Shape coefficient is an important parameter which can influence the loss of water head and porosity of filter layer. In order to accurately describe the shape characteristics of sand particles,in this paper,the ratio of the surface area of the sphere with the same volume as the sand particle and the particle was used as the shape coefficient of sand particle,and the research objects were two kinds of quartz sand filter layer with the same thickness of 400 mm,but the diameter range were 1.18~1.4 mm and 1.4~1.7 mm respectively. Water filtration experiments were carried out in Farmland Irrigation Research Institute,Chinese Academy of Agricultural Sciences. The filtration velocity and corresponding resistance pressure drop of the filter layer were measured by experiments. At the same time,the porosity of filter layers was measured by the method of pouring water into the filter layers. And according to the average mass of sand particles,the average volume of the sand particles was calculated. Thus the equivalent diameter of equal volume sphere of the sand particles was obtained. Then,according to the momentum equation of the liquid phase in the porous medium,combining with the filter characteristics of the sand filter layers,the Ergun equation was derived. So the applicability of Ergun equation to sand filter layer was explained theoretically. Finally,according to the Ergun equation,in the condition that the filtration velocity and corresponding resistance pressure drop were given,the equivalent specific surface diameter of the sand particles was calculated. In order to eliminate the influence of turbulence on the measurement result,turbulence intensity was used to correct the calculation result of the equivalent specific surface diameter. Subsequently,the shape coefficient of the sand particles of the two kinds of quartz sand filter layer was obtained as 0.821 and 0.798 respectively. The maximum relative error of the calculation results was only 2.44%. It was proved that the calculation results of the shape coefficient were reliable. The calculation results showed that,due to the existence of the fluid boundary layer whose flow velocity was slowed down by the surface of the sand particle,with the increasing of filtration velocity,the calculation results of the equivalent specific surface diameter showed declining trend. At the same time,with the increasing of filtration velocity,the turbulence stability was increasing gradually,while the turbulence intensity decreased accordingly. In order to ensure the accuracy of the calculation results of the shape coefficient,in the process of water filtration experiment,the selection of filtration velocity should be controlled by turbulence intensity which can not be less than 10%. The research results provided a technical reference for the selection and processing of the sand filter materials.

In order to improve the accuracy of flow measurement in the irrigation area,reduce the cost and manpower investment,the pressure -type detection device for open channel was developed,which was based on Bernoulli equation. Based on Fluent software,the hydraulic characteristics of pressure-type detection device for open channel flow were numerically simulated with the VOF method and Realizable k-ε model. The data were analyzed in the post-processing software and verified with the experimental data. The results showed that the transverse velocity of the free surface decreased from the center to both sides of the channel,and the vertical velocity of the central section increased first and then decreased from the bottom of the channel to the free surface,and the maximum velocity point was below the free surface; The flow formed a vortex in the downstream area of the pressure-type detection device for open channel flow. The maximum error between the simulated velocity and the experimental velocity was not more than 4.08%,and the minimum error was only 0.29%; The error between the simulated flow and the actual flow of the pressure-type detection device for open channel flow in the rectangular channel was no more than 3%,which could meet the requirements of flow measurement accuracy and proves the feasibility of numerical simulation. Key words: open channel flow measurement; numerical simulation; pressure-type; sensor; flow measurement accuracy

In order to clarify the water-saving and yield-increasing effects of different mulching drip irrigation in Northern China,field experiments were conducted to examine the variations of soil water content,dry matter accumulation aboveground,yield,and water use efficiency ( WUE) . Four treatments were established in spring maize field,including white film mulched drip irrigation ( W) ,black film mulched drip irrigation ( B) ,straw mulched drip irrigation ( S) ,non- mulched drip irrigation ( N) . The results showed that different mulch treatments could improve soil water content. During the growth season,the soil water content the of the W,B and S treatments was 24.8%, 23.5%,and 22.6% in 0~40 cm,respectively,which was 15.2%,9.3%,and 5.0% higher than that of N treatment ( 21.5%) ,respectively. The vapor pressure deficit ( VPD) of W,B and S treatment was 7.8%,8.2% and 0.3% lower than that of N treatment. Each coverage treatment improved the average photosynthetic capacity by 8.3% to 17.28% than N treatment,and the stomatal conductance of each coverage treatment in the early growth period was also higher than that of N treatment. In the mature stage,the analysis of proportion of ear in total dry matter accumulation aboveground ( Rc /t) showed that,the W and B treatment reduced the Rc /t with no significant difference,and the S treatment reduced Rc /t by 15. 2% significantly,when compared with N treatment. Thereby W treatment improved the yield by 13. 4% significantly,and the B and S treatment improved yield with no significant difference. The evapotranspiration ( ET) varied between 425.6~ 444.6 mm of different treatments which was calculated by water balance method. The W treatment showed the lowest ET value,and its WUE ( 2.99 kg /m3) was 17. 0% higher than that of N treatment,the WUE value of B and S treatment was between W and N treatment. In summary,white film mulched with full drip irrigation can significantly increase spring maize yield and WUE,which is an effective mulching measurement to save water and increase production for drip irrigation in Northern China.

In order to understand the secondary salinization of the agricultural soil in the Fenhe Valley,the soil under different irrigation ( drip irrigation and furrow irrigation) was selected to determine the total salt and K+,Na+,Ca2+,Mg2+,Cl-,HCO-3,SO2-4 and CO2-3 content in the depth of 0~1 m,and the field soil was collected as a control. The results showed that: ① the total salt content showed a decreasing trend with depth at 0~1 m. The total salt content of drip irrigation ranged from 0~2 g /kg,while ranged from 1~10 g /kg under the furrow irrigation,and the salinity accumulated obviously on the soil surface ( 0~0.2 m) . There appeared moderately salinized on the surface under the furrow irrigation. ②the analysis of base cations found that the other six cations showed drip irrigation＜furrow irrigation except HCO- 3 . Thesoil cations were mainly Ca2+ and Mg2+ and the anions were mainly SO2-4 and Cl- in the greenhouse in Taigu County. The increase of Ca2+,Mg2+,SO2-4 ,Cl- was the main reason for the secondary salinization of furrow irrigation soil. ③The relative quality index of soil under drip irrigation was lower than that of furrow irrigation through the relative quality index analysis for the greenhouse soil between 0~0.4 m. Among them,the maximum value appeared in K+ under furrow irrigation soil,which was 18.66; while the minimum value appeared in Cl - under drip irrigation,which was 0.79. Drip irrigation could effectively slow down the accumulation of salt content in greenhouse soil and effectively inhibited the formation of secondary salinization in greenhouse soil. This study can provide a scientific reference for the sustainable development of facility agriculture in Taigu area.

In order to explore the effect of drought stress on winter wheat growth in Huaibei plain at different growth stages,based on the pot experiments of winter wheat suffering from drought in 2016-2017 ( referred to as 2017) and 2017-2018 ( referred to as 2018) ,nine water treatments including light drought and severe drought were set at the tillering stage,jointing stage,heading and flowering stage and maturity stage of winter wheat,and a total of 9 water treatments ( CK) were set at different growth stages. The effects of plant height,water consumption,yield,water use efficiency ( WUE) and the reasons of different results under the same treatment for two years were also discussed. The results showed that during the growth period of drought stress,the plant height of severe drought group was significantly lower than that of light drought group,and the plant height of severe drought group was significantly lower than that of light drought group,and severe drought at jointing stage also had irrecoverable impact on plant height; drought stress not only reduced the water consumption during the growth period,but also reduced water consumption during the whole growth period than that of CK group; Light drought had little effect on Wheat Yield in different growth stages,and severe drought stress caused wheat yield reduction,which showed as follows: jointing stage ＞ heading and flowering stage ＞ maturity stage ＞ tillering stage. Higher temperature and longer sunshine duration would aggravate the yield reduction of wheat; the effect of drought on WUE was different in different growth stages,and the effect of drought at tillering stage and maturity stage was small,and WUE was the lowest in severe drought treatment at jointing stage. The results indicate that the jointing stage and heading and flowering stage are the key growth stages of wheat plant growth and nutritional growth. In actual production,when the temperature is high and the sunshine time is long,it is necessary to avoid severe drought at the jointing stage and heading and flowering stage,while appropriate drought can be suffered at the tillering stage and mature stage to achieve the purpose of water-saving and stable yield.

In this study,under the condition of 40cm subsoiling,3 drip irrigation cycles ( 4,7,10 d / time) were set,and the total irrigation amount was 3600 m3 /hm2. The regulatory effects of different drip irrigation cycles on agronomic traits of cotton,dynamic distribution of buds and bolles,dry matter accumulation and distribution and yield composition were analyzed. The results showed that under subsoiling condition,the treatment of 7 d drip irrigation cycle was beneficial to improve the cotton plant height,number of main stem leaf,bud number, number of fluid,and could promote the accumulation of dry matter of vegetative organs to reproductive organs,improve the boll number per plant and single boll weight,which were increased by 8.53%,4.98%,9.31%,8.38% than those of the treatment of 4 d and 10 d drip irrigation cycle,respectively,eventually increased the seed cotton yield and water use efficiency by 15.72%,16.50%,17.48%,18.38%. Therefore,the treatment of 7 d drip irrigation cycle under 40 cm subsoiling condition is beneficial to the improvement of agronomic characters and yield.

In order to study the water consumption rule and growth index of tomato under different substrates,the experiment was carried out in the Farmland Water Conservancy Laboratory of Hebei Agricultural University in 2018. Three substrates were used in the experiment, including A ( prepared with sand and vermiculite by volume ratio of 8 ∶ 1 ∶ 1 after natural air drying) ,B ( seedling nutrient soil of Baoding Conservation and Cultivation Factory,Hebei Province) ,and C ( self-matching matrix,prepared by peat soil,perlite and vermiculite at 3 ∶ 1 ∶ 1 volume) . Two irrigation levels ( W of 40mm,D of 30mm) were designed. At the same time,BP neural network in Matlab was used to simulate training and forecast the growth index of tomato root. Finally,under three substrates ( A,B and C) and two irrigation levels,the average daily water consumption intensity of tomato was 0.66,0.43,1.43,1.22,0.68 and 0.54mm/d,respectively. The results showed that tomato plant height,stem diameter,root tip number,root length and other indicators were significantly affected by the substrate and irrigation amount; too low irrigation amount would easily cause water stress in the growth period; the combination mode of“B matrix + high irrigation W”was more suitable for tomato growth.

Precise subsidy and water-saving reward mechanism are important contents of agricultural water price comprehensive reform. In order to study and formulate a reward and subsidy mechanism for comprehensive reform of agricultural water price,which is suitable for the project area and can be replicated and promoted in the irrigation area of Yindan,this paper takes the actual situation that the measurement facilities in the project area of Lilou town cannot measure to the households,and takes each administrative village and large water users as the research unit of the reward and subsidy mechanism,puts forward the dynamic water-saving standard formulation methods such as empirical formula method and horizontal comparison method,and constructs and implements them. The dynamic precise subsidy mechanism of water price linkage and the “two - part”water - saving incentive mechanism have strong operability and reproducibility. The empirical formula method can be used as the main method to formulate the water-saving standard in the project area. For the project area without rainfall data or when the empirical formula has large deviation,the horizontal comparison method can be used to determine the water-saving standard modify the water-saving standard. According to the relative relationship between the approved water price,the implemented water price and the current water price,the subsidy object and subsidy standard can be adjusted dynamically to realize the accurate subsidy. Water saving reward is divided into two parts. It is not only a general reward for water saving,but also a key reward for water users with remarkable water -saving effect. It can better encourage water-saving behavior and enhance agricultural water-saving consciousness when the total amount of reward and compensation funds is limited.

Through the plot experiments,the effects of different drip irrigation belt layout and irrigation quota on the growth,yield and
quality of cotton under filmless drip irrigation in southern Xinjiang were compared and analyzed. The test set 2 kinds of drip irrigation belt
layout mode,including 2 belts with 6 rows and 3 belts with 6 rows,and each drip irrigation belt layout mode set 3 irrigation quotas,namely
360,450,540 cubic meters per square hectare. The results showed that under the same level of irrigation quota,the growth of cotton stems
of the treatment of 2 belts with 6 rows was higher than that of the treatment of 3 belts with 6 rows. Meanwhile,the daily growth of cotton
seedling height was also significantly higher than that of the treatment of 3 belts with 6 rows; while the daily growth of cotton plants after bud
period of the treatment of 3 belts with 6 rows was higher than that of the treatment of 2 belts with 6 rows. The number of bolls per plant,
single boll quality,seed cotton yield,irrigation water utilization coefficient and quality indicators of cotton of the treatment of 2 belts with 6
rows were higher than those of the treatment of 3 belts with 6 rows. Under the same drip irrigation belts layout mode,the number of bolls per
plant,single boll quality and seed cotton yield increased with the increase of irrigation quota,while the irrigation water use efficiency
decreased with the increase of irrigation quota. Considering the growth,yield and quality of cotton,the treatment of 2 belts with 6 rows of drip
irrigation belts layout mode and 540 cubic meters irrigation quota were adapt to be chosen for the filmless cotton in southern Xinjiang.

Climate change and drought events increase the stress of irrigation water resources,and improving irrigation efficiency is an effective way to solve the water shortage and ensure food output. Based on the survey data of Hubei Province and Stochastic Frontier Analysis, this paper calculated rice irrigation efficiency. At the same time,based on the daily precipitation data of the weather station,this paper calculated the index of maximum number of consecutive dry days ( CDD) . Then,this paper used the panel Tobit model to analyze effects of maximum number of consecutive dry days ( CDD) and farmers＇ adaptation on rice irrigation efficiency. The results showed that rice irrigation efficiency in different regions were different. The rice irrigation efficiency of Changyang,Hanchuan and Yunxian was lower,while that of Daye and Jingzhou was higher. In terms of time,the irrigation efficiency of rice in Hubei was the lowest in 2011,which was related to abnormal precipitation in Hubei. The regression results showed that the increase of CDD index significantly reduced the rice irrigation efficiency. When the index of CDD was increased by one day,the rice irrigation efficiency would decrease by 0.3%. Farmers＇ adaptation had a positive impact on rice irrigation efficiency,and could reduce the negative impact of continuous drying index on rice irrigation efficiency. Based on the above results,it is suggested that relevant departments should strengthen the early warning of climate change and provide training and technical guidance for rice growers to adapt to climate change.

Soil capillary water can be absorbed and utilized by plants. Aiming at the problem of soil water stress of individual Populus euphratica,which cannot be solved by emergency water supply in the lower reaches of Tarim River,the columnar soil replacement technology is proposed to improve the groundwater,supply the root soil layer of Populus euphratica,and realize the self recovery of Populus euphratica. In this paper,the rising height of capillary water in soil with different particle size distribution was analyzed by indoor vertical tube capillary rising height test,and the influence of pore structure on capillary water rising height and speed was analyzed. The influence of each particle group on the rising height of soil capillary water was simulated by using projection pursuit regression ( PPR) . The results showed that: ① the higher the content of particles larger than 0.05 mm,the faster the capillary water rises; the higher the content of 0.05~0.005 mm,the higher the rising height of capillary water. ② During the rising process of soil capillary water,the rising speed of capillary water was determined by macropores,and the rising height of capillary water was determined by small pores. ③The content of 0.05~0.005 mm particles played a decisive role in the rising height of soil capillary water. The optimal combination of soil particle size composition for capillary water rising was 0% for particles less than 0.005 mm,65% for particles with 0.05~0.005 mm,and 35% for particles larger than 0.05 mm. The results showed that the rising law of capillary water in natural soil along the Tahe River had enriched the theory of soil hydrodynamics,and provided a theoretical basis for the application of column soil replacement technology to the ecological restoration of Populus euphratica.

Trial computation method is often utilized for traditional canal cross section design. Its drawbacks include large computation cost, big cumulated error,and high dependency on the designers. In this paper,the mathematical expression of quadratic parabolic canal cross section was developed and an optimization problem was formulated to minimize the difference between the computed flow rate and the designed flow rate. This problem was solved by using the Rao-1 algorithm. The design of the third main branch canal of the Beituan irrigation area was used to validate the effectiveness of the proposed method. The results demonstrated that when k was 5.023,Q was 0.330 0 m3 /s and the computed flow rate was closed to the designed one. Meanwhile,workload of the construction was reduced and the capital cost decreased. The convergence speed of Rao-1 algorithm was faster and the optimization accuracy was higher. Thus,it is practical to use Rao-1 algorithm for canal cross section design.

Water-saving irrigation project scheme is related not only to its own technical characteristics,but also to natural environment, social economy,operation and management. The selection of water-saving irrigation scheme in engineering design is a complicated multi- objective decision- making problem. Aiming at the fuzziness of evaluation index information of water - saving irrigation scheme and the connection and influence between index elements and each evaluation index,an evaluation method of water-saving irrigation project scheme based on grey fixed weight clustering with whitening weight was put forward. In this method,grey fixed weight clustering method was used to determine the turning point of the white weight function of clustering by mean value and standard deviation of index information,and the grey correlation model of information group was used to solve the correlation problem between index information in the evaluation process and obtain index weight. Finally,the gray value of irrigation scheme was used to optimize the scheme. Then this model was used to optimize a water-saving irrigation project. The results showed that the method had clear ideas and reliable evaluation results,which provided a scientific basis for the evaluation and optimization of water-saving irrigation project schemes.

In order to reveal the adaptation mechanism of the inverted senescing sequence wheat leaves to drought stress,the experiment took natural weather conditions as control,through the determination of meteorological elements and related physiological and ecological indicators in dry sheds and control,the hydrothermal conditions of farmland in experimental material at milk-filling stage under the drought stress were analyzed. The results showed that: ①The farmland net radiation of the inverted senescing sequence wheat leaves was 16.87~40.64 W/m2 lower than that of conventional leaf senescing sequences wheat,and the difference was not significant after t test. ②The turbulent heat flux of the inverted senescing sequence wheat leaves was 14.19~63.51 W/m2 and 28.54~85.83 W/m2 lower than that of conventional leaf senescing sequences wheat,at 0.2 m~2 /3 plant height and 2 /3 plant height~crown; and the latent heat flux of reverse aging wheat was 28.87~47.93 W/m2 and 51.17~135.18 W/m2 higher than that of conventional leaf senescing sequences wheat,respectively. After t test,the difference was significant ( P＜0.05) . ③The soil heat flux of the inverted senescing sequence wheat leaves farmland was 28.90~60.23 W/m2 lower than that of conventional leaf senescing sequences wheat,and the difference was significant ( P＜0.05) by t test. ④The transpiration rate of the inverted senescing sequence wheat leaves was higher than that of conventional leaf senescing sequences wheat,and the difference in soil moisture between the two treatments was significant at 60 cm of soil depth. Under drought stress,the water and heat distribution of the inverted senescing sequence wheat leaves farmland createed a relatively cold and humid microclimate environment,which effectively delayed the premature senescence of plants in the later stages of wheat growth.

In order to explore the growth and photosynthetic characteristics of maize under the influence of CO2 concentration and water treatment,the plant height,stem diameter and leaf area,net photosynthetic rate ( A) ,stomatal conductance ( Gs) and transpiration rate ( E) of two varieties of maize at jointing stage were analyzed with potted plants. The results showed that the stem of the two varieties and leaf area of Jingke 968 of maize were significantly reduced under low water treatment,and the A and Gs of the two varieties of maize were also significantly reduced. Except for the plant height of Zhengdan 958 treated with low water,the increase of CO2 concentration did not lead to significant changes in plant height,stem diameter,leaf area and SPAD. Under all water treatment,the increase of CO2 concentration did not cause significant change of A,while E and Gs of the two varieties of maize were significantly reduced to different degrees. The increase of CO2 concentration reduced the mean of Gs of Jingke 968 and Zhengdan 958 under all water treatment by 39.99% and 21.10%,respectively. The increase of CO2 concentration significantly improved WUE of Jingke 968 leaves,but had no significant effect on WUE of Zhengdan 958 leaves. Under the environmental CO2 concentration,the Gs of Jingke 968 in each water treatment was higher than that of Zhengdan 958. However, when the CO2 concentration increased,the Gs of Jingke 968 was lower than that of Zhengshan 958 due to more decrease,thus with higher WUE. The results indicated that different varieties of maize had different performance in coping with increased CO2 concentration,and Jingke 968 might had better drought resistance capability due to its lower Gs in the future environment with increased CO2 concentration.

In order to investigate the effects of water stress on the photosynthetic characteristics of winter wheat in the heading stage in North China,a winter wheat field experiment was conducted. The experimental data were analyzed through variance and regression analysis. The experimental results showed that: the soil water content of each layer was obviously stratified in the test area,and the stratification structure controled the vertical distribution of water to some extent.The soil moisture content of the layer with a depth of 10-30cm was higher than that of other soil layers in three different experimental stages,and its water retention performance was also better than that of other soil layers.The change of soil moisture at heading stage directly affected the photosynthetic rate and transpiration rate of winter wheat in this test area,and both of them had significant positive correlation ( P＜0.05) ,but the proportion coefficient of the primary term was significantly different.Under different treatments,photosynthetic rate and transpiration rate would peak at different times of the day,which was mainly affected by the interaction of temperature and water stress. According to the comprehensive physiological indexes of flag leaves of winter wheat,it was suggested that the optimal field water content at heading stage should be controlled at 60%~70% of the field water capacity in this test area, and the water content level was effective in yield stabilizing and water saving.

1.College of Water Conservancy and Civil Engineering,Xinjiang Agricultural University,Urumqi 830052,China; 2. Xinjiang Uygur Autonomous Region Soil and Water Conservation Ecological Environment Monitoring Station,Urumqi 830000,China; 3.Xinjiang Uygur Autonomous Region Water Conservancy Management Station,Urumqi 830000,China