This study was conducted in the Al-Kawtha Agricultural Project, Babil Governorate, Iraq (874 km²), with the aim of evaluating the spatial distribution of major soil nutrients. Four land-use types were considered: wheat, maize, eggplant, and uncultivated land. Soil samples were collected from two depths (0–30 cm and 30–60 cm) and analyzed to determine nitrogen, phosphorus, potassium, iron, and zinc.as well as key physical and chemical properties.The results showed substantial variation in nutrient levels among the different land uses, while soil pH remained relatively stable. Nitrogen concentrations ranged from 18.90 to 38.9 mg kg⁻¹, phosphorus from 4.30 to 11.27 mg kg⁻¹, potassium from 97.60 to 145.3 mg kg⁻¹, iron from 3.58 to 7.58 mg kg⁻¹, and zinc from 0.31 to 0.46 mg kg⁻¹. The highest nutrient concentrations were observed in uncultivated areas, reflecting minimal nutrient removal, whereas cultivated fields—especially maize—showed lower nitrogen and organic matter content. Phosphorus was more abundant in deeper layers, while other nutrients were concentrated in the topsoil .Statistical analysis (p ≤ 0.05) confirmed that Findings revealed that soil nutrient distribution was significantly influenced by both land-use type and soil depth. These findings emphasize the long-term impact of cultivation on soil nutrient depletion and highlight the necessity of sustainable management strategies, including organic fertilization and crop rotation, to preserve soil fertility and productivity.

The increasing accumulation of keratin-rich wastes and the growing demand for sustainable nutrient sources in agriculture necessitate the exploration of alternative organic fertilizers that promote resource recycling and soil fertility. The potential of keratin-rich waste, including sheep wool (SW), poultry feather (PF), and human hair (HH), as organic fertilizers were comparatively investigated. The morphological characteristics of these materials were examined using Scanning Electron Microscopy (SEM), and their functional properties were analyzed via Fourier Transform Infrared Spectroscopy (FTIR). Subsequently, they were applied to lettuce plants at a rate of 10 g kg−1. Sheep wool and HH significantly enhanced plant growth, whereas PF had a negative effect at the applied dose. In the control treatment, the N concentration of the plants was 31.8 g kg−1, whereas in the keratin-based waste treatments it exceeded 50 g kg−1. Keratin-rich waste significantly increased Ca, Mg, Fe, Zn, and Mn concentrations compared to the control. Post-harvest soil measurements showed that keratin-rich waste applications reduced soil pH from 8.12 to below 7.75 and increased EC from 0.54 mS cm−1 to above 1.80 mS cm−1. The study demonstrates that keratin-rich wastes, particularly SW and HH, can effectively improve plant growth and nutrient uptake, while also modifying soil chemical properties in a beneficial manner. Poultry feathers, at the applied dose, negatively affected plant growth, suggesting that lower application rates may be required to avoid adverse effects. These findings highlight the potential of keratin-based wastes as sustainable organic fertilizers, contributing to soil fertility and resource recycling.

Optimizing drip irrigation and organic fertilizer management across diverse environments: Global patterns of nitrogen-driven production efficiency

Understanding the microbial processes driving the nitrogen (N) cycle is crucial for enhancing plant productivity and mitigating environmental pollution. The long-term application of synthetic fertilizers induces significant alterations in the microbial community and functions. However, there is still limited research on how long-term application of N, P and K fertilizers over 60 years, either individually or in combination, especially in acidic grasslands, influences the abundance of microbial N-cycling genes and N 2 O emissions. Therefore, our study was conducted on an acidic semi-natural grassland, where the soil was subjected to chemical fertilizer: P (superphosphate), K (potassium sulfate), PK, N (ammonium nitrate), NPK, PK+N (PK applied in spring and N applied once in summer) over 65 years. Gene abundances associated with the N-cycle ( nifH , amoA , nirK , nirS , nosZ , and nrfA ) were quantified at seven different time points throughout the year considering the temporal effect caused by fertilizer application. Our findings reveal that soil pH emerged as the predominant factor influencing the gene abundance related to N-fixation and denitrification outweighing the effect of the temporal nutrient increases induced by fertilizer application. N 2 O emissions were significantly positively correlated with ammonia-oxidizing archaea (AOA) abundance, while no correlation was found with denitrifiers and nitrate ammonifiers. This suggests that further investigation into the mechanisms of N 2 O production by AOA in acidic grasslands is warranted. Our study highlights that the microbial community involved in N-cycling is shaped by the difference in soil pH resulting from long-term chemical fertilizer application rather than by the direct and temporal impact of fertilizer application. • Fertilizer type shaped soil pH, which consequently affected the abundances of diazotrophs and denitrifiers. • Long-term application of N fertilizer increased AOA abundance, whereas K fertilizer reduced AOA. • The ratio of ( nirK + nirS )/ nosZ gene did not correlate with N 2 O emissions. • N 2 O emissions were positively correlated with AOA abundance.

Long-term straw substitution for chemical fertilizers promotes an increase in phosphorus availability in greenhouse soils by modulating the microbial community structure

Although anaerobic soil disinfestation (ASD) is a promising alternative for managing soilborne pathogens in plasticulture systems, its inconsistent efficacy and high, often unavailable carbon inputs limit feasibility. In 2020, two ASD growth chamber and greenhouse experiments evaluated six cool-season cover crop biomasses and three local organic amendments to determine the effects on soil anaerobicity, viability of the soilborne fungal pathogen Agroathelia rolfsii , soil fertility, and vigor of tomato ( Solanum lycopersicum L.). Field-collected soil in pots was amended with carbon sources and inoculated with A. rolfsii sclerotia, mulched with polyethylene, saturated with water, and incubated at 15 °C /25 °C (12/12 hours) for 3 weeks. All carbon sources, except wood biochar and mushroom compost, induced anaerobic conditions. However, sclerotial viability was not reduced and decreased sclerotial colonization by Trichoderma sp. compared with the nonamended aerobic control. All carbon sources, except wheat and biochar, induced greater soil microbial activity compared with the nonamended control, with poultry litter showing the greater effect. Soil pH was generally increased by ASD treatments. Soil nitrate accumulation after ASD varied, but mushroom compost, poultry litter, Austrian winter pea, and spring oat increased nitrate concentrations in at least one experiment compared with nonamended aerobic control. Poultry litter, followed by Austrian winter pea, resulted in the greatest total fruit weight and shoot dry biomass, and both responses were positively associated with the effect of ASD on soil nitrate. The results demonstrate that cool-season cover crop biomass can serve as carbon source in ASD; however, further research is needed to optimize A. rolfsii control in mid-Atlantic US plasticulture systems. Because these experiments were performed under controlled conditions, field responses may vary; however, the findings provide references for field evaluations of cover crop-based ASD systems in the mid-Atlantic United States.

Effectiveness and mechanism of microbial remediation of heavy metal-contaminated soil by Bacillus thuringiensis and Acinetobacter calcoaceticus

Iron and calcium interaction for soil As remediation in As waste mine site: Risk assessment and In-situ stabilization.

This study evaluated the potential of a softwood biochar (B, added to soil at 5% w/w) to improve the chemical and biological properties of an acidic soil (pH=5.2) of a typical Mediterranean subhumid dryland silvopastoral ecosystem. Our hypothesis was that biochar can be a complementary or alternative material to lime to buffer soil acidity, thereby enabling the establishment and growth of acid-sensitive but drought-tolerant forage legumes in Mediterranean grazed grasslands. The experiment also included treatments with lime (L, added at 0.2% w/w), a combination of B+L (added at 4.8% + 0.2% w/w respectively) and an untreated control soil (Ctr). Soil pH increased by 1.0 unit after biochar addition and significant increases were also recorded for cation exchange capacity, dissolved organic carbon, and available phosphorus. The urease, β-glucosidase and phosphatase activities increased in B-treated soil by ~2.20, 1.03 and 1.06-fold respectively vs Ctr, while the dehydrogenase activity decreased by ~30%. Biochar (alone and with lime) increased soil microbial biomass and basal respiration (on average by ~2.75 and 1.6-fold vs Ctr, respectively) and had a significant impact on soil culturable microorganisms and community structure as assessed with Biolog Ecoplates. Sequencing of the partial 16S rRNA gene showed that all amendments augmented the bacterial α-diversity, with biochar increasing the relative abundance of taxa including several potential plant growth-promoting bacteria. The results from a pot experiment and a field trial showed that biochar, alone and with lime respectively, promoted significant increases in the growth and forage production of Sulla coronaria, an acid-sensitive, drought resistant perennial forage legume. Over two growing seasons, the forage production in the field trial was +50% higher for B+L (4700 kg ha -1 ) vs Ctr (3100 kg ha -1 ) highlighting the suitability of biochar, in combination with lime or as possible alternative, to improve soil health and productivity of acidic dryland environments.

Reactive transport of Cd(II) and Cr(VI) in natural porous media: Influencing factors and mechanism.

Microbial-chemical synergy in the immobilization of cadmium in contaminated floodplain soils: A field-mesocosm assessment of Sporosarcina pasteurii and SiO₂ nanoparticles.

Weeds pose a significant threat to agricultural productivity, causing economic damage. A comprehensive understanding of the distribution of weed species is essential for formulating efficient management strategies. Despite its ecological significance, limited research has been conducted on the native Australian weed species Button grass ( Dactyloctenium radulans ). In this study, four species distribution models (SDMs) were employed to estimate its potential habitat suitability across the entirety of Australia. The four SDMs used in this study were Maxent, random forest (RF), boosted regression trees, and artificial neural networks (ANN). We conducted and collected occurrence records from field surveys and also used historical occurrence records from GBIF with environmental and soil variables to build robust predictive models. Our results suggested that seasonal temperature and soil pH were critical determinants of D. radulans distribution, contributing up to 37% of permutation importance. Among the four SDMs, Maxent outperformed other models in predictive accuracy (area under the curve = 0.90), while RF and ANN demonstrated distinct advantages in specific contexts. The integration of field and GBIF datasets enabled us to broaden our scope, and we identified southeastern Australia as a high-risk zone for D. radulans proliferation. This research underscores the utility of machine learning algorithms, including Maxent in ecological modelling, providing actionable insights for weed management and habitat restoration.

Fe-modified clay minerals enhances iron oxide transformation and microbial ecological succession for simultaneous stabilization of As, Pb, and Cd in smelting soils.

Deep sand soils are inherently fragile with surface layers that are very low in organic matter and clay. Previous studies demonstrate that strategic deep tillage such as soil inversion and deep soil mixing can increase crop production on these soils in Southern Australia. However, the majority of the organic matter and nutrients are concentrated in the top organically stained layer and deep tillage incorporates 50–60 % of the organic layer into the subsoil below 200 mm. The physical composition of the soil (percentage of sand, silt, clay and organic matter) and the chemical properties of the soil (pH, nutrient levels, cation exchange capacity) can strongly influence the soil adsorption of trifluralin. Modest levels of organic matter and clay particles in the topsoil particularly following deep tillage equate to the scant attenuation of herbicides on sandy textured soils. Soil samples (0–100 mm) were collected from three experimental sites; two Arenic Solonetz soils near Esperance and one Arenic Arenosol soil near Geraldton in Western Australia. At all three sites, three experimental treatments were sampled; control (no tillage), deep mixed with a spader to 350 mm and soil inversion with a mouldboard plough to 350 mm. Soil samples were taken on two growing seasons post tillage at Geraldton, three post tillage at Esperance TJM and twelve post tillage at Esperance E1. Tillage reduced the measured soil-liquid partition coefficient (K d ) of trifluralin (p ≤ 0.05) at all three experimental sites. A greenhouse bioassay was developed to determine if soil changes from strategic tillage at one of the Esperance sites and the Geraldton site could be directly related to herbicide bioavailability at two of the experimental sites. Intact cores were used to maintain integrity of the field soils. Cores from both field sites demonstrated that soil inversion reduced the effective dose of trifluralin (p ≤ 0.01) for the bioassay species Lens culinaris. Together these experiments illustrate that strategic deep tillage can increase the bioavailability of trifluralin. These findings offer a valuable insight into the soil behaviour of trifluralin and can help farmers estimate the risk of phytotoxicity based on measurable soil characteristics. • Field experiments applied strategic deep tillage to 350 mm on Solonetz and Arensol sandplain soils. • Soil surface composition was substantially altered by redistribution of clay and organic matter. • The altered composition reduced the measured soil-liquid partition coefficient of trifluralin. • Bioassays confirmed that Strategic deep tillage increased trifluralin bioavailability.

Plant rhizosphere enhances biochar's immobilization of cadmium: Divergent effects in flooded and unsaturated cultivation soils.

Sustainable alternative to biochar: Effects of oxychar on soil carbon sequestration pathway and microbial communities.

Soil pH adjustment and the neutralizing effect reshape the rhizobial community in the legume rhizosphere

This study evaluated the combined effects of liming and deficit irrigation on sunflower yield, leaf nutrient concentrations (nitrogen, phosphorus, and zinc), and soil pH in acidic soils of the Thrace Region, Türkiye, where soil acidity and water scarcity are major constraints to crop production. A two-year field experiment was conducted using a factorial randomized block design with three liming rates (0, 6, and 12 t CaCO₃ ha⁻¹) and three irrigation regimes (rainfed, 50%, and full irrigation at critical growth stages). Liming significantly increased sunflower yield in both years (p < 0.05), with the highest yield obtained under the combined application of 6 t ha⁻¹ lime and full irrigation, reaching 4.40 and 3.76 t ha⁻¹ in the first and second years, respectively, corresponding to an increase of up to 55% compared to the control. Soil pH increased markedly following liming, while irrigation enhanced the downward movement of liming effects within the soil profile. Leaf nitrogen (N), phosphorus (P), and zinc (Zn) concentrations were not significantly affected by treatments; however, slight increasing trends were observed under liming and irrigation, suggesting a potential improvement in plant nutrient status rather than a direct increase in nutrient uptake. Overall, moderate liming combined with appropriate irrigation represents an effective strategy for improving sunflower productivity in acidic soils; however, the limited response in nutrient concentrations indicates that additional nutrient management practices may be required.

Towards sustainable waste management: A systematic PRISMA review of environmentally responsible landfill siting.

The increasing demand for sustainable agricultural production has intensified the search for environmentally friendly strategies capable of mitigating soil degradation, climate-related stresses, heavy metal contamination, and the rising resistance of phytopathogens to conventional chemical control methods. In this context, the integration of soil amendments and biological control agents has emerged as a promising approach for enhancing plant health and maintaining soil functionality. This review critically evaluates the potential of biochar and microbial biological control agents as complementary tools for improving soil quality and suppressing plant diseases in agricultural systems. Biochar, a carbon-rich material produced through the pyrolysis of biomass under limited oxygen conditions, has gained considerable attention due to its ability to improve soil physicochemical properties, including soil structure, nutrient retention, pH regulation, and water-holding capacity. These improvements contribute to the development of a favorable rhizosphere environment that promotes beneficial microbial activity and enhances soil microbial diversity. In addition to its direct effects on soil properties, biochar plays a crucial role in the suppression of diverse plant pathogens, including fungi, bacteria, nematodes, oomycetes, and viruses, through both direct antagonistic interactions and indirect mechanisms such as the stimulation of plant defense pathways, including systemic acquired resistance (SAR) and induced systemic resistance (ISR). Recent studies further indicate that the combined application of biochar with microbial biological control agents, particularly members of the genera Trichoderma, Bacillus, and Pseudomonas, can significantly enhance microbial colonization, persistence, and antagonistic activity within the rhizosphere. This synergistic interaction leads to more consistent and effective disease suppression compared with single applications. Furthermore, the integration of biochar and beneficial microorganisms contributes to improved plant tolerance against abiotic stresses such as drought, salinity, and heavy metal toxicity while simultaneously supporting soil fertility and crop productivity. Despite these promising outcomes, variations in biochar characteristics and the limited number of long-term field studies highlight the need for standardized application strategies and further mechanistic research to optimize the biochar–microbial interaction for sustainable agricultural systems