To explore the compensation effect of aeration on tomato vegetative and reproductive growth in arid and semi-arid areas, a two-year field experiment was conducted with four micro-nano aeration ratios (0%, 5%, 10%, and 15%) and three nitrogen topdressing levels (80, 60, and 40 kg·ha⁻¹) during the tomato growth period in Ningxia, China. The results showed that increasing the aeration ratio in the range of 0–15% was conducive to the enhancement of tomato root vigor (the ability of triphenyltetrazolium chloride to be reduced, 3–104%) and the leaf net photosynthetic rate (14–63%), favorable to the facilitation of plant dry matter accumulation (3–59%) and plant nitrogen accumulation (2–70%), and beneficial to the improvement of tomato yield (12–44%) and fruit quality. Interestingly, since the aeration ratio exceeded 10%, the increase in the aeration ratio showed no significant effects on the single-fruit weight, tomato yield, and fruit quality. Moreover, with aerated underground drip irrigation, properly reducing the traditional nitrogen topdressing level (80 kg·ha⁻¹) by 25% was favorable for enhancing tomato root vigor (5–31%), increasing tomato yield (0.5–9%), and improving fruit soluble solid accumulation (2–5%) and soluble sugar formation (4–9%). Importantly, increasing the aeration ratio by 5% could compensate for the adverse effects of reducing the nitrogen topdressing level by 25% by improving the leaf photosynthetic rate, promoting plant dry matter accumulation, increasing tomato yield, and enhancing the soluble solid and soluble sugar accumulation in tomato fruits. Synthetically considering the decrease in the nitrogen topdressing amount, leading to plant growth promotion, a tomato yield increase, and fruit quality improvement, a favorable nitrogen topdressing level of 60 kg·ha⁻¹ and the corresponding proper aeration ratio of 10% were suggested for tomato underground drip irrigation in the Yinbei Irrigation District of Ningxia.

Soil’s hydraulic properties are an essential characteristic that influences the hydrologic cycle by influencing infiltration and runoff and the transport of soil water and salt in the process of vegetation rehabilitation in coastal saline soils. To date, few studies have specifically addressed the soil’s hydraulic properties and root–soil interactions of coastal saline soil under revegetation. This study aimed to identify the unique hydraulic characteristics of soil, the pore size distribution parameter, Gardner α, and the different contributions of soil’s physical properties and vegetation’s root morphological characteristics with regard to soil infiltration. For this purpose, disc infiltration experiments at different pressure heads were performed on three vegetation types, Salix matsudana (SM), Hibiscus syriacus (HC), and Sabina vulgaris (SV), after two years of vegetation rehabilitation. The results demonstrated that the initial and steady infiltration rate, Gardner α, and soil porosity fraction exhibit significant differences among the three plant species. A correlation analysis indicated that the soil water content, surface area, density, and dry weight of roots had inverse relationships with soil infiltration at heads of pressure of 0 cm and 9 cm. The regulation of soil infiltration was influenced by the root dry weight and root average diameter, which played crucial roles in determining the roots’ morphological properties and the formation of pathways and soil pores.

The improved multi-stage drip irrigation scheduling, combined with agronomic engineering, was successfully applied for spring re-vegetation in coastal saline soils. To date, few studies have addressed summer vegetation planting using this method. The aim of this study is to reveal the desalinization mechanism associated with summer afforestation and multi-stage drip irrigation. A three-year field experiment was conducted in the coastal saline land of southern China. The trial consisted of four irrigation stages, with the soil moisture potential (SMP) monitored directly beneath the drip emitter at a depth of 0.2 m, correspondingly controlled to be higher than −10 kPa (Stage I), −25 kPa (Stage II), and −45 kPa (Stage III), respectively. Results indicated that soil bulk density decreased by 14%, while soil moisture increased by 30% compared to initial conditions. The average electrical conductivity (EC) value across the entire soil layer decreased by 65.64% to 97.79%. Soil pH gradually increased during the first three irrigation stages, with the rate of increase accelerating during the rainfed stage, reaching values between 9.22 and 9.87. The concentrations of soil ions, including Ca²⁺, K⁺, Mg²⁺, Na⁺, and SO₄²⁻, decreased by 95.18%, 79.67%, 87.74%, 89.68%, and 57.19%, respectively, in the final irrigation stage. Throughout the entire soil profile, the average sodium adsorption ratio (SAR) decreased by 49.37%, while the average exchangeable sodium percentage (ESP) increased by 9.98%. This study demonstrated that multi-stage drip irrigation scheduling significantly influenced the soil physicochemical properties, soil salt ions, and vegetation growth, and thereby explained the efficient desalinization mechanism associated with this irrigation strategy. It is recommended to increase the amount of irrigation water and apply acidic regulators during the rainfed stage to reduce soil pH for vegetation establishment in coastal saline areas.

The transport–diffusion problem of point-source solutes in water environmental flows is an important issue in environmental fluid mechanics, with significant theoretical and practical implications for sustainable development and the ecological management and environmental protection of water. This study presents a model for instantaneously released multi-point-source solutes, utilizing the separation of variables method and Duhamel’s principle to solve classical mathematical physics equations. The zeroth-order and first-order concentration moment equations, which are crucial for predicting the cross-sectional average concentration of instantaneously released point-source solutes, are systematically addressed. The accuracy of the analytical results is confirmed by comparing them with the relevant literature. Furthermore, a general discussion is provided based on the study’s findings (including an ideal physical model of Couette flow), and an analytical solution (a recursive relationship) for higher-order concentration moments is deduced. Finally, this study quantitatively discusses downstream environmental ecological effects by examining the movement of released point-source solute centroids in the river, illustrating that the time needed for the released point-source solute to have an environmental–ecological impact downstream of the river is dependent on the initial release location. Under the specified engineering parameters, for the release location at the bottom boundary point of the channel (z₀ = 0 m), the midpoint (z₀ = 5 m), and the water-surface point (z₀ = 10 m), the time for additional displacement of released solute centroid to reach the asymptotic value in three cases is 4.0 h, 1.0 h, and 4.5 h; the asymptotic values are approximately −0.087 km, 0.012 km, and 0.055 km, respectively. These results not only correspond with the conclusions of previous research but also provide a more extensive range of numerical results. This study establishes the groundwork for theoretical research on more complex water environmental flow models and provides a theoretical basis for engineering computations aimed at contributing to the environmental management of rivers and lakes.