Search Results (2,099)

Soil health is essential for sustainable agricultural operations, as it supports farm production and ecosystem services. The adoption of sustainable agriculture practices such as conservation tillage, cover cropping, and crop rotation provides significant benefits for both crop productivity and environmental sustainability. These practices can increase soil biodiversity, nutrient cycling, and organic matter, which increase the resilience of agroecosystems. This narrative review synthesizes the insights of the soil health practices adoption literature, with a focus on common farming practices that can improve soil health and enhance crop yields, reviewing the results of various approaches and pointing out the challenges and opportunities for implementing sustainable agriculture on a larger scale. This paper discusses the effects of various tillage and cropping system approaches on soil health, including no-till and conventional tillage systems, crop rotation, cover cropping, cultivator combinations, and fertilizer application. This study found that conservation tillage is more beneficial to soil health than conventional tillage—which is still debated among scientists and farmers—and that different tillage methods interact differently. In contrast, agricultural yields increase more with intercropping, crop rotation, and cover crops than monocropping. For maintaining soil fertility, this study shows that agricultural yields could be increased by implementing zero tillage. This review identifies the most suitable farming practices for improving soil health while boosting crop production with minimal negative impact on the soil. It also highlights the benefits of these practices in maintaining soil quality. Full article

The use of sulfur (S) in polluted soils can reduce metal(loid) toxicity and enhance phytoremediation effectiveness. Here we studied the response of barley plants to As in soil amended with sulfate or elemental sulfur throughout the growing cycle. A greenhouse experiment was carried out using 4-L pots filled with clay-loam soil spiked with 60 mg kg⁻¹ As (Na₂HAsO₄·7H₂O). Two chemical forms of sulfur (elemental sulfur (S⁰) or sulfate (CaSO₄·2H₂O)) were applied at a dose of 1 and 3 Mg ha⁻¹, respectively, and two previously seeded barley plants were transplanted in each pot, using eight pots per treatment. At the end of the growing cycle, the biomass, nutrients, and metal(loid) content, as well as several physiological and biochemical parameters of the plants were analyzed. Moreover, the effect of the treatments on soil characteristics was also evaluated, including soil pore water. The treatment with sulfur promoted the growth of barley plants through their vegetative cycle, enhancing photosynthesis, although biomass did not significantly increase. Both sources of S promoted the accumulation of As in the root, thereby limiting its translocation to the aerial part of the plant, sulfate being more effective (an increase of 300%) than elemental S (an increase of 82%). The addition of S decreased soil pH. Furthermore, both treatments, but particularly sulfate, increased soluble sulfate and stimulated soil biological properties. In conclusion, the application of sulfate to As-polluted soil can enhance As phytostabilization by barley plants while simultaneously improving the biological properties of the soil. Full article

Paddy fields are the main agricultural source of greenhouse gas methane (CH₄) emissions. To enhance rice yield, various fertilization practices have been employed in rice paddies. However, the key microbial and abiotic factors driving CH₄ emissions under different fertilization practices in paddy fields remain largely uncharted. This study conducted field experiments in a traditional double-cropping rice area in South China, utilizing five different fertilization practices to investigate the key factors influencing CH₄ emissions. High-throughput sequencing and PICRUSt2 functional prediction were employed to investigate the contributions of soil physicochemical properties, CH₄-metabolizing microorganisms (methanogens and methanotrophs), and key genes (mcrA and pmoA) on CH₄ emissions. The results showed that CH₄ emission fluxes exhibited seasonal variations, with consistent patterns of change observed across all treatments for both early- and late-season rice. Compared to the no-fertilization (NF) treatment, cumulative CH₄ emissions were lower in early-season rice with green manure (GM) and straw returning (SR) treatments, as well as in late-season rice with GM treatment, while rice yields were maintained at higher levels. High-throughput sequencing analysis revealed that potential methanogens were primarily distributed among four orders: Methanobacteriales, Methanocellales, Methanomicrobiales, and Methanosarcinales. Furthermore, there was a significant positive correlation between the relative abundance of the CH₄-related key gene mcrA and these microorganisms. Functional analysis indicated that these potential methanogens primarily produce methane through the acetoclastic and hydrogenotrophic pathways. Aerobic CH₄-oxidizing bacteria, predominantly from the genus Methylocystis, were detected in all the treatments, while the CH₄ anaerobic-oxidizing archaea ANME-1b was only detected in chemical fertilization (CF) and cow manure (CM) treatments. Our random forest analysis revealed that the relative abundance of two methanogens (Methanocellales and Methanosarcinales) and two environmental factors (pH and DOC) had significant impacts on the cumulative CH₄ emissions. The variance decomposition analysis highlighted the CH₄-metabolizing microorganisms explained 50% of the variance in the cumulative CH₄ emissions, suggesting that they are the key microbial factors driving CH₄ emissions. These findings provide guidance for the development of rational measures to reduce CH₄ emissions in paddy fields. Full article

Pig manure, as an organic fertilizer, can significantly affect soil nutrient content, pH, and electrical conductivity. Moreover, the accumulation of heavy metals in pig manure and their potential ecological risks are also important concerns in soil management. Additionally, grazing systems may influence soil health and ecological balance by altering the soil microbial community structure. Therefore, this study investigates the impact of grazing Tibetan pigs on soil quality, focusing on the physicochemical properties, heavy metal accumulation, and microbial diversity. In the surface soil after grazing (GS0), pH, EC, AP, and AK were significantly higher than before grazing (NS0) (p < 0.05), while AN showed no significant difference. In the 10 cm soil layer, pH, EC, AK, and AN in GS10 were significantly higher than in NS10 (p < 0.05), whereas AP was significantly lower (p < 0.05). At the 20 cm depth, pH, EC, AP, and AK in GS20 were significantly higher than in NS20 (p < 0.05), but AN was significantly lower (p < 0.05). Overall, AN, AP, and AK decreased with increasing soil depth, while pH and EC showed no significant changes between the 10 cm and 20 cm layers (p > 0.05). In GS0 soil, the contents of Cd(II) and Zn(II) were significantly lower than those in NS0 (p < 0.05), while Pb(II) content was significantly higher (p < 0.05). There were no significant differences in Cu(II), Ni(II), Cr(VI), As(V), and Hg(II) (p > 0.05). In GS10 soil, Ni and Pb(II) contents were higher, whereas Cu(II), Zn(II), and Hg(II) contents were lower. In GS20 soil, Pb(II) and Cr(VI) contents were higher, while Cu(II) and Zn(II) contents were lower. Overall, GS had consistently lower Cd(II), Cu(II), Zn(II), and Hg(II) contents at all depths compared to NS, while Pb(II) and Cr(VI) contents were higher, showing depth-related variation trends, possibly due to plant absorption and heavy metal leaching. Probiotics such as Firmicutes, Bacteroidetes, and Acinetobacter increased significantly in soil, resulting in changes in the soil bacterial community. Full article

Fusarium oxysporum, the pathogen responsible for apple replant disease (ARD), is seriously threatening the apple industry globally. We investigated the antagonistic properties of Trichoderma strains against F. oxysporum HS2, aiming to find a biological control solution to minimize the dependence on chemical pesticides. Two of the thirty-one Trichoderma strains assessed through plate confrontation assays, L7 (Trichoderma atroviride) and M19 (T. longibrachiatum), markedly inhibited = F. oxysporum, with inhibition rates of 86.02% and 86.72%, respectively. Applying 1 × 10⁶ spores/mL suspensions of these strains notably increased the disease resistance in embryonic mung bean roots. Strains L7 and M19 substantially protected Malus robusta Rehd apple rootstock from ARD; the plant height, stem diameter, leaf number, chlorophyll content, and defense enzyme activity were higher in the treated plants than in the controls in both greenhouse and field trials. The results of fluorescent labeling confirmed the effective colonization of these strains of the root soil, with the number of spores stabilizing over time. At 56 days after inoculation, the M19 and L7 spore counts in various soils confirmed their persistence. These results underscore the biocontrol potential of L7 and M19 against HS2, offering valuable insights into developing sustainable ARD management practices. Full article

Lignocellulosic biomass (LCB) in the form of agricultural, forestry, and agro-industrial wastes is globally generated in large volumes every year. The chemical components of LCB render them a substrate valuable for biofuel production. It is hard to dissolve LCB resources for biofuel production because the lignin, cellulose, and hemicellulose parts stick together rigidly. This makes the structure complex, hierarchical, and resistant. Owing to these restrictions, the junk production of LCB waste has recently become a significant worldwide environmental problem resulting from inefficient disposal techniques and increased persistence. In addition, burning LCB waste, such as paddy straws, is a widespread practice that causes considerable air pollution and endangers the environment and human existence. Besides environmental pollution from LCB waste, increasing industrialization has resulted in the production of billions of tons of dyeing wastewater from several industries, including textiles, pharmaceuticals, tanneries, and food processing units. The massive use of synthetic dyes in various industries can be detrimental to the environment due to the recalcitrant aromatic structure of synthetic dyes, similar to the polymeric phenol lignin in LCB structure, and their persistent color. Synthetic dyes have been described as possessing carcinogenic and toxic properties that could be harmful to public health. Environmental pollution emanating from LCB wastes and dyeing wastewater is of great concern and should be carefully handled to mitigate its catastrophic effects. An effective strategy to curtail these problems is to learn from analogous systems in nature, such as termites, where woody lignocellulose is digested by wood-feeding termites and humus-recalcitrant aromatic compounds are decomposed by soil-feeding termites. The termite gut system acts as a unique bioresource consisting of distinct bacterial species valued for the processing of lignocellulosic materials and the degradation of synthetic dyes, which can be integrated into modern biorefineries for processing LCB waste and bioremediation applications for the treatment of dyeing wastewaters to help resolve environmental issues arising from LCB waste and dyeing wastewaters. This review paper provides a new strategy for efficient management of recalcitrant pollutants by exploring the potential application of termite gut bacteria in biorefinery and bioremediation processing. Full article

Synthetic microbial communities (SynComs) play significant roles in soil health and sustainable agriculture. In this study, bacterial SynComs (SCBs) and fungal SynComs (SCFs) were constructed by selecting microbial species that could degrade the potato root exudates associated with continuous cropping obstacles. SCBs, SCFs, and SCB + SCF combinations were then inoculated into organic fertilizers (OFs, made from sheep manure) to produce three bio-organic fertilizers (BOFs), denoted by SBFs (BOFs of inoculated SCBs), SFFs (BOFs of inoculated SCFs), and SBFFs (BOFs of inoculated SCB + SCF combinations), respectively. The OF and three BOFs, with a chemical fertilizer (CK) as the control, were then used in pot experiments involving potato growth with soil from a 4-year continuous cropping field. Microbial diversity sequencing was used to investigate the colonization of SCBs and SCFs into the rhizosphere soil and the bulk soil, and their effects on soil microbial diversity were evaluated. Source Tracker analysis showed that SCBs increased bacterial colonization from the SBFs into the rhizosphere soil, but at a relatively low level of 1% of the total soil bacteria, while SCFs increased fungi colonization from the SFF into the bulk soil at a much higher level of 5–18% of the total soil fungi. In combination, SCB + SCF significantly increased fungi colonization from the SBFF into both the bulk soil and the rhizosphere soil. Overall, the soil fungi were more susceptible to the influence of the BOFs than the bacteria. In general, the application of BOFs did not significantly change the soil microbial alpha diversity. Correlation network analysis showed that key species of bacteria were stable in the soils of the different groups, especially in the rhizosphere soil, while the key species of fungi significantly changed among the different groups. LEfSe analysis showed that the application of BOFs activated some rare species, which were correlated with improvements in the function categories of the tolerance of stress, nitrogen fixation, and saprotroph functions. Mantel test analysis showed that the BOFs significantly affected soil physicochemical properties, influencing bacterial key species, and core bacteria, promoting potato growth. It was also noted that the presence of SynCom-inoculated BOFs may lead to a slight increase in plant pathogens, which needs to be considered in the optimization of SynCom applications to overcome continuous cropping obstacles in potato production. Full article

Expansive soils, prone to significant volume changes with moisture fluctuations, challenge engineering infrastructure due to their swelling and shrinking. Traditional stabilization methods, including mechanical and chemical treatments, often have high material and environmental costs. This study explores fibrous by-products of flax processing, a sustainable alternative, for reinforcing expansive clay soil. Derived from the Linum usitatissimum plant, flax fibers offer favorable mechanical properties and environmental benefits. The research evaluates the impact of flax tow (FT) reinforcement on enhancing soil strength and reducing cracking. The results reveal that incorporating up to 0.6% randomly distributed FTs, consisting of technical flax fibers and shives, significantly improves soil properties. The unconfined compressive strength (UCS) increased by 29%, with 0.6% FT content, reaching 525 kPa, compared to unreinforced soil and further flax tow additions, which led to a decrease in UCS. This reduction is attributed to diminished soil–fiber interactions and increased fiber clustering. Additionally, flax tows effectively reduce soil cracking. The crack length density (CLD) decreased by 6% with 0.4% FTs, and higher concentrations led to increased cracking. The crack index factor (CIF) decreased by 71% with 0.4% flax tows but increased with higher FT concentrations. Flax tows enhance soil strength and reduce cracking while maintaining economic and environmental efficiency, offering a viable solution for stabilizing expansive clays in geotechnical applications. Full article

There is an unexplored knowledge gap regarding the relationship between soil quality and mean annual increment (MAI) in forest plantations in Tanzania. Therefore, this study aimed to identify soil quality indicators and their impact on the mean annual increment (MAI) of Pinus patula at Sao Hill (SHFP) and Shume forest plantations (SFP) in Tanzania. The forests were stratified into four site classes based on management records. Tree growth data were collected from 3 quadrat plots at each site, resulting in 12 plots in each plantation, while soil samples were taken from 0 to 40 cm soil depth. Analysis of variance examined the variation in soil quality indicators between site classes at two P. patula plantation sites. Covariance analysis assessed the differences in MAI and stand variables across various site classes, taking into account the differing ages of some stands, with stand age serving as a covariate. Linear regression models explored the relationship between soil quality indicators and MAI, while partial least squares regression predicted MAI using soil quality indicators. The results showed that, at SHFP, sand, organic carbon (OC), cation exchange capacity, calcium (Ca), magnesium (Mg), and available P varied significantly between site classes, while silt, clay, and available P varied significantly at SFP. At SHFP, sand and clay content were positively correlated with MAI, while at SFP, silt content, available P (Avail P), potassium (K), Ca, and Mg showed significant positive correlations. Soil quality indicators, including physical and chemical properties (porosity, clay percentages, sand content, and OC) and only chemical (K, Mg, Avail P, and soil pH) properties were better predictors of the forest mean annual increment at SHFP and SFP, respectively. This study underscores the importance of monitoring the quality of soils in enhancing MAI and developing soil management strategies for long-term sustainability in forests production. Full article

Agricultural industrial waste has demonstrated potential as a soil acidity corrector and fertilizer, in addition to reducing environmental impacts caused by inadequate waste disposal. Ornamental rock waste is a sustainable alternative as it contains essential elements for plant growth. (1) Background: this study aims to evaluate using marble waste in SENA and the Gallo Crudo Quarry in Colombia as an acidity mitigator in soils cultivated with maize (Zea mays) in a greenhouse. (2) Method: four treatments were applied: T0: without marble dust—MD; three doses of MD (T1: 1.1 Mg of MD ha⁻¹; T2: 2.2 Mg of MD ha⁻¹; and T3: 3.3 Mg of MD ha⁻¹). After 70 days, soil fertility analyses were carried out. (3) Results: The results show that the chemical properties of the soil improved with all treatments, mainly with T2, influencing the calcium (Ca), carbon (C), sulfur (S), and magnesium (Mg) contents. MD’s pH and Al + H values were higher than conventional treatments. The T2 treatment reduced soil acidity from 0.2 cmol + kg⁻¹ to 0.0 cmol + kg⁻¹ and increased pH to 7.91 compared to the control (5.4). The maize plants in the T2 treatment developed better, indicating that the dose of 2.2 Mg of MD ha⁻¹ can replace commercial limestone. (4) Conclusions: This agroecological technique is an innovative alternative in Colombia, replicable in areas with ornamental rock reserves, benefiting the agricultural economy and contributing to target the Sustainable Development Goals, which promote sustainability, responsible management of natural resources, and a reduction in environmental impacts. Full article

Plantations left for natural succession play a significant role in Tropical Rainforest National Parks. Studying the succession and restoration of plantations is crucial for achieving a park’s authenticity and integrity, as well as for maximizing its ecological functions. However, the changes in vegetation and soil properties during the natural succession of these decommissioned plantations remain unclear. In this study, we examined rubber [(Hevea brasiliensis (Willd. Ex A. Juss.) Muell. Arg] plantations in the Yinggeling area of the National Park of Hainan Tropical Rainforest. We used community surveys, field sampling, and soil property analyses to investigate the species richness, diversity, and species composition of the aboveground plant communities during three succession periods of rubber plantations left for natural succession, including 0 years (ZY), 3 years (TY), and 7 years (SY). The soil pH, total organic carbon, total nitrogen, total phosphorus, available phosphorus, nitrate nitrogen, ammonium nitrogen, and total potassium contents in the three succession periods were analyzed. These results showed that there were 92 species of understory plants in the decommissioned rubber plantations, belonging to 72 genera in 39 families. The highest number of understory plant species was found in the plantations with 3 years of natural succession, totaling 66 species from 49 genera in 29 families. The number of families, genera, and species followed the pattern TY > SY > ZY. The Margalef richness index (F), Simpson index (D), and Shannon–Wiener index (H) of understory plants in the 0-year succession plantations were significantly lower than those in the 3-year and 7-year succession plantations. However, there was no significant difference in the Pielou (EH) index among the succession gradients. The soil pH, nitrate nitrogen (NO3--N), and available phosphorus (AP) in the 0-year succession plantations were significantly higher than those in the 3-year and 7-year succession plantations. There were no significant differences in soil total nitrogen (TN), total phosphorus (TP), total organic carbon (TOC), and ammonium nitrogen (NH4+-N) across the three succession gradients. The soil total potassium (TK) in the 3-year succession plantations was significantly higher than that in the 0-year and 7-year succession plantations. Soil available phosphorus and total phosphorus (TP) were positively correlated with the Margalef index, Simpson index, Shannon–Wiener index, and Pielou index. The recovery rate of understory vegetation in decommissioned rubber plantations was faster than that of the soil. This indicates that the construction of the National Park of Hainan Tropical Rainforest has significantly promoted the recovery of the number of plant species and plant species diversity that have been left from rubber plantation operations. These findings not only deepen our understanding of soil property changes during the vegetation succession of artificial forests, particularly rubber plantations, but they also hold significant implications for guiding tropical forest management and sustainable development. Full article

Understanding the correlation between soil chemical properties and tea quality is essential for the comprehensive management of ancient tea gardens. However, the specific links between these factors in ancient tea gardens remain underexplored. This study analyzes the soil chemical properties of four distinct research regions in Nanhua County to explore their effects on key chemical components in ancient tea garden teas, providing a scientific basis for improving the quality of ancient tea garden teas through soil management. Employing high performance liquid chromatography (HPLC) and inductively coupled plasma mass spectrometry (ICP-MS), the chemical components of tea and the chemical properties of the soil were meticulously quantified. Following these measurements, the integrated fertility index (IFI) and the potential ecological risk index (PERI) were evaluated and correlation analysis was conducted. The results revealed that ancient tea garden tea quality is closely linked to soil chemical properties. Soil’s total nitrogen (TN), total sulfur (TS), and available potassium (AK) negatively correlate with tea’s catechin gallate (CG) component and AK also with polyphenols. Most other soil properties show positive correlations with tea components. The research also evaluated soil heavy metals’ IFI and PERI. IFI varied significantly among regions. Hg’s high pollution index indicates ecological risks; Cd in Xiaochun (XC) region poses a moderate risk. PERI suggests moderate risk for XC and Banpo (BP), with other areas classified as low risk. Implementing reasonable fertilization and soil amelioration measures to enhance soil fertility and ensure adequate supply of key nutrients will improve the quality of ancient tea gardens. At the same time, soil management measures should effectively control heavy metal pollution to ensure the quality and safety of tea products. Insights from this study are crucial for optimizing soil management in ancient tea gardens, potentially improving tea quality and sustainability. Full article

Forests play a key role in the global carbon (C) cycle through multiple interactions between above-ground and soil microbial communities. Deeper insights into the soil microbial composition and diversity at different spatial scales and soil depths are of paramount importance. We hypothesized that in a homogeneous above-ground tree cover, the heterogeneous distribution of soil microbial functional diversity and processes at the small scale is correlated with the soil’s chemical properties. From this perspective, in a typical Mediterranean holm oak (Quercus ilex L.) peri-urban forest, soil carbon dioxide (CO₂) emissions were measured with soil chambers in three different plots. In each plot, to test the linkage between above-ground and below-ground communities, soil was randomly sampled along six vertical transects (0–100 cm) to investigate soil physico-chemical parameters; microbial processes, measured using Barometric Process Separation (BaPS); and structural and functional diversity, assessed using T-RFLP and qPCR Real Time analyses. The results highlighted that the high spatial variability of CO₂ emissions—confirmed by the BaPS analysis—was associated with the microbial communities’ abundance (dominated by bacteria) and structural diversity (decreasing with soil depth), measured by H′ index. Bacteria showed higher variability than fungi and archaea at all depths examined. Such an insight showed the clear ecological and environmental implications of soil in the overall sustainability of the peri-urban forest system. Full article

Nitrogen (N) fertilizer is routinely applied in highbush blueberry (Vaccinium corymbosum L.) production. The recommended N fertilizer rate increases as the plants mature, and is usually determined based on regional growing conditions. However, the effects of N fertilizer rates and application methods over the long term remain poorly understood. In this study, ammonium sulfate was applied as an N source at the recommended rate (100%), which corresponds to a maximum of 155 kg N ha⁻¹ for plants older than eight years, along with higher rates at 150% and 200% of the recommended level, as well as a control treatment of no N. Treatments were applied to the blueberry cultivar ‘Duke’ as either broadcast (BROAD) or fertigation (FERT), and impacts were analyzed after 12 and 13 years of treatment. In the 14th year, the 100% N rate was uniformly applied as BROAD across all plants to separate the effects of different N rates from those caused by long-term soil condition changes. The BROAD treatment at the 100% N rate achieved the highest yield, and the FERT treatment at 200% resulted in the lowest yield in the 12th year, suggesting that excessive N rates can reduce fruit yield. However, no significant yield differences were observed in the 13th year. Higher N rates were associated with reduced titratable acidity in fruits and fewer flower buds. The soil pH declined across all N treatments, with the FERT at 200% showing the most significant reduction. All N treatments generally increased soil electrical conductivity (EC). High N rates also decreased plant accumulation of magnesium, calcium, and copper, with the latter reaching deficiency levels. These findings emphasize the importance of adhering to recommended N application rates and adjusting soil pH and EC to mitigate the adverse effects of prolonged N treatments. Full article

Gypseous soil is a collapsing soil that has not yet been approved as a construction material since its behavior under water, temperature, and pressure is unreliable and unpredictable. Researchers and scientists are always searching for new and creative ways to optimize the benefits of calcium carbide residue (CCR) recycling, which is a byproduct of the acetylene industry and includes a substantial quantity of Ca(OH)₂. Therefore, it is a suitable choice for utilization as a chemical stabilizer to improve the engineering features of problematic soils. However, this study explores the potential for enhancing the engineering characteristics of gypseous soil by utilizing (CCR) combined with linear alkyl benzene sulfonic acid (LABSA) to form a geopolymer. The soils utilized in this work are gypseous collapsible soils. Standard tests were conducted on these soils to identify the physical and mechanical characteristics. The geopolymer preparation was accomplished by merging a dilution of LABSA with a geopolymer (solid to liquid), blending the proportions. Three different types of disturbed natural granular-gypseous collapsible soils with different properties and various gypsum contents with percentages of 20%, 35%, and 50% were used. Mixtures of soils containing (2.5%, 5%, and 7.5%) of the geopolymer mix content were made. The single oedometer test (SOT) and the double oedometer test (DOT) were carried out to ascertain the lowest collapse potential value correlated with the ideal geopolymer mixing ratio. The adequate geopolymer percentage was found to be 5% since it resulted in the maximum reduction in collapse potential compared to the natural soil. The direct shear test is employed to ascertain the soil samples’ cohesiveness and friction angle. The results show a slight reduction in the angle of internal friction and increased cohesion (c). For stabilizing gypseous soil in engineering projects, a combination of LABSA and CCR can be utilized as a workable, sustainable, and environmentally friendly substitute. Full article