Total Glomalin Research Articles

The Content of Soil Glomalin Concerning Selected Indicators of Soil Fertility

The glomalin content is generally considered an indicator of the soil organic matter (SOM) quality. The content of easily extractable glomalin (EEG) and the total glomalin (TG) content was investigated across 71 different sites in the Czech Republic with arable soil and crop production (12 chernozems, 30 luvisols, 17 cambisols, and 12 fluvisols). The majority of the crops in the crop rotation were cereals (45.5%—mainly winter wheat, winter barley, and spring barley). The proportion of winter canola within the crop rotation was 15.9%. The contribution of other crops was substantially smaller (alfalfa, clover, potatoes, beet, silage maize, grain maize). The representation of crops in the crop rotation is standard for conventional farming in the Czech Republic. Based on the results of long-term field monitoring at 71 sites in different soil–climate conditions, we can state the following. The TG content was significantly correlated with the soil organic matter carbon content (CSOM), as well as another important indicator of SOM quality (humic and fulvic acid carbon content ratio—CHA/CFA). A significant and positive correlation was also determined for the TG and clay content (size < 0.002 mm), as well as particles smaller than 0.01 mm. The easily extractable glomalin content (EEG) did not differ based on the reference soil group (RSG). On the other hand, the total glomalin content (TG) was significantly higher in the chernozem RSG in comparison with other RSGs (luvisols, cambisols, fluvisols). There was no relationship between the pHCaCl2 and glomalin (EEG; TG). The same can be said about the relationship between glomalin (EEG; TG) and the bulk density and porosity. No link was established between the glomalin content (EEG; TG) and phosphorus plant-available content. There was no relationship between the amount of applied organic matter (carbon inputs) and the soil glomalin content (EEG; TG). This relationship was not influenced by the type of applied organic fertilizer. No significant relationship was found for either straw, manure, or compost. The data on the glomalin content are significantly influenced by the site (soil type and soil texture).

Combined Effect of Biological and Organic Fertilizers on Agrobiochemical Traits of Corn (Zea mays L.) under Wastewater Irrigation.

Corn (Zea mays L.) is an important annual grain that is cultivated as a food staple around the world. The current study examined the effect of wastewater and a combination of biological and organic fertilizers on the morphological and phytochemical traits of corn, using a factorial experiment based on a randomized complete block design with three replications. The first factor was biological and organic fertilizers at seven levels, including the control (no fertilization), bacterial biological fertilizers (NPK) along with iron and zinc Barvar biofertilizers, fungal biofertilizers made from Mycorrhiza and Trichoderma, biochar, a combination of bacterial and fungal biofertilizers, and a combination of bacterial and fungal biofertilizers with biochar. The second factor was irrigation at two levels (conventional irrigation and irrigation with wastewater). The traits studied included the morphological yield, phenols, flavonoids, polyphenols, glomalin, cadmium content in plant parts, and translocation factor (TF). The results disclosed that the best treatment in regard to the morphological traits was related to conventional water + biochar + mycorrhiza + Trichoderma + NPK. The highest phenol and flavonoid content were observed when biochar + mycorrhiza + Trichoderma + NPK treatments were used in both water treatments. Also, the wastewater + biochar + mycorrhiza + Trichoderma + NPK treatment demonstrated the highest total glomalin and phenylalanine ammonia-lyase (PAL) activity. The obtained results demonstrate that combined biological and organic fertilizer use on corn plants can effectively alleviate the deleterious effects of cadmium present in wastewater.

The Effect of Long-Term Farmyard Manure and Mineral Fertilizer Application on the Increase in Soil Organic Matter Quality of Cambisols

Soil organic matter (SOM) quantity and quality are important factors that significantly influence soil fertility. SOM quality indicators change throughout time. In this study, long—term field experiments (22–50 years in duration) on a Cambisol at four sites in the Czech Republic were selected. Seven crops were successively rotated in the sequence: clover, winter wheat, early potato, winter wheat, spring barley, potato, and spring barley with interseeded clover. Five treatments were investigated, including an unfertilized treatment, farmyard manure, and various combinations of farmyard manure and mineral fertilization. A total of 40 t ha−1 of farmyard manure was applied to the early potato and potato crops. Combining organic and mineral fertilizers increased soil organic matter quality and quantity over unfertilized or organic only treatment. The highest intensity of mineral fertilizers in our trials elevated the mean of carbon sequestration efficiency to 45.6% in comparison to pure manure treatment which reached only 22.9% efficiency. A strong correlation was established between the total glomalin content and soil organic matter carbon, fulvic acid, humic acid, carbon hot water extraction, potential wettability index (PWI), and aromaticity index. The PWI was also strongly correlated with these indicators. The E4/E6 ratio indicator was shown to be a much less sensitive method for reflecting the change in soil organic matter quality.

Long-Term Application of Manure and Different Mineral Fertilization in Relation to the Soil Organic Matter Quality of Luvisols

Long-term field experiments were conducted on luvisol at five sites in the Czech Republic (42–48-year duration). The average total organic carbon content in the soil varied between 9.0 and 14.0 g kg−1. In these trials, seven crops were rotated in the following order: clover, winter wheat, early potato, winter wheat, spring barley, potato, and spring barley with interseeded clover. Five treatments were studied: unfertilized treatment (Con), farmyard manure (F), and combinations of farmyard manure with three mineral fertilization levels (F+M1, F+M2, F+M3). Plant residues were not incorporated into the soil. An amount of 40 t ha−1 of farmyard manure fresh matter was applied twice during crop rotation. Intensive mineral fertilizer (F+M3) increased the average value of the carbon sequestration efficiency (CSE) by 12.9% and up to 26.3%. Combining organic and mineral fertilizers at moderate and higher intensities increased the soil organic matter quantity and quality compared to the unfertilized or manure treatment. Data on the glomalin content can be used to study the organic matter quality. We determined a strong correlation between the total glomalin content and the soil organic matter carbon, fulvic acid content, humic acid content, extractable carbon content, and dissolved organic carbon content, as well as the potential wettability index and aromaticity index.

Noticeable Shifts in Soil Physicochemical and Biological Properties after Contrasting Tillage Management in Crop Rotations of Bean, Maize, and Amaranth in Ecuadorian Highland Soils

Soil biological properties are sensitive indicators of soil quality changes due to perturbations occurred under agricultural management. The effects of contrasting tillage, increasing nitrogen fertilization doses, and crop rotations [e.g., bean, maize, bean (BMB) and bean, amaranth, bean (BAB)] on soil physicochemical and biological properties in an Andean soil from Ecuadorian highlands were evaluated in this study. Acid phosphatase, β-Glucosidase, fluorescein diacetate hydrolysis, microbial biomass carbon (Cmic), soil basal respiration (BR), arbuscular mycorrhizal fungi (AMF) spore density, total glomalin content (TGRSP), and soil physicochemical properties were analyzed. Conventional tillage (CT) and crop rotation showed significant effects on soil physicochemical and biological properties. Towards the final crop rotations, no-tillage (NT) promoted BR, TGRSP, and higher AMF spore density in both crop rotations; the Cmic kept stable along time in BMB and BAB, while BR doubled its value when compared to CT. Results indicated that the AMF spore density increased by 308% at the end of the BMB, and 461% at the end of the BAB, while TGRSP increased by 18% and 32% at the end of BMB and BAB, respectively. Biological traits demonstrated to be strongly associated to the organic matter accumulation originated from crop residues under the NT post-harvest which improved soil moisture, biological activity, and AMF interaction. The conservative soil management system has definitively improved general soil properties when compared to soil conditions under the intensive soil management system in this research.

Inoculation with Glomus mosseae: An Efficient Biological Management Strategy for Arsenic Mitigation in Wheat (Triticum Aestivum L.) Under Arsenic-Contaminated Soil

ABSTRACT A pot experiment was conducted to evaluate the effects of Arbuscular Mycorrhizal (AM) fungi on mitigation of arsenic (As) in As-contaminated soils with wheat (variety – HD 2967) as the test crop. Soil inbulk was collected from Bihar Agricultural University, Sabour, Bihar,India farm with physicochemicalproperties to conduct a pot experiment using three doses of As (5, 10, 20 mg L−1) and application of Glomus mossaea inoculation (no inoculated, 5 g/pot, and 10 g/pot). Result indicated that the treatment spiked with As 5 ppm and Glomus mossaea @1 g kg−1 showedthe lowest available As (21.80 µg kg−1 soil) and lowest total As (2.533 mg kg−1soil) as compared to all othertreatments. The As content in different parts of plants are found in the orderof roots > shoots> leaves > grain parts in wheat crop. As uptake in grain was found to be positively correlated with available (r = 0.883, p < .001) and total As content in soil (r = 0.869, p < .001) as well. The application of AM fungi @10.0 g kg−1 soil significantly (p < .005) reduced the As content in grain under all the applied treatments. As content ingrain was found to be negatively correlated with total glomalin content of soil(r = –0.430, p < .005), colonization by AM fungi (r = –0.261) and available phosphorus (P) content of soil (r = –0.864, p < .001). The study noticeably indicated that the mycorrhizal inoculation can reduce the As content in the various parts of the wheat in As-contaminated soils.

Biochemical characterization and mycorrhizal fungal community of plant species in the Brazilian seasonal dry forest.

Invasive alien plant species (IAPS) have the ability to change the biochemical properties and the arbuscular mycorrhizal fungal (AMF) community structure in their rhizosphere. Organic acids, microbial activity, and AMF play a key role in the invader's spread and also has interactions with the soil chemical factors. Our aim here was to assess the rhizosphere's biochemical factors, AMF community composition, and soil chemical properties associated with Cryptostegia madagascariensis (IAPS) and Mimosa tenuiflora (endemic plant species) from the Brazilian Seasonal Dry Forest. The highest values of total glomalin (5.87 mg g-1 soil), root colonization (54.5%), oxalic and malic acids (84.21 and 3.01 μmol g-1 , respectively), microbial biomass C (mg kg-1 ), Na+ (0.080 cmolc kg-1 ), Ca2+ (7.04 cmolc kg-1 ), and soil organic carbon (4.59 g kg-1 ) were found in the rhizosphere of C. madagascariensis. We found dissimilarities on AMF community structure considering the studied plant species: (i) Racocetra coralloidea, Dentiscutata heterogama, Dentiscutata cerradensis, Gigaspora decipiens, and AMF's richness were highly correlated with the rhizosphere of M. tenuiflora; and (ii). The rhizosphere of C. madagascariensis was highly correlated with the abundance of Claroideoglomus etunicatum, Rhizoglomus aggregatum, Funneliformis mosseae, and Funneliformis geosporum. The results of our study highlight the importance of considering C. madagascariensis as potential hosts for AMF species from Glomerales, and a potential plant species that increase the bioavailability of exchangeable Na and Ca at semi-arid conditions.

Glomalin mediation of plant functional traits unveiled in an extreme ecosystem

Edaphic filters associated with symbiotic relationships are determinants of plant phenotypes. Here we investigate whether glomalin, a by-product of mycorrhizal fungi that improves soil structure and quality, is involved in the filtering of traits that determine plant ecological strategies. This study was developed in two substrate types (ferruginous and quartzitic) of the harsh and ancient Brazilian grasslands known as campo rupestre. We carried out a vegetation functional survey along with soil sample analyses for glomalin content. We compared glomalin content (and its proportion in relation to soil iron content) between habitats and applied the fourth corner analysis to evaluate its relationship with various plant functional traits. Glomalin content in the ferruginous habitat was significantly higher than in the quartzitic habitat. In ferruginous plots, the persistent form of glomalin (total glomalin, TG) was associated with enhanced plant ruderality, increased specific leaf area and reduced leaf dry matter content. In contrast, in quartzitic plots the freshly produced and more volatile form of glomalin (easily extractable glomalin, EEG) was associated with enhanced plant competitiveness evident as larger leaf area, and reduced ruderality evident as increased leaf density and reduced specific leaf area. The pattern of trait filtering in relation to glomalin content was scale dependent, and differed markedly between the ferruginous and quartzitic habitats, underlining the idiosyncratic nature of plant-soil relationship in these two adjacent plant communities. Our study unveils the association between plant life history and a metabolite produced by a soil symbiont, showing how close interspecific interactions are to ecosystem functionality.

Elevated CO2 alters aggregate‑carbon and microbial community but does not affect total soil organic C in the semi-arid tropics

Elevated CO2 increases biomass productivity, however, the retention of added C under such condition is less known in the arable soils of the Tropics. Hence, an experiment was conducted in free-air atmospheric carbon-dioxide enrichment (FACE) rings to assess the impacts of eight years of elevated CO2levels (550 ppm) on soil aggregation, soil organic carbon (SOC), microbial community and greenhouse gas (GHG) emission in a sandy loam soil. Aboveground biomass productivity of all crops increased significantly under elevated CO2as compared to the ambient CO2, however, soils under elevated and ambient CO2 had similar total SOC in all layers, up to 0–90 cm profile. Soils under elevated CO2 had ~54 % higher large macroaggregates, but had ~14 % fewer microaggregates than ambient CO2 in the 0–5 cm layer. Elevated CO2 led to ~25 % less microaggregate-associated C when compared to the ambient CO2 in the topsoil. Elevated CO2 led to 10 % more large macroaggregates than ambient CO2 in the 5–15 cm soil layer. β-glucosidase activity within microaggregates in the topsoil under elevated CO2 was 25 % higher than ambient CO2. Moreover, soil macro- and microaggregates under elevated CO2 had ~31 and 35 % higher phenol oxidase activities, respectively, than those under ambient CO2in the topsoil. Microaggregates under elevated CO2 also contained ~13 and 21 % more total glomalin in the topsoil and 5–15 cm soil layers, respectively, as compared to the ambient CO2. The functional diversity (0–15 cm soil) was significantly higher under elevated CO2 than ambient CO2. Soils exposed to elevated CO2 had higher relative abundances of fungi than ambient CO2. A 23.4 % higher qCO2 and higher global warming potential was observed in elevated CO2 exposed soil as compared to ambient. These results reveal that under elevated CO2, carbon sequestration is hindered by higher fungal activity and higher activities of soil C degrading enzymes.

Drought Changes the Trade-Off Strategy of Root and Arbuscular Mycorrhizal Fungi Growth in a Subtropical Chinese Fir Plantation

As a consequence of changing global rainfall patterns, frequent extreme droughts will significantly affect plant growth and ecosystem functions. Fine roots and arbuscular mycorrhizal fungi (AMF) both facilitate Chinese fir nutrient uptake. However, how the growth of fine roots and AMF is regulated for the Chinese fir under drought conditions is unclear. This study used a precipitation reduction treatment (−50% throughfall) to study the seasonal effects of drought on a subtropical Chinese fir plantation. The effects measured included the fine root production, root diameter, specific root length, specific surface area, root tissue density, mycorrhizal hyphal density, spore number, mycorrhizal infection rate and total glomalin. Drought had no significant effect on Chinese fir fine root production but decreased the diameter and tissue density of primary and secondary roots while increasing the specific surface area of secondary roots. Additionally, drought significantly decreased the arbuscular mycorrhizal infection rate and significantly increased hyphal density. The results showed that drought caused the decrease in root diameter, which decreased the surface area available for AMF infection and led to the increase in mycorrhizal hyphal density. Redundancy analyses showed that soil-dissolved organic carbon and nitrogen were the key factors affecting AMF. Our results show that drought could enhance the cooperative strategy of nutrient and moisture absorption by roots and mycorrhizae of the Chinese fir, improving the resistance of Chinese fir growth to drought.

The impact of the long-term application of mineral nitrogen and sewage sludge fertilizers on the quality of soil organic matter

BackgroundSoil fertility is substantially influenced by soil organic matter quality and quantity. Much attention has also been given to glomalin content as one of the qualitative parameters of soil fertility. Glomalin content is considered an indicator of soil fertility due to its positive correlation with soil organic carbon.AimThis study aim to (i) determine the influence of different fertilization systems on maize yield and soil organic matter quality parameters, (ii) ensure that changes in total glomalin content (TG) and easily extractable glomalin (EEG) content are sensitive enough to reflect changes in the SOM quality resulting from long-term fertilization, and (iii) determine whether both forms of glomalin must be determined or if the easily extractable glomalin (EEG) content is sufficient, even for a fertile chernozem.Materials and methodsLong-term field experiments with silage maize monocultures were used to study relationships under different rates of mineral nitrogen and sewage sludge fertilization. The trials comprised 5 treatments: (i) no fertilization control (Con), (ii) and (iii) two different calcium ammonium nitrate rates (N120 and N240 at doses of 120 and 240 kg N ha−1 year−1, respectively), and iv) and v) two different sewage sludge rates (S120 and S240 corresponding to mineral N doses). Topsoil (0–30 cm) analysis was performed 28 years after the onset of the experiment to determine soil organic carbon, the fractions of humic substances, potentially mineralizable carbon and dissolved organic carbon, the potential wettability index, soil aggregate stability, EEG, and total glomalin (TG).ResultsThe control treatment, which did not include fertilization, showed significantly lower average yields (9.76 t DM ha−1 year−1) than the fertilization treatments (on average 12.3 DM ha−1 year−1). Significant differences in yields were not found between the fertilization treatments. A positive correlation between glomalin (EEG, TG) content and soil organic matter carbon content was observed. A periodic application of sewage sludge increased the content of glomalin. However, the highest quality of SOM was found in the control treatment (nonfertilized). This treatment had the highest values for the humic/fulvic acid ratio and the highest contents of humic acids and potentially mineralizable carbon. Furthermore, the Con treatment showed the highest soil aggregate stability and potential wettability index. Mineral N fertilization significantly reduced soil aggregate stability values.ConclusionsThe unfertilized control showed the highest SOM quality but the lowest yields. The data on glomalin content can be used to study soil organic matter quality. Because the EEG extraction method is easy to apply, uses lower quantities of chemicals and consumes less time, it presents a better option than TG extraction. The sensitivity of the methods for SOM quality determination decreases with increasing SOM content.Graphical

Preservation of soil organic carbon in coastal wetlands promoted by glomalin–iron–organic carbon ternary system

AbstractIron‐bound soil organic carbon (Fe‐bound SOC) and microbial residues are vital for SOC preservation, a process crucial for drawdown of anthropogenic carbon. However, the relative importance of Fe‐bound SOC in coastal wetlands, and its interaction with microbial residues remain poorly understood. Here, we used glomalin as a proxy for microbial residues, with the goal of determining microbial residues binding to Fe and Fe‐bound SOC across a 1000 km coastline of China including seven typical mangrove wetlands. As hypothesized, it was found that the glomalin fraction was strongly associated with and likely bound to Fe‐bound SOC complexes, which accounted for 21.4% ± 1.6% of mangrove SOC. Mean level of Fe‐bound glomalin was 1.2 ± 0.1 mg cm−3, accounting for 40.6% ± 1.5% of total glomalin and 35.4% ± 3.2% of Fe‐bound SOC in the top 10 cm mangrove soil layer at regional scale. Due to the growing realization that Fe may be a crucial factor of glomalin cycling, we performed multiple chemical characterization techniques to identify the association between Fe and glomalin. Our results suggested that association to Fe was a main stabilization mechanism of glomalin in soils, and glomalin served as organic ligands in the formation of Fe‐bound SOC. We also found that the bulk glomalin extracts were a glomalin–Fe–OC ternary complex, which constituted an important proportion of mangrove SOC. These findings highlight the important effect of glomalin bound to Fe as a major mechanism of SOC persistence in coastal wetlands.

Recalcitrant C Source Mapping Utilizing Solely Terrain-Related Attributes and Data Mining Techniques

Agricultural practices affect arbuscular mycorrhizal fungal (AMF) hyphae growth and glomalin production, which is a recalcitrant carbon (C) source in soil. Since the spatial distribution of glomalin is an interesting issue for agronomists in terms of carbon sequestration, digital maps are a cost-free and useful approach. For this study, a set of 120 soil samples was collected from an experimental area of 310 km2 from the Sarab region of Iran. Soil total glomalin (TG) and easily extractable glomalin (EEG) were determined via ELISA using the monoclonal antibody 32B11. Soil organic carbon (OC) was also measured. The ratios of TG/OC and EEG/OC as the glomalin–C quotes of OC were calculated. A total of 17 terrain-related attributes were also derived from the digital elevation model (DEM) and used as static environmental covariates in digital soil mapping (DSM) using three predictive models, including multiple linear regression (MLR), random forests (RF), and Cubist (CU). The major findings were as follows: (a) DSM facilitated the interpretation of recalcitrant C source variation; (b) RF outperformed MLR and CU as models in predicting and mapping the spatial distribution of glomalin using available covariates; (c) the best accuracy in predictions was for EEG, followed by EEG/OC, TG, and TG/OC.

The Influence of Organic and Mineral Fertilizers on the Quality of Soil Organic Matter and Glomalin Content

The influence of different fertilizers (mineral/organic) on the quantity and quality of soil organic matter was monitored in long-term stationary experiments (27 years) with silage maize monoculture production on Luvisol. The main aim of this study was to investigate the relationship between easily extractable glomalin (EEG), total glomalin (TG), and parameters commonly used for the determination of soil organic matter quality, i.e., the content of humic acids (CHA), fulvic acids (CFA), and potential wettability index (PWI). A significant correlation was found between EEG content and CSOM content, humic acid content (CHA), humic acid/fulvic acid ratio (CHA/CFA), PWI, and index of aromaticity (IAR). Furthermore, the contents of EEG and TG correlated with soil organic carbon (CSOM). Periodical application of sewage sludge and cattle slurry increased the content of glomalin in soils. From the results, it is obvious that data about glomalin content can be used to study soil organic matter quality. A more sensitive method (a method that reacts more to changes in components of soil fertility) seems to be the determination of EEG rather than TG. The factors supporting use of EEG extraction in agronomic practice are mainly the substantially shorter time of analysis than TG, CHA, and CFA determination and lower chemical consumption. Furthermore, the PWI method is even suitable for studying soil organic matter quality. On the other hand, the humus quality ratio (E4/E6) does not provide relevant information about soil organic matter quality.

Soil Carbon, Glomalin, And Aggregation in Onion Crop Under No-Tillage with Cover Crops or Conventional Tillage Systems for Eight Years

Crop systems using cover crops affect soil physical, chemical, and biological attributes, including aggregate formation. This work aims to evaluate winter cover crop species' effect on soil total organic carbon, glomalin, and aggregation in areas with onion crops in a no-tillage vegetable production system (NTVS) and conventional tillage system (CTS) for eight years. The experiment treatments were: control, with natural vegetation(NV); black oats (Avena strigosa); rye(Secale cereale);oilseed radish(Raphanus sativus);intercropped black oats and oilseed radish; intercropped rye and oilseed radish; and a conventional tillage systems area. A 33-year old adjacent secondary forest was evaluated as a reference for undisturbed conditions. We assessed soil total organic carbon, total glomalin, and easily extractable glomalin in three soil layers (0-5, 5-10, and 10-20 cm depth). Undisturbed samples were used to quantify soil aggregate stability, aggregation indexes (weighted mean diameter; geometric mean diameter), aggregate mass distribution (macroaggregates, mesoaggregates), and macroaggregate carbon contents. The conventional tillage areas had the lowest weighted mean soil aggregate diameter, geometric mean diameter, and macroaggregate mass. Those areas also had the lowest bulk soil and aggregate organic carbon contents and the lowest total and easily extractable glomalin. Winter cover crops' use resulted in a 10% higher aggregate weighted mean diameter and geometric mean diameter. Areas with cover crops had 13% higher organic carbon contents in aggregates and 17% higher macroaggregate mass than conventional tillage areas. The highest values of total and easily extracted glomalin occurred in plots with black oats. Winter cover crops, single or intercropped, improved physical attributes of soils with onion crops under not-tillage compared to conventional tillage areas.

Unraveling the distribution of AMF communities and their metabolites associated with soils of minor millets

Arbuscular Mycorrhizal Fungal (AMF) diversity in three different soil types and five different crop types of minor millets growing regions of Tamil Nadu, India was assessed. 24 species belonging to 11 genera namely Glomus, Gigaspora, Claroideoglomus, Rhizophagus, Funneliformis, Paraglomus, Entrophosphora, Acaulospora, Ambispora, Septoglomus and Scutellospora were reported for the first time in minor millet ecosystem exhibiting the richness of AMF. Glomus fascicultum, Rhizophagus intraradices and Funneliformis mosseae were most commonly present species with high relative abundance in both soil and crop types of minor millets. Comparatively, the soil types recorded higher species richness and isolation frequency than crop types. However, the species Acaulospora scrobiculata, Glomus hoi, Entrophosphora sp., Entrophosphora infrequens and Scutellospora erythropha were not recorded in soil types, whereas all the 24 species were observed in crop types. Interestingly, the species Acaulospora scrobiculata was found only in the soils of foxtail millet among the crops and soil types observed. Diversity indices viz., Shannon (1.46 ± 0.02 to 2.00 ± 0.03), Simpson (0.76 ± 0.01 to 0.85 ± 0.02) and species evenness (0.66 ± 0.01 to 0.77 ± 0.01) showed significant variation among soil and crop types. Principal component analysis of soil physico-chemical properties on AMF diversity revealed N, P and K contents had a positive influence on spore density, total glomalin content, species richness, Simpson and Shannon index in both soils and crop types. In contrast, soil pH, EC and organic carbon indicated a negative influence in soil type and positively influenced on crop types. Pearson coefficient results confirmed that soil available P content positively correlated with spore density (R2 = 0.92) and total glomalin (R2 = 0.90) content in minor millets. Further 50 to 90 per cent root colonization and increased plant growth parameters were observed in all the 24 species. Mycorrhizal associated root metabolites revealed that a total of 117 compound with 26 different groups encompassing predominant group namely Alkane, fatty acyls, hydrocarbon, Fatty alcohols, Fatty acids and carboxylic acid which conferred the multifunctional role of AMF towards management of biotic and abiotic stresses. Among the spores, Glomus fascicultum reported 46% compounds followed by Rhizophagus intraradices (34%) and Funneliformis mosseae (23%) over non mycorrhizal roots.

Total and labile pools of organic carbon in relation to soil biological properties under contrasting land-use systems in a dry mountainous region

This study evaluated the effect of contrasting land-use systems on changes in pools of total organic carbon (TOC) and its labile fractions, and identified the sensitivity of soil properties as a minimum data set (MDS) for assessing soil quality change in a dry, mountainous Himalayan region in India. The soils under mono (barley/mustard/oats)- and double (barley-buckwheat/barley-turnip)-cropping systems had significantly (p < .05) lower TOC by ∼34 and 20%, while the less labile C (Fract. 3) concentration was lower by ∼46 and 48%, respectively, compared with the agro-forestry (popular/willow). The stable C pool (Fract. 3 + Fract. 4) comprised ∼74, 77, 86, 74 and 73% of TOC in soils under mono-cropping, double-cropping, agro-forestry, orchards and vegetable crops, respectively. Land-use significantly impacts the sensitivity of labile C fractions, viz. water extractable organic C (WEOC), microbial biomass C (MBC) and organic C fractions of variable oxidizability (i.e. Fract. 1, Fract. 2, Fract. 3 and Fract. 4). The sensitivity analysis showed a change of ∼21.5–56.2% in the TOC pool, with the highest change for soils under vegetable crops and the lowest for double-cropping. Soil protein exhibited a significant relationship with TOC and its fractions, enzymatic and biochemical properties, and soils’ fine fraction (silt and clay). The stable C pool exhibited a significant linear relationship with soils’ finer fraction (silt = 0.82**; clay = 0.78**, p < .01), indicating that the mineral matrix had a profound influence on C stabilization in soils. The land-use systems with higher soil total glomalin (TG) content had higher moisture retention capacity and stable C pool. The principal component analysis (PCA) identified TG, Fract. 3 and available-K as most important soil quality indicators for discriminating change in soil health in a cold, dry Himalayan region.

Arbuscular mycorrhizal fungi and pistachio husk biochar combination reduces Ni distribution in mungbean plant and improves plant antioxidants and soil enzymes.

Soil pollution with nickel (Ni) casts detrimental effects on the quality of crops. Low-cost amendments can restrict Ni mobility in soil and its uptake by the plants. In this pot experiment, the effects of pistachio husk biochar (PHB) and arbuscular mycorrhizal fungi (AMF) on the distribution of Ni in mung bean and its bioavailability in Ni-spiked soil were evaluated. Plant parameters like Ni plant height, root dry weight, shoot dry weight, grain yield, chlorophyll contents, oxidative stress, Ni distribution in the roots, shoot, and grain, as well as the nutritional potential of grains, were measured on plants grown on Ni-contaminated soil amended or not (control) with AMF, zeolite (ZE), PHB, ZE + AMF, and PHB + AMF. Moreover, DTPA (diethylenetriamine pentaacetate)-extractable Ni in the soil, microbial biomass carbon (MBC), total glomalin (TG), extractable glomalin (EG), mycorrhizal root colonization (MRC), and the activities of soil enzymes (i.e. urease, acid phosphatase, and catalase) were also assessed after the plant harvest. With few exceptions, all treatments had significant effects on plant and soil parameters. The PHB + AMF treatment showed the topmost significant increment in plant physical parameters while reducing the Ni distribution in plant parts and oxidative injury. Based on these findings, it is proposed that PHB + AMF treatment can reduce Ni distribution and oxidative stress in mung bean plants and improve the biochemical compounds in grain.

Mycorrhizae and a soil ameliorant on improving the characteristics of sandy soil

&lt;p&gt;Agricultural constraints on sandy soil are poor chemical characteristics and low biological activity resulting in the soil becoming less productive to be planted. One of the efforts to improve the quality of sandy soil are application of mycorrhizae and a soil ameliorant. The purpose of this study was to determine the effect of mycorrhizae and a soil ameliorant on soil chemical characteristics and soil biological activity. The experiment was arranged using a Complete Randomized Design that had two factors. The first factor (1) was mycorrhizae dose, without mycorrhizae (M0) and six spores of mycorrhizae/plant (M1), and the second factor (2) was types of soil ameliorant, without ameliorant (S0), cow dung (S1), rock phosphate (S2), biochar (S3), cow dung–rock phosphate (S4), cow dung–biochar (S5), and rock phosphate–biochar (S6). The results indicated that combination of six spores mycorrhizae/plant–cow dung 60 tons ha&lt;sup&gt;−1&lt;/sup&gt;–biochar 25 tons ha&lt;sup&gt;−1&lt;/sup&gt; (M1S5) increased soil organic carbon (SOC) (235%), available P (675%), cation exchange capacity (CEC) (216%), total glomalin (101%), and easily extracted glomalin (69%), decreased exchangeable sodium percentage (66%), and increased absolutely for root infection and spore density than without mycorrhizae and a soil ameliorant (control). The lowest of SOC in non-mycorrhizae and rock phosphate, available P, CEC, root infection, spore density were found on the control, but the lowest of total glomalin and easily extracted glomalin were found on non-mycorrhizae–rock phosphate. The application of mycorrhizae, cow dung, and biochar improved the sandy soil characteristics.&lt;/p&gt;

Shifts in arbuscular mycorrhizal fungal community composition and edaphic variables during reclamation chronosequence of an open-cast coal mining dump

Arbuscular mycorrhizal fungi (AMF) contribute to the restoration of soil ecological functions and may facilitate the revegetation of degraded ecosystems by decreasing abiotic and biotic stresses on plants. The diversity and composition of AMF communities on the revegetation were assessed during an open-cast mining dump reclamation chronosequence of the soil at <1, 5, 10, 15 and 20 years after reclamation began. Total glomalin (TG), easily extractable glomalin (EEG), soil pH, electrical conductivity, soil organic carbon (SOC), total nitrogen (TN), available phosphorus (AP), and C:N:P stoichiometry were measured. Based on high-throughput sequence analysis on partial Glomeromycota 18S rRNA, 156 AMF operational taxonomic units were identified, which belonged to 12 genera and nine families. AMF diversity indices were significantly different between the community early in reclamation (<1 year) and later (P < 0.05), and were correlated with TN, AP, TG, N/P, C/P, EEG/SOC and TG/SOC ratios (P < 0.05). Network analysis and nonmetric multidimensional scaling analyses revealed that AMF community composition was significantly different early in the process of reclamation (<1 year) and at the end of reclamation (20 years) (P < 0.05), but were similar in the intermediate reclamation stages (5–15 years). Overall, the study suggests the rapid and stable re-establishment of a species-rich AMF community on a degraded ecosystem over time, following artificial re-vegetation.