The increase in irrigated maize plantings in Northern China has increased the demand for irrigation water in the region, resulting in chronic water shortages in drier years. Efficient irrigation and water use are essential for the sustainable development and management of water resources in the area. This research applied DSSAT-maize in the Loess Plateau (Fenhe basin) to determine the suitable irrigation management and optimum sowing dates to ensure the stability of spring maize production. The model was calibrated using the full irrigation treatment of 2017–2019 growing seasons. Crop data, such as plant phenological phases, aboveground biomass, crop yield, and leaf area index, were used for model calibration. The calibration showed great consistency between the measured and simulated data, with nRMSE (normalized root mean square error) ranging from 0.77% to 21.6%. The field values of crop yield, aboveground biomass, LAI, soil water content, and water use efficiency were used to evaluate the calibrated model’s performance, the model evaluation was found to be satisfactory with acceptable nRMSE ranging from 1.9% to 25.3%. Optimum simulated sowing dates for increased productivity and water efficiency were between 15 and 25 May. The optimum irrigation timing and volume of irrigation water application were 85 mm at the tasseling phase and 85 mm at the grouting phase respectively. Therefore, the yield of maize can be increased by applying irrigation and altering the sowing date in case rainfall is insufficient to satisfy the water demand of the crops in the Fenhe basin.

Problems such as population growth and climate change have led to a reduction in the use of water for irrigated agriculture, constraining the growth of crops. Subsurface irrigation, as a widely used and efficient water-saving irrigation technology, varies in its effect on increasing yields and saving water under different environmental, management, and other conditions. To investigate the effects of subsurface irrigation on yield, water productivity (WP), and irrigation water productivity (IWP) of three typical crops (wheat, maize, and cotton), this paper conducted a meta-analysis of 528 pairs of studies from 64 papers worldwide to quantify the response of crop yield, WP, and IWP to subsurface irrigation. Overall, the yield, WP and IWP increased by 5.96%, 21.62%, and 27.72%, respectively, with subsurface irrigation compared with surface irrigation. Compared with other conditions, the greatest rate of change was observed at around 200–500 m above sea level, 10–15 °C average annual temperature, 1.45–1.55 g/cm³ soil bulk density, alkaline soil, and when the crops were planted with equal row spacing. Meanwhile, the amount of irrigation water, as well as the subsurface pipeline arrangement and burial depth, had significant effects on crop yield, WP, and IWP. The maximum increase in crop yield, WP, and IWP was favored when the irrigation volume of the subsurface irrigation was reduced by 50–100% compared with surface irrigation or when both had the same volume of irrigation but a mild water deficit. In addition, the yield, WP, and IWP were also affected by fertilization factors. The recommended fertilizer application rates were ≤90 kg P ha^–1 (phosphorus) and <150 kg N ha^–1 (nitrogen). Compared with surface irrigation, subsurface irrigation showed the greatest yield increase when fertilizer was applied in a one-time application, and the WP and IWP increased significantly when the number of fertilizer applications was <3.

Salinity is one of the main abiotic stresses, and the stomatal conductance (gs) is an important physiological index in plants that is used to measure their responses to salt stress, as stomatal closure leads to lower yields. However, the factors that affect the gs after biochar application in saline soil remain unclear. To explore the stomatal adaptation mechanisms of facility vegetables under salt stress after the addition of biochar, Chinese cabbage was selected for the pot experiment in this study. The soil and plant Na⁺ and K⁺ concentrations, water status, and plant stomatal parameters were measured following treatments with different salt concentrations (25, 50, and 100 mM) and biochar application rates (0, 2, and 4%). The results showed that salt stress induced the physiological closure of the stomata in Chinese cabbage. Compared with the salt-stress treatment without biochar, the biochar application significantly increased the plant gs (20.29–128.79%). Moreover, in the biochar treatment, the open state of the stomata was maintained by sustaining the plant osmotic adjustment, reducing the abscisic acid (ABA) content, and improving the water status. The Na⁺/K⁺ ratio had the most pronounced effect on the stomata (0.702). The actual photochemical efficiency of the photosystem II (ΦPSII) and electron transport rate (ETR) of the Chinese cabbage increased by 0.75–3.41% and 0.65–2.88%, respectively, after the biochar application, which supported the photosynthetic capacity and yield formation. According to the current findings, biochar application can mitigate salt stress and regulate stomatal opening, thereby improving the photosynthesis and the overall yield of Chinese cabbage. Therefore, the application of biochar is a promising method to maintain the productivity of Chinese cabbage under salt stress.

The ridge–furrow mulching system with plastic film (RFMS) has been widely used in semi-arid areas in order to improve soil water and heat conditions, crop yields and water use efficiency. It is of practical significance to study the effect of mulching and ridge types on soil water and heat in order to optimize mulching measures and improve the effectiveness of the ridge and furrow system. To clarify the combined effect of soil water and heat beneath the system and the influence of ridge morphology on it, field experiments were conducted with three treatments, including conventional planting in bare land (CK), a ridge–furrow (wide ridge with 70 cm width and 10 cm height, narrow ridge with 40 cm width and 15 cm height) mulching system with complete plastic film (RFWN) and a ridge–furrow (equal ridge with 55 cm width and 15 cm height) mulching system with complete plastic film (RFE). An insufficient irrigation system was adopted and the two-dimensional numerical software HYDRUS-2D was used to simulate the soil water and heat flow under the experimental conditions. The model was calibrated and verified according to test data for the period of 2018 to 2019, which showed good agreement between the simulated and measured values. The simulation results revealed that the ground temperatures of RFWN and RFE were much higher than that of CK, and the average value of 0–25 cm during the growth period could increase by 2.29–4.61%. Compared with CK, RFWN and RFE reduced soil evaporation (84.71–93.73%) and field evapotranspiration (12.02–21.75%), while they increased root water uptake (25.87–40.98%) and T/ET (48.85–80.15%). Plastic film mulching and ridge morphologies affected the infiltration range and the direction of soil water movement, increased soil moisture when there was no rainfall or irrigation and reduced soil water and heat fluctuations, which was more conducive to crop growth, especially under the RFWN system. The simulation method proposed in this paper is an effective technique for calculating the soil water and heat dynamics under different ridge and furrow sections under the condition of film mulching, and it can be used for the optimal management of soil water and heat in this area.

It is of great significance to explore the strategy of regulated deficit irrigation (RDI) under mulched drip irrigation to stabilize tomato yield and improve quality and efficiency. This experimental study was conducted on a drip-irrigated greenhouse in two consecutive years (2020 and 2021). Three deficit levels were set for the flowering and fruit development stage (Stage I), and three were set for the fruit-ripening stage (Stage II). As a combination evaluation method, the fuzzy Borda model was used to optimize the RDI strategy of greenhouse tomato. The results showed that the net photosynthetic rate, stomatal conductance, transpiration rate, and total shoot biomass of tomato decreased with an increase in the water deficit, while the intercellular CO₂ concentration had an opposite trend. The mild and moderate water deficit at Stage I reduced tomato yield by 16–24% and 30–40% compared to full irrigation. The water deficit at Stage II was able to improve various quality parameters and the water-use efficiency of tomato; the irrigation water-use efficiency (32.8–33.9 kg/m³) and leaf water-use efficiency (3.2–3.6 μmol/mmol) were the highest when the soil water content was 70–90% θ_f (field capacity) at Stage I and 40–60% θ_f at Stage II (T3). Based on the fuzzy Borda combination evaluation model, T3 was determined as the treatment with stable yield, high quality, and efficient irrigation under the experimental conditions. The irrigation regime was as follows: irrigating 20–25 mm in the transplanting stage, no irrigation in the seedling stage, irrigating 193.2–220.8 mm at Stage I, and then irrigating 27.6 mm at Stage II.

Agricultural producers in China are presently confronting the challenge of “white pollution” caused by the continuous expansion of plastic film area coverage. The main objective of this research is to address the increasing interest in the effects of film residual on tomato growth, yield, and quality under drip irrigation. To reveal the effects of film residual on tomato physiology, field trials were conducted with five levels of film residual treatment applied in two consecutive cropping seasons from 2019 to 2020. Soil water content, plant height, stem diameter, photosynthetic characteristics, yield, soluble sugar content (SSC), organic acid (OA), vitamin C (VC), and nitrate content (NC) were measured; furthermore, four analysis methods were used to assess the comprehensive tomato quality. The results showed that film residuals significantly affected soil water content in 2019 and 2020 and inhibited tomato plant height and stem diameter. The variations in photosynthetic rate and stomatal conductance showed practically the same trend, increasing with an increase in the film residual at the seedling stage. The maximum yields were observed at 94.02 ton/hm² and 84.44 ton/hm² in 2019 and 2020, respectively, and tomato yield exhibited a shape reduction with increasing amounts of film residual in all years. SSC, VC, and NC showed an increasing trend with increasing amounts of film residual. The best tomato comprehensive quality was observed when the amount of film residual was lower than 200 kg/hm² and declined with an increasing amount of film residual. Overall, the soil water content, tomato growth, and fruit quality changed significantly under the influence of film residual. These results not only deepen our understanding of the harm caused by film residual to tomato growth and fruit quality but also provide reasonable advice to establish a management system for residual pollution on cultivated land.