Search Results (186)

Cellulose-derived carbon inputs to paddy soils have increased with the widespread adoption of straw return as a sustainable rice cultivation practice. However, the effect of cellulose-derived carbon inputs on photosynthesized C allocation from aboveground to belowground and the utilization of the photosynthesized C by soil microbial groups remain poorly understood. In this study, using continuous ¹³CO₂ labeling, ¹³C allocated to the above- and belowground C pools was measured to study the effects of cellulose and nitrogen fertilization on photosynthetic dynamics and microbial rhizodeposit utilization. Cellulose, nitrogen, and combined fertilization of cellulose and nitrogen promoted the allocation of photosynthates to the shoots. The combined fertilization of cellulose and nitrogen maximally decreased the allocation of photosynthesized C in the belowground C pools, including roots, soil organic matter, dissolved organic C, microbial biomass C, and phospholipid fatty acids (PLFAs), leading to a dominant microbial community that utilized the rhizodeposit shift by different fertilization practices. Cellulose or nitrogen fertilization increased the percentage of ¹³C in the Gram-positive (G+) (a15:0, i15:0, and i16:0) and Gram-negative (G−) (17:1ω8c) groups, while the combined fertilization of cellulose and nitrogen stimulated the G+ (a17:0), actinomycetes (10Me16:0 and 10Me18:0), fungi (18:1ω9c), and anaerobes (cy19:0) groups. Moreover, cellulose promoted the incorporation of rhizodeposits into soil macro-aggregates, thereby decreasing the utilization of rhizodeposits by microorganisms (¹³C-PLFA). The findings of this study suggest that under the prevalent practice of cellulose-derived C and N fertilization inputs, belowground photosynthetic C allocation and microbial utilization may decrease, potentially facilitating the retention of rhizodeposit-derived C in paddy soils. Full article

Soil health is central to sustainable agriculture, but remains challenging to assess in diversified agroecosystems such as permaculture. Soil condition reflects the interaction of physical, chemical, and biological properties, but practical assessment commonly relies on a limited set of informative indicators. In this study, a PCA-weighted Soil Health Index (SHI) was constructed from five surface soil indicators: organic carbon, total nitrogen, microbial biomass (PLFA), bulk density, and gravimetric water content. The first principal component explained 75.30% of the total variance. The analysis used 84 observations collected between 2019 and 2021 from permaculture and conventional farming systems across nine locations in Germany and Luxembourg, encompassing different land use types and two soil depths. Permaculture plots showed higher SHI values overall than conventional plots, with the same trend observed across all nine locations, although land use imbalance limited fully matched comparisons. To avoid circular prediction of the PCA-derived target, the five surface variables used directly to construct the SHI were excluded from the predictive feature set. Machine learning models were evaluated using grouped validation in which entire locations were held out from model training. The best-performing full-profile Ridge model achieved an out-of-fold $R^2$ of 0.710, an MAE of 0.159, and an RMSE of 0.214. Out-of-fold SHAP analysis indicated that magnesium, zinc, soil pH, subsoil bulk density, and copper made the largest model-specific contributions to SHI estimation. These findings demonstrate that PCA-based soil health assessment can distinguish systematic differences between studied farming systems and that a leakage-aware, interpretable modeling framework can provide moderate predictive performance across held-out locations. The results should be interpreted as internal evidence from a small multi-location dataset rather than as externally validated or causal estimates of management effects. Full article

Plant biostimulants are increasingly recognized as natural solutions that enhance plant growth and support sustainable agriculture. However, their effects on soil microbial communities remain poorly understood. This study evaluated three biostimulants: Plantiful™ (fermented marine algae with beneficial bacteria), CelexT07™ (fermented medicinal plants with beneficial bacteria), and Phylgreen™ (seaweed extract), compared with water and conventional NPK fertilization. Rhizospheric microbial biomass, community structure, and metabolic potential were assessed using metabarcoding, phospholipid fatty acid (PLFA) profiling, and Biolog EcoPlates™ assays. Total microbial biomass did not differ significantly from the untreated control. Similarly, bacterial biomass (7.4–9.8 µg/g soil) remained stable across treatments. Saprotrophic fungal biomass was 2–4-fold lower under Phylgreen^TM and CelexT07^TM than NPK, but comparable to the control. Bacterial and fungal communities were dominated by Actinobacteriota, Pseudomonadota, Acidobacteriota, Chloroflexota, and Ascomycota, with similar richness and diversity across treatments in wheat rhizosphere soil after 9 weeks of growth. Functional analyses revealed only modest shifts, with AWCD being significantly reduced by 43.5% under Phylgreen™ (64.11) compared with NPK (113.44), while remaining comparable to the untreated control (94.74). The network analysis results were also consistent with the previous results, indicating that biostimulant treatments maintained microbial richness. Overall, these findings support the use of the tested biostimulants as sustainable crop management tools that preserve rhizosphere microbial communities. Full article

Biochar has been used to improve soils and promote sustainable agricultural development. The effects of applying different doses of biochar on soil aggregate structure and stability, aggregate-associated microbial communities, aggregate carbon fractions, and underlying mechanisms in planted forest soil ecosystems remain unclear. This study aimed to explore the effects of biochar amendment (7 years) on carbon stabilization in plantation soils. The effects of biochar application (0%, 0.5%, 1.0%, 2%, 4%, and 6%) on water-stable aggregate distribution, stability indices such as mean weight diameter (MWD), geometric mean diameter (GMD), and fractal dimension (D), aggregate-associated microbial communities (fungal and bacterial phospholipid fatty acids (PLFAs)), and carbon fractions such as soil organic carbon (SOC), easily oxidized organic carbon (EOC), dissolved organic carbon (DOC), particulate organic carbon (POC), microbial biomass carbon (MBC), recalcitrant organic carbon (ROC) and black carbon (BC) were investigated based on a seven-year in situ field experiment in a Eucalyptus plantation in northern Guangxi. The results showed that after 7 years, biochar application significantly increased the proportion of macroaggregates (≥0.25 mm). The MWD and GMD increased significantly with increasing biochar application rates, whereas D decreased significantly, indicating enhanced soil structural stability. Biochar significantly increased the abundance of fungi and bacteria across all aggregate size classes and changed the microbial community structure towards conditions that promoted increased carbon stabilization. Additionally, biochar application significantly increased both recalcitrant (ROC and BC) and labile carbon (EOC, POC, DOC, and MBC) in all aggregate fractions, with the largest increments in macroaggregates. Based on correlation analysis and structural equation modeling (SEM), we speculated that biochar might enhance the physical protection and chemical sequestration of organic carbon by optimizing the physical structure of the aggregates and synergizing with the microbial carbon pump. The 7-year application of biochar significantly enhanced the SOC content in plantation soils, primarily by increasing recalcitrant organic carbon, demonstrating that biochar application constitutes a viable approach to augmenting persistent soil carbon stabilization in plantation ecosystems. The 4% and 6% treatments produced the largest responses for most of the measured indicators, underscoring the importance of biochar application. Full article

Microbial necromass C (MNC) represents a substantial pool of soil organic C (SOC), but its long-term response to organic N substitution remains poorly resolved in open-field vegetable soils. We examined endpoint soils from a 13-year equal-N field trial on a calcareous cinnamon soil in North China. The four regimes were mineral N alone (N₁₀₀), 25% N substitution with manure (N₇₅M₂₅), 25% with straw (N₇₅S₂₅), and 50% with equal manure and straw contributions (N₅₀M₂₅S₂₅). Fungal necromass C (FNC), bacterial necromass C (BNC), and total MNC were quantified and related to soil nutrient stoichiometry, extracellular enzyme stoichiometry, and PLFA-based microbial community structure. All organic substitution treatments increased FNC, BNC, and MNC relative to N₁₀₀. N₅₀M₂₅S₂₅ showed the highest FNC, BNC, and total MNC contents, which were 100.28%, 88.68%, and 97.68% higher than those under N₁₀₀, respectively. FNC comprised 77.32–80.19% of total MNC. N₇₅S₂₅ had the highest FNC/BNC ratio and increased FNC/SOC and MNC/SOC by 25.26% and 21.25%, respectively. Organic substitution also increased SOC and total N, altered nutrient and enzyme stoichiometry, and raised the fungi-to-bacteria and Gram-positive-to-Gram-negative bacterial ratios. Random Forest ranked EEC:EEN highest for FNC and total MNC, whereas soil N:P ranked highest for BNC. PLS-PM indicated that MNC variation was most strongly associated with microbial community structure within a network linked to soil nutrient and enzyme stoichiometry. Overall, combined manure–straw substitution was associated with the highest bulk-soil MNC content, together with coordinated shifts in nutrient stoichiometry, enzyme allocation, and microbial community structure, highlighting its potential to enhance microbial-derived C accumulation in open-field vegetable soils. Full article

Despite the pivotal importance of soil microbial communities in regulating the terrestrial carbon (C) cycle and ecosystem functioning, their vertical patterns and their responses to long-term nitrogen (N) deposition, in terms of microbial biomass and relative abundance, still remain unclear, particularly for fungi versus (vs.) bacteria and Gram-positive (GP) vs. -negative (GN) bacteria, where they traditionally have contrasting biological characteristics. In this study, we investigated the responses of GP and GN bacteria, total bacteria (TB), and fungi (TF) and their relationships with four nutrient ratios to 10 years of N addition with three N addition rates (control, N2, and N10 representing 0, 2, and 10 g m⁻²yr⁻¹, respectively) across a 100 cm soil profile (0-10-20-30-40-70-100 cm) in a semiarid grassland, both in terms of absolute biomass and relative abundance represented by the amount and percentage of phospholipid fatty acids (PLFAs) (e.g., GP bacterial PLFAs: total PLFAS) of specific microbial groups, respectively. Our results showed that N addition has significant negative effects on the biomass of these four microbial groups across the whole soil profile, while N addition significantly decreased the relative abundance of GN bacteria and increased those of TF and GP bacteria. Additionally, N addition significantly decreased the biomass of TF and GP bacteria in 0–10 cm soil, and of TB and GN bacteria in 0–10, 40–70, and 70–100 cm soils, with the significant increase or decrease mainly occurring at the N10 rate. Our results also showed that the biomass of these four microbial groups decreased with soil depth regardless of N addition, but that of TB and GN bacteria decreased faster than that of TF and GP bacteria did, and further caused the relative abundance of TF and GP bacteria to increase with soil depth. Significant Pearson correlations among the biomass and relative abundance of these microbial taxa with soil pH, total phosphorus, NH₄⁺-N, and NO₃⁻-N were mainly found in 0–10 cm soil. C:N and NH₄⁺-N: NO₃⁻-N ratios increased with increasing soil depth, while C: phosphorus (P) and N:P ratios decreased. N addition significantly increased C:P and NH₄⁺-N: NO₃⁻-N ratios and decreased N:P ratios, especially under the N10 rate. Among these four nutrient ratios, N:P significantly explained the highest variations in F:B (76%) and GP:GN (38%) across the whole soil profile. Together, these results underline the different responses of soil microbial relative abundance and biomass along the soil profile under long-term N addition. They also suggest a relationship between soil microbial diversity and biomass relationships, and how this links to nutrient ratios in the subsoil needs to be investigated in future. Full article

Clarifying SOC sequestration via physical and microbial processes is key for improving farmland fertility, yet the relative contributions of agronomic practices to carbon fractions and aggregate sizes remain unclear. This study (2010–2019, rice–wheat rotation, Funiu Mountain eastern plain, central China) examined tillage and organic amendment effects on SOC dynamics and underlying mechanisms across aggregate sizes under six treatments (conventional/reduced tillage with no fertilizer, chemical fertilizer, or organic manure). SOC, particulate organic carbon (POC), and mineral-incorporated organic carbon (MOC) were measured in bulk soil and water-stable aggregates (>2000, 250–2000, 53–250, <53 μm), and physical fractionation and phospholipid fatty acid (PLFA) analysis were conducted to assess interactions among aggregates, carbon quality, and microbial communities. Results showed that, compared with conventional tillage without fertilization, both conventional tillage and reduced tillage with organic manure significantly increased bulk SOC by 92–122% and macroaggregate (>250 μm) mass by 15–110%. The combined application of organic manure and reduced tillage redirected SOC from micro- to macroaggregates. Moreover, POC and MOC were the primary contributors to bulk SOC, with POC showing a strong direct effect on SOC accumulation. Furthermore, a positive priming effect was detected exclusively in macroaggregates, identifying them as key sites for SOC turnover and confirming that optimized tillage with manure shifts aggregates to larger sizes and boosts SOC through physical protection. The micro-to-macro cascade offers a robust framework for SOC dynamics, and its persistence under diverse climates warrants future research for sustainable management. Full article

The Azores are characterized by intense volcanic activity, creating unique environments such as fumarole sites, where geothermal gases and high temperatures drive distinct chemical and biological processes. To investigate small-scale heterogeneity within such a site, six visually distinct samples were collected within a 30 cm radius at an active fumarole on São Miguel Island. The samples were analyzed for elemental and mineralogical composition, bacterial lipid biomarkers (PLFAs), and microbial community structure using a novel DNA separation technique to specifically target the living microbiome. Despite mineralogical similarities across all samples—predominantly composed of alunite, alkali-feldspar, and quartz—significant microbial heterogeneity was observed. Both PLFA and bacterial iDNA analyses revealed distinct microbial communities associated with specific conditions indicated by the specific colors: red and brown samples were dominated by Proteobacteria and Actinobacteriota, yellow and green by Thermoplasmatota and Actinobacteriota, and white and gray by Crenarchaeota. Interestingly, the gray samples exhibited a broader microbial composition, sharing some taxa with all other samples. These striking color variations are likely driven by differences in both specific mineral composition and microbial pigmentation, reflecting localized biogeochemical processes. Our findings demonstrate that extreme microbial heterogeneity can occur over remarkably small spatial scales within fumarolic systems, underscoring the complex interplay between chemical and biological factors in these dynamic volcanic habitats. Full article

Microplastic pollution is a problem of global concern, but its effects on forest soils are largely overlooked. This study is based on a laboratory experiment where the effects of soil-added polyethylene microplastic particles (MP-) of two sizes (60 μm and 140 μm) (Cospheric LLC, USA) were measured to examine their effects on three types of temperate forest: dry pine forest, beech-dominated forest, and ash-dominated riparian forest that differ greatly in several physicochemical and biological soil properties. The addition of MP- did not significantly alter the respiration rate of any of the forest soils studied (p = 0.6303), as shown by ANOVA. Soil microbial biomass, as measured by the phospholipid fatty acid (PLFA) method, decreased under 60 µm MP treatment but not under 140 µm MP treatment (p = 0.0094). MP- did affect microbial community structure, especially increasing the proportion of bacteria in the community under 60 µm MP treatment (p = 0.0023). MP- affected the PLFA pattern, as shown by PERMANOVA analysis along with NMDS ordination; the effect was similar in the three studied forest types. As shown by SIMPER analysis, there was a relative decrease in fatty acid 16:1ω7 and a simultaneous increase in 16:0 and 18:0 under both MP treatments. This may potentially serve as an indication of MP pollution in temperate forest soils. Our results suggest that forest soil bacteria, as a group, may benefit from MPs at the expense of fungi, which provides a new perspective on how soil microorganisms interact under globally common MP pollution. Full article

Grassland restoration through grazing exclusion is a key strategy for enhancing soil organic carbon (SOC) sequestration, yet the dynamic contributions of plant- versus microbial-derived carbon (C) remain incompletely understood. We hypothesized that with increasing restoration duration, microbial-derived C would become a major contributor to SOC relative to plant-derived C, and that the relative proportion of bacterial necromass would increase compared to fungal necromass. To explore this, we investigated a 25-year restoration chronosequence (3, 10, 19, 25 years) of a degraded typical steppe on Kastanozem soil in Inner Mongolia, China. While acknowledging the inherent limitations of a space-for-time substitution approach, such as potential unquantified variations in initial pre-enclosure soil conditions and plant species composition, we used lignin phenols, amino sugars, and PLFA analysis to estimate the dynamics of plant- and microbial-derived C. Grassland restoration was associated with significant increases in total PLFAs (15.4–58.8%), bacterial PLFAs (14.5–82.4%), lignin phenols (16.9–91.8%), and estimated microbial-derived C (5.0–8.8 g kg⁻¹). Based on these specific biomarker estimates, which track only a subset of total C and do not equal 100% of the SOC pool, microbial-derived C accounted for 52.8–63.3% of SOC, compared to 10.1–15.5% for plant-derived C. Within the estimated microbial-derived C, the bacterial fraction increased over the restoration chronosequence, while the fungal fraction declined. Correlational analyses, including structural equation modeling, indicated that soil pH, bulk density, SOC, and microbial biomass were key factors closely associated with both C sources. Our findings suggest that microbial-necromass C, particularly from bacteria, is a major contributor to SOC accumulation during long-term grassland restoration in this semi-arid typical steppe, and that grazing exclusion can enhance SOC sequestration under the studied conditions and biomarker-based estimations. Full article

Vegetation mosaics characterize mountainous agroforestry ecosystems, yet how their spatial configuration shapes soil microbial assembly and functions remains unresolved. This study investigated how mosaic elements (monocultures, shrublands, and ecotones) drive microbial communities and enzyme activities across a forest–shrubland–farmland mosaic in western Hunan, China. Nutrient stoichiometry, microbial biomass (PLFA), and six enzyme activities were analyzed via variance partitioning, partial least squares regression, and ordination analysis. Fungal biomass dominated, peaking in ecotones and showing the lowest values in monocultures and shrublands. Microbial assembly was regulated by soil nutrients (31%) rather than soil texture (15%). Fungi (variable importance in projection, VIP = 1.287) and bacteria (VIP = 1.003) were key drivers, indicating distinct functional compartmentalization: fungi drove oxidative enzymes, whereas bacteria mediated nutrient cycling. Actinomycetes and total PLFA acted as secondary drivers, with VIP values of 0.932 and 0.939, respectively. Soil organic matter, dissolved organic carbon, silt content, and available nitrogen were key abiotic predictors. Collectively, vegetation configuration regulates soil functioning via nutrient-mediated microbial assembly and functional differentiation across mosaic elements. These findings underscore the role of landscape heterogeneity in sustaining soil fertility, suggesting that protecting ecotones and maintaining mosaic complexity should be prioritized in mountainous agroforestry management to enhance soil ecological functioning under global land-use change. Full article

Microbial necromass carbon (MNC) is recognized as an important and relatively stable component of soil organic carbon (SOC); however, it is often overlooked and poorly understood in soil management practices, particularly in the context of Loess Plateau farmlands. Here, a 13-year field experiment was carried out to examine the differences in MNC distribution, the role of MNC in SOC storage, and the impact of environmental factors under long-term mulching practices. The experiment used four treatments: (1) no mulching (NT), (2) straw mulching (NSM), (3) plastic mulching (NPM), and (4) ridge mulching (NRM). Compared to NT, all mulching methods increased SOC levels, phospholipid fatty acids (PLFAs), and amino sugar (AS) content. Straw mulching enhanced microbial biomass carbon (MBC), reduced the gap in AS content between rhizosphere and non-rhizosphere soils, and significantly increased MNC. Conversely, NPM and NRM primarily increased MBC and MNC within the rhizosphere soil. Generally, the rhizosphere soil had higher AS content than non-rhizosphere soil. However, regarding the proportion of MNC contributing to SOC, non-rhizosphere soil showed a significantly greater contribution than rhizosphere soil (p < 0.05). The contribution of MNC to SOC ranged from 10.70% to 26.38% under different treatments. Fungal-derived MNC generally contributed more to SOC (7.96–19.73%) than bacterial-derived MNC (2.62–6.65%). Soil temperature, the C/N ratio, pH, and total phosphorus influence microbial community structure and MBC, which in turn affect MNC and regulate SOC. These results enhance our understanding of how agricultural management practices on the Loess Plateau affect carbon sequestration. Full article

Litter decomposition regulates the quantity and quality of plant-derived carbon (C) and nitrogen (N) inputs to soil and is closely associated with microbial community structure. However, how elevated ozone (O₃) and nitrogen (N) addition interactively affect residual litter inputs and their associations with soil microbial communities remains poorly understood, especially in agroforestry systems. Here, we conducted a 12-month in situ litter decomposition experiment using two poplar clones (107 and 546) under ambient or elevated O₃ with or without N addition (60 kg N ha⁻¹ yr⁻¹) at an O₃-FACE platform in northern China. Litter mass and chemical traits were measured during decomposition, and endpoint soil microbial community structure was characterized using phospholipid fatty acid (PLFA) profiling. Treatment effects and litter–microbe associations were evaluated using linear mixed-effects models, correlation analysis, and redundancy analysis (RDA). Endpoint litter mass remaining was significantly affected by O₃, clone identity, and their interactions with N addition, while endpoint litter chemical traits showed trait-specific responses. PLFA-derived microbial community indices also showed treatment- and clone-dependent responses, particularly in bacterial groups, AM fungi, and the fungal-to-bacterial ratio. Endpoint litter mass remaining showed the strongest statistical association with PLFA-derived microbial community structure, whereas individual nutrient concentrations showed weaker independent effects. These findings suggest that O₃- and N-induced changes in residual litter quantity and quality are associated with shifts in PLFA-derived microbial community structure. Because PLFA characterizes microbial community structure rather than process rates, these findings should be interpreted as evidence of structural microbial reorganization associated with altered residual litter inputs, rather than direct evidence of changes in C or N cycling rates. Full article

In high-resolution remote sensing imagery, farmland areas commonly exhibit blurred boundaries, discontinuous internal structures, and high similarity to non-farmland objects such as roads, bare soil, and low vegetation. Meanwhile, because pixel-level annotation is costly and training samples are difficult to obtain, only limited training data are often available in practical applications, making methods that rely on large-scale samples and complex model structures difficult to generalize effectively. To address these two issues, this paper proposes A3UNet, a multi-level attention-enhanced lightweight segmentation network for farmland identification from high-resolution remote sensing imagery. Based on a three-level encoder–decoder structure, the network introduces Point-Local Fusion Attention (PLFA), Medium-Range Attention (MRA), and Tri-Global Attention (TGA) into the skip connections, bottleneck layer, and intermediate decoder layer, respectively, thereby enhancing farmland feature representation from three levels: local boundaries, medium-range connected structures, and global semantic constraints. Few-sample experiments on two public datasets, GID and LoveDA, show that A3UNet achieves IoU values of 83.22% and 75.87%, respectively, with only 2.51 MB of parameters and 2.92 G FLOPs. Compared with the second-best methods on the corresponding datasets, the IoU is improved by 4.78 and 5.68 percentage points, respectively. These results indicate that the proposed method can achieve favorable identification accuracy and result stability while maintaining low model complexity, providing a lightweight solution with stronger practical application potential for farmland identification from high-resolution remote sensing imagery. Full article

The application of organic residues in agriculture helps to replenish soil organic carbon (OC), improve soil fertility and biodiversity, reinforce aggregate stability, and favour water infiltration. Moreover, its application as a soil amendment alters the fate of herbicides applied to the soil. The objective here was (i) to evaluate soil quality by determining the physicochemical and biological parameters of an agricultural soil (Soil) amended with green compost (Soil + GC) over an arable pea–wheat crop rotation in a short-term experiment; and (ii) to study the dissipation and persistence of iodosulfuron-methyl-sodium applied in field plots sown with winter wheat under real field conditions. The experimental field design consisted of 24 plots (10 m²) involving 12 with control and 12 with GC-amended soils. The plots were sown with pea after GC application (~11 t ha⁻¹) in February 2023, and with winter wheat in October 2023. Iodosulfuron-methyl-sodium (Hussar^® Plus, Bayer CropScience S.L., Barcelona, Spain) was applied in post-emergence at the agronomic dose (D1 = 176 mL ha⁻¹) and double dose (D2 = 352 mL ha⁻¹). Soil samples were taken from the plots to assess the soil physicochemical and biological parameters at six sampling times after GC application, with extraction and determination of residual herbicide and metabolite (metsulfuron-methyl) concentrations. In addition, the yield and characteristics of the pea and wheat grain crops were determined. The application of GC to the soil significantly increased pH (0.5 units by July 2024) and electrical conductivity (up to 5.2 times) compared to control soil, which remained constant throughout the experiment. The OC in Soil + GC increased by 40% in July 2024 compared to control soil. Total nitrogen content increased up to 2.0 and 1.3 times during the pea–wheat growing seasons in Soil + GC compared to unamended soil. Soil dehydrogenase activity, respiration, and biomass increased by up to 1.4, 2.2 and 1.4 times, respectively, in Soil + GC compared to unamended soil over the growing seasons. The soil microbial structure, determined by phospholipid fatty acid (PLFA) analysis, recorded no significant differences between the microbial groups in both soil treatments. A non-significant increase in pea and wheat yield was observed in Soil + GC compared to unamended soil. The results revealed an increase in the residual amounts of herbicide and metabolite, being slightly more persistent, with DT₅₀ and DT₉₀ values up to 1.6 times higher, in the Soil + GC plots over time. Much higher amounts of metabolite (DT₅₀ = 24.8–29.7 days) than iodosulfuron-methyl (DT₅₀ = 5.2–8.8 days) were found in all the treatments. This may be due to wheat plants intercepting the herbicide initially at the time of application in post-emergence, the rapid dissipation of the herbicide reaching the soil, and/or the higher persistence of the metabolite compared to that of the herbicide. Overall, the soil’s physicochemical and biological properties were improved in GC-amended soil, and organic amendment increased slightly the persistence of iodosulfuron-methyl-sodium and its metabolite in the soil. Full article