To study the appropriate numerical simulation methods for venturi injectors, including the investigation of the hydraulic performance, mixing process, and the flowing law of the two internal fluids, simulations and experiments were conducted in this study. In the simulations part, the cavitation model based on the standard k–ε turbulence and mixture models was added, after convergence of the calculations. The results revealed that the cavitation model has good agreement with the experiment. However, huge deviations occurred between the experimental results and the ones from the calculation when not considering the cavitation model after cavitation. Thus, it is inferred that the cavitation model can exactly predict the hydraulic performance of a venturi injector. In addition, the cavitation is a crucial factor affecting the hydraulic performance of a venturi injector. The cavitation can ensure the stability of the fertilizer absorption of the venturi injector and can realize the precise control of fertilization by the venturi injector, although it affects the flow stability and causes energy loss. Moreover, this study found that the mixing chamber and throat are the main areas of energy loss. Furthermore, we observed that the internal flow of the venturi injector results in the majority of mixing taking place at the diffusion and outlet sections.

The problem of emitter clogging has become the main obstacle restricting the application and promotion of drip irrigation technology. Studying the process of emitter clogging helps improve irrigation efficiency and save water resources. A large number of researchers have tried to solve the problem of emitter clogging from many perspectives. However, the influence of micro-nano bubbles as well as generated blockage on the clogging process of drip irrigation systems is less studied. Here, the influence of aeration on emitter clogging was studied by adding micro-nano bubbles to groundwater. Four different emitters were selected. Two treatments, micro-nano aeration and non-aeration, were set up, with a total of eight sets of experiments, running for 1500 h. The degree of emitter clogging was quantitatively characterized using the discharge ratio variation (Dra). The Christiansen uniformity coefficient (Cu) and statistical uniformity coefficient (Us) were used to evaluate the influence of emitter clogging on the performance of the drip irrigation system. Compared with the non-aeration treatment group, the Dra of aerated E1–E4 decreased by 64.74%, 54.22%, 64.20%, and 94.69% in 800 h, respectively. At the same time, the Us of the aerated E1–E4 decreased by 100%, 60.05%, 92.32%, and 100%, while the Cu of aerated E1–E4 decreased by 76.64%, 53.79%, 74.11%, and 100% compared with the unaerated group. The Cu and Us of all emitters under the aeration treatment were smaller than those comparison group. As for the blockage, the main components were typical physical blockage SiO₂ and chemical blockage CaCO₃. Most of the blockages in the non-aeration treatment group are 5–10 μm in length, while those in the aerated treatment group were generally less than 5 μm. Aeration treatment made the blockage more broken and dense and more likely to accumulate in the flow channel, obstructing the flow of water and thus intensifying the clogging process. As a result, micro-nano aeration treatment increased the risk of emitter clogging, accelerated the development of blockage in the emitter, and disturbed the uniformity of the entire drip irrigation system. This study provides a reference idea for solving the problem of blockage in drip irrigation systems.

Salinization severely impairs crop growth by inducing oxidative stress and disrupting cellular homeostasis. This study systematically investigates the synergistic effects of salt-tolerant plant-growth-promoting rhizobacteria (ST-PGPR) and foliar silicon fertilizer spraying (FSFS) on antioxidant responses in Pak choi under salt stress. Two-season pot experiments were carried out to evaluate key indicators, including antioxidant enzyme activities (superoxide dismutase: SOD; peroxidase: POD; catalase: CAT), oxidative stress (malondialdehyde: MDA), osmolyte accumulation (proline, soluble protein), and hormones (Jasmonic Acid: JA; Salicylic Acid: SA; Abscisic acid: ABA). The results demonstrate that combining ST-PGPR with FSFS significantly enhances SOD (6.18–2353.85%), POD (3.44–153.29%), and CAT (25.71–319.29%) activities while reducing MDA content (8.12–35.87%). Proline and soluble protein levels increased by 1.56–15.71% and 5.03–188.87%, respectively. Hormonal regulation increased JA, SA, and ABA levels by 1.05–31.81%, 2.09–34.29%, and 3.18–30.09%, respectively. Notably, ST-PGPR treatments at 10⁴ and 10⁶ cfu·mL⁻¹, combined with foliar silicon application, consistently ranked highest in overall antioxidant performance across both seasons based on a principal component analysis. These findings provide novel insights into microbial–mineral interactions for sustainable saline agriculture.

Developing efficient water-saving irrigation technologies that utilize high sand-laden water is an important approach to alleviating agricultural water scarcity in the Yellow River Basin. This study aims to investigate sedimentation patterns and fluid movement characteristics in drip irrigation emitters under such challenging water conditions. The dynamic changes in Dra and Cu were determined through short-period intermittent clogging tests to evaluate the anti-clogging performance of four different emitter types. The distribution and particle size composition of the deposited sediments inside the emitters were analyzed using a high-resolution electron microscope and a laser particle size analyzer. Additionally, the RNG k-ε turbulence model was used to simulate the fluid movement inside the emitters. The results showed that the B drip irrigation belt had better sediment tolerance and operational stability. The anti-clogging capacity of drip irrigation can be improved by optimizing the combination of emitter channel structure and sediment content. The fluid in the channel was divided into mainstream zone and vortex zone. Sediment particles increased in the backing-water zone and vortex center, where particles of 0.05–0.1 mm were more prone to settling due to reduced transport capacity. Energy dissipation primarily took place at the curvature of the emitter channel, and within each channel unit, gradually decreasing along the vortex flow direction, with the lowest dissipation aligning with sediment deposition zones. These findings provide a theoretical basis for mitigating clogging in high sand-laden water drip irrigation systems, offering valuable insights for improving the effective utilization of water resources in the Yellow River Basin.

Long-term operation of drip emitters under sediment-laden water conditions readily induces particle deposition and clogging, leading to discharge reduction and deterioration of irrigation uniformity. To clarify the temporal evolution and spatial distribution of clogging and to support structure-oriented anti-clogging improvement, three integrated drip tape emitters with different labyrinth-channel geometries were tested at sediment concentrations of 1, 2, and 3 g·L⁻¹ under a constant pressure of 100 kPa. The average relative discharge ratio (Dra) and Christiansen’s uniformity coefficient (CU) were continuously monitored, and cross-sectional observation and numerical simulation were combined to identify dominant deposition hotspot regions within the labyrinth channel. The results showed that increasing sediment concentration significantly accelerated clogging development and shortened operating lifetime. At 1 g·L⁻¹, the times required for the three emitter types to reach the clogging criterion of Dra < 75% were 120, 81, and 107 h, respectively, whereas at 3 g·L⁻¹ these values decreased to 39, 42, and 39 h. CU continuously declined with operating time and, in some treatments, responded earlier than Dra to system deterioration. Sediment deposition was mainly concentrated in the inlet section and bend regions, indicating that these locations were the dominant hotspots for clogging initiation and propagation. These findings demonstrate that clogging in drip emitters is jointly regulated by sediment load and labyrinth-channel geometry, and that hotspot-based structural optimization provides an effective basis for improving anti-clogging performance under sediment-laden water conditions.

Brassica chinensis L. is often grown using ‘excessive water and fertilizer’, which has a negative impact on the inter-root soil environment and the yield and quality of the plant. As the concept of green and sustainable development takes root in people’s minds, it is important to determine the right amount of water and fertilizer. Based on this, the effects of different irrigation rates and microbial fertilizers on the inter-root soil environment and yield and quality of B. chinensis were investigated. A pot experiment was carried out with two irrigation levels (W1: 80–90% of field water capacity; W2: 70–80% of field water capacity) and three fertilizer treatments (F0: no fertilizer; F1: CPS Powder Drill microbial fertilizers; F2: Maya 85 microbial fertilizers). The results showed that microbial fertilizer and irrigation amount, as well as their interaction, all had significant effects on yield, polyphenol content, soluble protein content, nitrate content, and the activities of soil enzymes, such as urease, sucrase, and catalase (p < 0.05). Increases in irrigation amount and the application of microbial fertilizer can increase the yield of B. chinensis, effectively improve the activities of sucrase, urease, and catalase in soil, increase the contents of vitamin C, chlorophyll, soluble protein, and total phenol in leaves, and reduce the content of nitrate. In addition, the findings of the principal component analysis indicated that the F2W2 treatment was the optimal treatment. The results of this study demonstrate that an 80–90% field water capacity, in conjunction with Maya 85 microbial fertilizers, yields an optimal outcome, with a score of 1.86. This outcome suggests that this combination of water and fertilizer can be used as a recommended protocol for the cultivation of Brassica chinensis L.