Agronomy

To address the challenge of synergistically mitigating multiple constraints—structure, nutrients, and microorganisms—in newly reclaimed farmland, and to comprehensively improve soil quality and crop productivity, a field experiment was conducted. Treatments with different combinations and application rates of microbial agents, organic fertilizer, modified biochar, and minerals were established. The effects of these treatments on soil physicochemical and biological properties, as well as wheat growth, were analyzed to identify key synergistic measures and their mechanisms for rapidly enhancing soil quality and crop productivity. Results showed that the integrated treatment (MCN), which consisted of organic fertilizer at 6 t ha⁻¹, modified biochar at 1.5 t ha⁻¹, minerals at 0.75 t ha⁻¹, and an appropriate amount of Bacillus amyloliquefaciens agent, was the optimal scheme balancing improvement efficacy and economic benefits. MCN significantly improved soil physical structure and chemical nutrient status. Compared to other treatments, it reduced bulk density by 0.14–0.18 g cm⁻³, increased large aggregate content by the greatest margin (12 g kg⁻¹), raised field water-holding capacity by 13.0–22.7 g kg⁻¹, elevated pH by 0.41–0.87, and increased soil organic matter by 0.55–4.43 g kg⁻¹, while effectively enhancing phosphorus availability and calcium content. MCN also effectively reshaped the soil microbial community toward a healthier ecological state. Compared to other treatments, it markedly increased the absolute abundance of beneficial bacterial classes, with Fibrobacteria being 2.0–9.4 times more abundant. It also increased β-glucosidase activity by 14.4–73.9 nmol g⁻¹ h⁻¹ and markedly enhanced both α- and β-diversity. Meanwhile, MCN significantly promoted wheat growth indicators such as plant height and spike length, and the yield was more than 3.5 times that of the NPK treatment. This study constructed a cascading efficiency path for improving soil quality and crop productivity in newly reclaimed farmland using PLS-SEM: The integrated treatment improved soil physical structure and provided balanced chemical nutrients and energy, thereby promoting microbial community restructuring and enhanced activity. Subsequently, changes in the microbial community may have further improved soil physicochemical properties and strengthened positive soil–crop interactions, ultimately leading to simultaneous improvements in crop yield and plant growth. The model had a good fit (GOF = 0.70, R² = 0.90), and through RDA, PCoA, and Pearson correlation, the synergistic efficiency mechanism of four materials (fertilizer, organic fertilizer, biochar, and minerals) in improving soil quality and crop productivity was analyzed. Based on this, this study established a mechanism model for improving soil quality and crop growth in newly reclaimed farmland through integrated treatment, providing a theoretical basis and practical paradigms for improving soil quality and achieving crop yield increase in newly reclaimed farmland.

Nitrogen application rate and topping are two key agronomic factors affecting tobacco leaf quality, but the synergistic regulatory mechanisms remain unclear. This study aimed to elucidate the physiological and molecular mechanisms by which nitrogen application rate and topping synergistically regulate tobacco leaf quality, and to identify key candidate genes involved in nicotine biosynthesis. Using the tobacco cultivar K326, three nitrogen application levels were established: low (0 kg/ha), medium (120 kg/ha), and high (210 kg/ha). Agronomic traits and rhizosphere soil physicochemical properties were monitored, carbon and nitrogen metabolism enzyme activities were measured before and after topping, and mature leaf chemical composition was determined, integrated with transcriptomic and metabolomic analyses. The results showed that medium nitrogen achieved high yield while enhancing organic matter turnover efficiency, reducing rhizosphere water-soluble chloride content, and alleviating soil acidification and ammonium–potassium ion uptake competition caused by excessive fertilization. Combined with topping, it significantly enhanced carbon and nitrogen metabolism, promoted starch-to-soluble-sugar conversion, and increased nicotine accumulation, thereby optimizing leaf chemical composition. Integrated transcriptomic and metabolomic analyses revealed that medium nitrogen combined with topping exerted the most pronounced effects on gene expression and metabolite accumulation. Weighted gene co-expression network analysis (WGCNAs) identified a module highly correlated with nicotine biosynthesis, with hub genes mainly annotated as cytochrome P450 and terpene synthase family members. In conclusion, this study elucidated the molecular mechanisms by which the combination of medium nitrogen application and topping, as an integrated agronomic practice, improves tobacco leaf quality through coordinating carbon-nitrogen metabolism and optimizing chemical composition, and identified key candidate genes potentially regulating nicotine biosynthesis, providing a theoretical basis for nitrogen fertilizer management and high-quality cultivation of tobacco.

Warm-season greenhouse crops such as tomato (Solanum lycopersicum L.) and paprika (Capsicum annuum L.) require nutrient supply strategies that respond dynamically to temperature, solar radiation, vapor pressure deficit (VPD), root zone water status, and electrical conductivity (EC). This systematic review assessed four operational strategies: (1) solar radiation-proportional irrigation; (2) radiation-rate-based volume and EC adjustment; (3) supply–drainage and substrate-feedback control; and (4) temperature, humidity, and VPD-based supervisory correction. Scopus, Web of Science, IEEE Xplore, ScienceDirect, and MDPI were searched on 15 August 2026 for studies published from 2010 onward, yielding 4088 records (2326 after removal of duplicates). Studies were eligible if they addressed a controlled-environment production system, a warm-season crop, a nutrient-management component, and the use of sensing, automated control, models or decision-support systems, or IoT/AI tools. After title/abstract screening and full-text assessment, 90 studies were included: 29 studies from the database search and 61 studies identified by manual searching of publisher platforms, the three other references were from textbooks. Radiation-based approaches provide practical feedforward estimation but incompletely represent humidity and root zone dynamics. Supply–drainage feedback offers stronger closed-loop information, while temperature and VPD-based correction improves responsiveness to atmospheric demand. Tomato requires careful calcium and potassium management during reproductive stages, whereas paprika demands stable substrate moisture, EC, and drainage. A conceptual hierarchical framework is proposed in which solar radiation establishes the baseline nutrient-solution supply, radiation-rate information provides short-term adjustment, root-zone and drainage measurements provide feedback correction, and temperature or VPD serves as a supervisory layer. Ion-specific sensing, mechanistic models, and AI/ML approaches can further support nutrient-specific and predictive management. Few included studies evaluated these strategies under explicitly imposed high-temperature conditions; therefore crop, cultivar, and growth-stage-specific validation under commercial high-temperature greenhouse conditions is required before operational thresholds can be generalized.