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【Objective】 Water storage pit is a technology used in arid regions in northwestern China to collect rainwater for irrigation. In this paper, we studied the three-dimensional distribution of water, heat and oxygen in soil in an orchard under water storage pit irrigation using numerical simulation. 【Method】 Water flow was based on the Richard equation and heat transfer and oxygen diffusion in soil were modelled by convection - diffusion equations. These coupled equations were solved using the COMSOL - a Multiphysics software. The model was verified against data measured from a field, and the validated model was then used to analyze the effect of the water storage pit on distribution of water, heat and oxygen in soils in the proximity of the pit. 【Result】 The three-dimensional coupled model is accurate and can reproduce the measured spatiotemporal changes in soil water, temperature and oxygen, with the RMSE for soil water, temperature and oxygen being 0.036 7, 1.609 9 and 0.013 8, respectively. The water storage pit changed the distribution of water, heat and oxygen in the pit wall greatly. As time elapsed, soil water content in the regions proximal to the pit decreased, while oxygen concentration increased. Temperatures in the pit and soil surface were mainly impacted by atmospheric temperature. Spatial water distribution was ellipsoidal around the pit. Soil water content was the highest in the proximity of the pit bottom, while oxygen concentration and temperature in this region were the lowest. The distribution of water, temperature and oxygen tended to uniformize as time elapsed, despite that temperature and oxygen are less sensitive to irrigation than soil water. Oxygen concentration decreased with the distance from the soil surface and pit wall. 【Conclusion】 Water storage pit irrigation increased the interface between soil and water, thereby affecting transport of water, heat and oxygen in the soil. Numerical simulations indicated that the dynamics of water, heat and oxygen in the soil was affected by evaporation, rainfall, atmospheric temperature, atmospheric oxygen concentration and other environmental factors.

【Objective】 Turgor pressure in crops varies with root water uptake as a response to occurrence of water stress. This paper investigates how turgor pressure in the leaf of celery responds to drip irrigation and the factors which affect the pressure variation. 【Method】 The experiment was conducted in a greenhouse. It consists of sufficient irrigation (FI) and deficit irrigation (NI) treatment. Change in leave turgor pressure, characterized by expansion parameters Pp and Pp*, in each treatment was measured using a probe. We also measured the environmental factors and physiological traits of the plant, and analyzed their relationship with Pp/Pp* using multiple regression, path analysis and time warping methods. 【Result】 ① The parameter Pp* maximized at daytime and minimized at night on typical sunny days, regardless of the irrigation treatments and growing stage. However, Pp* started to increase earlier in NI than in FI treatment, with the peak of Pp* in the former being 39.3%~66.7% higher than that in the latter. ② The diurnal change in Pp* was similar to that in the stomatal conductance (Gs) and transpiration rate (Tr). Pp* was positively correlated to Gs and Tr, but negatively to leaf water potential (Ψ). ③ The change in leaf turgor pressure varied with irrigation. The maximum and minimum Pp increased gradually priori to irrigation and decreased rapidly after irrigation, especially in the NI treatment where the change was more profound. ④ Pp* was positively correlated to atmospheric temperature (TA) and vapour pressure deficit (VPD), but negatively to relative humidity (RH) and wind speed (WS). Path analysis showed that the highest correlation between Pp* and TA, and VPD was an indirect factor affecting Pp*. Stepwise regression indicated that WS impacted Pp* significantly only in NI. We also found that the impact of TA on Pp* was not instant but existed a delay, especially in NI where the delay was more than 10~30 min than that in FI. 【Conclusion】 Variation in leaf turgor pressure in greenhouse celery was closely related to irrigation amount and meteorological factors. Insufficient irrigation increased the maximum turgor-pressure variation parameter but delayed the effect of atmospheric temperature on the turgor pressure.

Precision irrigation relies on accurate perception of plant water statue. Plant-based sensors is a potential method to online monitor change in plant water statues due to its convenience , automaton and being able to measure water in both leaf stomata and other plant organs simultaneously. Among all available sensor, the non-invasive and in-situ leaf patch clamp pressure probe (LPCP) technology is a promising one as it allows continuous monitoring of plant leaf turgor pressure over at predefined interval. The principle of the LPCP is to measure the attenuated pressure of a leaf patch in response to a constant clamp pressure, and it has become a new versatile method to diagnose plant water status with high precision and sensitivity. LPCP has been applied in plant stomatal physiology to measure water status, and it can also help irrigation scheduling and has thus received increased interest over the recent years. We review in this paper its principle for plant water status diagnosis, installation and derivative parameters selection. Combined with leaf turgor measured by it for celery under drip irrigation, we analyzed the relationship between the change in turgor, environmental factors and plant water physiological parameters to explain the application of the device. We also outlined its pitfalls and the ways to improve it. We concluded that further studies on its application to canopy, predicting the impact of multi-environmental factors and evaluation of multi-source continuous indicators were needed. The research focus should be shifted from exploring the mechanism of plant physiological feedback to developing rational irrigation strategies.

Introduction: Accurate diagnosis of the water status of fruit trees is a prerequisite for precise irrigation. Measurement of leaf turgor pressure provides a means to explore the water utilization mechanisms of fruit trees and their responses to water stress. However, there are few studies on the use of daily minimum leaf turgor pressure (Ppmax) to indicate water information in apple tree. Methods: We monitored Ppmax, stem flow rate (Vstem), leaf water potential, soil water, and the main meteorological factors under two drip irrigation levels (fully irrigated and under-irrigated) to elucidate the temporal dynamics of the daily leaf turgor minimum of apple trees and diagnose the water status of fruit trees. Results: The results showed that soil water deficiency could reduce leaf turgor pressure and increase Ppmax. In both years, the signal intensity and sensitivity of Ppmax were better than those of Vstem, and the sensitivity was 3.31 and 2.94 times of Vstem, respectively. Compared to Ppmax, Vstem had a higher correlation with meteorological factors and was more affected by meteorological conditions, independent of irrigation treatment. Ppmax was significantly negatively correlated with soil and leaf water potential, and its correlation coefficient was 2.58–4.89 times higher than that between Vstem and both. Discussion: These results not only enhance our understanding of the water regulation strategies employed by apple trees under drought conditions but also provide a theoretical foundation for developing efficient water-saving practices and precision irrigation strategies for fruit trees. [ABSTRACT FROM AUTHOR]

Research on water abstraction techniques in sandy rivers is crucial for addressing water scarcity issues in northern China. This study introduces an artificial percolation water intake riverbed structural model designed to prevent sand intake and facilitate the extraction of clear water from sandy rivers, the main function of which is to artificially construct a helical flow field to realize the separation of water and sand and, at the same time, percolate the water. In this paper, we use a numerical orthogonal test method to study the influence of structural parameters and their combinations on water extraction by percolation, and the preferred combination of structural parameters. The main conclusions of this paper are as follows: Under the condition of certain structural parameters of the artificial riverbed, the single-width flow rate has an important effect on the mean circumferential flow rate of the vortex tube and the vortex tube seepage volume. The effect of different structural parameters on the mean circumferential flow rate of the vortex tube and the vortex tube seepage varies in magnitude. The longitudinal slope of artificial riverbed i had the greatest and most significant effect on the mean circumferential flow rate of the vortex tube, and each structural parameter had some effect on the vortex tube seepage Q but not to a significant level. When the sand content of the water flow is 15 kg/m3 and the maximum sand grain size of the suspended mass is 2 mm, the optimal structural parameter combinations of the artificial riverbed under different working conditions are as follows: Combination 20 is the optimal structural parameter combination for q = 0.3 m2/s; Combination 24 is the optimal structural parameter combination for q = 0.6 m2/s; and Combination 24 is the optimal structural parameter combination for q = 0.9 m2/s. The present study is of great significance for understanding the influence of each structural parameter and its combination on the effect of the water intake and sand discharge of an artificial percolation intake riverbed, and for optimizing the combination of the structural parameters of an artificial percolation intake riverbed. [ABSTRACT FROM AUTHOR]

It is important to evaluate any effects that biochar may have on tomato yield under deficit-irrigation to develop water-saving and yield-increasing best management practices for greenhouse tomato production. For this purpose, greenhouse trials were conducted in 2021 and 2022 with five biochar (B) application rates and three irrigation (W) levels. The B treatments were B0: 0 t ha−1; B1: 15 t ha−1; B2: 30 t ha−1; B3: 45 t ha−1; and B4: 60 t ha−1, and the W levels were W1: 50–70% of field capacity (θf); W2: 60–80% of θf; and W3B0: 70–90% of θf full irrigation without biochar, which was designated as the control. Our objective was to quantify the effects of biochar on the characteristics of tomato sources and sinks to determine, first, the optimal irrigation–biochar combination to achieve high yield tomato production, and, second, evaluate the mechanisms of this effect. At W1 and W2 irrigation levels, the addition of 30–60 t ha−1 and 45–60 t ha−1 biochar could compensate for the adverse effects of deficit-irrigation on the tomato source and sink characteristics. Our results show that in both years the highest tomato yield was obtained with the W2 irrigation level and the B3 biochar application rate, with 52% higher tomato yield compared to the lowest value obtained with the W1 irrigation level and B0 application rate. We conclude that biochar application can improve tomato yield by promoting the filling rather than the building of the sink capacity. The tomato yield was mainly affected by the net photosynthetic rate (Pn), followed by the leaf area, and the leaf chlorophyll content indirectly affected tomato yield through Pn. The W2 irrigation level combined with the B3 biochar application rate resulted in the best water–biochar combination under the experimental conditions. [ABSTRACT FROM AUTHOR]

CdTe and related II–VI compound semiconductors have been widely utilized in the field of optoelectronic devices, detectors, solar cells and so on. As the surface treatment on the wafer involved in the device fabrication process has an important impact on its subsequent photoelectric performance, the investigations on the change in structures and properties of the wafer after different surface treatments, especially the formation of new phases at the surface, have important theoretical significance and practical application value. In this work, the surface morphology and microstructure of CdTe single crystal wafers after different chemical etching processes were investigated by atomic force microscopy (AFM), Raman spectroscopy and transmission electron microscopy (TEM). With the increase of etching time to 10 min, the surface gradually became smoother with a significantly reduced surface roughness from 61.4 nm to 30.5 nm. In addition, the I–V curves of Au/CdTe contact structure illustrate the optimized ohmic contact characteristics after chemical etching with the surface leakage current increasing from 4.723 × 10−10 A to 3.640 × 10−9 A when the etching time extends up to 10 min. TEM analysis on the chemical etched surface of CdTe confirms the formation of Cd2Te2O7 phase with two variants. The d-spacing of (100)CTO and twice that of {111}CdTe being similar is the main reason for the existence of low lattice mismatch and formation of coherent interface between Cd2Te2O7 and CdTe. Furthermore, the chemical etching process is also confirmed to remove the surface damage caused by mechanical polishing effectively by comparing the interface microstructures of Au/CdTe contacts without and after 10 min of chemical etching. The formation mechanism of Cd2Te2O7 and the structure model of Au/CdTe interface are also proposed based on the TEM results. [ABSTRACT FROM AUTHOR]

The heat induced self-welding of nanomaterials is an important method for the artificial design and synthesis of heterogeneous composite materials. The connection and growth of solid-state crystalline nanomaterials under heat treatment normally follow the oriented attachment growth mechanism. However, there is a lack of systematic research on the interface crystallography under such formation conditions, especially for crystals with relatively large structure differences. In this work, hydrothermally grown TiO2 (B) (TB) nanofibers are chosen as examples to investigate the welded interface structure and crystallography between the same and different TiO2 polymorphs. Through the manipulation of calcination temperature, TB–TB and TB–anatase (TA) self-welded nanofiber pairs can be firstly obtained. The transmission electron microscopy (TEM) results suggest that two TB nanofibers with the same {100} single crystal form (SCF) can be connected with the same orientation or by being rotated along the fiber growth direction for certain angles. In addition, the TB nanofibers with different SCFs can also be welded through the extension and growth of (010)TB. For TB–TA self-welded pairs, the welding direction is confirmed along the long axis direction of the fiber, which is different from that of TB–TB self-welded pairs. Moreover, it is proved that the TB nanofibers with both SCFs can be welded with TA, leading to the formation of two different interfaces with typical orientation relationships. Furthermore, fewer dislocations can be found in the welded pairs with the {100} SCF of TB, which is due to the similar distribution of the voids between TiO6 octahedra for TB and TA with the orientation relationships of [010]TB//[010]TA, [100]TB//[100]TA and [106]TB//[001]TA. For the self-welded cases between TA nanofibers, the mutual rotation along different axes followed by the attachment growth was considered to be the mechanism of different interface formations. The results of this work can provide useful experimental support for the controlled synthesis of heat induced self-welded metal-oxide nanofibers. [ABSTRACT FROM AUTHOR]

A field experiment using PVC growth tubes was conducted in the Loess Plateau of China to determine the effective root depth (ERD) of winter wheat and its relationship with root distributions and soil water conditions. The water stable isotopes technique was used to estimate the water uptake contributions of different root depths during the growth stages. On the basis of IsoSource and the Romero-Saltos model, the ERD was 0-40 cm in the majority of the growth stage. However, in the heading and filling stages, the ERD could reach 60%-75% of the maximum root depth. Furthermore, the contributions to water uptake of different root depths were correlated with variations in soil water and root length density (r=0.395 and 0.368, respectively; p<0.05). However, by path analysis, the low decisive coefficient indicated that root distribution and soil water content did not always follow the same trend as water uptake. The conclusions of this study can help with understanding winter wheat water uptake mechanisms in arid and semi-arid regions and increasing water use efficiency. [ABSTRACT FROM AUTHOR]

Scarce rainfall and low water productivity (WP) are the primary problems constraining development of the grape industry in the extremely arid region of Xinjiang. Reducing evaporative loss and improving deep soil water use are important measures to solve this problem. In this study, a root zone irrigation (RI) method was introduced and studied in irrigation experiments in Shanshan, Xinjiang, to compare the effects of three types of irrigation emitter burial depths and furrow irrigation (FI) on soil water–root system coupling characteristics, root water uptake strategies, and leaf water physiology, yield, and quality. The results showed that RI optimized the coupling level of the soil water–root system and improved root water uptake strategies. Compared with FI, RI increased the water contribution rate of the middle and deep soil layers, resulting in an increase in the average root water uptake depth by 50.1–74.5 %. RI expanded the root water uptake range, which in turn increased the midday leaf water potential (ψ m) and net photosynthetic rate (Pn) by 8.9–15.6 % and 9.9–18.9 %, respectively. Increasing the burial depth of the irrigation emitter under RI could lead to the migration of water, root, and average root water uptake depth to the deep soil, however, the ψ m and Pn would also decrease. RI reduced evaporative loss and actual crop evapotranspiration (ET c act), however, the RI yield and WP were higher than those of FI by 8.6–18.7 % and 27.1–52.3 %, respectively. Moreover, RI significantly increased the soluble solid content, berry volume, and berry weight of grapes compared with that of FI. Under RI, increasing the burial depth of the irrigation emitter did not significantly affect WP, however, the yield and grape quality gradually decreased. The results showed that an irrigation emitter burial depth of 0–40 cm under RI in an extremely arid region is a scientific and reasonable irrigation method. • Root zone irrigation induced root growth in deep soil and improved soil water–root degree of coupling coordination. • Root zone irrigation was beneficial for enhancing root water uptake in the middle and deep soil layers. • Increased soil water–root degree of coupling coordination improved leaf water status and photosynthetic capacity. • The irrigation emitter burial depth of 0–40 cm could obtain the optimal soil water–root coupling level and yield. [ABSTRACT FROM AUTHOR]

Introduction: Accurate diagnosis of the water status of fruit trees is a prerequisite for precise irrigation. Measurement of leaf turgor pressure provides a means to explore the water utilization mechanisms of fruit trees and their responses to water stress. However, there are few studies on the use of daily minimum leaf turgor pressure (Ppmax) to indicate water information in apple tree., Methods: We monitored Ppmax, stem flow rate (Vstem), leaf water potential, soil water, and the main meteorological factors under two drip irrigation levels (fully irrigated and under-irrigated) to elucidate the temporal dynamics of the daily leaf turgor minimum of apple trees and diagnose the water status of fruit trees., Results: The results showed that soil water deficiency could reduce leaf turgor pressure and increase Ppmax. In both years, the signal intensity and sensitivity of Ppmax were better than those of Vstem, and the sensitivity was 3.31 and 2.94 times of Vstem, respectively. Compared to Ppmax, Vstem had a higher correlation with meteorological factors and was more affected by meteorological conditions, independent of irrigation treatment. Ppmax was significantly negatively correlated with soil and leaf water potential, and its correlation coefficient was 2.58-4.89 times higher than that between Vstem and both., Discussion: These results not only enhance our understanding of the water regulation strategies employed by apple trees under drought conditions but also provide a theoretical foundation for developing efficient water-saving practices and precision irrigation strategies for fruit trees., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Chen, Xu, Wan, Jiang, Ma and Zheng.)