Accurate water measurement methods and technology in irrigation areas are important means to reduce invalid waste water in irrigation areas and ensure water safety in the irrigation area. Aiming at the methods and techniques of open channel water measurement in irrigation areas, this paper systematically expounds the research progress of four methods of hydraulic structure water measurement, special water measurement equipment water measurement, velocity-area method water measurement, and water level-flow method water measurement, summarizes and analyzes the applicable conditions and measurement accuracy of the four water measurement methods, and expounds the application of open channel water measurement methods in different scenarios. The results show that the water-measuring buildings equipped with water level sensors and other equipment provide convenience for data acquisition and transmission. Optimizing the structural characteristics of buildings can improve the scope of application and measurement accuracy of buildings, and promote the development of special water measuring equipment technology. The flow velocity-area method is often used to calibrate other water measurement methods because of its high measurement accuracy, but its operation is complicated and time-consuming, resulting in low flow measurement efficiency. With the maturity of ultrasonic technology, it can be used for the measurement of complex flow rates. The velocity distribution law is the basis of the velocity-area method for measuring water. The relationship between the point velocity and the average velocity of the section can be established by using the velocity distribution law, and then the section flow can be obtained by the point velocity. The water level-flow method is significantly affected by the section parameters and is only available for specific working conditions, so it is difficult to promote. The machine learning method is used to process a large number of historical data on the relationship between water level and flow, which provides a data processing method for water level prediction flow. Finally, the development prospect of non-contact water measurement technology and model algorithm for flow prediction is discussed. Combined with the current research foundation and actual demand, the future research direction is discussed to provide a valuable reference for further improving the accuracy of water measurement and reducing the cost of water measurement equipment.

Different physiological growth characteristics of crops exist in wind-sand areas, and the existing irrigation system lacks generality. A field experiment was conducted to examine the impact of drip irrigation water amount on soybean growth, dry matter accumulation, and yield in windy sandy soil by setting five irrigation levels of 0.4 (W1), 0.6 (W2), 0.8 (W3), 1.0 (W4), and 1.2 E _pan (W5) based on the evaporation of crop canopy evaporation dispersion. The results showed that soybean yield, dry matter accumulation, and plant height were all considerably decreased. The findings demonstrated that as irrigation water levels increased, plant height, stem thickness, chlorophyll, leaf area index, dry matter accumulation, and yield of soybean increased, and then decreased. The irrigation water level of 1.0 E _pan was found to be the most beneficial for soybean growth, and the highest yield and water use efficiency were obtained at the same time. When compared to conventional rainfed soybean, the soybean yield was 3.61 t·hm^-2 and the water use efficiency was 0.59 kg·m^-3, respectively, improvements of 97.3% and 96.7%. In conclusion, in locations with wind-sand soil, the suggested irrigation volume for soybean under film drip irrigation with water and fertilizer integration is 1.0 E _pan.

The application environment of the ultrasonic Doppler flowmeter is complex and variable, and the accurate extraction of the echo signal is crucial to improve its measurement accuracy and error. In order to better filter out the noise in the echo signal, a noise reduction model integrating variational mode decomposition (VMD) and singular spectrum analysis (SSA) is innovatively proposed. Firstly, this method uses the Cauchy variation operator (CV) to generate a random iteration process to overcome the seagull optimization algorithm (SOA) easy to fall into the local optimal solution problem; secondly, adopts the envelope spectrum entropy value as the fitness function, optimizes the VMD parameter combination to overcome the subjective problem, and introduces cloud similarity value as the criterion of the intrinsic mode functions (IMF) screening; Finally, for the medium and low-frequency oscillation phenomenon after transformer mode decomposition, SSA introduces secondary filtering to further improve the signal-to-noise ratio. The noise reduction effect of CVSOA-VMD-SSA is analyzed by analyzing ultrasonic simulation signals and experimental data examples and comparing them with wavelet threshold (WD) and empirical Mod decomposition (EMD). The results show that, for the simulation signals, The CVSOA-VMD-SSA can overcome the modal stacking and the SOA can easily fall into the local optimal solution problem, more effectively suppressing the noise interference as compared to the EMD-SSA, SOA-VMD-SSA, The signal to noise ratio is up to 30.78 dB, and the lowest RMS error is 0.01. For the automatic car-walking experiment, using a multiple-group signal statistical analysis, To determine a cloud similarity threshold of 0.6, And comparing the detection accuracy of different vehicle flow rates, CVSOA-VMD-SSA with minimal error, Range is in the 0.01~0.03 m/s, Provide theoretical support for practical engineering applications.

To explore the effects of different covering materials on the soil properties and fruit quality of citrus orchards in mountainous yellow soil areas, the "Eyuan 38" citrus was used as the research object to study the effects of four covering methods on the surface soil nutrients, enzyme activity, citrus yield, and fruit quality of citrus orchards, including white film (T1), black film (T2), horticultural cloth (T3), and corn straw (T4). The results showed that: Compared with CK, except for T4 treatment, which significantly increased the pH value of orchard soil, T1, T2, and T3 treatments significantly decreased the pH value of citrus orchard soil. The four mulching treatments all effectively increased the content of organic matter and available nutrients in the surface soil of the citrus orchard, among which the content of organic matter, alkali hydrolyzable nitrogen, available phosphorus, and available potassium in the T4 treatment significantly increased by 15.76%, 62.12%, 22.71%, and 44.28% compared to CK. The four mulching treatments all improved soil enzyme activities to a certain extent, and the activities of catalase, urease, sucrase, and acid phosphatase in T4 treatment significantly increased by 23.08%, 61.11%, 172.54%, and 72.73% compared to CK treatment. The four mulching treatments also effectively improved the quality of citrus fruit, significantly increasing the yield, weight per fruit, edible rate, juice percentage, soluble solids, and solid acid ratio by 6.89% ~ 14.22%, 8.84% ~ 15.51%, 2.51% ~ 4.47%, 3.12% ~ 7.59%, 4.60% ~ 10.73%, and 11.39% ~ 25.65%, respectively, compared to CK. The content of vitamin C in T4 treatment was the highest, significantly increasing by 23.33% compared to CK, while the content of titratable acid in T4 treatment significantly decreased by 11.11% compared to CK. The correlation analysis results indicate that organic matter, alkali hydrolyzed nitrogen, and available potassium content are the main influencing factors on citrus yield and fruit quality. In summary, continuous coverage can effectively improve the soil fertility of citrus orchards, improve the level of soil nutrient supply, stimulate soil enzyme activity, and improve the quality of citrus. Corn straw mulching has the best effect.

In order to explore the effect of long irrigation intervals on the economic benefits of daylily in the Hongsibao Yanghuang Irrigation Area in Ningxia, different irrigation methods Conventional irrigation CK, Single tube and single row D1, Double pipe, and single row D2, Surface infiltration irrigation S1, and Underground infiltration irrigation S2 were used in this paper. The growth index, yield, water use efficiency, and soil moisture variation of perennial daylily were studied. The results showed that under different irrigation methods, the change of soil moisture in the vertical direction of daylily was mainly within 0~60 cm, the soil moisture content of each treatment gradually decreased with the increase of depth, and the soil moisture content of each treatment in the horizontal direction was at 20~40 cm. The relative content of chlorophyll in leaves gradually increased with the change of the growth period of daylily in each treatment, and the relative content of chlorophyll and nitrogen in leaves of CK and other treatments were significantly different (P<0.05); S2 treatment had the highest plant height in each growth period, there was a significant difference with other treatments (P<0.05), D2 treatment had the largest diameter of 4.59 mm, and had no significant difference with CK, D2, and S1 treatments (P>0.05); CK treatment was a conventional irrigation method, with the largest water consumption of 402.01 mm. mm, the longest flower bud, the heaviest single flower bud weight, and the highest yield were 11.86 cm, 4.38 g, and 15 446 kg/hm² in the S2 treatment, which was significantly different from other treatments (P<0.05); the S1 treatment had the highest water use efficiency of 4.66 kg/m³, with no significant difference between S2 and D2 treatments (P>0.05). To sum up, in the arid area of Ningxia, the buried depth of the underground infiltration irrigation pipe is 10 cm, the irrigation quota is 2 475 m³/hm², the weight of each flower bud is 4.38 g, the yield of daylily is 15 446 kg/hm², and the water utilization rate is 4.38 g. The higher water use efficiency i is 4.45 kg/m³, which helps to improve the yield and water use efficiency of daylily and can achieve high-efficiency production of daylily.

Based on the theory of organization support, this paper uses 702 micro-survey data of farmers in Shaanxi and Shanxi provinces to explore the influence and mechanism of organization participation on farmers' willingness to pay for water-saving irrigation technology. The study found that organization participation has a significant effect on farmers' willingness to pay for water-saving irrigation technology, which is mainly achieved by improving farmers' sense of institutional support, tool support, and emotional support. Heterogeneity analysis found that: ①organization participation has a stronger incentive effect on households with higher per capita income and education level; ②There is no significant difference between different types of organizations in promoting farmers' willingness to pay. Finally, the contractual relationship has a two-way promoting effect on farmers' technical willingness to pay and organizations to provide stronger support. Therefore, it is recommended that relevant departments increase the number of beneficial agricultural organizations and encourage contractual cooperative relationships, in order to stimulate the potential demand of farmers for water-saving irrigation technology and assist in the popularization and promotion of water-saving irrigation technology.

To study the effect of layered soil on water and salt transport and vegetation growth, and further understand the effective utilization of plant water, based on the water and salt transport test of indoor one-dimensional soil column with layer (loam in the upper layer and river sand in the lower layer) under the condition of plant growth, the Layered soil water solute transport and crop growth model ( Layered soil water solute transport and crop growth model, LAWSTAC)developed by the research group was used for the corresponding simulation and analysis. The results show that:①The LAWSTAC model can well simulate the water and salt migration of homogeneous loam during infiltration, and relevant parameters of the model can be directly used in the model of the layered soil column. ②The LAWSTAC model can well simulate the water and salt migration in the fine-upper and coarser layered soil under infiltration conditions. However, for the evaporation process, due to the error in the selection of the parameters of the lower river sand, or the poor applicability of the current water and salt migration theory in the layered soil with preferential flow, the simulation effect of the evaporation process is not good. ③Covering fine soil with coarse soil can effectively reduce evaporation and transpiration, the upper coarse soil can inhibit water movement and salt migration. The evaporation and water loss of the upper coarse-lower fine layered soil is mainly from the upper coarse-grained soil, The evaporation and water loss of the upper fine layer soil and the lower coarse layer soil mainly came from the lower coarse soil, And the cumulative evaporation is much larger than that of the upper coarse and lower fine layered soil. As a result, the LAWSTAC model can provide data support for the study of salinization control and efficient utilization of irrigation water in farmland with large differences in soil texture in nature.

Since the 21st century, the intercepting sewer system had been widely used in the water pollution control of urban rivers and lakes in China. Influenced by the shortage of urban land resources, there are also a large number of non-standard overflow devices. On the one hand, the outflow efficiency of overflow devices and their impacts on rainwater drainage have not received enough attention. On the other hand, the lack of urban hydrological monitoring facilities also brings technical difficulties to the quantification of these impacts. Taking the Qingshanhu overflow device of Nanchang City as a case, the physical model and numerical model of the non-standard thin-plate weir are constructed, the flow regime and flow efficiency of the overflow weir are analyzed, and a feasible reconstruction scheme is proposed for the existing problems. The results indicate that: ①The outflow efficiency of the original device is low, and the overall overflow capacity is weak under the free-flow condition. The discharge coefficient of this weir is 0.301, 28% lower than that of a standard thin-plate weir under the same condition (0.418). The phenomena such as “vortex”, “drift away the wall” and “air cavity at the top” are more serious, and the problem with the flow regime is more prominent inside the original device. ②After the scheme of "replacing weir with sluice" is adopted, the flow of Scheme A and Scheme B is 24% and 19% higher than that of the original scheme, which improves the discharge capacity, and the unit width flow is 719% and 683% higher under the free-flow condition. Similarly, after the scheme of "combining sluice and weir" is adopted, the convenience of drainage management is retained while the discharge capacity is improved. The physical model and CFD numerical simulation methods are both adopted in this paper, which can not only solve the difficulty in calibrating and verifying the numerical model of urban overflow weir but also complete the problem diagnosis of overflow weir and the comparison and selection of reconstruction schemes in numerical simulation experiments, which provides a new idea for the construction and renovation of urban drainage system.

There are difficulties in the current water and fertilizer system, such as poor adaptive ability, nonlinearity, time-varying, lag and low automation level. To solve the problems of precision fertilization and waste of water resources in traditional water and fertilizer irrigation, this study designed an intelligent water and fertilizer remote control system, which is suitable for facility agriculture. In the system, fuzzy PID was optimized based on the Whale Optimization Algorithm (WOA), which controls the opening of local electric ball valves and then precisely controls the electrical conductivity (EC) of water and fertilizer solution, realizing remote control of the electrical conductivity in the setting range. MATLAB/Simulink was used to simulate PID, fuzzy PID and WOA-optimized fuzzy PID control system. The results showed that the overshoot of the system was only 2.7% of the PID control, the adjustment time decreased by 86.5%, and the steady-state error increased by 99.8%, compared to the traditional PID control model. This study has achieved real-time monitoring of sensor data by the intelligent terminal and the remote precise control of EC value of water and fertilizer solution by intelligent algorithms, which is important to practical application.

Subsurface irrigation with ceramic emitter (SICE) is a new type of subsurface water-saving irrigation technology. It can use the micron pores inside the ceramic emitter to achieve a continuous micro-supply of water and fertilizer and create a safe, stable, and suitable soil moisture environment for the crop root zone by continuous subsurface irrigation. Different from the water and nitrogen co-application method based on intermittent irrigation, the soil water and nitrogen transport and loss characteristics of SICE are still unclear. which limits the application of SICE in practice. Therefore, in this study, HYDRUS-2D was used to establish a soil water and nitrogen combined transport model under SICE continuous micro-supply, and a field experiment of irrigating wolfberry with SICE was carried out in Qinghai, China, to calibrate and verify the accuracy of the model. Finally, subsurface drip irrigation (CK) was used as a control to study the soil water and nitrogen transport and loss characteristics of SICE under three nitrogen fertilizer concentrations (211.54 mg/L, 169.23 mg/L, 126.92 mg/L). The results showed that the combined transport model of soil water and nitrogen performed well in predicting soil water and nitrogen. Compared with CK, SICE slowed down the rate of nitrogen fertilizer entering the soil, prolonged the effective supply time of water and nutrients (from 6.67 h to 480.00 h), reduced the time fluctuation of water, ammonium nitrogen (NH₄ ⁺-N) and nitrate nitrogen (NO₃ ^--N) in the root layer soil, ensured the relative abundance of soil water and nitrogen, and maintained the relative stability of soil water and nitrogen environment, which provided an effective guarantee for the efficient utilization of water and nitrogen in wolfberry. Secondly, during the continuous micro-supply period of nitrogen fertilizer solution, SICE maintained soil moisture, NH₄ ⁺-N and NO₃ ^--N at the soil depth where the root density of wolfberry was the highest, which fully ensured the high matching of root, water, and fertilizer. In addition, SICE was significantly better than CK in reducing deep leakage and nitrogen leaching loss, which could save more water and nitrogen in the wolfberry's root layer, increase nitrogen availability and reduce the risk of nitrate contamination of groundwater.

Water Saving Management Contract (WSMC) is an important water conservation measure, and the benefit-sharing contract is an important type of WSMC project. But there is a lack of theoretical analysis on the range of contract parameters such as benefit-sharing period, water-saving investment, and water-saving volume, which restricts the effective implementation of WSMC projects. We use engineering economics to construct the benefit net present value function for water users and water conservation service companies and propose a suitable analysis method for the range of benefit sharing period, water saving investment, and water saving volume based on the goal that both water users and water conservation service companies can obtain the expected benefits. Based on two university WSMC cases, the method was validated, and the sensitivity of water users' and companies' benefits to the discount rate, expect cost margins, and benefit-sharing period was analyzed. Results show that the method is effective in evaluating the reasonableness of WSMC projects, and expect cost margin is the most important variable affecting the benefits of WSMC. Frameworks for the bidding and evaluation of WSMC projects are proposed. The study can provide a reference for the bidding and evaluation of benefit-sharing WSMC projects.

In order to study the rule of water utilization and nitrogen and phosphorus loss in paddy fields under different irrigation modes, and to integrate water-saving irrigation and pollution reduction technology reasonably, to realize the unity of high yield, water saving and pollution reduction, a plot experiment was carried out in agricultural drainage and irrigation technology demonstration base in Pinghu City. Four irrigation modes were set up in the experiment, namely conventional irrigation, thin dew irrigation, improved rain storage thin dew irrigation, and trench and furrow irrigation suitable for rain irrigation. The irrigation and drainage quantity in the field and the indexes of TN, TP, NH₄ ⁺-N, NO₃ ^--N, and COD in drainage and seepage water were measured. The results showed that the irrigation quantity of thin dew irrigation improved thin dew irrigation, and furrow and furrow irrigation with rain reduced by 38.6%, 73.4%, and 91.4% compared with conventional irrigation, respectively. Compared with conventional irrigation, thin dew irrigation reduces the load of TN, NO₃ ^--N, NH₄ ⁺-N, TP, and COD by 25.1%, 6.2%, 64.3%, -29.7%, and 7.5%, while improved rain thin dew irrigation reduces 72.5%, 72.4%, 77.2%, 69.9%, and 69.4%. Rain irrigation in furrow and furrow decreased by 79.9%, 74.6%, 89.9%, 81.8%, and 81.1%. In general, furrow and furrow suitable for rain irrigation has the best effect on water saving and pollution reduction.

The research of water resources carrying capacity is significant in the study of regional socio-economic sustainable development, and has received considerable attention in recent years. This paper constructed the index evaluation system of water resources carrying capacity and evaluated the water resources carrying capacity of Jiuquan by combining with AHP or variation coefficient method. The results showed that: The carrying capacity of water resources in Jiuquan was evaluated as grade II by AHP from 2010 to 2021, which indicated slight overload. The variation coefficient method showed that the water resources carrying capacity of Jiuquan fluctuated between grades II and III from 2010 to 2017. After 2018, the water resources carrying capacity has changed to grade III, which means approaching overload. The comprehensive analysis believed that the evaluation results of the variation coefficient method were more in line with the actual situation of Jiuquan.

To explore the effects of different irrigation methods on the soil respiration of plantation in the semi-arid area, the soil respiration rate of three irrigation methods was measured using a LI-8100 soil carbon flux measurement system in platycladus orientalis plantation, and to analyze the characteristics of soil respiration and its response mechanism to temperature and water. The results showed that the diurnal variation of soil respiration rate in the three irrigation methods showed a unimodal variation of first increase and then decrease, and the daily average value in different months showed the order of flood irrigation (2.07 μmol/(m²?s))>hole irrigation (1.65 μmol/(m²?s))>sprinkler irrigation (1.36 μmol/(m²?s)), soil respiration in sprinkler irrigation forestland showed a significant(p<0.01) positive correlation with surface temperature and 5 cm soil temperature and 10 cm soil moisture. The temperature sensitivity coefficient Q ₁₀ was between 1.54 and 2.34, and the sensitivity of soil respiration rate to temperature in sprinkler-irrigated woodland was higher than that of the other two irrigation methods. The research results can provide a reference for regulating soil carbon emissions and selecting appropriate irrigation methods for plantations in semi-arid areas.

In order to define the effects of ridge shape and irrigation amount on the agronomical appearance, water and fertilizer nutrients utilization of flue-cured tobacco during the root extending stage, a field experiment was carried out to study the effects of five kinds of ridge shape (pond ridge, groove ridge, dish ridge, trapezium ridge, and arch ridge) and three irrigation amount (0.5 L/plant per event, 1.0 L/plant per event and 1.5 L/plant per event) on the growth, water use efficiency and N, P, K accumulation of flue-cured tobacco during the root extending stage, in 2022. The results showed that an extremely significant effect of the ridge shape and irrigation amount was examined on the agronomical appearance, biomass of plant parts, water use efficiency and N, P, K accumulation (P＜0.01), and the interaction effect of the two factors were also extremely significant (P＜0.01). The effect of the ridge shape on the agronomical appearance, water, and fertilizer nutrients utilization was varied with irrigation amount, namely the pond ridge was observed the best performance of agronomy, water, and fertilizer nutrients utilization when irrigated with 0.5 L/plant per event, while the dish ridge was examined the best performance of those indexes when irrigated with 1.0 L/plant and 1.5 L/plant per event. extremely significant positive correlation ship was observed between the main agronomical appearance, biomass of plant parts, N, P, K accumulation, and irrigation amount, respectively (P＜0.01). Among the treatments arranged in this study, dish ridge with 1.5 L/plant per event obtained the best performance of agronomy, water and fertilizer nutrients utilization. The pond ridge could significantly improve water use efficiency on the condition of limited irrigation water, which is an important cultivation method help to mitigate the staged drought stress in the tobacco area of southwest China. Meanwhile, the dish ridge is conducive to the growth of tobacco, water, and fertilizer nutrients utilization during the root extending stage on the condition of enough irrigation water, which provides a feasible reference to the choice of ridge shape when irrigation water is guaranteed.

The different arrangements of transducers will lead to uneven distribution of flow velocity on the same channel, which will affect the flow measurement accuracy of the ultrasonic flowmeter. To solve this problem, based on the velocity-area method, this paper sets two installation forms of transducer V-type and Z-type on the rectangular channel through the combination of measurement and simulation and analyzes the flow measurement accuracy of the transducer installation angle of 30°~60°(gradient of 5°) ultrasonic flowmeter. The experimental results show that the relative error value of the flow rate is-0.06 when the installation angle of the transducer V-type arrangement is 40°~ 45°, and the relative error value of the flow rate is-0.09 when the installation angle of the Z-type arrangement is 40°~45°. The error value is reduced by 0.03, and the transducer V-type arrangement has higher flow measurement accuracy. The three-dimensional model of the rectangular channel is established, and the flow pattern and velocity distribution of the channel under different working conditions are simulated by CFD. The simulation results show that when the installation angle of the transducer is 60 °, a vortex with a diameter of 5.6 cm is generated. When the installation angle is 30 °, the distance from the inlet to the uniform distribution of the flow velocity is 0.5 m. When the installation angle is 45 °, the distance from the inlet to the uniform distribution of the flow velocity is 0.3m, and a vortex with a diameter of 3 cm is generated. When the installation angle of the transducer is 45 °, the flow velocity in the flow measurement section is symmetrical and evenly distributed, which has little effect on the eddy current and flow velocity distribution.

The rectangular side weir, as a kind of water-measuring device, is simple in shape, cost inexpensive, installed and removed easily while with high precision. It can be used for water measuring of the small channel and field inlet. Experiments are taken on different heights of rectangular side weirs under different discharges in rectangular channel. Water profiles near rectangular side weirs were obtained. Backwater height and head loss were analyzed. We obtained the discharge formulae with a simple form yet with high accuracy. The results show that water-surface waves on the wall near the side weir, the centerline, and the wall in the main channel differ. The backwater height and head loss increase with the increase of weir height. The absolute value of maximum relative error and the mean relative error are respectively 4.98% and 4.27%, meeting relevant standards and the accuracy of flow measurement in the irrigation district.