Search Results (2,763)

Panax ginseng, a high-value medicinal plant, faces substantial yield losses due to black spot disease, while conventional chemical controls cause pesticide residues and soil ecological damage, necessitating green biocontrol strategies. Here, two antagonistic strains, Bacillus sp. WY17 and WY26, were isolated from the surface-sterilized internal root tissues of 10-year-old ginseng. Through systematic optimization of carbon/nitrogen sources, inorganic salts, and fermentation parameters (temperature, pH, agitation, inoculum size, and duration), the optimal culture conditions were established. The optimal consortium consisted of WY17 and WY26 in a 2:1 ratio (WY17:WY26 = 2:1), which achieved an antifungal inhibition rate of 84.94% against the pathogen compared to the untreated control group (pathogen only). Mechanistic investigations revealed that the crude protein extract exerted its antifungal effect by compromising the integrity of the pathogen’s cell membrane, leading to increased permeability and leakage of intra-cellular contents, and produced cell wall-degrading enzymes (chitinase and β-1,3-glucanase), thereby inhibiting mycelial growth and spore germination. In vitro efficacy tests demonstrated that this crude protein extract performed comparably to the chemical fungicide 70% mancozeb, with no statistically significant difference observed between them (p > 0.05). These findings identify a promising compound biocontrol agent derived from indigenous Bacillus strains, offering an effective and environmentally friendly alternative for managing ginseng black spot disease. Full article

Sustainable soil health management is a major challenge for modern agriculture, particularly under increasing water constraints and progressive soil degradation, prompting the evaluation of innovative soil conditioners such as water-soluble polymers. This study assessed the effects of the anionic copolymer SNF FLOBOND™ DI 2010 (FDI2010) on soil physical structure and microbial properties through three complementary experiments, including one lysimeter trial and two controlled microcosm incubations using contrasting agricultural soils under different moisture regimes. The results consistently showed a significant improvement in soil aggregate stability following polymer application, while effects on water retention were variable and dependent on soil type and moisture conditions, with clearer improvements observed under drought conditions and in lysimeter setups. Microbial responses were largely indirect, with increased respiration and enzymatic activities but no significant change in total microbial biomass. Under water-limited conditions, FDI2010 contributed to sustaining microbial activity, particularly for carbon and nitrogen mineralization. Overall, these findings indicate that FDI2010 primarily enhances soil structural stability and indirectly supports microbial functioning, highlighting its potential as a soil conditioner to improve soil resilience to hydric stress, although further field validation remains necessary. Full article

The intensive use of mineral fertilizers in horticultural systems has improved crop productivity but also increased concerns regarding soil degradation and environmental sustainability. In this context, vermicompost derived from buffalo manure may represent a sustainable alternative for nutrient management and organic waste valorization. This study evaluated the effects of four fertilization strategies on tomato (Solanum lycopersicum L.) grown in loam and clay soils: unfertilized control, mineral fertilization, vermicompost applied at an equivalent nitrogen rate, and the residual effect of vermicompost from a previous cauliflower crop. Agronomic performance, fruit quality, carbon and nitrogen metabolism, and antioxidant-related traits were assessed. Mineral fertilization produced the highest marketable yield, reaching 9.68 and 7.69 kg m⁻² in loam and clay soils, respectively, mainly through increased fruit number. Direct vermicompost application maintained substantial productivity, with yields of 7.55 and 5.18 kg m⁻² in the two soils. The fertilization strategies also induced distinct changes in fruit composition. Mineral fertilization increased total free amino acids to approximately 160 mg g⁻¹ DW, mainly through the accumulation of glutamine, glutamate, asparagine and γ-aminobutyric acid, but was associated with lower soluble solids and antioxidant activity. Vermicompost promoted the highest lycopene concentration, approximately 2.1 mg g⁻¹ DW, in clay soil and maintained intermediate antioxidant activity and amino acid concentrations. Soil texture also influenced carbohydrate partitioning, with greater fructose accumulation in clay soil and greater starch accumulation in loam soil. The residual vermicompost treatment alone did not adequately sustain tomato productivity or metabolic activity, particularly in clay soil. Overall, vermicompost partially replaced mineral fertilization while maintaining satisfactory yield and modulating fruit metabolic quality, although its effectiveness depended strongly on soil texture. Full article

Post-fire plantations play a crucial role in recovering carbon stocks, yet how carbon is partitioned among vegetation, litter, and soil pools during stand growth dynamics remains insufficiently resolved for Quercus acutissima plantations. Forest ecosystems play a crucial role in the global carbon cycle. This study quantified carbon-storage allocation and identified stand characteristics and soil factors associated with carbon recovery in fire-affected Q. acutissima plantations. Using a chronosequence design, we compared five stand-age classes (4, 10, 25, 45, and 50 years) on Huangfu Mountain, China, and measured carbon stocks in tree organs, understory vegetation, litter, and the 0–30 cm soil layer. Ecosystem carbon stock increased from 31.64 t ha⁻¹ in 4-year-old stands to 230.66 t ha⁻¹ in 50-year-old stands, representing a 629% increase. Soil was the dominant carbon pool, with 0–30 cm soil carbon rising from 25.32 to 126.56 t ha⁻¹ (a 400% increase). The contribution of soil carbon to total ecosystem storage declined from approximately 80% in 4-year-old stands to 55% in 50-year-old stands, indicating a shift in allocation toward vegetation biomass over time. Carbon accumulation was primarily concentrated in the 0–10 cm layer. Tree basal area was significantly associated with ecosystem carbon stocks, identified as a key structural factor linked to carbon accumulation through potential direct and indirect pathways involving light availability and soil carbon. Soil organic matter and nitrogen were also positively correlated with carbon accumulation. These findings suggest that stand development and topsoil carbon formation are closely linked to post-fire carbon recovery processes. Future management measures should optimize stand density, maintain soil fertility, and protect surface carbon to enhance long-term carbon sequestration. Full article

Variable-rate nitrogen (VRN) management in dryland crop rotations requires prescription maps that remain valid across years and for different crops, and that can be generated from sensors compatible with standard farm equipment. We examined how the ranking of yields in individual fields remained consistent from one season to another, how much of the variation in yields among individual field locations could be attributed to differences in the permanent physical characteristics of those field locations, and if the spatial structure of fertility was transferable among the different crops in a rotational sequence using a multi-seasonal wheat–corn–millet crop rotation dataset from northeast Colorado (n = 721; n = 18 management units; n = 321 location points; 2019–2022). There was a significant positive correlation between wheat yield rankings from non-consecutive growing seasons (ρ = 0.39–0.59), with 80.80% of the total variability explained by spatial effects that are stable over time. Approximately 20% of the within-field yield variability in wheat, the only crop with repeated within-position measurements, could be attributed to permanent differences in physical properties of the field such as topography (TPI) and soils (soil: 2.20%; TPI: 11.50%, both unique; 6.30% both shared), which represented an estimate of the maximum amount of within-field variability possible to explain based on static variables alone in this dataset. After accounting for year and field effects, all three Spearman correlations for each combination of two crops were positive and statistically significant (Wheat–Corn: ρ = +0.29; Wheat–Millet: ρ = +0.48; Corn–Millet: ρ = +0.30), indicating a common spatial fertility structure among all three crops in the rotational sequence. These results suggest that a pedotopographic map created using RTK-GPS elevation data and on-the-go soil sensors provides a partially transferable baseline spatial framework for variable-rate N applications throughout the entire cropping cycle. This baseline would need to include adjustments for average rate applied per crop, while the remainder of the within-field variability (approximately 80%) could be addressed through additional layers of annual sensing (e.g., UAV multispectral indices, active optical sensors, satellite imagery). Full article

Brackish water irrigation induces secondary soil salinization and severe nitrogen (N) leaching, restricting crop N uptake and grain yield. To address these constraints in coastal saline farmlands, a 140-day field soil column experiment was conducted using coastal saline soil with a salinity of 2.60 g kg⁻¹. We evaluated the individual and interactive effects of three straw return methods (straw removal (S1), straw incorporation (S2), and straw burial (S3)) and three N fertilizer managements (sole conventional urea (N1), 1:1 mixture of polyurethane-coated urea (PCU) and urea (N2), and sole PCU (N3)) on salt dynamics, rice agronomic traits, root morphological characteristics, N use efficiency (NUE), and yield components. The results indicated no significant interactive effects between straw return methods and N fertilizer managements on the measured variables (p > 0.05). S2 significantly decreased soil salinity and exerted the highest efficiency with regard to salt leaching, thereby promoting rice growth (p < 0.05). PCU markedly optimized root development, as evidenced by increased root tip number, branch number, and root crossing density (p < 0.05), which strengthened water and nutrient uptake, ultimately mitigating detrimental impacts of brackish water irrigation on grain yield and NUE. Notably, PCU application ratios showed no significant differences in crop yield (p > 0.05). Overall, straw incorporation combined with a 1:1 ratio of PCU and urea is verified as the optimal strategy for rice cultivation in brackish water-irrigated coastal saline regions. This practice effectively alleviates brackish water-induced salt stress and elevates crop yield and NUE. The outcomes provide solid scientific references and practical guidance for coordinated water–salt–nutrient management and sustainable utilization of fragile coastal saline soils. Full article

Soil organic matter replenishment is essential for sustainable viticulture because it improves nutrient cycling, water retention, and vineyard resilience. This study evaluated the effects of different compost application methods on leaf chlorophyll content, grape yield, and grape quality of Vitis vinifera L. cv. Sauvignon Blanc grafted onto Kober 5BB rootstock under Central European conditions during 2020–2022, following compost application in fall 2019. Leaf chlorophyll content was monitored weekly using an atLeaf+ chlorophyll meter calibrated against spectrophotometrically determined chlorophyll concentrations. At harvest, grape yield, soluble solids, titratable acidity, pH, and yeast assimilable nitrogen (YAN) were determined. Deep compost application consistently produced the highest chlorophyll concentrations, increasing seasonal means by 10.4%, 24.7%, and 25.4% compared with the unfertilized control in 2020, 2021, and 2022, respectively. Yield responses also increased over time, with deep compost application improving grape yield by 53.8% in 2021 and 60.7% in 2022. Effects on grape quality were smaller and varied among years, although compost-treated vines generally exhibited higher titratable acidity and YAN. The calibration of atLeaf+ readings against spectrophotometrically determined chlorophyll concentrations in grapevine leaves showed high accuracy (R² = 0.9542). These results indicate that deep compost application may enhance grapevine physiological status and productivity while supporting circular nutrient management and may contribute to improved vineyard resilience under variable climatic conditions. Full article

Soil multifunctionality (SMF) is a core indicator of plantation soil ecological function, and microbial diversity plays a vital role in sustaining it. However, cross-site rhizosphere and bulk SMF disparities and their microbial driving mechanisms remain unclear in Eucommia ulmoides plantations. Here, we collected rhizosphere and bulk soils from three typical sites (Mengzhou, MZ; Liangyuan, LY; and Yuanyang, YY). Soil chemical properties, extracellular enzymes, microbial alpha diversity, community composition and cross-kingdom network topology were measured. Correlation heatmaps, random forest, Redundancy analysis (RDA) and Partial least path modeling (PLS-PM) were adopted to quantify SMF predictors and regulatory pathways. Rhizosphere soils possessed significantly higher alkaline hydrolyzable nitrogen (AN), available phosphorus (AP) and available potassium (AK) than bulk soils at all sites. LY rhizosphere showed the greatest soil organic carbon (SOC), total potassium (TK), available nutrients and enzyme activities, while YY had higher total nitrogen (TN) and AP, yet the lowest enzyme levels. Rhizosphere bacterial and fungal alpha diversity was consistently higher across locations. SMF varied distinctly by site and compartment: LY had substantially higher SMF than MZ and YY in both rhizosphere and bulk soils, with rhizosphere SMF being consistently greater than bulk values across all sites. The PLS-PM (GOF = 0.70) indicated that soil chemical properties regulated SMF via dual pathways: they directly promoted microbial co-occurrence networks and indirectly modified network structure by altering fungal diversity, while suppressing bacterial diversity. Total effect analysis identified soil chemical properties and microbial co-occurrence networks as the core drivers of SMF variation. This work clarifies that rhizosphere effects and soil chemical properties jointly drive SMF by regulating microbial diversity and co-occurrence networks, offering theoretical guidance for sustainable soil management in E. ulmoides plantations. Full article

Agriculture underpins global food security; yet, inefficient or excessive nitrogen (N), phosphorus (P), and potassium (K) fertilization can generate interconnected environmental pressures. Direct environmental effects are much more extensively documented for N and P than for K, which is more often examined through nutrient imbalance, soil–plant interactions, and its interactions with N and P. This study combines a bibliometric analysis of 3649 articles and reviews indexed in the Web of Science Core Collection (SCIE and SSCI) from 1991 to 2024 with a literature review. The objective is to map the evolution, knowledge structure, and emerging frontiers of research on the environmental effects of agricultural NPK fertilization and to identify the knowledge gaps and priorities for sustainable nutrient management. The analysis shows a sustained growth in publication output, increasing interdisciplinarity, and major research hotspots involving nutrient cycling, environmental impacts, sustainability, and nutrient-management technologies. The synthesis further identifies persistent gaps in integrated N–P–K interactions, the long-term evaluation of precision nutrient management, compound climate-related risks, and the links between scientific evidence and governance. Based on these findings, we develop an integrated NPK environmental-management framework connecting fertilizer inputs, nutrient interactions, soil processes, environmental outcomes, management interventions, and policy support. The combined bibliometric and literature-review approach therefore moves beyond mapping the field to provide a structured basis for future research and more integrated nutrient-management strategies. Full article

Cover cropping can be a promising management strategy to improve soil health in the tropics. Our study evaluated physical, chemical, and microbiological indicators of soil health three years after implementing a maize and cowpea cover crop rotation with five fertilizer rates in replicated plots on a Torrifluventic Haplustepts in the southern semiarid coast of Puerto Rico. The Soil Management Assessment Framework (SMAF) was used to integrate different soil parameters to provide a comprehensive overview of soil health changes. Water aggregate stability (WAS) was not affected by cover crops. Soil pH significantly decreased with increasing nitrogen (N) fertilization rate and with cover crop rotation. Chemical and microbial indicators of soil health related to organic matter dynamics and nutrient cycling potential [e.g., microbial biomass nitrogen (MBN), potentially mineralizable N (PMN), β-glucosidase activity, combined enzyme activity for carbon (C), N, and phosphorus (P) cycling (β-glucosidase, β-glucosaminidase, and acid phosphatase] were significantly (p < 0.1) improved by cover crop but were not affected by fertilizer rate or cover crop x fertilizer rate. Fatty acid methyl esters (FAME) analysis showed that only G+ bacteria were significantly higher due to cover cropping. Principal component analysis revealed that total FAMEs and markers for G+ bacteria, G− bacteria, actinobacteria, and saprophytic fungi responded similarly to management and were generally influenced by cover cropping. Overall, improvements in microbial communities led to significant increases in key functions supporting soil health and sustainability within just three years of cover cropping adoption. The SMAF, as a well-known soil quality/health index, detected early benefits of using cover crops. Our study provided evidence that these indicators can serve as tools to assist farmers in selecting sustainable management practices such as cover crops in the tropics, yet long-term monitoring is still needed. Full article

As key drivers of soil biogeochemical cycles, soil microbial communities play essential roles in maintaining soil fertility, nutrient cycling, and plant growth. In this study, high-throughput sequencing of 16S rRNA and ITS genes was used to investigate the diversity, the composition, and the driving factors of bacterial and fungal communities in bulk soils across four soil groups collected from different vegetation covers (forest soil (FS), soybean field (PGS), and two Atractylodes japonica cultivation soils (ALO and ALR)) under identical climatic conditions. The results showed that the bacterial α-diversity remained stable across all the vegetation types, whereas the fungal α-diversity and richness were more sensitive to the vegetation type, with the PGS generally exhibiting lower Shannon and Chao1 indices. The β-diversity analysis revealed significant differences in the microbial community structure among the vegetation types, with a stronger effect on fungi (R² = 0.737, p = 0.001) than on bacteria (R² = 0.493, p = 0.001). At the phylum and genus levels, the fungal communities displayed more pronounced shifts than the bacterial communities, which remained relatively stable. A redundancy analysis indicated that the soil chemical properties significantly shaped the microbial community structure (p = 0.002). The microbial communities in the A. japonica soils (ALO and ALR) were primarily driven by pH, available phosphorus, and available potassium, while the FS and PGS communities were more strongly influenced by soil organic carbon, total nitrogen, and nitrogen forms (NH₄⁺-N and NO₃⁻-N). The Spearman correlation and functional prediction analyses further confirmed that the key soil factors differentially regulated the abundance and ecological functions of the dominant microbial taxa. These findings demonstrate the vegetation-specific assembly of soil microbial communities and highlight the distinct edaphic drivers associated with A. japonica cultivation, providing a scientific basis for soil health management and the sustainable cultivation of this medicinal plant. Full article

The rhizosphere microbiome is critical for plant health, yet how soil type and intensive management jointly govern its assembly remain unclear. Here, we hypothesized that soil type acts as a primary environmental filter, while intensive cultivation (plant growth plus fertilization) imposes additional selective pressures that differentially shape bacterial versus fungal communities. Using flue-cured tobacco (K326) grown in clay loam and sandy loam soils under field conditions, we examined the rhizosphere microbiome at the topping stage. Intensive cultivation significantly altered rhizosphere physicochemical properties. Key nutrients, including organic matter (OM), dissolved total nitrogen (DTN), available phosphorus (AP), and available potassium (AK), were markedly enriched. Rhizosphere soil pH exhibited a bidirectional shift relative to the corresponding bulk soil, converging to a narrow range (7.4–7.8) in both soil types. Root activity and fertilization imposed contrasting selective pressures on the two microbial kingdoms: bacterial diversity declined slightly, indicating strong deterministic selection, whereas fungal diversity increased, reflecting adaptation to root-generated niches. Differential abundance analysis identified 38 bacterial OTUs as a core rhizosphere-adapted microbiome shared across both soil types, demonstrating robust fitness in the nutrient-enriched rhizosphere environment under intensive management. No shared core fungal OTUs were detected, underscoring strong soil legacy effects and higher habitat specificity in fungi. Notably, the core bacterial microbiome was dominated by K-strategists (slow-growing, resource-efficient taxa) that exhibited opportunistic traits capable of rapidly exploiting nutrient pulses in the rhizosphere. Together, these findings reveal that soil type acts as a critical filter modulating plant–microbe interactions under intensive agriculture, while bacteria and fungi employ divergent ecological strategies in response to selection pressures. This work provides both theoretical and practical insights for optimizing tobacco cultivation and sustaining soil microecological health. Full article

In double-cropping rice regions, soil organic carbon (SOC) levels are crucial for crop yield, and soil fertility drives rice productivity. This study clarified the driving patterns of oxidizable soil organic carbon fractions on rice yields across fertility gradients to guide fertility management. Soil properties and yields were monitored across eight representative double-rice counties in Hunan Province. Total organic carbon was partitioned into four pools (Fractions I–IV) using a modified Walkley–Black acid-gradient oxidation method, and multiple linear regression (MLR) was used for seasonal modeling. High-productivity fields achieved an annual yield of 16.69 t·ha⁻¹ (65% higher than low-productivity fields), consistent with SOC enrichment; the combined proportion of the C_frac1 and C_frac2 decreased significantly from 45.6% in HPPS to 36.8% in LPPS. MLR models (R² = 0.593–0.759) showed that high-productivity early rice was driven by the synergy of C_frac1 with nitrogen/phosphorus, while late rice was driven by C_frac1. Conversely, C_frac2 was the universal driver in low-to-medium productivity fields. Total nitrogen negatively correlated with yield across all productivity levels, highlighting nitrogen inefficiency. Future management must transition to carbon-based nitrogen promotion, optimizing active carbon proportions to balance seasonal and fertility-specific nutrient turnover. Full article

Objective: Hainan is an important natural rubber planting area in China. Due to topographical influences, rubber plantations in Hainan exhibit a distinct east–west distribution. The factors driving the differences in latex yield between the eastern and western regions remain unclear. This study aims to quantify the effects of climatic and soil factors on rubber yield in these regions, identify key factors, and provide a scientific basis for developing region-specific rubber plantation management strategies. Method: This study is based on 409 rubber plantation samples collected over a continuous 15-year period in Hainan Province (eastern region (n = 252) and western region (n = 157)). We analyzed regional differences in multiple indicators including soil pH, organic matter (OM), alkali-hydrolyzable nitrogen, available phosphorus, and available potassium, and core climatic variables (mean annual temperature, MAT; mean annual precipitation, MAP) between eastern and western Hainan. We further explored the relationships between these factors and rubber latex yield and identified the key yield-limiting factors for rubber plantations in different regions. Result: The yield per plant in the eastern region (3.38 kg) was significantly higher than that in the western region (3.25 kg). In the eastern region, annual precipitation (1707.78 mm), soil organic matter (24.43 g kg⁻¹), alkali-hydrolyzable nitrogen (73.64 mg kg⁻¹), and available potassium (42.73 mg kg⁻¹) were all significantly higher in the eastern region than in the western region (1604.76 mm, 15.14 g kg⁻¹, 60.75 mg kg⁻¹, and 24.55 mg kg⁻¹, respectively); while the annual mean temperature (24.02 °C) and soil pH were significantly lower than in the western region (24.17 °C, 4.81). Univariate quadratic regression revealed that both soil OM and AP exhibited significant positive correlations with rubber yield in western rubber plantations. However, after simultaneously controlling the joint variation of all climate and soil variables via multivariate stepwise regression, only OM was retained in the final predictive model. Conclusions: The key factors influencing rubber yield vary by region, with soil pH being the primary factor in the eastern region and organic matter in the western region. We explicitly differentiate two effects: short-term regional yield variations are mainly controlled by soil spatial heterogeneity rather than current climate differences, while long-term climate drives spatial divergence in soil fertility via pedogenic processes. The differences in key limiting factors between the eastern and western regions identified in this study provide data support and a scientific basis for formulating precise soil management plans for rubber plantations in Hainan Province, thereby promoting cost savings, efficiency gains, and sustainable development in Hainan’s rubber industry. Full article

Sapindus delavayi (Franch.) Radlk. is a non-wood tree species of considerable ornamental, ecological, and medicinal value, and its fruits are rich in saponins, with notable cleansing and skin-care properties. However, this tree species is currently facing the dilemma of low fruit yield and unstable fruiting. Fertilization is an effective measure to improve this cultivation situation. Considering the harm of nitrogen fertilizer in soil, we designed four schemes to replace nitrogen fertilizer with organic fertilizers in this study, aiming to obtain the optimal fertilization combination for the growth of Sapindus delavayi (Franch.) Radlk. Three-year-old seedlings were subjected to applications of nitrogen fertilizer, organic fertilizer, and their combinations to evaluate their effects on plant physiological responses and soil physicochemical properties. Results revealed that the sole application of organic fertilizer significantly promoted the elongation of new shoots. Compared with the unfertilized control, the combined treatment of 30% organic fertilizer and 70% nitrogen fertilizer significantly increased soil nitrate nitrogen content by 161.54%, while ammonium nitrogen content decreased by 24.30%. Principal component analysis indicated that glutamine synthase (GS), glutamate synthase (GOGAT), and nitrate reductase (NR) were the major enzymes influencing leaf physiological responses. Therefore, we concluded that fertilization has affected the rate of nitrogen assimilation and altered the process of amino acid synthesis, thereby influencing the metabolism and maintenance of cellular function in Sapindus delavayi (Franch.) Radlk. Structural equation modeling further indicated that fertilization primarily influenced total carbon content in plant leaves by affecting soil organic matter and alkali-hydrolyzable nitrogen. These findings elucidate the regulatory relationship between plant physiological processes and soil properties under co-application of nitrogen and organic fertilizer, providing a scientific reference for field fertilization management of this tree species. Full article