Search Results (45)

This study evaluated the effects of different types and rates of locally produced organic residues on soil organic matter (SOM) and soil health in highly degraded loamy soils of olive orchards in arid southern Tunisia. Three residues were tested: poultry manure, raw date palm waste, and composted date palm waste mixed with manure. A randomised field trial was conducted over three years. Two years after application, soil samples were analysed for physical and chemical properties, basal respiration, nitrogen mineralisation, microbial biomass, enzyme activities (dehydrogenase, phosphomonoesterase, β-glucosidase, urease, arylsulphatase), and community-level physiological profiles. All residues increased SOM and available phosphorus (Pi), with dose-dependent effects sustained over time, though significant increases were only observed at the highest application rates. The most notable improvements occurred in soils amended with composted date palm waste. In contrast, biological and biochemical parameters showed little response, even after remoistening to stimulate microbial activity. This limited response was attributed to the absence of vegetation and, consequently, of root exudates and plant residues. This will be further investigated by assessing changes in the same biological and biochemical properties following the implementation of an intercropping system, which is expected to enhance both SOM content and microbial activity in these soils. Full article

Biochar is increasingly being applied to improve various degraded soils. However, studies on its use in ameliorating saline–alkaline grasslands remain limited. This study conducted experimental trials using soil collected from an alkalized meadow grassland in the Horqin Steppe, applying biochar with the application rates of 0, 1.5, 3.0, and 4.5 kg/m² in planting boxes. The objectives were to evaluate the effects of biochar addition on soil properties and microbial community and to explore the feasibility of using biochar for alkalized grassland improvement. Biochar addition to alkalized meadow soil enhanced the biomass of planted Astragalus adsurgens and improved soil properties. Soil bulk density was reduced; porosity, moisture content, and field moisture capacity significantly increased; soil nutrients were significantly ameliorated. Simultaneously, soil enzyme activities, including urease, phosphomonoesterase, protease, and polyphenol oxidase, significantly increased. Biochar application altered the microbial community structures in the alkalized meadow soil, primarily through the shifts in the relative abundance of dominant taxa rather than the fundamental changes in dominant phyla or genera. Biochar addition significantly raised the abundance of phoD- and nifH-harboring microorganisms, suggesting the enhancement in functions of soil N fixation and P transformation. Key factors influencing bacterial community structure included electrical conductivity, total P, total K, bulk density, and available K, whereas fungal communities were primarily affected by bulk density, porosity, and available N. Excessive biochar application can diminish its yield-enhancing effects, and the recommended biochar application rate for alkalized meadow grasslands in practice is 1.5 kg/m². These findings are expected to provide experimental evidence for utilizing biochar in degraded grasslands improvement. Full article

Soil microorganisms play a crucial role in improving soil phosphorus (P) availability. However, few studies have explored the changes in microbial community structure and their underlying mechanisms for improving soil P availability with the application of biochar and lime. Three kinds of biochar, made from rice straw (SB), Chinese fir wood sawdust (WB), and pig manure (MB), alone and with lime (SBL, WBL, and MBL), were applied to paddy soil to reveal the biochemical mechanisms for enhancing soil P availability. High-throughput sequencing and real-time PCR were used to investigate soil microbial communities and P functional genes. The three biochars increased the soil’s available P in the order of MB > SB > WB. Biochar co-applied with lime increased the available P (Olsen-P by 169–209%) and inorganic P (Al-P by 53.4–161%, Fe-P by 96.3–198%, and Ca-P by 59.0–154%) more than biochar alone, compared to the control (CK). Both biochar alone and co-applied with lime increased the activities of alkaline phosphomonoesterase (ALP), phosphodiesterase (PD), and inorganic pyrophosphatase (IPP) by 369–806%, 28.4–67.3%, and 37.9–181%, respectively, while it decreased the activity of acidic phosphomonoesterase (ACP) by 15.1–44.0%, compared to CK. Biochar, both alone and co-applied with lime, reduced the copy number of phoC gene by 5.37–88.7%, while it increased the phoD, gcd, and pqqC genes by 51.3–533%, 62.1–275%, and 25.2–158%, respectively, compared to CK. A correlation analysis and partial least squares path modeling (PLS-PM) indicated that Olsen-P, Bray-1 P, and inorganic P were significantly positively correlated with the activities of ALP, PD, IPP, and the phoD gene. Biochar co-applied with lime increased the relative abundances of the phoD-harboring bacteria Proteobacteria, Firmicutes, and Acidobacteria, which promoted the transformation of P to the effective state. Meanwhile, the dominant species Anaerolinea, Ascomycota, Mucoromycota, and Chaetomium provided rich effective nutrients for the soil microorganisms by accelerating the decomposition of soil organic matter, thus promoting phosphatase activity. It could be inferred that the optimized microbial community structure improved phosphatase activity by increasing the phoD gene and available nutrients, thus promoting the soil P availability. Biochar co-applied with lime had a better effect on increasing the P availability and rice yields than biochar alone. Full article

Traditional forest management models could potentially be used to combat changes in environmental conditions by stimulating soil properties and supporting tree growth. In this study, we compare the effects of different oak (Quercus petraea /Matt./Liebl.) forest models [coppice, coppice-with-standard, stocked coppice (reference)] on seasonal variability in soil properties at upland igneous and sedimentary sites (280–418 m a.s.l.). Soils were sampled at 0–5 and 10–15 cm in 50 × 50 m model and reference plots in January, April, July and October between 2015 and 2019, and soil organic matter, soil respiration, enzyme activity, pH and water-holding capacity were determined. The effects of forest model and seasonality were then compared using time-series analysis, analysis of variance and discriminant analysis. Overall, the models differentiated subsurface soil horizons from the topsoil and their feedback varied between sites. While water-holding capacity increased at the igneous stands, acid phosphomonoesterase activity increased and nitrogen content decreased at the sedimentary site. While the most significant negative influence of the forest model on soil properties was observed at the sedimentary site, the greatest increase in soil organic matter and water holding capacity was registered at the igneous coppice-with-standards site. Consequently, using the appropriate forest management model on different subsoil types could be valuable for improving carbon sequestration and drought resistance. Full article

Understanding how transport and storage conditions affect enzymatic activity is essential for accurate biomonitoring of nitrogen metabolism in plants. This study evaluated the effects of transport conditions and low-temperature storage on the enzymatic activities of nitrate reductase (NR), glutamine synthetase (GS), and phosphomonoesterase (PME) for Chloris gayana, Fraxinus uhdei, and Trifolium repens. Enzymatic activities were measured for leaf samples immediately after collection, after 18 h at room temperature, or after 18 h on ice. Additionally, samples were stored at −16 °C or −45 °C for up to 28 days. NR activity decreased to near-zero levels under all storage conditions, indicating that this enzyme is unsuitable for delayed analysis. In contrast, GS and PME activities showed species-dependent responses to storage, with increased activity observed for T. repens and C. gayana, potentially reflecting tissue degradation processes. F. uhdei exhibited greater stability in enzyme activities, suggesting a higher resilience to storage. These findings highlight the importance of minimizing storage time to preserve enzymatic integrity, particularly for NR, while providing insight into the potential for delayed analysis of GS and PME in specific species. This work offers practical recommendations for future biomonitoring efforts in nitrogen deposition studies. Full article

Hydrodynamic cavitation (HDC) as a pre-treatment method is innovative and has potential for wide-scale industrial applications. The novelty of this research involves evaluating the enzymatic activity in the anaerobic co-digestion (AcD) of hydrodynamically cavitated coffee waste (CW) and municipal sewage sludge (SS) as well as its influence on the AcD performance. The effectiveness of AcD was assessed on the basis of changes in the physico-chemical composition of the feedstock and digestate as well as the biogas/methane yield, and attention was paid to the effect of coffee waste on enzyme activity, including that of β-Glucosidases (β-Glu), protease (PR), urease (URE), phosphomonoesterases acid (ACP) and alkaline (ALP). Moreover, the changes in the heavy metal content after the AcD of CW and SS were investigated. Comparing the enzymatic activity of the feedstock and digestate, we observed that the URE, ACP and ALP activities were 4.5 to 11 times higher for the feedstock than the enzyme activities in the digestate. Moreover, when using CW cavitated for 30 min, the highest enzymatic activity in both the feedstock and digestate occurred. The results indicated that the relationship between the β-Glu activity and biogas yield showed the strongest positive correlation (r = 0.98 at p ≤ 0.05). At the same time, a positive correlation between the PAC, PAL, URE and PR activity and methane yield and methane content at p ≤ 0.05 was observed. The obtained results allow us to conclude that, in the future, such a digestate could be used as a bio-fertilizer to improve degraded soil to activate microbial populations. Full article

The aim of this study was to assess the effect of Pseudomonas fluorescens (P) application on isofetamid (IS) dissipation; the number of specific genes of archaea, bacteria and ammonia-oxidizing bacteria (AOB); and the activity of β-Glucosidase, phosphomonoesterase, N-acetyl-glucosaminidase and arylsulfatase. It was observed that the IS concentration was lower in the P+IS than in IS throughout the entire study period, which indicates the potential of P. fluorescens to decompose isofetamid faster. IS+P application significantly influenced N-acetyl-glucosaminidase, arylsulfatase and phosphomonoesterase activity in soil compared to the control by approximately 29%, 72% and 6.5%, respectively. Moreover, it was observed that on day 21 in IS+P, the number of bacterial genes was significantly higher than in the control and IS and than on day 1, by 10% and 20%, respectively. On day 21, the number of archaea was significantly higher in all variants and ranged from 3.61 (control) to 6.88 log₁₀ gene copies/g dm (IS+P). Correlation analysis showed a positive correlation between IS and TOC, while there was a negative correlation between IS and β-Glu and the number of archaea and AOB genes. The tested strain has the potential to be a biofertilizer and an agent in the bioremediation of contaminated soils. Full article

Cancer, a group of diseases characterized by uncontrollable cell proliferation and metastasis, remains a global health challenge. This study investigates quercetin, a natural compound found in many fruits and vegetables, for its potential to inhibit the phosphomonoesterase activity of protein tyrosine phosphatase nonreceptor type 22 (PTPN22), a key immune response regulator implicated in cancer and autoimmune diseases. We started by screening seven (7) natural compounds against the activities of PTPN22 in vitro. The initial screening identified quercetin with the highest percentage inhibition (81%) among the screened compounds when compared with ursolic acid that has 84%. After the identification of quercetin, we proceeded by investigating the effect of increasing concentrations of the compound on the activity of PTPN22. In vitro studies showed that quercetin inhibited PTPN22 with an IC₅₀ of 29.59 μM, outperforming the reference standard ursolic acid, which had an IC₅₀ of 37.19 μM. Kinetic studies indicated a non-competitive inhibition by quercetin with a Ki of 550 μM. In silico analysis supported these findings, showing quercetin’s better binding affinity (ΔGbind −24.56 kcal/mol) compared to ursolic acid, attributed to its higher reactivity and electron interaction capabilities at PTPN22′s binding pocket. Both quercetin and ursolic acid improved the structural stability of PTPN22 during simulations. These results suggest quercetin’s potential as an anticancer agent, meriting further research. However, in vivo studies and clinical trials are necessary to fully assess its efficacy and safety, and to better understand its mechanisms of action. Full article

Studying the altitudinal variation and driving factors of soil acid phosphomonoesterase (ACP) activity in subalpine regions is crucial for understanding nutrient cycling processes within mountainous ecosystems. This study focused on fir (Abies fabri (Mast.) Craib) forests located at three altitudes (2781 m, 3044 m, and 3210 m) on the eastern slope of Mt. Gongga in southwest China. We measured soil ACP activity alongside soil climate, nutrients, and microorganisms at various depths and elevations to investigate how these factors influence ACP activity. The results indicated that in the organic matter horizons (Oe and Oa horizons), ACP activity gradually decreased with elevation. However, the surface mineral horizon (A horizon) did not show a decline in ACP activity with increasing elevation, which could be attributed to significantly lower ACP activity recorded at the 2781 m sample site compared to the 3044 m site. Variance partitioning analysis revealed that among soil climate, nutrients, and microorganisms, soil nutrients had the most substantial impact on ACP activity across all horizons, with a particularly high contribution of 89.4% observed in the A horizon. Random forest model analysis further demonstrated that soil total carbon (TC) played a crucial role in determining ACP activity in the Oe and Oa horizons, with importance values of 8.5% and 7.3%, respectively. Additionally, soil total nitrogen (TN) was identified as the primary factor influencing ACP activity in the A horizon, with an importance value of 12.6%. Furthermore, soil ACP activity was positively regulated by the soil TC:TP and TN:TP ratios, indicating a stoichiometric control of ACP activity in the Abies fabri (Mast.) Craib forests on Mt. Gongga. Full article

Extreme precipitation and flooding frequency associated with global climate change are expected to increase worldwide, with major consequences in floodplains and areas susceptible to flooding. The purpose of this review was to examine the effects of flooding events on changes in soil properties and their consequences on agricultural production. Flooding is caused by natural and anthropogenic factors, and their effects can be amplified by interactions between rainfall and catchments. Flooding impacts soil structure and aggregation by altering the resistance of soil to slaking, which occurs when aggregates are not strong enough to withstand internal stresses caused by rapid water uptake. The disruption of soil aggregates can enhance soil erosion and sediment transport during flooding events and contribute to the sedimentation of water bodies and the degradation of aquatic ecosystems. Total precipitation, flood discharge, and total water are the main factors controlling suspended mineral-associated organic matter, dissolved organic matter, and particulate organic matter loads. Studies conducted in paddy rice cultivation show that flooded and reduced conditions neutralize soil pH but changes in pH are reversible upon draining the soil. In flooded soil, changes in nitrogen cycling are linked to decreases in oxygen, the accumulation of ammonium, and the volatilization of ammonia. Ammonium is the primary form of dissolved inorganic nitrogen in sediment porewaters. In floodplains, nitrate removal can be enhanced by high denitrification when intermittent flooding provides the necessary anaerobic conditions. In flooded soils, the reductive dissolution of minerals can release phosphorus (P) into the soil solution. Phosphorus can be mobilized during flood events, leading to increased availability during the first weeks of waterlogging, but this availability generally decreases with time. Rainstorms can promote the subsurface transport of P-enriched soil particles, and colloidal P can account for up to 64% of total P in tile drainage water. Anaerobic microorganisms prevailing in flooded soil utilize alternate electron acceptors, such as nitrate, sulfate, and carbon dioxide, for energy production and organic matter decomposition. Anaerobic metabolism leads to the production of fermentation by-products, such as organic acids, methane, and hydrogen sulfide, influencing soil pH, redox potential, and nutrient availability. Soil enzyme activity and the presence of various microbial groups, including Gram+ and Gram− bacteria and mycorrhizal fungi, are affected by flooding. Waterlogging decreases the activity of β-glucosidase and acid phosphomonoesterase but increases N-acetyl-β-glucosaminidase in soil. Since these enzymes control the hydrolysis of cellulose, phosphomonoesters, and chitin, soil moisture content can impact the direction and magnitude of nutrient release and availability. The supply of oxygen to submerged plants is limited because its diffusion in water is extremely low, and this impacts mitochondrial respiration in flooded plant tissues. Fermentation is the only viable pathway for energy production in flooded plants, which, under prolonged waterlogging conditions, is inefficient and results in plant death. Seed germination is also impaired under flooding stress due to decreased sugar and phytohormone biosynthesis. The sensitivity of different crops to waterlogging varies significantly across growth stages. Mitigation and adaptation strategies, essential to the management of flooding impacts on agriculture, enhance resilience to climate change through improved drainage and water management practices, soil amendments and rehabilitation techniques, best management practices, such as zero tillage and cover crops, and the development of flood-tolerant crop varieties. Technological advances play a crucial role in assessing flooding dynamics and impacts on crop production in agricultural landscapes. This review embarks on a comprehensive journey through existing research to unravel the intricate interplay between flooding events, agricultural soil, crop production, and the environment. We also synthesize available knowledge to address critical gaps in understanding, identify methodological challenges, and propose future research directions. Full article

Mining and metallurgy are the main sources of soil contamination with harmful metals, posing a significant threat to human health and ecosystems. River floodplains in the vicinity of metal mines or industrial plants are often subject to flooding with sediments containing heavy metals, which can be harmful to the soil ecosystem. This study aimed to investigate the microbial properties of the soil at a metal-contaminated site and to determine the significant relationships between the biological and chemical properties of the soil. The study site was located near the village of Gyöngyösoroszi, in the Mátra mountain region of Northwest Hungary. A phytoremediation experiment was conducted in a metal-polluted floodplain using willow and corn plantations. The soil basal respiration, substrate-induced respiration, soil microbial biomass carbon (MBC), acid phosphatase activities, and soil chemical properties were measured. The soil of the contaminated sites had significantly higher levels of As, Pb, Zn, Cu, Cd, and Ca, whereas the unpolluted sites had significantly higher levels of phosphorus and potassium. The substrate-induced respiration showed a positive correlation with MBC and negative correlations with the metabolic quotient (qCO₂). The soil plasticity index and phosphorus showed a positive correlation with MBC, whereas salinity and the presence of Cd, Pb, Zn, As, and Cu showed a negative correlation. Acid phosphomonoesterase activity negatively correlated with the plant-available phosphorus content and MBC, but was positively correlated with the contents of toxic elements, including cadmium, lead, zinc, arsenic, and copper. This study found a significant correlation between the qCO₂ and the toxic element content. This suggests that an enhanced metabolic quotient (qCO₂), together with a decreased MBC/SOC ratio, could be used to indicate the harmful effect of soil contamination by heavy metals in floodplain soils. Full article

The purpose of this research is to investigate the interactions among wheat varieties and microorganisms within rhizosphere and how conventional agriculture affects these dynamics during the growing season. Indeed, little is known about how commercial bread varieties modulate root exudates and how agrochemicals affect the microbiological processes. Therefore, this study investigated the changes in soil microbiological features such as enzyme activities (β-glucosidase, xylosidase, glucoronidase, chitinase, leucine-aminopeptidase, acid and alkaline phosphomonoesterases, inositol phosphatase, phosphodiesterase, pyrophosphatase–phosphodiesterase, arylsulphatase) and microbial biomass as a function of treatment (fungicides and plant growth regulator—PGR) and wheat varieties (Skyfall, SY Moisson, Aquilante, Bandera, Tintoretto, Antille, and Bologna) at the sowing, heading, and harvesting stage. A total of 168 samples (2 treatments × 7 varieties × 3 field replicates × 4 sub-samples taken in each plot) were collected in each period and analyzed. We found that soil microbial biomass was a sensible indicator in the fungicide/PGR application, with reduced values in treated plots at the heading. At this stage, the soil enzymatic activities were in general more expressed, confirming that the microbial processes are more proactive due to the growth of plants. Overall, the soil enzymatic activities responded differently according to the wheat varieties, highlighting specific capabilities to interact with microbes. Full article

Circular economy recycling-derived fertilizers (RDF) have the potential to replace linear economy fertilizers such as unsustainable superphosphates. Here, effects of ash RDF treatments in Irish grassland cultivation were investigated in a simulated second growing season. Soil fertilized in a preceding pot trial with superphosphate (SP), poultry-litter ash (PLA) and sewage-sludge ash (SSA) at P concentration of 60 kg P ha⁻¹ and a P-free control (SP0) was reused in a microcosm trial. Lolium perenne was cultivated for 54 days in six replicates with a full complement of micro- and macro-nutrients other than P. PLA treatments provided higher dry weight shoot yields than SP0, while SSA and SP overlapped with SP0 and PLA. Most probable number (MPN) analysis showed that phosphonate- and phytate-utilizing bacterial abundance was significantly increased in PLA. Alkaline (phoD) phosphomonoesterase gene fragments were significantly more abundant (qPCR) in the ashes than the superphosphate or P-free control. Bacterial communities were significantly affected by the P application. Similarly, a significant separation of treatments was confirmed in a canonical correspondence analysis of the phoD-harboring community. The genera Streptomyces and Xanthomonas were significantly higher in abundance in the ash RDFs. These results demonstrated the potential benefits of ash RDF treatments as an alternative P source. Full article

Soil phosphorus (P) partitioning could contribute to species diversity and structure in plant communities, but field-scale evidence for P partitioning remains scarce. We hypothesized that the presence of P partitioning could be inferred from statistical associations between the spatial distributions of plants and chemical forms of bioavailable soil P. We investigated this in a diverse tropical tree community on Barro Colorado Island, Panama. We quantified potentially bioavailable forms of soil P by extraction in 2 mM citric acid followed by treatment with phosphatase enzymes. We then linked these P forms to the distribution of 189 tree species in a 50 ha forest dynamics plot by testing species–P associations against null models of random dispersal. We found that 20% of tree species were significantly ($\alpha$ = 0.05) associated with the depletion of at least one soil organic P fraction, although around half of these associations might be false rejections of the null hypothesis due to type I error. Species in the Fabaceae (legumes), which are known to express high rates of phosphatase in their roots, were most frequently associated with soil P fractions. We interpret our findings as evidence of widespread P partitioning at the community scale, affecting a relatively small proportion of tree species in this moderately fertile forest. We predict that stronger evidence of partitioning will be found at sites with lower P availability. Full article

Phosphorus (P) is a vital macronutrient crucial for crop productivity. Plants absorb P salts, mainly orthophosphate, from the soil, yet the primary P source resides in organic materials. Acid and alkaline phosphatases (the predominant forms of soil phosphomonoesterases (APases)) are crucial for alleviating P deficiency in plants and play a vital role in releasing P from organic materials via hydrolysis. Our aim was to summarize the direction of the relationship between a variety of influential factors on acid and alkaline phosphatase activity in agricultural lands and identify gaps in knowledge. Our findings indicate a strong linkage between both APases and soil pH, positively influenced by clay content, organic matter, microbial biomass carbon, and nitrogen. Adopting healthy soil practices like balanced organic fertilizer usage, optimal soil water levels, reduced tillage, crop rotation, and using beneficial plant microbes help boost both APase activity. However, the connection between APases and crop productivity remains uncertain due to insufficient research in this area. We identified gaps in knowledge in relation to meso-macrofauna, alongside essential plant nutrients such as potassium, nutrient ratios, and the synergistic effects of various factors on APase response. Understanding the rapid, efficient assimilation of P through APases in the plant-soil and/or plant-microbiota ecosystem it can be crucial for crop productivity and yields. Full article