2026-03-27
Chen Sun, Guolong Huai, Bin Wang, Jiusheng Sun, Lei Cui
This study investigated the effects of combining chemical fertilizer and fulvic acid (FA) organic fertilizer on soil enzyme activity, bacterial communities, and peanut yield. Seven treatments were established using the peanut cultivar Shanhua No. 9: no fertilization control (CK), conventional chemical fertilizer (A), 100% FA (B), 20% FA + 80% chemical fertilizer (C), 40% FA + 60% chemical fertilizer (D), 60% FA + 40% chemical fertilizer (E), and 80% FA + 20% chemical fertilizer (F).High-throughput sequencing was used to analyze bacterial community structure, and economic benefits were evaluated. Results showed: (1) Treatments C, D, and E significantly increased catalase activity; treatment F elevated urease activity by 77.67% vs. CK; treatment E enhanced sucrase activity by 60.71%. (2) FA application had a ratio-dependent effect, enhancing bacterial richness and diversity in treatments C and D, while excessive FA substitution in treatment E did not increase richness.(3) Treatment E enriched Proteobacteria and Alphaproteobacteria, promoted Azotobacter and Rhizobium, and decreased Bacillus and Streptomyces abundance. (4) Soil nutrients, pH, salinity, and enzyme activity drove bacterial community shifts. (5) Treatment D yielded 5893.35 kg ha-¹, exceeding CK and A by 28.52% and 8.39%, with optimal seed weight and kernel recovery. (6) Treatment D showed highest economic return (49,089.3 yuan ha-¹; input-output ratio 1:13.42). Treatment D (40% FA + 60% chemical fertilizer) optimally enhanced soil biological activity and microbial structure while achieving high yield and efficiency, supporting reduced chemical fertilizer use.
DOI: 10.3389/fsoil.2026.17541882026-03-23
Marycarmen Verduzco Garibay, Alberto Fernández del Castillo, Diego Díaz-Vázquez, Martín Esteban González-López, Carlos Yebra-Montes, Osiris Díaz-Torres, Diego A. Tuesta-Popolizio, Adriana Pacheco, Sarah Forrester, Misael Sebastián Gradilla-Hernández, Carolina Senés-Guerrero
Tequila production yields 10–12 liters of tequila vinasses (TV) per liter of product, posing significant waste management challenges. Land application offers a cost-effective disposal method with potential fertilization benefits, though its impact on soil microbial ecology remains uncertain. In this one-year field case study in Amatitán, Jalisco, Mexico, seven TV treatments were tested: raw TV at 1, 3, 5, and 10 L/m²/month; neutralized TV at 10 L/m²/month; and raw or neutralized TV at 30 L/m² every three months. These were compared with three controls (fertilizer, no input, water). Physicochemical properties were measured quarterly, and bacterial communities analyzed via 16S rRNA sequencing. Results showed that TV irrigation increases soil organic matter, potassium, and heavy metal levels without exceeding regulatory safety limits. However, chromium concentrations were higher than initial conditions, indicating potential risk of accumulation. Soil pH rose from 6.4 to 6.5 across all treatments. Phosphorus peaked at 1,231 mg/kg in August with neutralized TV, then returned to baseline by December 2022. Bacterial communities were mainly composed of Actinomycetota (36–47%) and Pseudomonadota (21–27%). Low TV doses increased beneficial bacteria such as Conexibacter, Bradyrhizobium, and Burkholderia-Caballeronia-Paraburkholderia, while high raw TV favored stress-tolerant genera like Desulfitobacterium and Kocuria. Redundancy analysis showed that Kocuria was positively correlated with As, Cd and Pb, while Amphiplicatus, Nitrospira, Chryseolinea, and Actinocorallia were positively correlated with Cu, Cr, Ni and Zn. Neutralized TV supported nitrogen-fixing bacteria such as Micromonospora and Frankia. Moderate TV doses improved soil fertility while maintaining bacterial diversity. However, high doses caused shifts in bacterial communities, highlighting the need for dose optimization in sustainable TV management.
DOI: 10.3389/fsoil.2026.17710152026-03-06
Sundar Sapkota, Juan P. Frene, Nitesh Kumar Kasera, Pradip Adhikari, Sushil Adhikari, Rajan Ghimire
Biochar amendment improves soil health and mitigates the impacts of climate change on agriculture by promoting sustained crop production. Biochar is modified to further optimize its agronomic and environmental benefits; however, the magnitude and mechanism of microbial community, soil organic carbon (SOC), and crop yield responses remain unclear. This study evaluated the impact of different feedstock-derived pristine biochars and their modifications on soil health, short-term SOC dynamics, and the relationship between these changes and crop productivity. Pine-derived pristine or unmodified biochar (BC), carbon dioxide-modified biochar (C-BC), sulfur-modified biochar (S-BC), and poultry litter biochar (P-BC) were applied to the soil (1% w/w), and sorghum (Sorghum bicolor) was cultivated for three months in greenhouse conditions. Pine biochar nearly doubled short-term SOC storage, with BC, C-BC, and S-BC accumulating 97%, 105%, and 96% more SOC than the unamended soil, respectively, alongside increased particulate organic carbon (POC). Notably, BC increased soil fungal abundance by 16% compared to unamended soil. S-BC simultaneously enhanced short-term SOC accumulation and crop yields, with more significant positive effects on soil fungi, K, and S than C-BC, resulting in 9% and 13% greater grain yields than C-BC and unamended soil, respectively. In contrast, P-BC increased soil nutrient availability and grain yield but reduced microbial abundance (e.g., soil fungi) and SOC accumulation in the short term, with these effects likely depending on application rate, experimental duration, and soil type. Modified pine biochar, specifically S-modified biochar, can enhance short-term SOC accumulation and improve productivity in low-fertility arid soils by boosting microbial activity and improving nutrient cycling. While SOC storage was positively correlated with biochar C, C/N ratio, surface area, and pore volume, as well as with soil POC and microbial biomass C, the yield response was more closely related to biochar nutrient content and soil pH regulation.
DOI: 10.3389/fsoil.2026.16693562026-03-04
Laila Ait Mansour, Laila Tajeddine, Ali Boularbah, Fassil Kebede
The accumulation of potentially toxic elements (PTEs) in agricultural soils poses significant risks to food safety and ecosystem health, necessitating rapid and cost-effective monitoring approaches. While inductively coupled plasma optical emission spectroscopy (ICP-OES) provides accurate PTE quantification, its high cost, time requirements, and chemical reagent necessitate the search for green, fast, robust, and cost-effective alternatives. This study aims to evaluate the suitability of mid-infrared Fourier transform infrared (MIR-FTIR) spectroscopy combined with partial least squares regression (PLSR) as an alternative rapid method for predicting PTE concentrations and calculating pollution indices in semi-arid agricultural soils of central Morocco. A total of 67 surface soil samples (0–20 cm) were collected from three distinct soil types: Lithic Calciustolls (n=23), Typic Haplusterts (n=23), and Typic Calciustolls (n=21). Ten PTEs (As, Ba, Cd, Cu, Mn, Pb, Se, Sr, Ti, and Zn) were measured by ICP-OES and predicted using MIR-FTIR (4000–400 cm−1) coupled with PLSR. Mean PTE concentrations varied substantially across soil types, with Cd ranging from 0.95 to 3.91 mg·kg−1, Sr from 56.25 to 535.14 mg·kg−1, and Zn from 38.23 to 59.63 mg·kg−1. PTE Pollution Index (PI) was calculated using both datasets for comparative pollution assessment. Results demonstrated strong to excellent predictive performance (R² = 0.82-0.95) with the highest correlations for Ba, Zn, and Sr. PI calculations showed exceptional concordance between methods (mean PI: 1.54 for both), with all samples classified as low pollution. FTIR spectroscopy maintains the same geochemical relationships as ICP-OES (correlation differences <0.083), confirming method equivalence for soil pollution indexation. This approach offers significant advantages for large-scale monitoring programs while maintaining classification accuracy for environmental risk assessment.
DOI: 10.3389/fsoil.2026.17735752026-03-03
Juan Emilio Herranz-Luque, Juan Pedro Martín-Sanz, Javier González-Canales, Marco Antonio Jiménez-González, Pilar Carral, Blanca Sastre, María José Marqués
ContextSoil degradation and water scarcity pose critical challenges for vineyard sustainability in semi-arid regions.ObjectivesThis study evaluates the long-term effects of spontaneous cover cropping (CC) on soil health in a rainfed vineyard in central Spain, managed without irrigation or pesticides for over two decades.MethodologyBy comparing soils under CC and conventional tillage (TILL), we assessed changes in soil physical properties (porosity and water retention), nutrient content, and microbial function up to 30 cm depth. Stepwise regression analysis was used to explore management-driven relationships among CC, soil properties and nutrient dynamics.ResultsSoils under CC showed significantly higher organic matter content (1.74 ± 0.37% in the topsoil with CC vs. 0.83 ± 0.24% in TILL) and porosity (51.2 ± 2.5% vs. 44.0 ± 1.8% at 10–30 cm depth). Available phosphorus tended to be higher under CC (19.13 ± 0.60 mg/kg in CC vs. 14.13 ± 4.52 mg/kg in TILL), and this trend was further supported by stepwise analysis, which identified P availability as a variable influenced by management practices. Enzymatic activities were consistently elevated under CC, particularly in the topsoil; β-glucosidase (25 ± 9 mU/g) nearly doubled the value observed under tillage. Although soil water availability showed a non-significant trend in the topsoil (10 cm), it was higher in the subsoil (30 cm) under CC (29.0 ± 0.97% vs. 25.1 ± 0.32% in TILL). The stepwise regression analysis supported a management-driven model where CC influence soil organic matter (SOM) and nutrient availability. SOM and soil moisture strongly influenced extractable phosphorus (R² = 0.790, p =0.0047) and mineral nitrogen (R² =0.907, p =0.00018), with moisture at the time of sampling emerging as the dominant driver of nitrogen dynamics.ConclusionsThe analysis supports a management-driven pathway in which long-term vegetation inputs under CC enhance SOM accumulation. Soil water availability tended to increase in the subsoil under CC, while SOM together with short-term moisture conditions emerged as the main regulators of nutrient dynamics under semi-arid conditions.ImplicationsBy aligning ecological processes with practical agronomic outcomes such as nutrient retention and soil structure, these findings offer compelling evidence to support the broader adoption of sustainable ground cover practices in Mediterranean viticulture.
DOI: 10.3389/fsoil.2026.17335232026-02-12
Henry Díaz-Chuquizuta, María Esmilda Malca Quezada, Geomar Vallejos-Torres, Juan Pablo Cuevas-Giménez, Hugo Alfredo Huamaní Yupanqui, Martín Sánchez Ojanasta, Richard Solórzano, Boris Martínez
IntroductionIn the San Martın region, several studies have reported Cd concentrations in surface soils approaching the upper limit (UL), with mean values ranging from 0.27 to 1.351 mg·kg-¹.MethodsCadmium (Cd) transfer to Theobroma cacao (CCN-51) seedlings was evaluated under 12 factorial combinations of phosphate rock (RFP) and foliar zinc sulphate (ZnSO4) applications, using relative uptake (foliar Cd/soil Cd) as the primary response variable. ResultsThe treatment showing the highest Cd uptake was T4, defined as RFP = 0 mg·kg-1 and ZnSO4 = 527.80 mg·plant-1, with a value of 53.12. The observed range in relative uptake was 33.08 units, indicating substantial variation among management combinations. At the factor-level analysis, the high RFP treatment (114.55 mg·kg-¹) was associated with an average reduction of approximately 26.5% in relative uptake and lower within-group variability compared to the 0 mg·kg-¹ level. Interaction plots indicated that the effect of ZnSO4 on nutrient uptake depended on RFP level, with a descending response profile at high RFP concentrations. In parallel, soil correlation analyses identified available phosphorus and pH as the principal modulators of Cd transfer from soil to plant. Leaf-level principal component analysis showed that Zn and K were projected in the opposite direction to P2O5 and Cd, consistent with an ionic balance mechanism regulating Cd accumulation, and achieved an overall classification accuracy of approximately 81%, thereby confirming multivariate separability among treatments. DiscussionCollectively, these integrated results support identifying T4 as the treatment with the highest Cd uptake within the evaluated set. Accordingly, the presence of Zn²+–Cd²+ antagonism can be asserted; however, its expression is strongly influenced by soil pH and, most critically, by the availability of phosphorus derived from RFP.
DOI: 10.3389/fsoil.2026.1746654