Reference crop evapotranspiration is an important part of energy balance and water cycle. Clarifying the evolution characteristics and causes of reference crop evapotranspiration in Jilin Province is helpful to understand the impact of climate change on hydrological cycle and scientific irrigation. Based on daily meteorological data from 28 meteorological stations in Jilin Province from 1970 to 2019, Penman-Monteith method and detrend analysis method were used to explore the characteristics of evapotranspiration and quantify the driving effects of meteorological factors on its annual and seasonal variations. The results showed that : In the past 50 years, the annual average reference crop evapotranspiration in Jilin Province showed an insignificant increasing trend. In the four seasons, the evapotranspiration decreased in summer, and increased in other seasons. In the past 50 years, the difference of meteorological factors in Jilin Province was obvious. The annual and seasonal average temperature and water vapor pressure difference increased, and the wind speed and sunshine hours decreased. The variation of wind speed and water vapor pressure difference was significantly greater than that of temperature and sunshine hours. The annual average evapotranspiration change in Jilin Province was dominated by water vapor pressure difference and wind speed, and the positive contribution of each factor slightly exceeded the negative contribution, which made the annual average evapotranspiration show a weak increase trend. The evolution of average evapotranspiration in spring was mainly driven by water vapor pressure difference and wind speed. The average evapotranspiration in summer was driven by water vapor pressure difference, wind speed and sunshine hours. The evolution of average evapotranspiration in autumn and winter was driven by water vapor pressure difference and wind speed. Spatially, the change of annual evapotranspiration in the western region was mainly driven by wind speed, while the central and eastern regions were driven by the change of water vapor pressure difference. The change of spring evapotranspiration in western Jilin Province was mainly driven by the negative contribution of wind speed decrease, while the spring evapotranspiration in central and eastern Jilin Province was dominated by the positive contribution of water vapor pressure difference increase. The summer average evapotranspiration in the western and central regions was mainly driven by the negative contribution of sunshine hours, while the eastern region was mainly driven by the positive contribution of water vapor pressure difference. The variation of evapotranspiration in autumn and winter in the western and central regions was mainly affected by wind speed, while the eastern region was mainly driven by the change of water vapor pressure difference.

Cantilever multistage centrifugal pumps are widely used in various fields of national economy, and their vibration-related studies are important in view of their unique structural forms. In this paper, the method of numerical simulation was used to analyze the response performance of cantilever multistage centrifugal pump under "dry state". It is found that the vibration amplitude of the pump body increases with the increase of the unbalance torque, especially, the instability mutation of the radial displacement is obvious within 2.6~3.0 s after the pump starts. Based on SAMCEF harmonic response analysis, it is found that the second-order vibration type is torsional coupling vibration, and the response amplitude of the first-stage impeller at the second-order critical speed is influenced by the phase change of unbalance mass. When the unbalance mass phase of the first stage impeller is 180°, the first order acceleration and displacement amplitude of the nut and the first stage impeller reach the minimum. Therefore, by improving the machining accuracy of the parts to reduce the unbalanced moment of the parts and staggering the phase of the unbalanced mass of the impellers at all stages, the radial vibration of the rotor can be reduced, thus improving the operation stability of the cantilever centrifugal pump.

This paper explored the regional differentiation and influencing factors of the green efficiency of agricultural water resources to provide reference for decision-making of sustainable utilization of agricultural water and promote green transformation in agriculture. The SE-SBM model was used to reveal agricultural water green efficiency level from 2006 to 2020, on the basis of which Dagum Gini coefficient was applied to investigate the regional differences among the three major basins of the Songhua River, the Yangtze River and the Yellow River, and the comprehensive feasible generalized least squares method was used for analysis of its influencing factors. It can be indicated that the overall green efficiency of agricultural water in major grain producing areas presents a fluctuating downward trend with a multi-year average value of 0.922, and distinct heterogeneity characteristics exist in different basins. There is an apparent spatial disequilibrium of agricultural water resources green efficiency in major grain producing areas, the contribution rate of regional disparity shows hypervariable density (47.760%) > intra-regional differences (32.097%) > inter-regional differences (20.043%), and the hypervariable density is the main source of the overall variance. The green efficiency of agricultural water is influenced by a combination of factors, among which water resources with endowment, economic development level and agriculture opening to the outside world have significant positive effects on the green efficiency of agricultural water, while industrial structure, fiscal support for agriculture and effective irrigation level have remarkable negative effects. Basins in major grain producing areas should adopt the context-specific policies according to its resource endowment and production conditions, explore the green and efficient use of agricultural water path, and promote the coordinated development of agricultural water green efficiency.

The karst is characterized by discontinuous soils and common rocky exposures, with a variety of types of farmland. In order to study the effect of straw mulching on the characteristics of rainfall runoff in different types of karst slope farmland, the characteristics of surface runoff and subsurface runoff in three typical slope farmland types of bare slope land (BS), rock exposure type (RE) and rock fragment type (RF) under four straw mulching degrees (0, 20%, 50%, 80%) were studied through field artificial simulated rainfall test. The results showed that: ①In the three types of karst slope farmland, the average surface runoff of RE was significantly higher than that of other types, which was 1.8 and 7.8 times of that of BS and RF, respectively. At the same time, the average subsurface flow coefficient of RF was significantly lower than that of other types, which was 83.7% and 78.9% lower than that of BS and RE, respectively. ②The flow reduction effect of straw mulching in BS and RE was better than that of RF. The flow reduction effect of 20% coverage in BS was the best, which was 26.2% lower than that of no coverage. The flow reduction effect of 50 % coverage in RE was the best, which was 44.5% lower than that of no coverage. ③The effect of straw mulch on the subsurface runoff was more complex. Straw mulching increased subsurface runoff in RF, but straw mulching decreased subsurface runoff in BS, and there was no obvious rule for straw mulching on the effect of subsurface flow in RE. The results can provide a reference for the reasonable arrangement of soil and water conservation measures in karst slope farmland.

Water status directly determines the yield and quality of greenhouse crops. It is a hot topic to reflect the water stress status according to the phenotypic changes of crops. Crop phenotypic parameters comprehensively consider the cumulative effect of water stress caused by soil (or matrix) water reduction and evapotranspiration demand. Based on this, the level of crop water stress can be judged more accurately, and then provide a relevant basis for precise irrigation. In this paper, the research status of greenhouse precision irrigation strategy based on crop phenotype (stem diameter change, stem flow, canopy temperature) at home and abroad were analyzed and summarized. Relevant studies showed that the three diagnostic indicators of stem diameter change, stem flow, and canopy temperature could reflect the water status of plants, but the crop phenotype was greatly affected by environmental factors. Generally, the influence of environmental factors on crop phenotype or the comprehensive analysis and modeling of external factors such as environmental factors should be excluded, and the crop water requirement model based on crop phenotype-environmental factors should be established to guide irrigation；At the same time, it is pointed out that there are still some problems in domestic irrigation based on crop phenotype, such as imperfect basic theory, unadvanced technology research and development, and inaccurate equipment monitoring. The future development direction of irrigation strategy based on crop phenotype is prospected. In the future, the domestic greenhouse irrigation field needs to strengthen the basic theoretical research of crop phenotype and irrigation, actively explore new technologies, develop new equipment, and improve the level of greenhouse environment control. This paper can provide a reference for promoting relevant research in this field and realizing precision irrigation for greenhouse crops.

In this paper, the effects of common construction waste in soil on water consumption and water use efficiency of plants were studied to provide a theoretical reference for the management of greening plants and soil water in urban area. In the pot experiment, three types of construction waste-brick, concrete fragment and pebble-were selected. The two contents of construction wastes were 20% and 40% in volume. After a mixture of soil and construction waste, the typical greening plant (Euonymus japonicus Thunb.) was planted, and the soil without construction waste was taken as the control treatment. The mass water content of soil, construction waste, and construction waste-soil mixture was regularly measured. According to the change of water content, the water consumption of plants was obtained. The water use efficiency of plants was calculated by combining with plant biomass. The results showed that: compared with the control treatment, the total water consumption of 20% brick-soil mixture, 40% brick-soil mixture, 20% concrete fragment-soil mixture, 40% concrete fragment-soil mixture, 20% pebble-soil mixture and 40% pebble-soil mixture during the research decreased by 25.8%, 28.8%, 23.0%, 34.4%, 21.8% and 37.7%, respectively. The time when the water content of construction waste began to decrease lagged behind that of soil during the period when plants consumed water. Construction waste had the effect of alleviating drought, and brick was better than concrete fragment and pebbles. The mixture of soil and construction waste had the effect of improving plant water use efficiency. The water use efficiency of plants in high-content treatments of brick and concrete fragment was 32.8% and 24.3% higher than that of the control treatment. In conclusion, the mixing of construction waste with soil reduced the water content of the soil, inhibited the water consumption of the plant and improved the water use efficiency of the plant. It can be seen that construction waste effectively alleviates soil drought, which is of great significance to the efficient use of soil water in urban areas.

Rain and heat synchronization provides sufficient water and heat resources for agricultural production in most areas of China, but it is still to be further studied to evaluate the change characteristics of crop growth and precipitation process matching degree from the perspective of water demand mechanism. Based on AquaCrop model, this study simulated the changes of crop water demand, irrigation water requirement, effective precipitation and yield of summer maize during 1978-2017 in Guanzhong Area, and analyzed the changes of crop water demand and precipitation matching degree on the basis of fully considering the difference in water demand at different growth stages of maize. The results showed that the changes of cumulative precipitation during maize growth period in Guanzhong Area was relatively small, but the precipitation process shifted significantly backward, and most of them occurred in the form of heavy rainfall; During the growth period of maize, both water requirement and irrigation water requirement showed significant increase trends, which increased by 4.1 mm/10a and 13.38 mm/10a, respectively. While the effective rainfall decreased at a rate of -10.28 mm/10a; the average matching degree of water demand and precipitation during maize growth period was 58%, and the overall rate decreased at -2.7%/10a; The above results show that the change of precipitation pattern in Guanzhong Area is becoming more and more difficult to meet the water demand process of summer maize, and delaying sowing can be used as one of the countermeasures to improve the matching between crop water demand and precipitation.

The investment efficiency issue of China's increasing investment in farmland water conservancy cannot be ignored. A combination of EBM and GML was used to measure the total factor productivity (TFP) of China's farmland water conservancy investment based on non-expected output, and the Dagum Gini coefficient method was used to investigate the source of regional differences. The results show that: the average annual growth rate of TFP in China's farmland water conservancy investment is 3.60%, showing a "two-wheel drive" characteristic; the growth rate is relatively fast in the northeast and eastern regions, while the growth rate is relatively slow in the central and western regions; the regional differences are fluctuating, mainly contributed by the hypervariable density; the spatial and temporal shifts are influenced by spatial factors, making it difficult to form a "rank lock". Accordingly, it is recommended that: focusing on water resources investment and water resources efficiency in the central and western regions, strengthening the synergy of investment in farmland water resources in neighboring provinces, promoting the process of market-oriented operation of farmland water resources investment, and stimulating local conditions to make good use of their own water resources advantages.

Nitrogen loss has become an important problem to be solved in the restoration and treatment of rocky desertification areas. Taking wheat straw as additive and soil in typical rocky desertification area as test soil, the infiltration test of water and fertilizer was carried out to explore the migration law and distribution characteristics of soil water and nitrogen in rocky desertification area under irrigation and fertilization. The results showed that: ①In one-dimensional water infiltration test, straw mixing hindered the infiltration of soil water in rocky desertification area. Compared with the control group, the cumulative infiltration of the treatment group was reduced by 5.07% to 59.32%. The cumulative infiltration and the migration distance of the wetting front were inversely proportional to the amount of straw applied, and the straw length varied irregularity between levels. ② The infiltration process was in line with Philip's infiltration model, and the fitting coefficients were all above 0.99. The response of the imbibition rate S to the applied dose was that it was higher than CK at the applied dose level of 0.7%, and then with the increase of the applied dose, the imbibition rate decreased, among which the lowest decreased by 31.11% and the highest decreased by 48.92% compared with the control group. The influence of straw length on imbibition rate was more significant at the level of 3cm length, which was reduced by 47.21% compared with the control group, which was the lowest value among all treatments. ③The nitrate nitrogen content in each soil layer was high in the range of 0~5cm, and then decreased gradually with the migration of the wet front. However, the increase of straw application increased the nitrate nitrogen content in the lower part of the wet soil at the length of 1cm, 2cm and 3cm, and the maximum increase was 44.7% compared with the control group. Different from the above law, under the straw powder level, the nitrate nitrogen content decreased with the increase of the applied amount, and the maximum reduction of A3 was 47.55mg/kg compared with A1. Under the same applied amount level, the nitrate nitrogen distribution under the straw length treatment of 2cm and 3cm was higher than that under the treatment of 1cm. In summary, for the shallow soil layer of rocky desertification, straw mixing slows down the trend of nitrate nitrogen infiltration with water, so that nitrate nitrogen can accumulate in the upper part of the wet front during the migration of fertilizer liquid, which has a positive effect on the restoration and treatment of shallow soil layer in rocky desertification area.

The objective of the study was to establish water-saving irrigation system and propose a standard of irrigation for summer maize in North China Plain. The effects of effective precipitation in maize growth duration on the yield-increasing efficiency of supplementary irrigation at 12^th leaf stage were studied. The experiment was carried out with split plot design, the main plots were assigned with limited water (W1) and suitable water (W2), and the sub-plots were assigned with nitrogen application rate of 0, 60, 120, 180, 240 and 300 kg N/hm², respectively. The results showed that the nitrogen application rate significantly affected the yield-increasing ratio of supplementary irrigation at the 12^th leaf stage. The soil total N and organic matter content of treatments for 0 and 60 kg/hm² declined gradually from the second and fourth years respectively, and no positive effect of W2 on yield was observed in most years. When the nitrogen application rate was ≥120 kg/hm², the soil nutrient content increased or basically maintained a balance, and the yield-increasing efficiency of supplementary irrigation was large. The yield-increasing effect of supplementary irrigation at the 12^th leaf stage was influenced by the effective precipitation from sowing to 12^th leaf stage. When the effective precipitation from sowing to 12^th leaf stage was ≥136 mm, irrigation once before sowing could maintain a high yield level. When the effective precipitation was ＜136 mm, supplementary irrigation at the 12^th leaf stage could increase grain number per ear and 1000-grain weight, and the yield increasing effect was significant. In conclusion, under the condition of irrigation at pre-sowing, the effective precipitation from sowing to 12^th leaf might be considered as an important criterion to determine the necessity of supplementary irrigation at the 12^th leaf stage of summer maize in North China Plain.

Efficient utilization of water resources is the key for high-quality agricultural development. In this paper, entropy weight TOPSIS method was used to construct a comprehensive evaluation index system of high-quality agricultural development to measure the level of high-quality agricultural development in nine provinces of the Yellow River Basin. Based on the Tapio elastic decoupling model, the decoupling index of high-quality agricultural development and agricultural water footprint was obtained. The decoupling drivers were decomposed by LMDI model. The results showed that: ①From the perspective of time, the state of decoupling between agricultural water footprint and agricultural high-quality development in the Yellow River Basin changed steadily, and there was a strong trend on the whole; From the perspective of space, there were obvious differences in the decoupling status of different provinces and regions. The decoupling status was roughly "low in the middle southwest and high in the east". ②Technology effect decoupling factor is a negative driving factor, which inhibits the decoupling change; the decoupling factor of scale economy and the driving factor of population size are positive driving factors, which promote the decoupling change on the whole. Therefore, it is necessary to promote water-saving technology, adjust the layout of agricultural water use, define the optimal agricultural scale, and divide functional regions and other policies to promote the high-quality development of agriculture in the Yellow River Basin.

In arid and semi-arid areas, water-saving irrigation is an important measure to increase crop yield. In order to provide theoretical basis for the application of soil seepage control measures in water saving irrigation, in this paper, the infiltration redistribution, evapotranspiration, crop root growth, yield and water use efficiency of irrigation water during winter wheat growth period under two anti-seepage measures were studied by using a large-scale weighing lysimeter. The results showed that during the growth period of winter wheat, the mean soil water storage above the impervious layer (0~40 cm) was significantly increased by soil compaction (C) and film treatment (P), which were 6.8% and 10.0% higher than that of the control group (CK), respectively. The proportion of transpiration (T) in evapotranspiration (ET) was significantly increased to promote the absorption and utilization of irrigation water by crops. The root biomass of 0~100 cm in C and P treatments increased by 10.4% and 28.0%, respectively. The yield of C and P treatments was 5.4% and 18.3% higher than that of CK treatment, and the WUE was 0.94% and 3.19% higher than that of CK treatment, respectively. Considering the environmental factors, soil compaction treatment is more suitable for dryland agricultural production in northwest China.

The precipitation in Hetao irrigation district (HID) is scarce, the temperature difference between day and night is large, and the low temperature in early spring affects the growth of spring maize. In this study, different combinations of mulching and irrigation were used as research objects to explore suitable mulching farming modes for moisture retention and warming, quality and efficiency, so as to provide theoretical guidance and technical support for the efficient utilization of hydrothermal resources in HID. Four treatments were tested: irrigation + no mulching (CK), irrigation + transparent plastic film mulching (QB), ridge mulched with plastic film-furrow irrigation + transparent plastic film mulching (GB), ridge mulched with plastic film-furrow irrigation + black plastic film mulching(GH), in order to explore the soil moisture content and soil temperature variation law, spring maize yield and water and heat resource utilization efficiency of spring maize field under different mulching irrigation methods. The results showed that ridge mulched with plastic film-furrow irrigation could improve the water content of topsoil and the water storage in the root zone. 61 days after sowing, the soil water storage in the root zone treated with GH, GB and QB increased by 36.01%, 36.61% and 21.37%, respectively, compared with CK, and the ridge mulched with plastic film-furrow irrigation was significantly higher than that of mulching furrow irrigation. 133 days after planting, the soil water storage in GH root zone increased by 19.02% and 17.40% compared with CK and QB. Ridge mulched with plastic film-furrow irrigation effectively increased the average daily soil temperature, and the average daily soil temperature during the GB growth period increased by 1.01 °C and 1.59 °C compared with QB and CK, and the GH increased by 0.86 °C and 1.44 °C compared with QB and CK. The effective accumulated soil temperature of ridge mulched with plastic film-furrow irrigation was significantly higher than that of furrow irrigation, and GB was increased by 7.78% and 16.70% compared with QB and CK, GH was increased by 6.26% and 14.46% compared with QB and CK. The yield of spring maize showed the same significant difference as that of 100-grain weight, among which QB increased by 16.19% compared with CK, GB increased by 13.64% compared with QB, and increased by 32.04% compared with CK. The water use efficiency (WUE) and soil effective accumulated temperature production efficiency (TUE) of GB treatment increased by 25.79% and 5.41% compared with QB, and 45.69% and 13.66% compared with CK. GB can effectively increase the soil storage and temperature in the root zone, improve the utilization efficiency of water and heat resources of spring maize, and increase the grain yield. In summary, it is suggested to implement furrow irrigation + transparent mulch ridge covering technology in HID of Inner Mongolia to improve the yield of spring maize and the utilization efficiency of water and heat resources.

In order to explore the effects and differences of different drought stresses on the growth and development of winter wheat in lime concretion black soil and yellow tide soil in different growth periods, based on the barrel-planted drought experiment in Wudaogou Hydrological Experimental Station in 2022, water control was carried out in the rejuvenation-jointing, jointing-ear pumping and ear-milking stages of Winter Wheat, and the three stress levels of light, medium and severe drought and drought-free control (CK) of the whole growth period were set to analyze the effects of different drought stresses on plant height, water consumption and WUE of winter wheat in two soils. The results showed that: ①under the influence of drought in each growth period of winter wheat in two soils, the plant height was smaller than that of the control group, the inhibition of plant height by severe drought was the most significant, and the drought during the jointing-panicle stage had the continuous inhibition effect on plant height. At the time of harvest, the plant heights of all treated yellow tide soil were lower than those of sand ginger black soil, but under the influence of drought, the plant height inhibition level of dry group in each growth period of yellow aquic soil was lower than that of sand ginger black soil. ②The water consumption of each growth period of the two soils decreased with the aggravation of drought, the trend of severe drought reduction was the most significant, and the reduction of water consumption made the total water consumption lower than that of the control group, but the reduction level of the drought-affected group of the yellow tide soil was lower than that of the sand ginger black soil. ③The yield reduction of the two soils intensified with the aggravation of drought, and the yield of each treatment group of sand and ginger black soil was greater than that of yellow tide soil, but the yellow tide soil had certain drought resistance compared with the rejuvenation-jointing stage and jointing-ear pumping stage. During the pumping-milk-ripening period, the drought resistance of sand ginger black soil was better than that of yellow tide soil. ④The WUE of sand ginger black soil was higher than that of yellow tide soil, the gap between ear pumping and milk ripening was the most significant, and the impact of drought on winter wheat in yellow tidal soil was greater than that of sand ginger black soil in this growth stage.

"Electricity to water" is the main management measure for measuring agricultural groundwater extraction in Hebei Province, it is of great significance to optimize water resource allocation, save energy and improve efficiency by scientifically utilizing water-electricity conversion coefficient of irrigation wells and analyzing its variation law. Based on the relevant monitoring data of 177 agricultural irrigation wells in Cangxian County, Hebei Province, the factors such as groundwater depth, pump efficiency, pipeline pressure, and water pipeline length, which affect the water-electricity conversion coefficient of the wells were analyzed by the single factor method, and a regression model was established. The results show that: the water-electricity conversion coefficient of pumping well is greatly affected by the buried depth of groundwater level, and the path coefficient is -0.882; the direct path coefficient and indirect path coefficient of the pump efficiency and the water delivery length of the pipeline are both small, which has little impact on the change of the water-electricity conversion coefficient. The calculated and measured water yields of shallow wells and deep wells under different groundwater depths are well fitted, and the fitting accuracy of shallow wells is higher than that of deep wells, and the value of R² is 0.88 and 0.85, respectively. The research results have important practical significance for speeding up the promotion of "electricity to water" metering management measures.

In order to explore the current research trends and hot spots of water-saving irrigation at home and abroad, based on CNKI and WOS core database, this paper retrieved the scientific and technological literature on water-saving irrigation from 2002 to 2021, and used VOSviewer visual analysis software and database analysis results to analyze the annual publication volume, publication countries and institutions, publication journals, high-yield authors and highly cited literature, and research topics and keywords. The results showed that from 2002 to 2021, the annual publication volume of CNKI database fluctuated greatly, while that of WOS database was on the rise, among which Chinese scientific research institutions had become the main force of published papers in WOS database. The literature in this field was mainly published in journals such as ' water-saving irrigation ', ' rural water conservancy and hydropower in China ', ' Journal of Irrigation and Drainage ', and ' Agricultural Water Management ', among which ' water-saving irrigation ' had the highest number of publications (752). The author with the highest number of articles published in the CNKI database in this field is Professor Peng Shizhang of Hohai University, with 42 articles published, while the author with the highest number of articles published in WOS database is Professor Dukes Michael D of the University of Florida, with 28 articles published. The research direction in this field mainly focused on irrigation methods, irrigation systems, water use efficiency and so on. Water-saving irrigation research in the future is still a hot issue, Chinese scientific research workers in this field have significant contributions, and the future development direction of water-saving irrigation should be regionalization, intellectualization and precision.