The current fertilizer recommendations for melon plantation have many limitations and exhibit deficiencies regarding future development. Therefore, in this study, the optimal quantities of fertilizer, in terms of the effects of single factors and interaction effects, are studied. There were significant interaction effects between N and P, N and K, P and K; the contents of soluble protein, vitamin C (Vc), and soluble sugar in melon could be improved using the optimal fertilization ratios. The optimal ratio of N:P:K was 2.33:1:3.85, with the amounts of N, P₂O₅, and K₂O, respectively, being 157.5, 67.58, and 260.38 kg/hm², yielding 8.73 g/kg of soluble protein in melon. The optimal ratio of N:P:K was 2.03:1:3.36, with amounts of N, P₂O₅, and K₂O being 157.50, 77.40, and 260.38 kg/hm², respectively, yielding 25.32 g/kg Vc content in melon. Finally, the optimal ratio of N:P:K was 1.53:1:3.36, with the amounts of N, P₂O₅, and K₂O being 118.07, 77.40, respectively, and 260.38 kg/hm², yielding 13.34% soluble sugar content in melon.

Soil antibiotic pollution is a global concern. It has been confirmed that straw or earthworm can enhance microbial degradation of antibiotics in soil. However, in the C/N transformation processes of soil ecosystems, straw and earthworms are closely interconnected. Whether their interaction can further enhance microbial degradation of antibiotic pollution and the underlying mechanisms remain to be explored. This study conducted a 90 days co-incubation experiment with four treatments: straw + earthworms + sulfamethoxazole (RS-EW-SMX), straw + SMX (RS-SMX), earthworms + SMX (EW-SMX), and SMX alone (SMX). Residual SMX, its degradation intermediates, and microbial communities were monitored at multiple timepoints. Results indicated an exponential decline in SMX degradation rates across treatments. By day 90, SMX was nearly completely degraded in all treatment groups. However, the combined effect of straw and earthworms significantly enhanced the degradation efficiency of SMX. During the rapid degradation phase, SMX in above four treatments decreased from 20.0 mg kg^-1 to 0.93, 1.88, 5.26 and 7.02 mg kg^-1, respectively at day 10. Furthermore, the RS-EW-SMX treatment promoted SMX transformation into low-molecular-weight intermediates and increased the relative abundance of SMX-degrading bacteria by 1.35, 2.01, and 2.17-fold compared to RS-SMX, EW-SMX, and SMX, respectively. SMX degradation efficiency exhibited a strong positive linear correlation with the relative abundance of degrading bacteria across all treatments (R² = 0.961). Concurrently, analysis revealed that straw presence facilitated the targeted enrichment of SMX-degrading bacteria within the earthworm gut, concomitant with a reduction in associated antibiotic resistance genes (ARGs). This synergistic interaction between straw and earthworms, mediated through the gut microbiome and carbon utilization, constitutes a primary mechanism underpinning the accelerated SMX degradation observed. These findings reveal a novel macrofauna-plant residues interaction mechanism for improved in situ antibiotic bioremediation, providing practical solutions for soil pollution mitigation.

Coastal reclamation reshapes both soils and vegetation, yet their coupled trajectories remain poorly understood. Here we investigated soil–vegetation co-evolution across a 15-year chronosequence on Hengsha Island in the Yangtze River estuary. The reclaimed soils were formed primarily from dredged estuarine silt and clay slurry deposited during hydraulic filling. Four representative sites were studied, spanning 3 (Y3), 7 (Y7), 10 (Y10), and 15 (Y15) years since reclamation. Soil physicochemical properties (pH, electrical conductivity, salinity, nitrogen, phosphorus, potassium) were measured, while vegetation cover was quantified using NDVI and fractional vegetation cover (FVC) derived from satellite data. Soil conditions improved markedly with reclamation age: pH, conductivity, and salinity declined, whereas nitrogen, phosphorus, and potassium accumulated significantly (p < 0.001). Vegetation shifted from salt-tolerant pioneers (e.g., Suaeda salsa, Phragmites australis) to mixed communities and cultivated rice fields (Oryza sativa), reflecting progressive improvements in soil quality. Vegetation cover increased in parallel, with NDVI rising from 0.12 ± 0.05 (Y3) to 0.35 ± 0.09 (Y15), reflecting a shift from salt-tolerant pioneers to structurally complex communities. Mantel tests revealed strong positive associations of NDVI with organic matter, nitrogen, and phosphorus, and negative associations with pH, conductivity, and salinity. Structural equation modeling identified organic matter and nitrogen enrichment, along with declining pH and dissolved salts, as dominant drivers of vegetation recovery. These results highlight a co-evolutionary process in which soil improvement and vegetation succession reinforce one another, offering insights for ecological restoration and sustainable management in coastal reclamation landscapes.

Vermiremediation, using earthworms to remove contaminants from soil is proved to be an alternative, low-cost technology. However, the impacts of earthworm activity on the fate of sulfamethoxazole (SMX), especially the degraders in earthworm intestine and the effects of intestinal bacteria on external soil degrading bacteria were still unclear. In this study, the effect of earthworms on the fate of SMX and related antibiotic resistance genes (ARGs) were investigated. Special attention was focused on the impacts of earthworms on SMX degradation efficiencies, degradation products, related ARGs and degraders in both soil and earthworm intestine, and the effect of intestinal bacteria on external soil bacteria associated with SMX was also studied. Results showed that earthworms significantly accelerated SMX degradation by both intestinal detoxification and stimulation of soil indigenous degraders. Compared with the treatment without earthworms, the residues of SMX in the treatment with earthworms were reduced by 25.1%, 49.2%, 35.7%, 34.2, and 35.7% in the 10th, 20th, 30th, 60th, and 90th day, respectively. Compared with the soil (treated with earthworms), the residues of SMX in wormcasts were further reduced by 12.2%-29.0% during the 2th to 20th day along with the formation of some metabolites which were distinct from soil. In earthworm intestine, the SMX degradation was enhanced by Microvirga, Sphingomonas, Methylobacterium, Bacillus, and Tumebacillus. Meanwhile, all of them (except Bacillus) entered and colonized the soil with wormcasts, further promoting SMX degradation. Additionally, the earthworms significantly removed the ARGs through increasing the potential SMX degraders and inhibiting the potential hosts of ARGs and int1. Our study implied that earthworm could remediate the SMX-contaminated soil via enhancing the removal of SMX and ARGs.

To improve the degradation rate of sulfamethoxazole (SMX) under hypoxic conditions in paddy fields during the flooding period, a laboratory microcosm experiment was established in this study to investigate the regulatory effect of straw return on the hypoxic degradation of SMX and its underlying microbial mechanisms. The results demonstrated that straw addition significantly promoted the hypoxic degradation of SMX. By the 10th day of the experiment, the residual SMX content in the straw-amended group was only 11.3% of that in the non-straw control group, and the average degradation rate throughout the experimental period was increased by 85.7%. Straw provided complex carbon sources, including organic carbon (e.g., starch, sugars, and humus) and cellulose, which not only reshaped the microbial community structure and created new ecological niches but also increased the microbial network density under SMX stress from 0.010 to 0.024. Acinetobacter, Bacillus, and Pseudomonas, which possess both straw decomposition and SMX degradation capabilities, sequentially became the dominant bacterial taxa. These dominant taxa can adapt to hypoxic fermentation in the flooded environment and co-metabolize SMX by activating the metabolic pathways of aromatic compounds and sugars. This study is expected to open up a novel approach for the remediation of SMX-contaminated flooded paddy fields and provide valuable innovative insights for technological breakthroughs and practical applications in related fields.

Continuous greenhouse watermelon cultivation is widely constrained by declining soil function, impaired nutrient cycling, and increasing soil-borne disease pressure. Developing biologically driven strategies to restore soil–crop coupling is therefore critical for sustainable protected horticulture. Here, we conducted a two-year field experiment (2024–2025) using a randomized block design with three treatments (CK, ST, and STE), three replicates per treatment, and a plot area of 22.5 m² to evaluate how straw application alone and in combination with earthworms regulate soil processes and crop performance in a continuous greenhouse watermelon system. Compared with CK and ST, earthworm–straw co-application (STE) exerted stronger effects, particularly during the mid-to-late growth stages. In 2024, STE increased soil organic matter by 25.34% and 30.28% relative to CK at the fruiting and harvest stages, respectively; in 2025, the corresponding increases were 25.22% and 27.62%. STE also significantly increased total nitrogen at nearly all growth stages, with the maximum increase reaching 67.23% relative to CK at harvest. In 2025, total phosphorus under STE was significantly higher than under CK and ST across all growth stages, with increases of 75.82% and 79.63%, respectively, at the fruiting stage. Neutral phosphatase activity was markedly enhanced, increasing by 292.24% at the fruiting stage in 2025. These improvements were accompanied by higher plot yield and lower wilt disease incidence, with yield increasing by 34.00% in 2024 and 21.29% in 2025 relative to CK, while disease incidence decreased by 41.46% and 56.06%, respectively. Integrative Mantel tests showed that total nitrogen was the factor most strongly associated with watermelon yield, with the correlation coefficient increasing from r = 0.490 (p = 0.001) in 2024 to r = 0.662 (p = 0.001) in 2025. Co-occurrence network analysis further revealed a strong positive correlation between yield and total nitrogen (r = 0.848 in 2024; r = 0.673 in 2025) and a negative correlation between disease incidence and total nitrogen (r = −0.661 in 2024; r = −0.822 in 2025), indicating progressively strengthened soil–plant functional coupling over time. Our findings demonstrate that earthworm–straw co-application strengthened soil nutrient transformation capacity and enhanced soil suppressiveness against wilt disease, thereby providing an effective ecology-based strategy for alleviating continuous-cropping constraints in greenhouse watermelon systems.