exacerbated under phosphorus addition. Under nitrogen-limiting conditions, phosphorus addition had no marked impact on species diversity compared to the control; however, there were substantial differences between different levels of phosphorus addition, exhibiting a unimodal change. Under both experimental nitrogen conditions, the addition of 6g P·m-2·a-1 was the threshold for affecting the community species diversity. Nitrogen addition reduced the relative biomass of legumes, bunch grasses, and forbs, but substantially increased the relative biomass of rhizomatous grasses. In contrast, phosphorus addition only markedly affected the relative biomass of forbs and rhizomatous grasses, with the former showing a unimodal pattern of first increasing and then decreasing with increasing phosphorus addition level, and the latter exhibiting the opposite pattern. The different responses of rhizomatous grasses and other functional groups to nitrogen and phosphorus addition were observed to have a regulatory effect on the changes in grassland community structure. Phosphorus addition may increase the risk of nitrogen deposition-induced species loss. Both nitrogen and phosphorus addition lead to soil acidification and an increase in the dominance of the already-dominant species, and the consequent species loss in the forb functional group represents the main mechanism for the reduction in community species diversity.

What makes decomposition faster under conspecific trees? The factors controlling the magnitude of home‐field advantage

The ‘home‐field advantage (HFA)' for decomposition means that leaf litter decomposes faster on soils under the conspecific species (i.e. the home field) than on soils under different species (i.e. ‘away'). Many previous studies have demonstrated the HFA, but the underlying mechanisms remain unclear. We conducted a reciprocal litter‐decomposition experiment using two species with different leaf traits: Abies mariesii, an evergreen conifer, and Fagus crenata, a deciduous broad‐leaved tree. Dominance of these species shifts along an elevation gradient with a transition zone where both species coexist. In mixed forests of the transition zone along the elevation gradient, we explored how the magnitude of HFA between these two species was influenced by temperature, soil properties, or leaf litter traits which could directly affect the decomposition rate. The magnitude of HFA observed between the two species varied widely from −3.89 to 28.3%. Our modeling showed that the magnitude of HFA increased with decreasing soil pH and leaf litter N, i.e. in more acidic soil and for less decomposable litter. Soil pH affected leaf litter decomposition in the home plots of each species, whereas leaf litter N did not. The magnitude of the HFA increased as the difference in soil pH between the F. crenata and A. mariesii plots at the same elevation became greater, but decreased as the difference in soil C became greater. Thus, the response of leaf litter decomposition to environmental changes might vary not only through direct effects of vegetation traits but also through indirect effects of the HFA. This highlights the importance of considering HFA for accurately predicting the response of local carbon and nutrient cycles to climate change, particularly in communities where a replacement of dominant species by others is expected due to climate change.

Impact of Climate Change on Sericulture

Climate change is likely to pose problems to agriculture and its related industries in the future, which could result in both global and local development. The sericulture sector is impacted by climate change in a number of ways. Rising annual mean temperature, irregular rainfall, humidity, lack of management practices, accumulation of anthropogenic greenhouse gases in the atmosphere and lack of management practices will lead to reduced production of raw silk, mulberry leaf yield, silk content, breakage in silk thread during reeling or spinning, water stress, drought, risk of soil acidification and salinization, decomposition of organic matter, Nitrogen fixation, and mineralization of N, P, and S and unpredictable monsoon. The impact of global warming on silkworms is more concerned as they participate in several biotic interactions that are critical to the ecological functioning of our country and significantly boost its GDP.

Experimental investigation of dewatering silty tailings using electrokinetic method

Mining and using underground resources demand high water usage, producing significant waste with environmental risks. Methods like electrokinetics prove effective in accelerating dewatering and stabilizing structures. This research provides the results of experimental investigation on dewatering silty tailings obtained from Sungun Tailings Dam (East Azerbaijan, Iran) using the electrokinetic water recovery method. Previous studies primarily examined the electrokinetic process in steady-state flow and saturated soil, with limited exploration of unsaturated soil parameters. In this research, the electrokinetic process in steady-state flow was initially investigated, and the saturated electro-osmotic permeability was determined. Subsequently, experiments were conducted in non-steady-state flow and unsaturated conditions, measuring the influential parameters with soil moisture sensors and tensiometers. Results show that decreasing sample moisture through electro-osmotic flow increases negative pore water pressure. Tailings' electrical conductivity is more influenced by moisture content, with a steeper reduction slope concerning volumetric moisture reduction over time. pH assessments show soil acidity at anode side and alkalinity on the cathode side. Higher applied voltage increasing maximum power consumption. Importantly, the results caution against assuming that higher applied voltage improves the electro-osmotic process, as it may lead to issues such as deep sample cracking; void space creation, interrupted electrical flow, and energy loss.

Potential of Tropically-Adapted Exotic Acid Tolerance White Maize Donor Lines in Sub-tropical Breeding Programmes for Low pH Adaptation

Low pH in soils is attributed as the main contributor to the low yields characteristic in maize production regions of Angola. Here, eight white-kernel acid soil tolerant donor lines (ASTDLs) sourced from CIMMYT-Colombia (testers) were crossed with eight white elite lines adapted to the mid-altitude climatic conditions from CIMMYT-Zimbabwe, in order to identify donor lines, which can be potential sources of acid tolerance genes in breeding programmes in Angola. The two groups of parents were crossed using a line by tester (L&amp;times;T) mating design, yielding 47 crosses with sufficient seed, which were evaluated alongside eight acid tolerant commercial hybrids, during the 2014-16 cropping seasons at nine sites, representing acid and non-acid soils in Angola and Zimbabwe. Effects of general combining ability (GCA) due to lines and testers, as well as specific combining ability (SCA) on grain yield were significant (P &amp;lt; 0.05) under acid soils. From the CIMMYT-Zimbabwe breeding programme, inbred lines identified as ZW1, ZW4 and ZW5 together with the CIMMYT-Colombia ASTDLs (i.e., CW4 and CW8) seemed to be ideal parents for crosses that can do well under both the acid and non-acid soils. The best specific cross for acid soils was identified as ZW1 &amp;times; CW8 (CH142512), whereas for non-acid soils, ZW3 &amp;times; CW4 (CH142500) was identified. Interestingly, the cross ZW1 &amp;times; CW8 was also observed as stable under both acid and non-acid soil conditions. Overall, data showed potential of exotic acid tolerance donor lines for enhancing low-pH adaptation in sub-tropical maize populations.

Hydrogel Effects on Soil Nitrogen Transformations in pH-Contrasting Soils

ABSTRACT Superabsorbent hydrogels (HGs) are three-dimensional, polymeric networks that have been shown to increase soil water holding capacity, but little is known about their effect on nitrogen (N) transformations in soil. The objective of this study was to determine the effect of two types of HGs (polyacrylate (TS) or cellulose-based (H30)) applied as soil amendment on pH, urea hydrolysis, nitrification, NH3 volatilization, and soil respiration in two soils receiving urea or ammonium sulfate. Separate studies with each HG in each of two soils (four studies) were conducted with an acidic sandy loam collected in Georgia (USA) and a basic sandy loam collected in the Veneto region of Italy. The results showed that the addition of TS increased the pH of the acidic soil, whereas H30 did not have a major effect on soil pH in either soil. In the acidic soil receiving urea, H30 increased nitrification, whereas TS decreased initial nitrification. Neither HG affected urea hydrolysis, N immobilization and NH3 volatilization in either soil, but both HGs increased soil respiration in the basic soil, possibly due to HG degradation by microorganisms. These results show that the use of HGs together with N fertilizers may affect soil pH, nitrification, and respiration.

Natural forming of vegetation cover on black coal mining dumps in the environs of Kopeysk (Chelyabinsk Oblast)

The article considers the current forming of vegetation and biotopes as a result of natural overgrowth of territories disturbed during black coal mining in the environs of Kopeysk town (Chelyabinsk Oblast). The 88 species of vascular plants were detected on the waste banks and spaces between them, the 7 species of vascular plants are woody species. It has been established that in the process of natural overgrowth of dumps, forest and meadow plant communities are actively formed from pioneer ruderal and halophytic communities. By methods of multidimensional statistics, 15 phytocoenochores have been determined and the discriminate of which is d identified by the tree species, which are forming the forest canopy. The identified plant communities are characterized by specific regimes of the fundamental abiotic factors of biotopes and make up a series of biotopic and coenotic substitution, forming a sylvant (forest) and pratant (meadow) successional series. It has been shown that in the process of natural overgrowth, the formation of forest (primarily birch) and meadow coenoses proceeds in parallel, and the invasive species Acer negundo L. plays an active role in sylvatization. It has been established that the leading hand in the formation of the coenotic structure of communities belongs to soil mineralization, acidity, aeration and variability of soil moisture. The obtained data on biotopes and successional series can be used in the development of the biological stage of landfill revegetation after coal mining impacts with the formation of woody or grass plant communities.

Receptor-like cytoplasmic kinase 58 reduces tolerance of maize seedlings to low magnesium via promoting H2O2 over-accumulation.

ZmRLCK58, a negative growth regulator, reduces tolerance of maize seedlings to low Mg via enhancing H2O2 accumulation in the shoot. Magnesium (Mg) deficiency is one of critical limiting factors for crop production in widespread acidic soils worldwide. However, the molecular mechanism of crop response to Mg deficiency is still largely unclear. Here, we found higher concentrations of H2O2, soluble sugars, and starch (1.5-, 1.9-, and 1.4-fold, respectively) in the shoot of low-Mg-treated maize seedlings, compared with Mg sufficient plants under hydroponic culture. Consistent with over-accumulation of H2O2, transcriptome profiling revealed significant enrichment of 175 differentially expressed genes (DEGs) in "response to oxygen-containing compound" out of 641 DEGs in the shoot under low Mg. Among 175 DEGs, a down-regulated receptor-like cytoplasmic kinase ZmRLCK58 underwent a recent duplication event before Poaceae divergence and was highly expressed in the maize shoot. ZmRLCK58 overexpression enhanced H2O2 accumulation in shoots by 21.3% and 29.8% under control and low-Mg conditions, respectively, while reducing biomass accumulation compared with wild-type plants. Low Mg further led to 39.7% less starch accumulation in the ZmRLCK58 overexpression shoot and lower Mg utilization efficiency. Compared with wild-type plants, overall down-regulated expression of genes related to response to carbohydrate, photosynthesis, H2O2 metabolic, oxidation-reduction, and ROS metabolic processes in ZmRLCK58 overexpression lines preconditioned aforementioned physiological alterations. Together, ZmRLCK58, as a negative growth regulator, reduces tolerance of maize seedlings to low Mg via enhancing H2O2 accumulation.

Influence of Mining on Nutrient Cycling in the Tropical Rain Forests of the Colombian Pacific

Nutrient recycling is a fundamental process for the functioning of tropical forests; however, anthropogenic activities such as mining could affect this process in tropical ecosystems. Given that little is known about the effects of mining on nutrient recycling in tropical forests, the objective was set to evaluate the influence of mining on nutrient cycling in tropical rainforests of the Colombian Pacific. Additionally, the hypothesis that nutrient cycling could be lower in post-mining areas was evaluated. To evaluate the effect of mining on nutrient cycling, permanent plots were established in mature and post-mining forests. In both forests, soil acidity, aluminum (Al), organic matter (OM), total nitrogen (N), available phosphorus (P), magnesium (Mg), potassium (K), calcium (Ca), and effective cation exchange capacity (ECEC) were considered. Likewise, the litter production, decomposition, and accumulation on the ground were determined; additionally, nutrient content and nutrient use efficiency (NUE) were determined. It was observed that mining influenced the nutrient contents of the soil in a different way. It was evident that total N and soil OM were similar in both forests, while the contents of P, K, Ca, Mg, Al, and ECEC available were higher in post-mining. The litterfall production and litter mass accumulation on the ground were greater in post-mining, while litter decomposition was greater in mature forests. In mature forests, there was higher foliar content of N, Ca, and B and, in addition, higher NUE of Ca. However, in post-mining, there was higher leaf content of K, Mg, P, Fe, Cu, Mn, and Zn and, in addition, greater NUE of N, P and K. In conclusion, an increase in post-mining nutrient cycling was noted as a strategy for nutrient conservation, and recovery of the functioning and maintenance of productivity in degraded Pacific ecosystems. Consequently, it is expected that in the future, if mining continues in the region, productivity and nutrient recycling will be altered.

Biochar Blended with Alkaline Mineral Can Better Inhibit Lead and Cadmium Uptake and Promote the Growth of Vegetables.

Three successive vegetable pot experiments were conducted to assess the effects on the long-term immobilization of heavy metals in soil and crop yield improvement after the addition of peanut shell biochar and an alkaline mineral to an acidic soil contaminated with lead and cadmium. Compared with the CK treatment, the change rates of biomass in the edible parts of the three types of vegetables treated with B0.3, B1, B3, B9, R0.2 and B1R0.2 were -15.43%~123.30%, 35.10%~269.09%, 40.77%~929.31%, -26.08%~711.99%, 44.14%~1067.12% and 53.09%~1139.06%, respectively. The cadmium contents in the edible parts of the three vegetables treated with these six additives reduced by 2.08%~13.21%, 9.56%~24.78%, 9.96%~35.61%, 41.96%~78.42%, -4.19%~57.07% and 12.43%~65.92%, respectively, while the lead contents in the edible parts reduced by -15.70%~59.47%, 6.55%~70.75%, 3.40%~80.10%, 55.26%~89.79%, 11.05%~70.15% and 50.35%~79.25%, respectively. Due to the increases in soil pH, soil cation-exchange capacity and soil organic carbon content, the accumulation of Cd and Pb in the vegetables was most notably reduced with a high dosage of 9% peanut shell biochar alone, followed by the addition of a low dosage of 1% peanut shell biochar blended with 0.2% alkaline mineral. Therefore, the addition of a low dosage of 1% peanut shell biochar blended with 0.2% alkaline mineral was the best additive in increasing the vegetable biomass, whereas the addition of 9% peanut shell biochar alone was the worst. Evidently, the addition of 0.2% alkaline mineral can significantly reduce the amount of peanut shell needed for passivating heavy metals in soil, while it also achieves the effect of increasing the vegetable yield.

Organic fertilisation enhances network complexity among bacteria, fungi, and protists by improving organic matter and phosphorus in acidic agricultural soils

Research has explored the impact of organic fertilisation on improving agroecosystem productivity and resilience, highlighting the significant contributions of protists in addition to bacteria and fungi. However, the interactions among bacteria, fungi and protists in organically fertilised soils remain largely unknown. In this study, soil samples were collected from four long-term fertilisation treatments: no fertilisation (Control), inorganic fertilisation (NPK), organic fertilisation (OM), and combined inorganic and organic fertilisation (NPKOM). The abundance and composition of bacteria, fungi, and protist communities, as well as co-occurrence networks, were analysed under different fertilisation treatments. Our results showed that the total abundance of bacteria, fungi, and protists increased by a minimum of 2.95, 3.47, and 0.66 times, respectively, after organic fertiliser application. Moreover, the application of organic fertilisers significantly altered the structures of soil microbial communities by enriching bacterial Proteobacteria and Actinobacteria, fungal Ascomycota, and protist Conosa. Changes in the total abundance of bacteria, fungi, and protists, and their community structures in soils with organic fertilisers were associated with increases in soil organic carbon and phosphorous. Additionally, microbial networks exhibited greater complexity in organically fertilised soils than in non-organically fertilised soils by possessing higher linkage density. The increased complexity may be attributed to potential interkingdom associations among bacteria, fungi, and protists in high soil organic carbon and phosphorus. These results highlight that the application of organic fertilisers has the potential to enhance the complexity of microbial coexistence in acidic agricultural soils.

Properties of biochars derived from different straw at 500℃ pyrolytic temperature: Implications for their use to improving acidic soil water retention

Climate change cause extreme weather effects with temperature increases and drops in humidity, such as drought and heatwaves, which will lead to more evaporation in arid and semi-arid lands. The application of biochar made from crop straw without burning to farmland can effectively improve the water retention capacity of soil. A testing program has been carried out in a climate simulation laboratory to study the effects of different straw biochars on the cracking and evaporation of soils due to drying. Biochar from wheat straw (WS), corn straw (CS) and rice straw (RS) is produced at a pyrolysis temperature of 500℃. Thermogravimetric analysis and elemental analysis are carried out to obtain the properties of the biochar. Five percent of WS, CS and RS biochar by weight is added to acidic soil. Digital camera and digital image processing technology are used to analyze the crack morphology of the samples during evaporation. The results indicate that the RS biochar has the highest ash content (32.5 %), CS biochar has the highest content of volatile solid (25.36 %) and WS biochar has the highest content of fixed carbon (55.38 %). Biochar can effectively improve the water retention capacity of soil. The final water contents of the WS, CS and RS biochar soil samples are 132.3 %, 101.0 %, and 20.7 % respectively higher than that of the soil without biochar. Moreover, biochar can effectively reduce the degree of soil cracking. The addition of WS, CS and RS biochar can reduce soil cracking by 9.21 %, 16.57 %, and 7.46 %, respectively. WS contains more total cellulose than CS and RS, so WS biochar is the best choice to improve soil water retention ability. Therefore, biochar technology helps to optimize soil water retention while avoiding environmental pollution from straw burning.