Soil Microbiological Properties Research Articles

Short-term effect of compost amendment on the fertility of calcareous soil and basil growth

ABSTRACT Organic wastes can also be used to increase the amount of organic matter in humus-poor agricultural soils and thus maintain soil fertility. After obtaining sugar from sugar beet plant, a food industry waste rich in organic matter and nutrients called vinasse emerges. In this study, it was aimed to determine the effects of vinasse compost on soil fertility. In this context, the compost was applied alone and together with chemical fertilizer to a calcareous soil. Then, an aromatic plant was produced under greenhouse conditions. The study was carried out in a randomized complete block with three replications according to factorial experiment design. Chemical and microbiological analyses were carried out on soil samples taken during the plant’s growth. According to the results obtained, it was determined that the nutrients examined in terms of soil chemical properties (excluding exchangeable potassium) showed a significant increase with high application rate of the compost supplemented with chemical fertilization. Enzyme activities (excluding dehydrogenase) examined in terms of soil microbiological properties showed a significant increase (urease = 84.96%, alkaline phosphatase = 53.02%, β-glycosidase = 83.61%) compared to control with the application of the compost alone. It was determined that the compost should be supported with chemical fertilizer in terms of its use in terms of improving soil fertility, and its pragmatic effect in plant production is high during early vegetative growth of the plant.

Application of spent mushroom substrate suppresses Fusarium wilt in cucumber and alters the composition of the microbial community of the cucumber rhizosphere

One of the main cucumber (Cucumis sativus) diseases in China is Fusarium wilt caused by the fungus Fusarium oxysporum f. sp. cucumerinum (FOC). The aims of this study were to evaluate the suppressive capacity of different spent mushroom substrate (SMS) amendments against Fusarium wilt and to analyse their effects on soil microbiological properties. A greenhouse experiment was carried out with four treatments: (1) CK: unamended control, (2) FV: application of spent Flammulina velutipes substrate, (3) LE: application of spent Lentinus edodes substrate, and (3) PO: application of spent Pleurotus ostreatus substrate. Cucumber disease incidence, the abundance of FOC, Bacillus, Pseudomonas and Lysobacter (using real-time PCR), and the microbial community (using Biolog EcoPlate and phospholipid fatty acid (PLFA) analyses) in rhizosphere were studied 15, 30, 45 and 60 days after transplantation. At the end of the 60-day pot experiment, the FV, LE and PO treatments significantly (p < 0.05) reduced disease incidence by 53.3%, 25.7% and 37.9%, respectively, compared to the CK treatment. All three SMS amendments significantly (p < 0.05) increased the growth of cucumber seedlings and suppressed the FOC population compared to the control. The three SMS amendments, in particular spent F. velutipes substrate, increased the abundance of beneficial microbes (Bacillus spp., Pseudomonas spp. and Lysobacter spp.). Biolog and PLFA data showed that average well colour development (AWCD), total PLFAs, bacterial, and Gram (+) and Gram (−) bacterial PLFAs were increased in the FV, LE and PO treatments. Overall, the results of this study suggest that the application of three SMS amendments, especially FV, could effectively suppress cucumber Fusarium wilt and reducing the population of FOC.

PROPIEDADES FISICOQUÍMICAS Y MICROBIOLÓGICAS DE SUELOS CON CAÑA DE AZÚCAR Y MAÍZ BAJO CONDICIONES DE RIEGO Y TEMPORAL

&lt;p&gt;&lt;strong&gt;Background&lt;/strong&gt;: Sugarcane and maize are two main crops in Mexico, and the soil characteristics are important for their proper grow. Soil suitability is assessed through indicators which are chemical, physical and biological. &lt;strong&gt;Objective&lt;/strong&gt;: We compared physical, chemical and microbiological soil properties in two agroecosystems, one with sugarcane and one with maize, under irrigation and rainfed conditions, so as to detect soil quality changes in each condition. &lt;strong&gt;Methodology&lt;/strong&gt;: Soil samples were evaluated for pH, N, P, K, Ca, Mg, Na, organic matter, cationic exchange and texture, based on the NOM-021-RECNAT-2000. The number of microorganisms was quantified in each agroecosystem, using four culture media. Data was examined with an analysis of variance and Tukey mean test (P ≤ 0.05). &lt;strong&gt;Results&lt;/strong&gt;: Soil quality was low in localities with maize, and there were not statistical differences among them; but it was better in sugarcane under rainy season-based cropping system than under irrigation. More microorganism colonies were found in maize under irrigation and sugarcane under rainy season-based cropping system. &lt;strong&gt;Implications&lt;/strong&gt;: It is important to establish conservation measures that allow buffering and preserving soil and nutrient losses to maintain their productive capacity, especially in soils with more years of production. &lt;strong&gt;Conclusions&lt;/strong&gt;: Soils under rainy season-based cropping system, with both agroecosystems, presented better nutritional contents in comparison with those under irrigation. The largest number of microorganisms in corn under irrigation and sugarcane under rainfed conditions could be because the pH was higher than the other two agroecosystems.&lt;/p&gt;

Long-term influence of conservation tillage on soil organic carbon and microbial diversity

The physico-chemical and microbiological properties of soil may be modified by long-term tillage practices and crop-rotations. The tillage system, may also affect soil properties under various climatic conditions. In present investigation, soil microbial diversity at different depths was studied in long term tillage experiment continued since 1997-98 (pearl millet-wheat), 2000-01 (sorghum-wheat) and 2015-16 (mungbean-wheat) that was carried out in sandy loam textured soil at Hisar (Haryana) during 2017-18, with 20 years of zero tillage (ZT) under sorghum-wheat, 17 years under pearl millet-wheat and 2 years under mungbean-wheat cropping system, respectively. Adoption of ZT practice positively affected soil organic carbon, microbial biomass carbon, microbial biomass nitrogen, dehydrogenase activity and viable counts of microbes. So, indicating that ZT is an effective measure to improve the physico-chemical and microbiological properties of soil that may lead to improved soil health along with enhanced crop productivity.

Change of microbiological properties of disturbed permafrost soils during their restoration under the influence of fertilizers

The extent of microbiological processes in soil is determined not only by the number of microorganisms, but mainly by their activity. Therefore, it is extremely relevant to study the influence of various organic, mineral fertilizers, lime used for the cultivation of gley-podzolic soils of the Far North, on the change of intensity and development of the most important microbiological processes in these soils. In its natural state, soils are a multi-component system consisting of many heterogeneous microenvironments inhabited by microorganisms with different food chains. In anthropogenic activities, and in particular, in the introduction of organic and mineral fertilizers, the environmental conditions in soils change significantly, leading to a significant adjustment in taxonomic structure of microbial cenoses and their functional activities. Particularities of soil-climatic conditions also significantly affect species composition and features of functioning of microbocenoses in soils. Therefore, when choosing the most effective methods of soil cultivation in each particular climate zone, a lot of attention is paid to their biological assessment. The studies show that fertilizer and lime has a positive effect on the prokaryote complex of soil microorganisms of everfrozen soils.

The effects of whey application on the soil biological properties and plant growth

Whey is an industrial dairy by-product. Whey proteins present in whey are valuable functional ingredients with a variety of applications. Because of high investment and management costs, many medium and small-scale cheese manufacturing plants choose the way to waste whey by discharging it to land without refining while large companies prefer to evaluate it. In this experiment were investigated the effects of whey application on some growth parameters of test plant and soil biological properties. For this purpose, greenhouse experiment was conducted to determine the effects of different whey powder solution (6% dry matter) such as no demineralized whey powder (NDWP), 50% demineralized whey powder (50% DWP) and whey protein powder (WPP) on maize growth and biological properties of soils using increasing application rates (0, 50, 100, 150 and 200 ml/kg) as three replication. At the end of the study generally, all whey treatments influenced the soil microbiological properties in comparison with the control, indicating activation by microorganisms. The addition of different doses of different whey solutions caused a rapid and significant increase in microbial biomass C, soil respiration, dehydrogenase activity and catalase activity in soil; this increase was especially noticeable in soils treated with NDWP and 50% DWP. Similarly, addition of 50% DWP to the soil increased values of plant height, fresh plant weight and fresh root weight compared to the control and other whey. Whey has a positive effect on soil biological properties. In conclusion, we can say that this waste product, which has high nutrient element content, could be used in fertilization practices especially as a nitrogen source and multi-perspective studies need to be carried out on this topic.

Plant species and season influence soil physicochemical properties and microbial function in a semi-arid woodland ecosystem

This research investigated the effects of woody plant identity and season on soil physicochemical properties and microbiological function in the semi-arid Zagros forest, one of the old-growth semi-arid oak forests in the world. Soil sampling was conducted beneath the canopy of six woody (tree and shrub) species in spring and winter. Microbial variables analysed included soil basal respiration (BR), microbial biomass C and N (MBC and MBN), microbial entropy index (MIE), substrate induced respiration (SIR) and enzymatic activities (i.e., urease and alkaline phosphatase). Soil physicochemical properties were also analysed and included pH, electrical conductivity (EC), available calcium and magnesium (Ca2+ and Mg2+), organic carbon (OC), total nitrogen (Ntot), lime, water content (WC), bulk density (BD), clay, silt and sand. Results demonstrated significant differences among the woody species (Pseudo-F = 56.31; p = 0.001), season (Pseudo-F = 97.37; p = 0.001) and their interaction (Pseudo-F = 2.96; p = 0.005) for the matrix of microbiological soil parameters. Differences were species-specific for shrubs and trees with a marked effect for tree species such as Quercus brantii. Microbial parameters were consistently higher in spring when higher temperature and lower moisture were recorded. Soil OC, Ntot, BD, and WC were important drivers of the soil microbial function. Our results evidenced a strong effect of season and plant species on soil physicochemical and microbiological soil properties in a semi-arid forest ecosystem. Higher values of microbiological soil parameters, including urease and phosphatase activities, were recorded for tree species during spring season.

Influence of various types of fertilizers and equipment on the physical and microbiological properties of soil

The cultivation of corn hybrids on silage, corresponding to the terms of ripeness of the district, and their timely harvesting allow to harvest silage containing 6.09-6.29 MJ per 1 kg of feed. High-quality silage should contain about 30 % SV, more than 10.8 MJ of exchange energy per 1 kg SV, at least 32% starch, no more than 4.5% crude ash, about 20% crude fiber and have a coefficient of digestibility of organic mass of at least 75 %. Therefore, it became necessary to improve the technology of its cultivation in the fields of crop rotations in order to increase the concentration of metabolic energy in the feed. It should be noted that an important role in the technology of growing corn should be assigned to the variety, fertilizers, biological products, growth stimulants and biological fungicides.

Influence of Zinc Oxide Nanoparticles on Soil Physicochemical Properties and Arachis hypogea Rhizosphere Microbial Community

We evaluated the effect of 4000 mg zinc oxide (ZnO, 99%, 30 nm) nanoparticle on the physicochemical and microbiological properties of organic manure amended ultisol and loam soil cultivated with Arachis hypogaea using standard methods. The results indicate varying effects on the physicochemical properties in relation to the soil type. The pH of the control ultisol at 7.85 ± 0.17 and 8.3 ± 0.12 in the amended ultisol whereas, the control loam was 7.15 ± 0.17 and 7.41 ± 0.11 in the amended soil indicating 1.06- and 1.04-times higher difference than the controls respectively. Phosphorus concentration at 57.82 ± 0.54%, 50.81 ± 0.22% and 55.97 ± 0.04%, 59.97 ± 0.02% was 1.14 times lower in the ZnO amended ultisol and 1.07 times higher in amended loam soil compared to the respective controls. The organic matter content in the control and amended ultisol was 2.28 ± 0.32% and 0.91 ± 0.02%, 3.68 ± 0.36% and 0.36 ± 0.02% in the control and amended loam soil. The concentration of nitrate in the control ultisol was 0.05 ± 0.01% and 0.03 ± 0.01% in the amended soil. The nitrate in the control loam soil was 0.08 ± 0.01% relative to 0.02 ± 0.01% in the treated soil and these differences were significant at p = 0.05. The concentration of nutritive salts was reduced and in contrast iron, copper, exchangeable acids, exchange capacity, clay and silt increased in the amended soils. Further to this, heterotrophic ammonia and nitrate-oxidizing bacterial population were inhibited in the amended soils and denitrifying organisms were stimulated. The organisms were members of the genera Pseudomonas, Xanthobacter, Enterobacter, Bacillus, Lactobacillus, Citrobacter, Nitrosomonas, Agromyces and Rhizobium. ZnO nanoparticles altered the soil physicochemical properties which exacerbated the negative effect on microbial abundance and varied with the soil type.

Influence of spent coffee grounds on soil microbiological attributes and maize crop

The objective of this work was to evaluate the influence of different doses of spent coffee grounds on soil microorganisms responsible for nutrient cycling and the development of corn crop under no-tillage. The trial was conducted in a field at the State Center for Agricultural Professional Education Fernando Costa, in a randomized block with 4 treatments, with increasing doses, 0, 3, 6 and 9 t ha-1 of coffee grounds. Microbial biomass carbon (CBM), baseline respiration (RBS), microbial and metabolic quotient (qMIC and qCO2), plant development (corn) and productivity were evaluated. At the dose of 9 t ha-1 of spent coffee grounds, there was an increase in organic matter and microbial biomass (219.01) and qMIC (1.5). With increased microbial activity, the development of the plant was 20% higher compared to the control, plant height (2.21) and stem diameter (2.99). Consequently, the productivity was 42 bags ha-1 higher than the control. Thus, we can conclude that spent coffee grounds can be a viable alternative for use as organic fertilizer in agriculture.

Restoring the plant productivity of heavy metal-contaminated soil using phosphate sludge, marble waste, and beneficial microorganisms

Assisted natural remediation (ANR) has been highlighted as a promising, less expensive, and environmentally friendly solution to remediate soil contaminated with heavy metals. We tested the effects of three amendments (10% compost, C; 5 or 15% phosphate sludge, PS5 and PS15; and 5 or 15% marble waste, MW5 and MW15) in combination with microorganism inoculation (rhizobacteria consortium alone, mycorrhizae alone, and the two in-combination) on alfalfa in contaminated soil. Plant concentrations of Zn, Cu, and Pb were measured, along with proline and malondialdehyde production. The microbiological and physicochemical properties of the mining soil were evaluated. Application of the amendments allowed germination and promoted growth. Inoculation with the rhizobacteria consortium and/or mycorrhizae stimulated plant growth. PS and MW stimulated the production of proline. Inoculation of alfalfa with the rhizobacteria-mycorrhizae mixture and the application of MW allowed the safe cultivation of the legume, as shown by the low concentrations of metals in plant shoots. Zn and Pb concentrations were below the limits recommended for animal grazing and accumulated essentially in roots. Soil analyses showed the positive effect of the amendments on the soil physicochemical properties. All treatments increased soil pH (around 7), total organic carbon, and assimilable phosphorus content. Notably, an important decrease in soluble heavy metals concentrations was observed. Overall, our findings revealed that the applied treatments reduced the risk of metal-polluted soils limiting plant growth. The ANR has great potential for success in the restoration of polymetallic and acidic mining soils using the interaction between alfalfa, microorganisms, and organo-mineral amendments.

Crecimiento de Citrange troyer y atributos químicos-microbiológicos del suelo en respuesta a diferentes fertilizantes orgánicos

La producción citrícola depende principalmente en la disponibilidad de portainjertos sanos, apropiados y vigorosos; parte de su reproducción está asociada con el uso de fertilizantes químicos, que contribuyen en la contaminación de los ecosistemas. El uso de fertilizantes orgánicos son alternativas para reducir el uso de fertilizantes químicos. El objetivo de este trabajo fue evaluar el efecto de tres fertilizantes orgánicos (estiércol de gallina, cachaza (1 y 2) y pinzote) suministrados en tres dosis (1, 2 y 3%), en las propiedades químicas y microbiológicas del suelo y en el crecimiento del portainjerto Citrange troyer, en invernadero. Se utilizó un diseño completamente al azar con 14 tratamientos y seis repeticiones cada uno, incluyendo dos testigos (absoluto y fertilizado). Mediante diluciones seriadas en medios específicos se cuantificó Azospirillum, Azotobacter, y bacterias solubilizadoras de fosfatos y de potasio. Los hongos micorrízicos arbusculares fueron evaluados según la técnica de clareo y tinción con azul tripano. El pH del suelo se incrementó 0.9 unidades al agregar 1% de cachaza-2; mientras que el carbono orgánico se elevó 0.7% con el estiércol de gallina al 1%. Las bacterias Azospirillum, Azotobacter y solubilizadoras de fosfatos, se incrementaron en los tratamientos suministrados con cachaza-1 1% y estiércol de gallina 1%. La cachaza-1 2%, indujo mayor colonización micorrízica y mayor crecimiento de la planta. Ocho de los doce tratamientos con fertilizantes orgánicos utilizados, modif icaron positivamente las propiedades químicas y microbiológicas del suelo, dando como resultado un mejor crecimiento de Citrange troyer comparado con los testigos.

Thinning Partially Mitigates the Impact of Atlantic Forest Replacement by Pine Monocultures on the Soil Microbiome.

Forest replacement by exotic plantations drive important changes at the level of the overstory, understory and forest floor. In the Atlantic Forest of northern Argentina, large areas have been replaced by loblolly pine (Pinus taeda L.) monocultures. Plant and litter transformation, together with harvesting operations, change microclimatic conditions and edaphic properties. Management practices such as thinning promote the development of native understory vegetation and could counterbalance negative effects of forest replacement on soil. Here, the effects of pine plantations and thinning on physical, chemical and microbiological soil properties were assessed. Bacterial, archaeal, and fungal community structure were analyzed using a metabarcoding approach targeting ribosomal markers. Forest replacement and, to a lesser extent, thinning practices in the pine plantations induced significant changes in soil physico-chemical properties and associated shifts in bacterial and fungal communities. Most measured physical and chemical properties were altered due to forest replacement, but a few of these properties reached values similar to natural forests under the thinning operation. Fungal alpha diversity decreased in pine plantations, whereas bacterial alpha diversity tended to increase but with little statistical support. Shifts in community composition were observed for both fungal and bacterial domains, and were mostly related to changes in plant understory composition, soil carbon, organic matter, water content, pH and bulk density. Among several other changes, highly abundant phyla such as Proteobacteria (driven by many genera) and Mortierellomycota (mainly driven by Mortierella) decreased in relative abundance in the plantations, whereas Acidobacteria (mainly driven by Acidothermus and Candidatus Koribacter) and Basidiomycota (mainly driven by the ectomycorrhiza Russula) showed the opposite response. Taken together, these results provide insights into the effects of forest replacement on belowground properties and elucidate the potentially beneficial effect of thinning practices in intensive plantation systems through promoting the understory development. Although thinning did not entirely counterbalance the effects of forest replacement on physical, chemical and biological soil properties, the strategy helped mitigating the effects and might promote resilience of these properties by the end of the rotation cycle, if subsequent management practices compatible with the development of a native understory vegetation are applied.

Effect of Cow Manure Compost on Chemical and Microbiological Soil Properties in Saudi Arabia.

The dairy industry in Saudi Arabia is producing huge quantity of Farm Yard Manure (FYM) resulting in potential environmental and health hazards. Raw FYM is processed into usable compost for increasing soil fertility and productivity. The main aim of this study was to analyze the effect of prepared Cow Manure Compost (CMC) on chemical and microbiological soil properties. A greenhouse experiment was carried out with 3 CMC treatments (control, 25 and 50 t ha-1). The plot size was 2×2 m2 with three replications and the test crop was corn (Zea mays, an American hybrid cultivar). The irrigation source was deep well water. Crop growth parameters, such as plant height and fresh biomass were determined. The microbiological soil properties measured were Soil Microbial Biomass (SMB), Microbial Nitrogen (MN), Dehydrogenase Activity (DHA) and Alkaline Phosphomonoesterase Activity (APA). Standard analytical methods were used for soil analysis and microbiological investigation. Addition of CMC increased significantly the mean plant height and fresh biomass. The microbial parameters such as SMB, MN, APA and DHA improved and depended on the doses application. The study results showed that the use of CMC improved the soil microbiological properties thus resulting in improved crop production.

Effect of Nutrient Management Regimes on Soil Biological Properties - A Review

Soil quality assessment is very important aspect in determining long term sustainability; however it is governed by different physico-chemical and bio-chemical parameters. These are interrelated among them and controlled by different management practices like tillage, water, organic and inorganic source of nutrients etc. Among the different soil parameters, it was considered that soil biochemical parameters provide rapid and accurate estimates on soil quality and its evaluation require understanding of biochemical and microbiological soil properties. Among the several biochemical and microbiological properties, soil organic carbon fractions, microbial biomass and soil enzymes activities may be considered as an important property which governed soil health or quality. Soil organic carbon fractions includes total organic carbon, soil organic carbon (oxidizable carbon), labile carbon etc., microbial biomass and enzymes activities include content of microbial biomass carbon, nitrogen, phosphorus and activities of different enzymes like dehydrogenase, acid and alkaline phosphatase, Urease, β-glucosidase, Aryl sulphatase etc. It is established and proved that, nutrient management practices (application of fertilizers and manures) marked significant effect on SOC fractions and soil enzymes activities. In most of cases, the application of organic sources of nutrients as well as integrated nutrient management resulted in significant improvement in the soil biochemical properties, however, microbial properties like microbial biomass carbon, nitrogen, phosphorus and enzymes activities are very sensitive to nutrient management options compared to soil organic carbon fractions.

Integrating Amendment and Liquid Fertilizer for Aided-Phytostabilization and Its Impacts on Soil Microbiological Properties in Arsenic-Contaminated Soil

Indiscriminate overuse of liquid fertilizer and arsenic (As) contaminated soil by abandoned mines is one of the important environmental issues in Korea. This study was carried out to solve these two problems. Amendments (limestone, red mud and acid mine drainage sludge), liquid fertilizer and plant vegetation (Hairy vetch; Vicia villosa Roth) were simultaneously treated. Some soil chemical properties (pH, dissolved organic carbon, inorganic nitrogen content, and bioavailable As), soil respiration and enzyme activity (urease activity and dehydrogenase activity) were determined for chemical and biological assessment. Amendments decreased bioavailable As in soil, and acid mine drainage sludge had the best reduction efficiency in alkali soil. Liquid fertilizer affects not only soil chemical properties but also biological properties. Through multiple regression analysis, the rhizosphere effect through plant cultivation using specific root length index was reflected in the result of soil microbial and enzyme activity. In the reclamation of As-contaminated soil, the synergistic effect of multiple treatments could be confirmed. In particular, biological assessment indicators could be useful when evaluating the complex treatment of various restoration techniques, including the phytoremediation method. Based on these results, a long-term follow-up study on the field scale will be possible.

Responses of Microbiological Soil Properties to Intercropping at Different Planting Densities in an Acidic Andisol

Intercropping could increase the capacity of crops to use soil resources. The aim of this study was to investigate the effects of lupin/wheat intercropping on soil properties, grain yield and nutrient uptake at different plant densities. Lupin and wheat were grown under field conditions as monocrops and intercrops. Soil nutrient availability and relative abundance of functional genes (acdS, phoD, phoC and nifH) were evaluated. The results obtained indicate that the cropping system had a significant effect (p &lt; 0.001) on N and P availability. Lupin monocrop led to significantly higher N availability compared to intercrop. Intercropping resulted in significantly lower Olsen-P and K in soil concentrations compared to monocropping. No significant differences were observed in enzyme activity, except for phosphatase, which was 152% greater in the treatments at high plant density. Foliar nutrients were significantly higher in intercropping compared to monocropping. Acid phosphatase gene phoC was more abundant than the alkaline phosphatase gene phoD, which plays a more relevant role in acidic Andisols. The results confirm that N and P mobilization can improve nutrient absorption on wheat. When intercropped, lupin had positive effects on wheat due to its P mobilization capacity, while no effects were observed on lupin.

Long-Term Fertilization with Potassium Modifies Soil Biological Quality in K-Rich Soils

Imbalanced fertilization without potassium (K) is a worldwide phenomenon in K-rich soils, but its long-term effects on soil quality are poorly understood. Here, in a wheat–fallow system with K-rich soil, soil nutrients and enzyme activities involved in C, N, P, and S cycling and microbial community composition were studied in a 27-year field study with three treatments: no fertilizer (CK); mineral N and P fertilizer (NP); and mineral N, P, and K fertilizer (NPK). Results revealed that long-term NP and NPK fertilization significantly increased soil quality index (SQI) scores and wheat grain yield by mediating soil fertility, which was characterized by a significant decline in soil pH and increase in soil organic carbon (SOC), total N, available N (AN), available P (AP), enzymatic activities, and the abundance of total bacteria, fungi, and actinomycetes, when compared to CK. NP exhibited significantly higher SOC, AN, AP, microbial biomass C (MBC) and N (MBN), N-acetyl-glucosaminidase, total bacteria, and fungi values compared to NPK; the opposite was true for soil pH and available K. Notably, the differences in wheat grain yield were not statistically significant, while SQI scores in NP (0.86 ± 0.02) were appreciably higher than NPK (0.79 ± 0.03), which was attributed to the differences in MBC, MBN, and microbial communities. Redundancy analysis (RDA) indicated that SOC was the key variable affecting enzymatic activities and microbial community composition. The partial least squares path model (PLS-PM) revealed that fertilization-induced changes in SQI were primarily associated with soil microbiological properties (e.g., microbial community composition), while fertilization-driven increases in wheat grain yield were regulated by the soil nutrients. These results suggest that long-term NPK fertilization decreases soil biological quality in K-rich soils, and further studies are required to elucidate the underlying mechanisms by which K affects soil quality in agricultural systems.

Assessment of Physicochemical and Microbiological Properties of Soil from Organic Vegetable Farms in Bangladesh

Assessment of Physicochemical and Microbiological Properties of Soil from Organic Vegetable Farms in Bangladesh

Physicochemical and Microbiological properties of soil in Ahoko: A Suspected Petroleum Bearing Site (SPBS)

Physicochemical and Microbiological properties of soil in Ahoko: A Suspected Petroleum Bearing Site (SPBS)