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We studied the non-polar a-plane GaN directly grown on an SiO2 stripe-patterned r-plane sapphire substrate along the [0001] crystallographic direction of GaN. The XRC-FWHM values of the optimized a-plane GaN were 386 arcsec along the c-axis and 289 arcsec along the m-axis. Detailed scanning electron microscopy (SEM), X-ray diffraction (XRD) reciprocal space maps (RSMs) and Raman scattering studies were performed to investigate the growth kinetics. It was found that the increase in mosaic block dimension could be the primary reason for the improved crystal quality. This work shows a very promising and simple method to achieve high-quality a-plane GaN films. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) was prepared by firstly the oxidation of flake graphite using modified Hummers method, and then separation under ultrasonic system. Reacting the epoxy on the surface with ammonia to introduce aniline groups (GO-g), and polyaniline modified graphene oxide (GO-g-PANl) was prepared by conjugate grafting polyaniline onto the surface of graphene. The products were characterized by FT-1R, SEM, TEM, XRD, and resistivity tester. The results showed that GO-g-PANl was successfully prepared. When the weight ratio of amino graphene to aniline is 1 : 3 and aminating reaction temperature is 85 °C, GO-g-PANI with the best conductivity is achieved, whose resistivity value is 3.35 Ω, ⋅ cm. This material has potential applications in conductive materials and electromagnetic shielding materials. [ABSTRACT FROM AUTHOR]

In order to understand the physiological response of oilseed rape ( Brassica napus L.) leaves to cadmium (Cd) stress and exploit the physiological mechanisms involved in Cd tolerance, macro-mineral and chlorophyll concentrations, reactive oxygen species (ROS) accumulation, activities of enzymatic antioxidants, nonenzymatic compounds metabolism, endogenous hormonal changes, and balance in leaves of oilseed rape exposed to 0, 100, or 200 μM CdSO were investigated. The results showed that under Cd exposure, Cd concentrations in the leaves continually increased while macro-minerals and chlorophyll concentrations decreased significantly. Meanwhile, with increased Cd stress, superoxide anion (O) production rate and hydrogen peroxide (HO) concentrations in the leaves increased significantly, which caused malondialdehyde (MDA) accumulation and oxidative stress. For scavenging excess accumulated ROS and alleviating oxidative injury in the leaves, the activity of enzymatic antioxidants, such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), was increased significantly at certain stress levels. However, with increased Cd stress, the antioxidant enzyme activities all showed a trend towards reduction. The nonenzymatic antioxidative compounds, such as proline and total soluble sugars, accumulated continuously with increased Cd stress to play a long-term role in scavenging ROS. In addition, ABA levels also increased continuously with Cd stress while ZR decreased and the ABA/ZR ratio increased, which might also be providing a protective role against Cd toxicity. [ABSTRACT FROM AUTHOR]

The problem ofpth moment asymptotic stability analysis is considered for stochastic delayed hybrid systems with Lévy noise. By virtue of Itô’s formula and M-matrix theories, we propose some sufficient conditions to guarantee the asymptotic stability and exponential stability of the system. The criterion of mean square asymptotic stability is derived as well for delayed neural networks with Lévy noise. A numerical example is provided to show the usefulness of the proposed asymptotic stability criterion. [ABSTRACT FROM PUBLISHER]

Reference crop evapotranspiration (ET0) is an important part of water cycle and water balance. Accurate estimation of ET0 becomes vital in planning and optimizing irrigation schedules and irrigation systems management. Numerous methods have been proposed for estimating ET0, among which Penman-Monteith (P-M) model recommended by Food and Agriculture Organization of the United Nations (FAO) in 1998 since it provids the highest accurate results across the world wherever in an arid or humid environment. But the main problems computing ET0 by P-M model are its complicated nonlinear process and requirements of many climatic variables. Thus, there is an urgent need to develop a much simpler and more appropriate model in areas with limited data, such as the Hargreaves-Samani (HS) method, which is modified in this paper. In order to obtain more accurate HS model of ET0 in hilly area of central Sichuan Basin, 3 parameters(including temperature index, temperature coefficient and temperature constant) were calibrated based on Bayesian Theory using daily meteorological data from 1953 to 2002. Then, the daily and monthly ET0 from 2003 to 2013 were computed by the modified HS model, original HS model and PM model. Compared with the value recommended by FAO (the temperature index, temperature coefficient and temperature constant are 0.0023, 0.5 and 17.8, respectively), the 3 parameters obtained from the modified HS model were much smaller, and increased by latitude (0.00213, 0.46 and 16.5 in north zone, 0.00217, 0.44 and 16.36 in central zone, 0.00212, 0.44 and 16.21 in south zone). The ET0 calculated by PM model was taken as the standard, the relative error of modified HS model decreased form 14.2%-60.9% to -1.1%-33.4% in north, 40.6%-92.6% to 16.9%-61.1% in central, 31.3%-96.0% to 8.5%-64.4% in south, and 32.1%-82.7% to 9.5%-52.6% in whole hilly area of central Sichuan Basin. Through the correlation analysis, the slope of regression curve between ET0 calculated by PM model and ET0 calculated by modified HS model were 1.16 in north (R² = 0.91), 1.02 in central (R² = 0.88), 0.99 in south (R² = 0.88), and 1.13 in whole hilly area of central Sichuan Basin (R² = 0.91), respectively. The trend analysis based on monthly ET0 showed that the trend of ET0 based on modified HS model was the same as that from PM model, which performed as the downwards Quadratic parabola in one year but increasing slightly in years from 2003 to 2013. The relative error of ET0 obtained from the modified and original HS model was above zero, and the former was smaller. Therefore, the modified Hargreaves-Samani model based on Bayesian Theory is more adaptive and accurate, and can be used as a simple method for the calculation of ET0 in hilly area of central Sichuan Basin. [ABSTRACT FROM AUTHOR]

Accurate flow measurement in irrigation areas is a fundamental part in the collection, distribution, delivery and application of water resources. Flow-measuring devices are used for continuous measurement of discharges in open channels. Compared with other existing flow-measuring devices, flumes are more suitable for flow measurement in open channels and easier to be widely applied. Much research has studied different kinds of flumes, such as airfoil-shaped flow flume, water-measuring column with round head, cut-throat flume, long-throat flume, providing a variety of adjustments of the channels. But there is not much work attempting for small-size flume or flume set in the field to measure discharges of water inlet in the field. Agricultural irrigation metrology is still the weak link of current metrological work. Owing to large head loss of long-throat flume and complex hydraulic performance of cut-throat flume, short-throat flume is appropriate for water discharge measurement of inlet in the field, which needs to satisfy the requirements such as simple structure, cheap price, reasonable accuracy and low head loss. One of the most widely used open-channel short-throat flumes is Parshall flume. However, owing to high price and complex structure, Parshall flume is not the optimum choice for water discharge measurement of inlet in the field. Originated from Parshall flume, a kind of portable short-throat flume with a flat base for the field is an emerging technique developed for water discharge measurement of inlet in the field, which consists of entrance, throat and exit sections. Based on the principle of critical flow, taking the flume with the width of 51 mm, the length of 774 mm and the discharge of up to 36 L/s as study subject, the experiments are conducted under 18 working conditions to determine its hydraulic performance. Hydraulic performance of portable short-throat flume with a flat base for the field is obtained from experimental analyses on water surface profile, Froude number, specific energy, location of critical depth section and head loss. Regression analyses developed for upstream depth versus discharge under free flow condition and submerged flow condition are satisfying with the relative error of within 10%, which meets the common requirements of flow measurement in irrigation areas. By analyzing variation of Froude number and specific energy along the flume under different discharges, it is concluded that the section of critical depth under free flow condition is located at the position with a distance of 475-485 mm downstream of the flume entrance (Section 1), and that under submerged flow condition is located at the position with a distance of 505-515 mm downstream of the flume entrance (Section 1). It is pointed out that the section of critical depth is located at the end of throat section under the two outflow conditions, and the location of critical depth section under submerged flow condition is more towards the downstream direction in the throat section than that under free flow condition. And the minimum and maximum head loss of portable short-throat flume with a flat base for the field account for 6.70% and 12.10% of total upstream head, respectively. Equations of upstream depth versus head loss under free flow condition and submerged flow condition are fitted with the maximum relative error of -9.80%. Compared with the long-throat flume, head loss of portable short-throat flume with a flat base for the field was significantly less. Further, for the portable short-throat flume with a flat base for the field, head loss under free flow condition is less than that under submerged flow condition. The flume placed at water inlet in the field, which is convenient to measure discharges and not constrained by type, size and slope of channels, is practical and portable in the field. [ABSTRACT FROM AUTHOR]

In this paper, water-measuring column with a round head was proposed to measure flow based on the cylindrical flow around theory. In the column, the cylindrical flume was improved by adding a V-shaped empennage behind it to reduce head loss, improve the accuracy of flow measurement and increase sediment transport capacity. The water-measuring column with a round head was installed vertically in a U-shaped channel and its symmetry plane was overlapped with the centerline of the channel bottom. By controlling the length of the V-shaped empennage, it could make the flow pattern steady and reduce head loss. Based on the cylindrical flow around theory and RNG k-ε turbulence model, hydraulic performance of the whole flow field of water-measuring column with a round head in 18 somatotypes under 5 working conditions were numerically calculated. And we obtained the time-averaged flow field, sectional velocity distribution, flow pattern behind the column as well as the measured values and the simulated values of the related hydraulic parameters. The comparison of simulated and measured hydraulic parameters values showed that they had good consistency. When the channel slope was 1/1000, discharge was 0.045m3/s, the contraction ratio was 0.50, and the aspect ratio was 2, the relative error of the maximum velocity of cross-section at a stagnation point between the simulated value and the measured value was 1.51%, and the relative error of the maximum velocity in a profile at 15 cm upward to water surface between the simulated value and the measured value was 0.45%. Therefore, simulation results can provide valuable information for rational design of a water-measuring column with a round head and its analysis of flow field measurements. On the one hand, an oversized contraction ratio may cause excessive upstream backwater and affect the normal operation of the channel. On the other hand, it was difficult to form a critical flow if the contraction ratio was too small. Based on the experimental data, a suitable range of contraction ratio was between 0.50 and 0.70, and it was ultimately determined by the channel slope. When the channel slope was small, the contraction ratio should be bigger. The analysis on the measuring effect of V-shaped empennage in model tests and numerical simulation revealed that V-shaped empennage of suitable aspect ratio could effectively improve the flow pattern. The recommended ranges of the aspect ratio λ were in 3/2∼2 when the contraction ratios changed between 0.50 and 0.75. In addition, the aspect ratio should correspondingly increase but should not be more than 5/2 when the contraction ratio was less than 0.50. The flow formula with higher accuracy was fitted by regression analysis, which is based on stagnation-point, contraction ratio, surface width and channel slope. The maximum measuring error was 4.95% and the average error was only 0.10% when the contraction ratio was 0.63. The formula was useful for the further application of the water-measuring column with a round head in a terminal irrigation system in North China, for the reason that it was concise, practical, in line with the principle of dimensionless harmony, and can meet the flow measurement accuracy. [ABSTRACT FROM AUTHOR]

Studying the variation of fruit and stem diameter is critical for optimizing irrigation schedule of tomato under alternate partial root zone drip irrigation (APRI) and improving water use efficiency in the green house. A plant physiology monitoring system (LPS-05MD) was used to measure the variation of fruit diameter and stem diameter during the fruiting stage of tomato under three different irrigation regimes: conventional drip irrigation (CDI), APRI and fixed partial root-zone irrigation (FDI). The soil under CDI were irrigated to 100% field capacity (FC) of the root-zones (from 0 m to a maximum depth of 0.40 m during the fruiting stage) by the drip irrigation system when the soil water content (SWC) in the root-zone reaching 80% FC. During the same day, the APRI and FDI treatments received about 2/3 of the irrigation amount for CDI, but only irrigated to one part of the root-zones (approximately 1/2 of the whole root-zone). For APRI, the irrigated root zone was alternatively changed from one side to another and consequently resulted in the SWC of different sides alternately high and low; whereas in FDI treatment, only the fixed side was irrigated and the other side was kept drying during the growing season. Results indicated that the variation of fruit diameter was significantly higher (P<0.05) in sunny days with high solar radiation rate than that of cloudy day with low solar radiation rate. The increase of tomato fruit diameter per day was not significantly linearly related to average SWC of the whole root zone (R²=0.30, P=0.16), but significantly related to the average solar radiation rate (R²=0.64, P=0.018). Previous studies indicate that the magnitude of MDS (maximum daily stem shrinkage) are not constant over a period of days with the same water status but different environmental conditions, and absolute MDS values registered without considering the evaporative demand might be meaningless. Based on this, there was a positive linear relationship between MDS and ET0 (R²=0.38, P<0.001), and the relationship between the value of MDS divided by ET0 (MDS/ET0) with SWC was significant different than MDS with SWC, which indicated that normalizing the absolute MDS values by environmental parameters, such as ET0, can help to indicate the soil water status precisely. Contrary to the previous results that MDS values increase in response to drought stress, in this study, MDS of APRI decreased with increasing water stress. This might be explained by the low resistance of water flow and high hydraulic capacitance of the tomato cultivar as well as the special physiological responses under APRI. For APRI, MDS/ET0 had a close relationships with SWC in the drying and wet root-zone (R²=0.60, P=0.006 and R² =0.88, P<0.001, respectively), which indicated that MDS normalized by ET0 under APRI was influenced both by SWC of drying side and wet side, and predominantly by the irrigated root-zone. Similarly, MDS/ET0 in FDI treatment was closely linearly related with the SWC in the irrigated root-zone (R²=0.61, P<0.001), but not with the fixed drying side (R²=0.02, P=0.64). This phenomenon can be explained by the decay of roots in the drying root-zone and the diminishment of the chemical signal generated from the drying roots of FDI. To the best of our knowledge, no study has been done to investigate the relationship between MDS (or MDS/ET0) and SWC of different root zone under APRI. The data in this study can help to reveal the mechanisms of variation of fruit diameter and stem diameter, as well as providing useful information for optimizing irrigation schedule of tomato under APRI grown in greenhouse. [ABSTRACT FROM AUTHOR]

Examines the transpiration coefficient and ratio of transpiration to evapotranspiration of pear tree under alternative partial root-zone drying conditions. Conventional flood irrigation (CFI), fixed partial root-zone drying and irrigation (FPRD) and alternative partial root-zone drying and irrigation; Percentages of seasonal transpiration; Need for improvements in water-use efficiency in pear orchards

Aerated irrigation (AI) significantly influences soil nitrogen (N) dynamics and biochemical characteristics, which are crucial for enhancing N absorption and utilization efficiency. However, AI's potential effects and mechanisms on gross soil N transformations remain unclear. In this study, a 15N tracing incubation experiment was conducted with four treatments, each receiving an equivalent N input (150 kg N ha–1): (1) AINPK, chemical fertilizer under AI; (2) AIOM, organic fertilizer (OM) under AI; (3) AINPK+OM, chemical fertilizer (75 % of applied N) with organic fertilizer (NPK+OM) under AI; (4) NPK, chemical fertilizer (NPK) under traditional drip irrigation. The results revealed that AINPK significantly increased crop yield by 12.42 %, gross N mineralization by 2.58-fold, and gross nitrification by 1.27-fold compared to NPK. The AIOM and AINPK+OM significantly increased yield by 18.74–12.34 %, gross N mineralization by 1.14–1.27-fold, and autotrophic nitrification by 1.05–1.11-fold compared to AINPK. The AIOM exhibits the highest rate of NH 4 + immobilization, being 1.16–1.26-fold greater than the other three treatments. Moreover, AINPK significantly reduced the turnover time of organic N compared to NPK, and the turnover time of organic N of AIOM and AINPK+OM was shorter than AINPK. Overall, AI increased gross N mineralization and gross nitrification rates, enhancing soil N availability. AINPK and AIOM elevated the NH 4 + immobilization rates compared to NPK, while the AIOM and AINPK+OM also enhanced NO 3 – immobilization rates, stimulating inorganic N retention capacity. Therefore, based on the N transformation dynamics observed in this study, AIOM and AINPK+OM, which accelerate organic N turnover, enhance N availability and retention capacity, and increase crop yields, are recommended for crop production in greenhouse tomato. • AI accelerated organic N turnover, enhanced N availability, minimized the risk of N losses. • AI increased crop yields than CK. • AI involving organic fertilizer substitution was recommended in greenhouse tomato soil. [ABSTRACT FROM AUTHOR]

Genetic code expansion technology allows the incorporation of unnatural amino acids (UAAs) into proteins, which is useful in protein engineering, synthetic biology, and gene therapy. Despite its potential applications in various species, filamentous fungi remain unexplored. This study aims to address this gap by developing these techniques in Aspergillus nidulans. We introduced an amber stop codon into a specific sequence within the reporter gene expressed in A. nidulans and replaced the anticodon of the fungal tRNATyr with CUA. This resulted in the synthesis of the target protein, confirming the occurrence of amber suppression in the fungus. When exogenous E. coli tRNATyr CUA (Ec. tRNATyr CUA) and E. coli tyrosyl-tRNA (Ec.TyrRS) were introduced into A. nidulans , they successfully synthesized the target protein via amber suppression and were shown to be orthogonal to the fungal translation system. By replacing the wild-type Ec.TyrRS with a mutant with a higher affinity for the UAA O -methyl-L-tyrosine, the fungal system was able to initiate the synthesis of the UAA-labeled protein (UAA-protein). We further increased the expression level of the UAA-protein through several rational modifications. The successful development of a genetic code expansion technique for A. nidulans has introduced a potentially valuable approach to the study of fungal protein structure and function. • Amber suppression in A. nidulans requires the exogenous amber suppressor. • E. coli tRNATyr CUA /Tyr-tRNA synthetase incorporates unnatural amino acids in fungus. • Increasing tRNA transcription improves unnatural amino acid incorporation efficiency in fungus. [ABSTRACT FROM AUTHOR]

Accurate estimation of soil moisture content (SMC) is vital for effective farmland water management and informed irrigation decision-making. The utilization of unmanned aerial vehicle (UAV)-based remote sensing technology to monitor SMC offers advantages such as mobility, high timeliness, and high spatial resolution, thereby compensating for the limitations of in-situ observations and satellite remote sensing. However, previous research has primarily focused on SMC diagnostics for the entire crop growth period, often neglecting the development of targeted soil moisture modeling paradigms that account for the specific characteristics of the canopy and root zone at different growth stages. Furthermore, the variations in soil moisture status between fields, resulting from the hysteresis of water flow in irrigation channels at different levels, may influence the development of soil moisture modeling schemes, an area that has been seldom explored. In this study, SMC models based on UAV spectral information were constructed using Random Forest (RF) and Particle Swarm Optimization-Support Vector Machine (PSO-SVM) algorithms. The soil moisture modeling paradigms (i.e., input–output mapping) under different growth stages and soil moisture conditions of summer maize were systematically compared and discussed, along with the corresponding physical interpretability. Our results showed that (1) the SMC modeling schemes differ significantly across the various growth stages, with distinct input–output mappings recommended for the early (i.e., jointing, tasselling, and silking stages), middle (i.e., blister and milk stages), and late (i.e., maturing stage) periods. (2) these machine learning-based models performed best at the jointing stage, while subsequently, their accuracy generally exhibited a downward trend as the maize grew. (3) the RF model demonstrates superior robustness in estimating soil moisture status across different fields (moisture conditions), achieving optimal estimation accuracy in fields with overall higher SMC in line with the PSO-SVM model. (4) unlike the RF model's robustness in spatial SMC diagnostics, the PSO-SVM model more reliably captured the temporal dynamics of SMC across different growth stages of summer maize. This study offers technical references for future modelers in UAV-based SMC modeling across various spatial and temporal conditions, addressing both the types of models as well as their input features. [ABSTRACT FROM AUTHOR]

Reference crop evapotranspiration (ET0) is an important indicator for precise regulation of crop water content, irrigation forecast formulation, and regional water resources management. The Hargreaves model (HG) is currently recognized as the simplest and most effective ET0 estimation model. To further improve the prediction accuracy of the HG model, this study is based on the data of 98 meteorological stations in southwest China (1961–2019), using artificial bee colony (ABC), differential evolution (DE) and particle swarm optimization (PSO) algorithms to calibrate the HG model globally. The standard ET0 value was calculated by FAO-56 Penman–Monteith (PM) model. We compare the calculation accuracy of 3 calibrated HG models and 4 empirical models commonly used (Hargreaves, Priestley–Taylor, Imark–Allen and Jensen–Hais). The main outcomes demonstrated that on a daily scale, the calibrated HG models (R2 range 0.74–0.98) are more accurate than 4 empirical models (R2 range 0.55–0.84), and ET0-PSO-HG has the best accuracy, followed by ET0-ABC-HG and ET0-DE-HG, with average R2 of 0.83, 0.82 and 0.80, average RRMSE of 0.23 mm/d, 0.25 mm/d and 0.26 mm/d, average MAE of 0.52 mm/d, 0.53 mm/d and 0.57 mm/d, and average GPI of 0.17, 0.05, and 0.04, respectively; on a monthly scale, ET0-PSO-HG also has the highest accuracy, followed by ET0-ABC-HG and ET0-DE-HG, with median R2 of 0.96, 0.95 and 0.94, median RRMSE of 0.16 mm/d, 0.17 mm/d and 0.18 mm/d respectively, median MAE of 0.46 mm/d, 0.50 mm/d, and 0.55 mm/d, median GPI of 1.12, 0.44 and 0.34, respectively. The calibrated HG models (relative error of less than 10.31%) are also better than the four empirical models (relative error greater than 16.60%). Overall, the PSO-HG model has the most accurate ET0 estimation on daily and monthly scales, and it can be suggested as the preferred model to predict ET0 in humid regions in southwest China regions. [ABSTRACT FROM AUTHOR]

A micro-sprinkling hose is promising water-saving irrigation equipment due to its low cost and ease of installation and dismantlement during operation. The performance of the micro-sprinkling hose depends on the kinetic energy generated during field irrigation, which in turn is determined by the distribution of water droplets sprayed into the air. This paper aims to investigate the droplet diameter distribution provided by micro-sprinkling hoses by determining drop characteristics and assessing the impacts of the pressure and spraying angle on the droplet diameter distribution. Therefore, an indoor experiment was conducted to investigate the drop diameter distribution provided by micro-sprinkling hose under different pressures (20, 24, 28, and 32 kPa) and spraying angles (20°, 30°, 40°, 50°, 60°, 70°, and 80°). Droplet characteristic parameters were measured and collected using a laser precipitation monitor (LPM). The results show that (1) the diameter of water droplets sprayed from a micro-sprinkling hose with a single-hole diameter increases with increasing pressure, resulting in an expanded distribution range. Moreover, the diameter of these droplets initially increases and then decreases with increasing spraying angle. The maximum droplet is observed at a spraying angle of 40°. (2) The percentage of water droplets increases with increasing distance from the ground, with a diameter distribution range of 0–2.00 mm and an increase in the droplet diameter from 0.50 to 0.75–1.00 mm. The results reflect the characteristics of the droplet diameter distribution obtained with micro-sprinkling hoses under different pressures and spraying angles, providing guidance for the design of hose structures. [ABSTRACT FROM AUTHOR]

To quickly and accurately obtain the moisture status of grape plants at the field scale, the treatments included three irrigation levels i.e. W3 (100%M, M as the irrigation quota), W2 (75% M) and W1 (50%M) and four fertilizer application rates i.e. F0 (0 kg/hm2), F1 (324 kg/hm2), F2 (486 kg/hm2) and F3 (648 kg/hm2). Grape leaf water content (LWC) was monitored nondestructively by an unmanned aerial vehicle (UAV) carrying multispectral (MS), visible light (RGB) and thermal infrared (TIR) cameras to extract band reflectance (BR), canopy coverage (CC) and canopy temperature (T) information, respectively. Using BR (included six bands: B, R, G, RE, NIR800, and NIR900), CC and T and their combinations as input variables brought into the partial least squares (PLS), random forest (RF), support vector machine (SVM) and extreme learning machine (ELM) algorithms. The prediction models for grape LWC were established by using four machine learning algorithms, and the optimal combination of variables was finally determined. The results represented that (1) the model built with BR + CC + T as predictor variables under different water treatments was better than other combinations of variables, with the coefficient of determination (R2) above 0.69 and the relative root mean square error (RRMSE) less than 2.5%; (2) modeling the LWC of grapes at different fertility periods based on the combination of BR + CC + T, the R2 ranged from 0.51 to 0.78 at the shoot-growing, anthesis, and fruit-inflating stages; (3) the top three important variables were T, NIR800, and NIR900 in the shoot-growing, anthesis, and fruit-inflating stages, while the top three important variables were RE, B, and T in the fruit-inflating stage. In summary, UAV multimodal data fusion has good application in predicting the LWC of grapes using RF algorithm modeling during the different growth stages. This study can supply a technical support for precise management of vineyard water regime using a UAV platform. [ABSTRACT FROM AUTHOR]

Crop water stress index (CWSI) has been widely used in soil moisture monitoring. However, the influence of the time lag effect between canopy temperature and air temperature on the accuracy of soil moisture monitoring with different CWSI models has not been further investigated. Therefore, based on the continuous record of canopy temperature and air temperature, this study explored the influence of canopy-air temperature hysteresis on the diagnosis of soil moisture with three CWSI models (CWSIT—theoretical, CWSIE—empirical, CWSIH—hybrid). The results show (1) the peak time of canopy temperature was ahead of that of air temperature, and the lag time varied under different soil moisture conditions. When the soil moisture was seriously deficient, the lag time decreased. However, from jointing-heading period to filling-ripening period, the lag time became longer. (2) The values of CWSIT, CWSIE, and CWSIH decreased when the time lag effect was considered. In jointing-heading period, heading-filling period, and filling-ripening period, CWSIT had the highest accuracy in soil moisture monitoring without the consideration of the time lag effect. When the time lag effect was considered, the monitoring accuracy of CWSIE and CWSIH was greatly improved and higher than that of CWSIT, while that of CWSIT was reduced. The findings provided a basis for further improving the accuracy of soil moisture monitoring with CWSI models. [ABSTRACT FROM AUTHOR]

As the main expenditure item in water balance, evapotranspiration has an important impact on the surface ecosystem. Assessing the impact of changes in meteorological elements on evapotranspiration is essential to identify the spatiotemporal heterogeneity of hydrographic responses to climate changes. Based on the actual evapotranspiration (ETa) product (GPR-ET) generated by Gaussian process regression (GPR), as well as temperature and precipitation datasets, our study employed various statistical analysis methods, including geographic detector, the center of gravity migration model, spatial variation coefficients, and partial differential models, to investigate the spatiotemporal variation in ETa in China from 2000 to 2018. The analysis covered future trends in ETa changes and the contribution of meteorological factors. Our results showed that the ETa in northwest China had stronger spatial heterogeneity and the mean value was generally lower than that in the southeast. But the center of gravity of ETa was shifting towards the northwest. In most areas, the future trend was expected to be inconsistent with the current stage. ETa in the regions of north and west was mainly driven by precipitation, while its increase in southeast China was largely attributed to temperature. In addition to spatial variations, the joint enhancement effect of temperature and precipitation on ETa exists. According to the contribution analysis, precipitation contributed more to the change in ETa than temperature. These findings have enhanced our comprehension of the contribution of climate variability to ETa changes, providing scientific proof for the optimization apportion of future water resources. [ABSTRACT FROM AUTHOR]

Micro-irrigation pipe network systems are commonly utilized for water transmission and distribution in agricultural irrigation. They effectively transport and distribute water to crops, aiming to achieve water and energy conservation, increased yield, and improved quality. This paper presents a model for the scaled micro-irrigation pipeline network system and provides a comprehensive review of the fundamental concepts and practical applications of optimization techniques in the field of pipeline network design. This paper is divided into four main sections: Firstly, it covers the background and theoretical foundations of optimal design for scaled micro-irrigation pipeline network systems. Secondly, the paper presents an optimal design model specifically tailored for scaled micro-irrigation pipeline networks. And then, it discusses various optimization solution techniques employed for addressing the design challenges of scaled micro-irrigation pipeline networks, along with real-world case studies. Finally, this paper concludes with an outlook on the ongoing research and development efforts in the field of scaled micro-irrigation pipeline network systems. In addition, this paper establishes a fundamental model for optimizing pipeline networks, to achieve minimum safe operation and total cost reduction. It considers constraints such as pipeline pressure-bearing capacity, maximum flow rate, and diameter. The decision-making variables include pipeline diameter, length, internal roughness, node pressure, future demand, and valve placement. Additionally, this paper provides an extensive overview of deterministic methods and heuristic algorithms utilized in the optimal design of micro-irrigation pipeline networks. Finally, this paper presents future research directions for pipeline network optimization and explores the potential for algorithmic improvements, integration of machine learning techniques, and wider adoption of EPANET 2.0 software. These endeavors aim to lay a strong foundation for effectively solving complex and challenging optimization problems in micro-irrigation pipeline network systems in the future. [ABSTRACT FROM AUTHOR]

Abstract In this paper, magnetic field with different strength was combined with Au Nanoparticles (Au NPs) in LIBS technology. The spectral intensity enhancement factor of the characteristic line (Cu I 521.8 nm) under different conditions was analyzed and the enhancement mechanism was analyzed. It is showed that when the magnetic field is applied alone, the magnetic field of 153 m T will reduce the spectral intensity. The 20 m T, 50 m T and 90 m T magnetic fields will enhance the spectral intensity, and the stronger the magnetic field, the stronger the enhancement. The application of a magnetic field (magnetic fields enhanced LIBS,MF-LIBS) or Au NPs (nanoparticles enhanced LIBS, NELIBS) alone can enhance the spectral intensity of the plasma, but for the enhancement effect, single constraint is weaker than the combination of the two methods, and the magnetic field confinement is weaker than that of the NELIBS. Through the combination of NELLBS and MF-LIBS, the trace elements can be detected easily. [ABSTRACT FROM AUTHOR]

Drip irrigation technology can directly transport fertilizer and water to the root zone of crops and effectively improve the fertilizer utilization rate, but improper fertilization can lead to emitter blockage, reducing fertilization uniformity and resulting in crop yield loss. This paper tested the clogging performance of common emitters (inlaid cylindrical labyrinth emitter, E1; inlaid patch labyrinth emitter, E2; flanking labyrinth emitter, E3) with urea (UREA), sulfate of potassium (SOP), muriate of potash (MOP), monoammonium phosphate (MAP), and diammonium phosphate (DAP) at different concentrations (0 g/L, 0.4 g/L, 0.8 g/L, 1 g/L, 1.2 g/L, 1.6 g/L). Using field emission scanning electron microscopy (FESEM), surface energy spectrum analysis (EDS), and X-ray diffraction (XRD), the effects of fertilizer type and concentration on blockages and blocked substance accumulation were analyzed in an indoor accelerated irrigation experiment. The results showed that UREA and DAP are sensitive fertilizers for E2 and E3, respectively. With increasing fertilizer concentration, the decrease rate of the relative flow for E3 accelerated, and the Dra and CU of irrigation in E2 decreased with increasing irrigation events. The dry weight of blocked substances increased with the increase in irrigation events, which is consistent with the trend that the relative flow and uniformity of the emitter decreased with the increase in irrigation events. Upon increasing fertilizer concentration, the more chemical clogging substances increase, the less significant the water shear force. Therefore, we recommend that fertilizer concentration of DAP and UREA should not exceed 1.2 g/L. The results of this study can provide a basis for controlling chemical clogging and extending the service life of emitters. [ABSTRACT FROM AUTHOR]

• High-frequency common expansion contributed to small ratio on diameter growth. • Low-frequency dramatic expansion contributed to large ratio on diameter growth. • Diameter dramatic expansion had obvious relationships with rainfall. • Leaf wetting time directly affected sap flow and diameter change process. • Common expansion was promoted, and shrinkage was alleviated after rainfall. The dry-hot valley regions of Southwest China suffer droughts and high temperatures coexist environment. The efficient use of rainfall makes it possible for plants to safely cope with the environmental stress in the region. To reveal the driving mechanism of rainfall on typical tree secondary growth, orange tree (Citrus sinensis L. Osbeck), the commonly grown economic tree in the region was selected. Trunk diameter, sap flow, leaf humidity, meteorological conditions and soil water content were simultaneously monitored for the 2020–2022 period. Based on frequency distribution of trunk diameter changes data, trunk diameter changes were classified into positive growth (dramatic expansion, and common expansion), and negative growth (dramatic shrinkage, and common shrinkage) types. Furthermore, the relationships among the different growth patterns and rainfall or drought events were analyzed. The results showed: i) Trunk diameter maintained positive growth on rainy days, whereas both positive and negative growth occurred on rainless days. Although rainy period was not frequent, a high proportion of the total growth occurred during that time. ii) The common expansion type with a high frequency contributed to approximately 30% of the total growth, whereas the dramatic expansion type with a low frequency contributed to approximately 70% of the total growth. iii) There was a highly significant correlation between dramatic tree diameter expansion and rainfall. iv) Cumulative growth in tree diameter during rainy period was significantly driven by the duration of rainfall, the wetting time of leaf and the amount of rainfall. v) Compared with rainfall amount, the time rainfall related indexes were more closely related with tree dramatic diameter expansion. vi) While increasing soil water content and dry air mitigation due to rainfall enhanced average growth, it concurrently suppressed negative growth of tree trunk diameter after rainfall. The study confirmed that rainfall was critical for tree diameter growth in dry-hot valley regions of Southwest China. Relevant results are beneficial for improving understanding of plant precipitation utilization mechanism and could provide useful information on extreme meteorological hazards assessment in the context of climate change. [ABSTRACT FROM AUTHOR]

The growth condition of initial medium (870 °C–920 °C) temperature (MT) layer is crucial to the quality of high temperature (HT) GaN layer and AlGaN/GaN heterojunction grown on flat sapphire substrate (FSS) with ex-situ sputtered AlN. The superior wetting of GaN and AlN makes the MT layer tend to directly two-dimensional (2D) growth mode at the initial stage. In this study, it was found that high pressure was effective in lowering Ga adatom diffusion and promoting early three-dimensional (3D) growth, which resulted in reducing (102) X-ray full-width-at-half-maximum as well as edge dislocation density significantly. The lowest X-ray rocking curve full-width-at-half-maximum of (002) and (102) were 35 arcsec and 220 arcsec respectively, which were comparable with GaN layer grown on patterned sapphire substrate (PSS). High quality AlGaN/GaN heterojunction was achieved with sheet electron density of 1.18 × 10 13 c m − 2 , Hall mobility of 1909 c m 2 / V ⋅ s and sheet resistance of 336 Ω / □. Controlled growth interruption was carried out to study the evolution mechanism of MT layer growth. • The effect of initial condition on the performance of GaN film and AlGaN/GaN heterojunction was studied.. • A high quality GaN film with FWHM of (002)/(102) of 35/220 arcsec was grown on flat sapphire substrate with sputtered AlN. • A high quality AlGaN/GaN heterojunction with sheet electron density of 1.18 × 10 13 c m − 2 and Hall mobility of 1909 c m 2 / V ⋅ s was grown. [ABSTRACT FROM AUTHOR]

• We developed a framework that integrates sensitivity, uncertainty and parameter calibration. • Water stress parameters were more sensitive in severe drought than in full irrigation. • Times series measured data help MCMC iteration to get more reliable posterior distribution. • Interannual variation and severe water stress caused extra uncertainty of model residual error. • The framework improved the simulations under four irrigation scenarios in drought climate. Crop modeling is affected by parameter uncertainty. We proposed a framework that integrates sensitivity, uncertainty and parameter calibration of crop models, to provide prediction intervals in place of single values for decision-makers to reduce management risks in agriculture. The framework includes four steps: (1) set prior distributions of parameters and collect measured data, (2) use Morris screening to find out sensitive parameters, (3) adopt Metropolis-Hastings within Gibbs algorithm to calculate posterior distributions of the sensitive parameters and model residual errors, and (4) analyze uncertainties propagation and their applications. The framework was firstly applied on 27 parameters of AquaCrop (version 6.1) on maize in four irrigation scenarios in arid Northwest China, given 5 time series and summary variables including canopy cover (CC), aboveground biomass (B t), soil water content (SWC), daily evapotranspiration (ET) and final yield (Y) with 1458 measured data points of 27 irrigation treatment-year combinations from 2012 to 2015. The results showed that water stress parameters in AquaCrop were more sensitive in severe drought situations than in full irrigation conditions. The parameter uncertainty brought more variation to simulated final yield than simulated time series variables of maize in arid Northwest China. Model residual error was found to be the major contributor to overall prediction uncertainty, and interannual variation and severe water stress increased its contribution. Adding high-quality measured data of time series variables into MCMC iterations can make the estimated parameters more reliable and more biologically significant. Medians of outputs using the framework were generally closer to the corresponding measurements when compared with the results of using trial and error method. Especially for SWC and Y, Nash–Sutcliffe coefficient (EF) improved from 0.364 to 0.739 and from 0.055 to 0.415, respectively. The framework is straightforward to be applied to other crop models that can be run in batches. [ABSTRACT FROM AUTHOR]

• Hybrid ELM models (PSO-ELM, GA-ELM and ABC-ELM) were proposed for estimating ET 0 in different climate zones of China. • PSO-ELM model had the highest accuracy, followed by GA-ELM and ABC-ELM. • Hybrid ELM models outperformed standalone ELM and empirical models in different climate zones. • PSO-ELM model with T max , T min and RH obtained accurate ET 0 estimates in TCZ, SMZ and TMZ. • PSO-ELM model with only T max and T min was better performance on ET 0 estimates in MPZ. Accurate prediction of reference crop evapotranspiration (ET 0) is important for regional water resources management and optimal design of agricultural irrigation system. In this study, three hybrid models (PSO-ELM, GA-ELM and ABC-ELM) integrating the extreme learning machine model (ELM) with three biological heuristic algorithms, i.e., PSO, GA and ABC, were proposed for predicting daily ET 0 based on daily meteorological data from 2000 to 2019 at twelve representative stations in different climatic zones of China. The performances of the three hybrid ELM models were further compared with the standalone ELM model and three empirical models (Hargreaves, Priestley-Talor and Makkink models). The results showed that the hybrid ELM models (R 2 = 0.973–0.999) all performed better than the standalone ELM model (R 2 = 0.955–0.989) in four climatic regions in China. The estimation accuracy of the empirical models was relatively lower, with R2 of 0.822–0.887 and RMSE of 0.381–1.951 mm/d. The R 2 values of PSO-ELM, GA-ELM and ABC-ELM models were 0.993, 0.986 and 0.981 and the RMSE values were 0.266 mm/d, 0.306 mm/d and 0.404 mm/d, respectively, indicating that the PSO-ELM model had the best performance. When setting T max , T min and RH as the model inputs, the PSO-ELM model presented better performance in the temperate continental zone (TCZ), subtropical monsoon region (SMZ) and temperate monsoon zone (TMZ) climate zones, with R 2 of 0.892, 0866 and 0.870 and RMSE of 0.773 mm/d, 0.597 mm/d and 0.832 mm/d, respectively. The PSO-ELM model also performed in the mountain plateau region (MPZ) when only T max and T min data were available, with R2 of 0.808 and RMSE of 0.651 mm/d. All the three biological heuristic algorithms effectively improved the performance of the ELM model. Particularly, the PSO-ELM was recommended as a promising model realizing the high-precision estimation of daily ET 0 with fewer meteorological parameters in different climatic zones of China. [ABSTRACT FROM AUTHOR]

The aim of this study was to address the problems of water scarcity and low water and fertilizer use efficiency in vineyards in the Guanzhong Plain of Shaanxi, China. In the experiment, drip fertigation technology was used, including three irrigation levels (W3 (100% M, and M as the irrigation quota), W2 (75% M) and W1 (50% M)) and four fertilization levels (F3 (648 kg/hm2), F2 (486 kg/hm2), F1 (324 kg/hm2) and F0 (0 kg/hm2)). Traditional fertilization (CG) and a rainfed (CK) treatments were used as control treatments. Field experiments were conducted in Yangling, Shaanxi, China from 2019 to 2021 (wet years in 2019 and 2020, and dry years in 2021) to determine irrigation and fertilization intervals corresponding to higher crop yields and water and fertilizer utilization efficiency in different precipitation patterns. The results showed that, compared with the CK and CG treatments, the drip irrigation and fertilization treatment increased grape yield and significantly improved water productivity and fertilizer agronomic use efficiency. The highest grape yields were obtained in the F2 treatment under drip fertigation, and the highest grape yields were 16044 kg/hm2 and 12728 kg/hm2 in wet years and dry years obtained at W1F2 and W2F2, respectively. With the same fertilization level (F2), the grape yields of the W1, W2 and W3 treatments in wet years increased by 37.95%, 23.73% and 23.50% compared with those in dry years, respectively. The optimal irrigation and fertilization intervals determined by the response surface method were: the irrigation amount ranged from 8 to 11 mm and 32–38 mm, nitrogen application ranged from 182 to 190 kg/hm2 and 162–164 kg/hm2, phosphorus application ranged from 116 to 131 kg/hm2 and 98–100 kg/hm2, and potassium application ranged from 216 to 225 kg/hm2 and 194–201 kg/hm2 in wet years and dry years, respectively. This provides a guideline for the precision management of irrigation and fertilization of grape under different precipitation year types in Guanzhong Plain of Shaanxi Province. ● Drip fertigation increased grape yield, WUE and FAUE. ● The optimal drip fertigation strategy for highest yield, WUE and FAUE was derived in wet and dry years. ● Response surface methodology was used to determine optimal irrigation and fertilization in wet and dry years. [ABSTRACT FROM AUTHOR]

Climate change has led to extreme weather events and food security issues, which have become urgent global problems. Crop models and hydrological models play important roles in analyzing these issues, but crop models have limitations in large-scale simulations, and hydrological models have shortcomings in depicting underlying surface details. Jointly using the two models to complement each other's shortcomings is becoming an important method, playing an important role in improving the quantitative characterization ability of different facets of agricultural production and is crucial to improving the efficiency of water resources utilization. This paper reviews the development process of crop and hydrological models and summarizes the widely used models at present, providing reference for researchers to select crop and hydrological models; secondly, it summarizes the types, methods, and examples of joint use of models, and analyzes possible problems in model combination; finally, some suggestions are put forward for the joint use of crop and hydrological models, providing a reference for researchers to combine models. • Retrospect on the development process of crop and hydrological models. • Summarized case studies on the combination of crop and hydrological models. • Provide an overview of cases where crop and hydrological models are used in conjunction. • General considerations and suggestions for future development. [ABSTRACT FROM AUTHOR]