Search Results (62)

Albic soil is a typical low-yield and problematic soil in Northeast China, which severely restricts crop growth and yield. Through a three-year field experiment in the albic soil of China, soil three-phase ratio, soil bulk density (soil BD), soil total porosity (soil TP), size distribution and water stability of soil aggregates, and changes in maize yield under crop rotations were studied. The following three treatments were established: conventional fertilization (T0), conventional fertilization + soil amendment (T1), and conventional fertilization + soil amendment + bio-organic fertilizer (T2). The results indicated that, compared with T0, the soil three-phase ratio deviation value (R) of T1 and T2 decreased by 23.69–74.94%, and the generalized soil structure index (GSSI) increased by 4.75–15.41% in soil layers of 0–20 cm and 20–40 cm. Soil BD and soil TP changed significantly in the soil layer of 20–40 cm under treatment of T2 (decreased 12.82% and increased 18.31%, respectively). Content of aggregates >0.25 mm (R_0.25) increased significantly in the soil layer of 0–20 cm, with increases of 13.71% and 23.21% under treatments of T1 and T2. The mean weight diameter (MWD) and geometric mean diameter (GMD) increased significantly under treatment of T2. Compared with T0, maize yield increased 13.45% and 18.85% under treatments of T1 and T2. Correlation analysis showed that maize yield was significantly correlated with soil physical indexes and aggregate stability. In summary, the combined application of soil amendments and bio-organic fertilizer is not only important for albic soil improvement, but also crucial to stabilize the crop production capacity in albic soil regions. Full article

The demand for ready-to-eat salads made from leafy vegetables such as wild rocket (Diplotaxis tenuifolia L.) continues to increase, driven by consumer preference for convenience foods with high levels of bioactive compounds. However, reducing the environmental impact of wild rocket production requires both organically enriched growing substrates and sustainable alternatives to conventional plastic packaging. This study assessed the effects of three cultivation substrates and three biodegradable packaging materials (polylactic acid (PL), cellulose kraft (CK), and kraft-reinforced polylactic acid (PLK)) on the postharvest performance of wild rocket stored at 4 °C for 7 and 14 days. Plants were grown in coco peat (CP), coco peat supplemented with livestock compost (90:10; CP+LC), and coco peat mixed with mushroom compost (50:50; CP+MC). Yield and key pre- and postharvest quality attributes, including nitrate accumulation, phenolic content, antioxidant capacity, colour, and weight loss, were evaluated. The CP+LC substrate resulted in the highest harvest yield, whereas CP promoted higher phenolic content and antioxidant capacity. Among the packaging materials, PLK provided the most balanced internal atmosphere, effectively reducing dehydration and condensation while preserving superior sensory quality after 14 days of storage. Overall, the combination of organic compost amendments, particularly CP+LC, with PLK bio-based packaging represents a promising and sustainable strategy for maintaining postharvest quality and reduce the environmental footprint of minimally processed wild rocket within short food supply chains. Full article

Converting marine biowaste into nano-bioproducts for their application as bio-sourced, circular biostimulants to enhance crop productivity is a promising approach. This study evaluated chitosan–TPP nanoparticles (nanochitosan, ~38 nm) derived from blue crab (Callinectes sapidus) shells as a soil-applied biostimulant and conditioner for tomato (Solanum lycopersicum) grown in loam soil without mineral fertilizer. Our results showed that nanochitosan application as a soil supplement by drench improved the soil moisture content (39% vs. 22%), water-holding capacity (84% vs. 70%), total nitrogen (3.8 vs. 1.4 gm N kg⁻¹), and organic carbon content (48.4 vs. 34.1 gm C kg⁻¹) in nanochitosan-amended soil compared with the non-amended soil. This was accompanied by higher biomass, better root/shoot development and synthesis of phytohormones leading to increased shoot length, early flowering, and increased total soluble solids of fruits in nanochitosan-amended soil compared with control, suggesting that nanochitosan can act both as a beneficial soil conditioner and as a plant biostimulant. The results further show that nanochitosan-based formulations may be used not only as fertilizer-saving bio-inputs but also as bio-based nanochitosan plant biostimulants, which can partly substitute mineral fertilizer application for sustainable production of tomato. Moreover, generic fabrication of such nanochitosan from marine biowaste would support the circular-bioeconomy model to further improve sustainability of agroecosystems. Full article

The interaction between organic and inorganic nutrients, bacterial communities, and soil fertility has been well documented over time. Conventional agricultural systems heavily utilize both inorganic and organic fertilizers, each exerting distinct effects on soil microbial dynamics and plant growth. The objective of our experiments was to identify the most effective fertilization strategy for improving the biological quality of a microbiologically impoverished and low-productivity soil. To this end, four fertilization strategies were evaluated: (i) organic fertilizers characterized by a high content of organic carbon (Fertil 4-5-7—variant 1); (ii) organic fertilizers with 12% organic nitrogen from proteins (Bio Ostara N—variant 2) (iii) combined inorganic–organic fertilizers (P35 Bio—variant 3) and (iv) mineral (inorganic) fertilizers (BioAktiv—variant V4). This study aimed to assess the short-term effects of fertilizers with varying chemical compositions on the density of cultivable heterotrophic bacteria and their associated dehydrogenase (DH) activity in a petrocalcic chernozem soil containing pedogenic carbonates. Soil sampling was conducted according to a randomized block design, comprising four replicates per treatment (control plus four fertilizer types). The enumeration of cultivable bacteria was performed using Nutrient Agar and A2R Agar media, whereas dehydrogenase activity (DHA) was quantified based on the reduction of 2,3,5-triphenyl-2H-tetrazolium chloride (TTC) to 1,3,5-triphenyl-tetrazolium formazan (TPF) by bacterial dehydrogenase enzymes. Marked differences were observed in both parameters between the plots amended with inorganic fertilizers and those treated with organic fertilizers, as well as among the organic fertilizer treatments of varying composition. The most pronounced increases in both bacterial density and dehydrogenase activity (DHA) were recorded in the plots receiving the fertilizer with a high organic nitrogen content. In this treatment, the maximum bacterial population density reached 6.25 log₁₀ CFU g⁻¹ dry soil after approximately two months (May), followed by a significant decline starting in July. In contrast, DHA exhibited a more rapid response, reaching its peak in April (42.75 µg TPF g⁻¹ soil), indicating an earlier DHA activation of microbial metabolism. This temporal lag between the two parameters suggests that enzymatic activity responded more swiftly to the nutrient inputs than did microbial biomass proliferation. For the other two organic fertilizer variants, bacterial population dynamics were broadly similar, with peak densities recorded in June, ranging from 5.98 log₁₀ CFU g⁻¹ soil (V3) to 6.03 log₁₀ CFU g⁻¹ soil (V1). A comparable trend was observed in DHA: in V3, maximum DHA was attained in June (30 µg TPF g⁻¹ soil), after which it remained relatively stable, whereas in V1, it peaked in June (24.05 µg TPF g⁻¹ soil) and subsequently declined slightly toward the end of the experimental period. Overall, the temporal dynamics of bacterial density and DHA demonstrated a strong dependence on the quality and biodegradability of the organic matter supplied by each fertilizer. Both parameters were consistently lower under inorganic fertilization compared with organic treatments, suggesting that the observed increases in microbial density and activity were primarily mediated by the enhanced availability of organic substrates. The relationship between the density of culturable heterotrophic bacteria and dehydrogenase (DH) activity was strongly positive (r = 0.79), indicating a close functional linkage between bacterial density and oxidative enzyme activity. This connection suggests that the culturable fraction of the heterotrophic microbial community plays a key role in the early stages of organic matter mineralization derived from the applied fertilizers, particularly in the decomposition of easily degradable substrates. Full article

Biochar produced from phosphorus (P)-rich feedstocks has often been promoted as an alternative P fertilizer. However, existing evidence has mainly been obtained from incubation experiments and field trials with a rather short duration, leaving uncertainty about whether repeated low-rate applications of biochar can meaningfully supply P and increase soil P pools over time. This study evaluates the agronomic effects of 10 years of application of biochar derived from plant biowaste (BIO) and bones (BC) at an application rate of 4 t ha⁻¹ yr⁻¹, compared with a mineral P fertilizer (MIN), compost application (COM), and a zero-P control. The application of P through BC and COM led to higher total soil P concentrations than the control. Changes in labile P pools (H₂O–P, NaHCO₃–P, Bray-P) were generally modest, but BC again tended to yield higher values relative to the other treatments. The ratio of organic to inorganic P was not influenced by fertilizer type. A clear effect of the amendments on maize yield was observed, with BC producing the highest yields among all amendments (6.4 t ha⁻¹; average 2020–2023), and yields were occasionally further increased when BC was combined with COM. The BIO treatments also achieved yields that were at least comparable to those of the MIN treatment (4.7 t ha⁻¹). Despite the limited effects on labile soil P pools, the amendments increased yields and can be considered effective substitutes for mineral P fertilizers at this application rate. Full article

This study evaluated the individual and combined effects of different bio-inputs—traditional filter cake, filter cake composted with ash, and a microbial inoculant—on the growth and physiological performance of Mucuna pruriens cultivated in soil contaminated with the herbicide tebuthiuron. The experiment followed a completely randomized design with twelve treatments and five evaluation periods (7, 21, 35, 49, and 70 days after sowing). Morphophysiological variables such as plant height, root length, dry biomass, and chlorophyll content were assessed. The results showed that the addition of traditional filter cake promoted significant growth in tebuthiuron-contaminated soil, while, in uncontaminated conditions, both organic residues and the microbial inoculant enhanced plant development, particularly at later stages. Initial phytotoxicity was observed in treatments with organic residues (up to 67% of samples before 35 days), but these effects decreased over time. The microbial inoculant performed better in the absence of organic amendments, suggesting possible antagonistic interactions. Tebuthiuron reduced chlorophyll content by inhibiting photosystem II, but this effect was mitigated by the addition of filter cake. Overall, the findings highlight the potential of integrating Mucuna pruriens cultivation with organic residues and microbial inoculants as an effective phytomanagement strategy for tebuthiuron-affected soils. This approach provides a sustainable model for improving soil health, supporting legume-based rehabilitation, and advancing biological alternatives to conventional remediation practices. Full article

Spent coffee grounds (SCGs), a globally abundant by-product of the coffee industry, represent a significant source of lignocellulosic biomass with considerable valorization potential. Rich in organic compounds, lipids, and antioxidants, SCGs are increasingly recognized as a sustainable feedstock for energy, materials, and environmental applications within a circular bioeconomy framework. This review critically examines recent advances in SCG valorization via thermochemical, biochemical, and material-based pathways. The review focuses on the conversion of SCGs into biofuels (biodiesel, bioethanol, biogas, and bio-oil), activated carbon for water and air purification, biodegradable polymers, and soil-enhancing amendments. Comparative analyses of process conditions, product yields, and techno-economic feasibility are provided through summarized tables. Although laboratory-scale studies demonstrate promising outcomes, challenges persist in terms of process scalability, environmental impacts, feedstock variability, and lack of regulatory standardization. Furthermore, comprehensive life cycle assessments and policy integration remain underdeveloped. By merging all findings, this review identifies key knowledge gaps and outlines strategic directions for future research, including the development of integrated valorization platforms, hybrid conversion systems, and industrial-scale implementation. The findings support the role of SCG valorization in advancing sustainable resource management and contribute directly to the achievement of multiple Sustainable Development Goals. Full article

The phyllosphere, the aerial part of plants, serves as a crucial habitat for diverse microorganisms. Phyllosphere bacteria can activate protective mechanisms that help plants resist disease. This study focuses on isolating and characterizing phyllosphere bacteria from cucurbits to evaluate their potential in controlling Colletotrichum orbiculare, a pathogen causing anthracnose in cucumbers. Among the 76 bacterial isolates collected, 11 exhibited strong antagonistic effects against C. orbiculare in vitro. Morphological and 16S rRNA analyses identified these isolates as different Bacillus species, including B. vallismortis, B. velezensis, B. amyloliquefaciens, and B. subtilis. These bacteria demonstrated essential plant-growth-promoting and biocontrol traits, such as motility, biofilm formation, phosphate solubilization, nitrogen fixation, and the production of indole acetic acid. Most of the bacterial strains also produced biocontrol compounds such as ammonia, acetoin, siderophores, hydrogen cyanide, chitinase, protease, lipase, and cellulase. The application of these bacteria significantly enhanced cucumber growth in both non-manured and organically manured soils, showing improvements in root and shoot length, chlorophyll content, and biomass accumulation. Additionally, bacterial treatments effectively reduced anthracnose severity, with isolates GL-10 and L-1 showing the highest disease suppression in both soil types. Colonization studies showed that phyllobacteria preferentially colonized healthy leaves over roots and diseased tissues, and they were more effective in manure-amended soils. These results suggest that Bacillus phyllobacteria have strong potential as sustainable bio-stimulants and biocontrol agents, offering an effective approach for enhancing cucumber growth and disease control under both fertilized and unfertilized soil conditions. Full article

Organic amendments, such as straw, biochar, and animal manure, have been demonstrated to enhance soil phosphorus (P) availability effectively; however, the long-term impacts and underlying mechanisms require further study. Based on a long-term field experiment, this research systematically analyzed the effects of biochar (BIO), biochar-based fertilizer (BF), straw-returning (CS), and pig manure compost (PMC) on soil phosphorus transformation and crop phosphorus uptake. Results showed that biochar significantly boosted soil available phosphorus (AP) by releasing soluble phosphorus, raising soil pH, reducing phosphorus fixation by iron and aluminum oxides, and enhancing soil cation exchange capacity (CEC) to promote phosphorus dissolution and transformation. Notably, biochar increased the proportion of NaOH-P, facilitating phosphorus accumulation in peanut grains and improving the phosphorus harvest index and utilization efficiency. Straw-returning primarily elevated soil AP by promoting organic phosphorus mineralization and inorganic phosphorus release; however, its acidification of the soil impaired phosphorus translocation to grains, resulting in lower phosphorus-use efficiency compared to biochar. Pig manure compost reduced soil phosphorus fixation and increased soil total organic carbon (TOC), thereby boosting phosphorus transformation. Despite enhancing phosphorus dry-matter production in plants, most phosphorus remained in stems and leaves, with limited translocation to grains, leading to lower phosphorus-use efficiency than biochar. In conclusion, biochar was most effective in enhancing soil phosphorus availability and crop phosphorus-use efficiency, highlighting its potential in sustainable soil fertility management and optimized crop production. Full article

The dual environmental challenges of karst areas lie in organic solid waste’s (OSW) massive generation scale and diffuse dispersion, which accelerate bedrock exposure and soil contamination, while simultaneously representing an underutilized resource for soil amendments through optimized composting. Bio-enhanced composting of multi-source OSW yields compounds with dual redox/adsorption capabilities, effectively improving soil quality and restoring ecological balance. The recycling and circular utilization of OSW resources become particularly critical in karst regions with vulnerable soil ecosystems, where sustainable resource management is urgently needed to maintain ecological balance. This review elucidates the ecological impacts of multi-source OSW compost applications on soil environments in ecologically fragile karst regions, specifically elucidating the mechanisms of heavy metals (HMs) migration–transformation and organic contaminant degradation (with emphasis on emerging pollutants), and the functional role of microbial carbon pumps in these processes. Furthermore, establishing a sustainable “multi-source OSW−compost−organic matter (adsorption and redox sites)−microorganisms−pollution remediation” cycle creates a green, low-carbon microenvironment for long-term soil remediation. Finally, this study evaluates the application prospects of the refined composting technology utilizing multi-objective regulation for OSW resource recycling and utilization in karst areas. This review provides critical insights for optimizing soil remediation strategies in karst ecosystems through organic waste valorization. Full article

Protecting the soil ecosystem’s functioning is one of the main goals of recent regulations of chemicals. It is important to take soil biodiversity into account when designing cropping systems and measuring their impacts. Our main objective was to evaluate the effects of an organic amendment on soil nematode biodiversity compared to two years of fumigation. The plot-trial was conducted on tomato and lettuce plants under greenhouse, and free-living nematodes were used as bio-indicators of soil health. Treatments included a soil fumigant (applied once or twice over time), water control, and an organic substance. Soil samplings were carried out to determine the Meloidogyne incognita reproduction factor and the soil nematode community analysis using soil biological indicators. Data showed that soil fumigation clearly made the soil increasingly dependent on chemicals. Furthermore, fumigants suppressed pests and pathogens as well as their natural antagonists, causing a lack of biodiversity. While soils treated with organic matter respond slowly to stressors, they are progressively more suppressive thanks to biodiversity enrichment. Nematodes have proven to be useful indicators of the soil biota in response to biotic or abiotic disturbances. Their species richness and functional diversity make them valid bioindicators of soil management impact. Full article

Excessive nutrient inputs from manure and synthetic fertilizers have caused great challenges for sustainable vegetable production. There is limited information about the nutritional yields and leaching losses of potassium (K), calcium (Ca), and magnesium (Mg) under various organic–inorganic fertilization practices. We hypothesized that nutritional yields and cation leaching would be influenced by different fertilization practices. A two-year cucumber-cultivating experiment was conducted in North China with the following three treatments: Farmers’ Traditional Practice (FP), based on local farmers’ practices; Current Recommended Nutrient Management (CRNM), based on pieces of literature, bio-organic fertilizer, and kaolin replacing chicken manure in FP; Nutrient Balance Management (DBNM), based on target yields and plant-based amendments replacing bio-organic fertilizers. The nutritional yields of Ca and Mg under CRNM and DBNM were 26.4–39.6% and 20.3–32.5% higher than FP. The K, Ca, and Mg leaching under CRNM were significantly reduced by 41.1%, 18.9%, and 18.5%, compared with FP. Ca leaching under DBNM was further significantly reduced by 7.9%. A significant negative relationship was observed between the leaching losses of K, Ca, and Mg and the surface soil pH (0–20 cm). These findings suggest that DBNM could play an important role in obtaining higher nutritional yields, reducing leaching losses, and alleviating soil acidification in vegetable production. Full article

The combined effects of tillage and organic amendments on microbial respiration and its contribution to soil hydraulic conductivity are still uncertain in the 0–40 cm layer of a loess soil. We conducted a two-year field experiment to explore the effects of organic amendments, tillage and their interaction on soil microbial respiration, aggregate stability, pore parameters, and hydraulic conductivity on the Loess Plateau. Three tillage methods (conventional tillage (CT), deep tillage (DT) and no tillage (NT)) plus five fertilizer treatments (mineral fertilizer (control) alone and along with 20 t ha⁻¹ wheat straw (MWS), wheat husk (MWH), farmyard soil (MFS) and bioorganic fertilizer (MBF)) were set up as experimental treatments. The findings demonstrated that the organic amendments significantly increased the soil microbial respiration and saturated hydraulic conductivity compared to the control in the 0–10 cm and 10–20 cm layers. Soil microbial respiration had indirect effects on hydraulic conductivity by improving the water aggregate stability and macroporosity. Additionally, the interaction effects of tillage and organic amendments on the pore and hydrological parameters were significant in the 20–40 cm layer. NT-MBF resulted in the greatest saturated hydraulic conductivity, which was directly correlated with the soil’s strong pore organization. Given the issue of subsurface soil compaction in our study area, it is recommended that local farmers adopt NT-MBF to enhance the soil’s microbial, structural and hydrological properties. Full article

Coastal mudflats are characterized by high salinity and alkalinity, along with low mineral nutrient availability, making it challenging to achieve high biomass or effective yields when directly cultivating food or fodder crops. Exogenous complex saline soil amendments can enhance forage production, but their effects on soil salinity reduction and nutrient activation remain unclear. This study used pot experiments and laboratory analyses to investigate these effects. A 0.3% saline–alkali soil was treated with a combination of organic acids (fulvic acid and citric acid), bio-based materials (cow dung and pine needles), and beneficial microbial mixtures (Priestia megaterium + Trichoderma harzianum, Bacillus subtilis + Aspergillus niger, and Bacillus pumilus + Paecilomyces lilacinus). The organic acid bio-modifier significantly alleviated salinity stress in sweet sorghum, reducing soil salinity, increasing soil nutrient levels, enhancing root vigor and photosynthesis, and improving plant morphology, resulting in higher biomass yields. Among the factors tested, bio-based materials had the most pronounced effect. Citric acid, pine needles, Priestia megaterium, and Trichoderma harzianum enhanced sweet sorghum growth during the seedling stage, whereas fulvic acid, pine needles, Bacillus pumilus, and Paecilomyces lilacinus were more beneficial during the elongation stage. Full article

Spent coffee ground (SCG) is a main byproduct of the coffee industry and has been revalorized as a source of value-added products. The direct application of SCG as a soil amendment has drawn much attention in recent years as a more environmentally sustainable option. In this work, a comprehensive review of studies on the agricultural application of SCG is presented. The aims of this review were (1) to summarize the impacts of raw SCG on soil health and to identify the factors limiting its direct soil use, (2) to outline methods that are often used to upgrade SCG for soil application, and (3) to highlight the potential of SCG and its derivatives as a biocontrol agent and biofertilizer. The results indicate that raw SCG could improve certain soil health attributes, but plant growth is often limited owing to its phytotoxicity and induced N immobilization. To eliminate phytotoxicity, composting, vermicomposting, and thermochemical treatments have been employed but to a limited extent. SCG and its derivatives may be used as biocontrol agents for weeds, soil-borne pathogens, and pests. Novel bio-organic fertilizers based on SCG have also been developed. Future research should focus on the long-term effects of SCG and its derivatives as soil amendments under real scenarios and the underlying mechanisms, particularly the soil–plant–microorganism interactions. Full article