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1.
Luoyang Instituti of Technology (former Luoyang Agricultural Machinery Institute) is a high engineering institute under the command of the Ministry of Machine Manufacture and Electronics Industry It is located in Luoyang, the ancient capital of nine dynasties, which has strong in science and tech-  相似文献   

2.
voirDu Jiying Gao Baoguo Yuan Mei Jin Pingxin(Hekou Oil Production Plant,Shengli Oilfield Branch Company,Dongying,Shandong,257200,China)According to characteristics of Boshen-6 buried hill reservoir,including deep depth,and high temperature(>170°),the capillary-steel-pipe pressure gauge system were introduced to well test the Boshen buried hill reservoir.The well test data were used to investigate the reservoir's geological characteristics,to determine the reservoir's type,to clarify the interwell connectivity and to provide the reliable basi  相似文献   

3.
Six-year old apple trees were selected for field experiment. The objective of this study was to obtain the reasonable arrangement of surge-root irrigation emitters in apple orchards. There were three factors: the buried depth H( 25,40,55 cm),the horizontal distance L( 30,40,60 cm) between the emitters and the trunk of the experimental tree,and the number of the irrigation emitters N( 1,2,4). The effect of the arrangement of surge-root irrigation emitters on the growth,yield and irrigation water use efficiency( IWUE) of apple trees were studied in Northern Shaanxi where the irrigation quota takes 60%-75% of the field water capacity. The results showed that the arrangement of emitters for surge-root irrigation had a significant effect on apple tree yield and IWUE,especially,the yield and IWUE reached 28 388. 17 kg/hm2 and 16. 83 kg/m3 in treatment T3,respectively. At the same L and N levels( T1,T2,and T3),the yield and IWUE in treatment T3 were the highest,and the yields in treatments T1 and T2 were decreased by 26.22% and 31.48%,while IWUE is reduced by14.02% and 18.12% compared with T3,respectively. At the same H and N levels( T3,T4,and T5),the yield and IWUE of apple trees were decreased with increasing L level. Especially,when L was 30 cm( T3),the yield and IWUE were the highest. The same L and H levels( T3,T6,and T7) could promote the growth of apple trees when N was 2( T3). Compared with treatment T3,it was found that the increment of new shoots was decreased by 8.07%-18.71%,and the fruit diameter was decreased by 5.41%-9.11%. Therefore,two emitters should be arranged symmetrically on both sides of an apple tree,each was buried at a 40 cm depth and 30 cm away from the trunk of the tree to effectively improve the yield and IWUE of the apple tree in mountainous areas in Northern Shaanxi.  相似文献   

4.
The discipline of Agricultural Mechanization Engineering in Shandong University of Technology is thefirst one in the history of the University with its own superiority and characteristics in the development ofdiscipline and professional training.About 40 0 0 undergraduate students have graduated from the disci-pline,34graduate students have enrolled M.Sc.program and1 1 students have enrolled joint- training Ph Dprogram with other universities in the area of agricultural mechanization engin…  相似文献   

5.
Knowledge of the spatial variability of soil–water properties is of primary importance for management of agricultural lands. This study was conducted to examine which spatial structure measure, the semi-variogram or the covariance variogram, is appropriate for inference of the spatial structure and performing interpolation of soil–water properties from sample data sets. Using the appropriate spatial structure measure, the spatial variability of these properties (saturated hydraulic conductivity, water table depth, groundwater salinity, and soil salinity and sodicity) as affected by subsurface drainage is also evaluated. The soil–water properties were sampled before and after the installation of subsurface drainage on a regular square grid of 500 m at 61 locations within 1470 ha in the Nile Delta of Egypt. The results showed that the covariance variogram reveals the character of spatial structure and that it is more appropriate for interpolation than the semi-variogram. Subsurface drainage has highly affected the spatial variability of soil–water properties. On average, the spatial correlation range increased by approximately 29%, whereas the ratio of structural heterogeneity to the total variation (relative structured heterogeneity) was doubled 4 years after drainage installation. Moreover, the nugget effect increased and was present for all soil–water properties with noticeably high values. Uneven spatial distributions were also observed. Further study of long-term spatial variation of soil–water properties as affected by subsurface drainage is suggested.  相似文献   

6.
The method for verification of numerical solution of water flow towards a drain in homogeneous soil under steady rainfall or steady irrigation recharge is presented in the paper. In 1979, Zaradny and Feddes proved that the accuracy of the numerical result depended, among other things, on the size and pattern of discretization applied. Ibidem, a partly verification of numerical solution was presented. It was based on the Thiem–Dupuit well formula and on the hodograph solutions given by Van Deemter [Van Deemter, J.J., 1950. Versl. Landb. Onderz. 56 (7), 1–67] and Childs [Childs, E.C., 1959. J. Soil Sci. 10 (1), 83–100]. Up till now, there was no full verification of this solution. The proposed method which depends on replacement of the drain by horizontal ‘well’ in a confined aquifer of a constant thickness, the geometry of which in the x–z plane is compatible, in shape and size, with saturated zone in the numerical solution gives the possibility of such verification. For this problem groundwater flow can be described by the Laplace equation. The analytical solutions for the hydraulic head φ and the stream function ψ, specification of boundary conditions for the considered problem and the method of determination of the Fourier series constants are given in the paper. Presented results confirm the correctness of numerical solution given by Zaradny and Feddes [Zaradny, H., Feddes, R., 1979. Agric. Water Manage. 2, 37–53] and they also show that when verification with respect to observed and measured data is impossible, such tests should be performed.  相似文献   

7.
【Objective】In order to obtain the irrigation infiltration recharge coefficient in the lower reaches of Aksu river and improve the numerical simulation accuracy of groundwater in the study area,the influencing factors of the irrigation infiltration recharge coefficient in this area were analyzed. 【Method】In this paper,field sampling and indoor irrigation experiments were carried out by selecting representative points under different irrigation schemes,vadose zone thickness and soil structure in the lower Aksu area,and numerical simulation of vadose zone flow was carried out in combination with Hydrus-1d. Hydrus-1d model was used to calculate irrigation inflow under this soil structure by changing irrigation schemes and vadose zone thickness. Change of seepage recharge coefficient. On the basis of the calculation results of the model,the relationship between irrigation schedule,aeration zone thickness and irrigation infiltration recharge coefficient is analyzed firstly,and then the main factors affecting irrigation infiltration recharge coefficient in soil structure are analyzed with the method of model calculation and mathematical statistics. 【Result】The results showed that the irrigation infiltration recharge coefficient ranged from 0.320 to 0.474 under drip irrigation and from 0.408 to 0.561 under border irrigation. The irrigation infiltration recharge coefficient varied under different irrigation schemes,while the irrigation infiltration recharge coefficient decreased with the increase of aeration zone thickness. The main factors affecting irrigation infiltration recharge are soil permeability coefficient,soil bulk density and initial soil water content. 【Conclusion】According to indoor experiment combined with numerical model to calculate the irrigation infiltration coefficient under different irrigation system range, it is concluded that the influence factors of irrigation infiltration coefficient of irrigation system, the thickness of the vadose zone and reflects soil permeability coefficient of soil structure, soil quality and soil initial moisture content, volume for the downstream area irrigation infiltration coefficient selection in arid areas and provides the theory basis for further research. © 2019 Journal of Irrigation and Drainage. All rights reserved.  相似文献   

8.
This paper presents a case study of Goulburn-Murray Water's approach to the development and implementation of its asset management program for irrigation infrastructure. The success and effectiveness of asset management is not a matter of technical aspects only, rather it depends on an integrated package of institutional, organisational, technical and financial aspects.  相似文献   

9.
【Objective】The purpose of this paper is to solve secondary salinization of soil in Northwest China. 【Method】the capillary water rising movement characteristics of layered soil has been analyzed through indoor test. And the variation characteristics of capillary water movement under the influence of common change of layer and thickness of sand layer has been considered in this paper, and functional relationship between groundwater recharge and height of capillary water rising with time changing has been built. Furthermore, contour distribution of groundwater recharge and capillary water rising height has been also comparative analyzed.【Result】There was a very significant positive correlation between the horizon and the volume constant and the height constant （P<0.01）. And there was a significant negative correlation between the horizon and the stable recharge rate of groundwater and the rate of steady increase of capillary water （P<0.05）. There was a significant negative correlation between the thickness of sand layer and stable recharge rate and steady rising rate（P<0.05）. When the duration of the capillary water height was rising was 0~4 days, the sandy layer was 30~50 cm, the thickness of sand layer was 0~15 cm, which has a significant effect on the change of groundwater recharge and height of capillary water. When the duration of the capillary water height was rising was 4~12 days, the sand layer is distributed in 15~30 cm, the thickness of sand layer was 15~30 cm, which has a significant effect on the change of groundwater recharge and height of capillary water. To summarize, the results of this study were of great significance for the study of water salt movement and soil salinization in layered soils.【Conclusion】The fitting parameters of the function including volume constant (v), stable recharge rate (q*), groundwater recharge time constant (τQ), capillary water rising height (υ), steady rising rate (μ*) and rising height time constant (τh) were determined by the variation of capillary groundwater recharge and capillary water height with time changing respectively. © 2019 Journal of Irrigation and Drainage. All rights reserved.  相似文献   

10.
Study was undertaken to assess the water use, moisture extraction and water use efficiency (WUE) of irrigated wheat, when grown in association with boundary plantation of poplar, at different distances (0–3, 3–6, 6–9, 9–12, 12–15 and >15 m (control)) from poplar (Populus deltoides M.) tree line. Presence of 3-year old poplar plantation at the boundary of wheat field caused 7.5% higher water use than control (plots having no effect of tree line) up to 3 m distance from tree line which further intensified up to 12.7% and extended up to 6 m distance with 4-year old plantation. Similarly, maximum moisture extraction, both laterally and vertically, observed near the tree line. Contrary to this, WUE of wheat was reduced by 4.6% between 0 and 3 m distance from tree line with 3-year old plantation, decline intensified further to 18.6% with 4-year old plantation. However, wheat was benefited by boundary plantation of trees between 3 and 9 m distance from the base of the tree line which resulted in increased WUE of the wheat crop up to 9%.  相似文献   

11.
By discretizing the convection terms with AUSM+ up scheme in the rotating coordinate system, a finite volume analysis code based on multi block structured grids was developed indepen dently so as to realize the numerical solving of internal flow fields of turbomachineries. Taking an unshrouded radial impeller with the working fluid of water vapour as the research object, the flow response to the fluctuation of rotational speed was calculated. By comparing the surface pressure profiles and velocity contours calculated by the code and commercial software respectively, the accuracy of flow solver was verified. The analysis of flow response data indicates that, as the wor king condition shifts closer towards the surge boundary, the response of flow parameters such as mass flow and aerodynamic torque will be more nonsynchronous with the fluctuation of rotational speed, and also the influence of density variation on mass flow variation will be smaller. Moreover, the transient variation region of working condition performance will deviate farther away from the steady performance curve as the working condition approaches the surge boundary. Compared to the working conditions with small mass flows, the distribution characteristics of pressure difference load on the blade surface vary little under large mass flow conditions. The reduction of fluctuation amplitude of rotational speed exerts no influence on abating the hysteresis of flow response.  相似文献   

12.
Intensification of the agricultural sector and the increase in quantity and decrease in quality of municipal and industrial wastewater, in particular during the past decades, resulted in many industrial countries, such as Belgium, in a sharp degradation of surface water and groundwater. To control the current degree of contamination and reduce the environmental impact of the agricultural sector, the Flemish government recently introduced a number of regulations aiming at controlling the use of nitrogen fertilisers. To facilitate the implementation and the control of the new regulations, threshold values of allowable doses of organic and inorganic nitrogen fertilisers, and their spreading in time were made soil independent. As the soil physical, chemical and biological response depends on the geohydrology of the site and the past fertilisation practice, fertiliser standards applied on different soil–crop systems result in different leaching patterns.To assess the effect of the soil on the nitrogen leaching, a number of past experimental field trials were analysed using the WAVE model as modelling tool for the reconstruction of the nitrogen dynamics. As a first step in the study, the historic data of the field experiments were used to calibrate and validate the WAVE model. The deterministic calibration and validation of the WAVE model yielded a set of model parameters for the examined soil–crop–fertiliser practice conditions. The bottlenecks in the calibration were the nitrogen mineralisation parameters and the initialisation and subdivision of the soil organic matter over the different organic pools. The model validation, being the second step in the study, revealed the power of the WAVE model to predict the evolution and transformations of nitrogen in the soil profile and the leaching of nitrate at the bottom of the root zone. In a third step, the WAVE model was used in a scenario-analysis exercise to examine the factors effecting the amount of nitrate leached at the bottom of the root zone. This analysis revealed that the nitrate leached out of the soil profile is controlled by the fertiliser practice, the rainfall depth and its distribution, the soil texture, the soil mineralisation capacity and the past fertilisation practice.  相似文献   

13.
The Hebei Agricultural University( HAU) is one of the key universities in Hebei Province.TheCollege of Mechanical &Electrical Engineering of HAU grew out of the department of AgriculturalMechanization in HAU,which was set up in the autumn of 1 95 8,It is one of the earliest provincialagricultural education institutions in China thatestablishes a course in agricultural mechanization and is theonly institution in the domain of agricultural mechanization in Hebei Province which is qualif…  相似文献   

14.
《Agricultural Systems》2007,94(1-3):170-190
Farmers within irrigation systems, such as those in Bali, solve complex coordination problems to allocate water and control pests. Lansing and Kremer’s [Lansing, J.S., Kremer, J.N., 1993. Emergent properties of Balinese water temples. American Anthropologist 95(1), 97–114] study of Balinese water temples showed that this coordination problem can be solved by assuming simple local rules for how individual communities make their decisions. Using the original Lansing–Kremer model, the robustness of their insights was analyzed and the ability of agents to self-organize was found to be sensitive to pest dynamics and assumptions of agent decision making.  相似文献   

15.
《Agricultural Systems》1999,60(2):113-122
The use of numerical optimization techniques on simulation models is a developing field. Many of the available algorithms are not well suited to the types of problems posed by models of agricultural systems. Coming from different historical and developmental backgrounds, both genetic algorithms and evolution strategies have proven to be thorough and efficient methods in identifying the global optimum of such systems. A challenging herd dynamics model is used to test and compare optimizations using binary and real-value genetic algorithms, as well as evolution strategies. All proved successful in identifying the global optimum of this model, but evolution strategies were notably slower in achieving this. As the more successful innovations of each of these methods are being commonly adopted by all, the boundaries between them are becoming less clear-cut. They are effectively merging into one general class of optimization methods now termed evolutionary algorithms.  相似文献   

16.
Three parameters were introduced here, in the second paper of the series, to evaluate layout structure of multi-quality water supply networks for irrigation. The first parameter was flexibility, which assesses the capability for a flexible supply of variable water quality values which can be obtained by dilution inside the network facilities. The second was separability which expresses the capability of the network to be divided into separate isolated sub-networks, each carrying a different water quality. The third was rigidity, which expresses a rigid allocation of one to one source?Cconsumer connections. Five types of network layout which were presented in Sinai (2011) were evaluated here, using these three parameters. The flexibility of a network was given special attention with the example of parallel and serial connection of fields to sources. A real example of a proposed network in the Hazeva region in Israel was analyzed. All feasible flow patterns (FFPs) were computed. The location of mixing and dilution junctions and computation of the QC feasibility domains were found and computed for every junction and consumer. Relative ranges of discharges and concentrations were conducted for all the FFPs found. However, no single optimal FFP with maximal flexibility was found. Therefore the FFPs were arranged in operational groups for possible sequential operation according to irrigation schedules.  相似文献   

17.
In a WTO battle and the press the argument is often made that eliminating US cotton subsidies would have a large effect on the incomes and competitive position of farmers in developing countries. In Francophone West Africa cotton productivity has stagnated after rapid gains in the first two decades following independence (1960-1980). A farm model was constructed based on farmers’ definition of their decision-making framework which they use to respond to income and weather risks. With this model the effects on farmers of eliminating US subsidies are compared with various productivity increasing measures for cotton and sorghum in Dioila, Mali. Dioila is located in a representative cotton region producing 16% of the cotton in Mali. We include sorghum due to its importance for consumption and the observation of Malian farmers substituting cereals (sorghum and maize) for cotton as the returns to cotton have fallen in the 21st Century. In the farm model, the elasticity of transmission of a change in the world cotton price to the farm gate price is taken into account. The gains from eliminating US subsides are small. In contrast, the various technological alternatives including Bt cotton introduction, the use of higher fertilization levels for cotton, and the introduction of improved sorghum cultivars and moderate fertilization along with a marketing package all have substantially higher returns Even with substantial improvement in the mechanisms enabling farmers to benefit from the higher prices resulting from elimination of US subsidies, there are still much higher returns resulting from the various types of productivity increases.  相似文献   

18.
In order to investigate the self-priming process of self-priming pump, an unsteady simulation was conducted where the Navier-Stokes equations were used with the Lagrangian-Eularian model. In course of this investigation, the volume fractions, pressure distribution and self-priming time were carried out. By analyzing the volume, velocity and pressure distribution of the gas-liquid two-phase flow at different time, the two-phase content via the variation law of the two-phase flow in the pump was carried out. By monitoring and analyzing the gas-liquid flow at the outlet of the pump, the self-priming time and crucial periods were given. Two phenomena were mainly characterized by the self-priming process such as the gas-liquid mixing and separation, which occur in the early stage of self-priming process. During that period the gas-liquid mixing clouds appear on the outer edge of the impeller, and the instantaneous void fraction at the inlet and outlet of the impeller decreases obviously. It was also established from the transient study that the effects of gas have a major influence on the hydraulic performance of the pump at the early stage of operation. To increase the usage of self-priming pump and to also understand the energy conversion of the pump it is very essential to investigate and establish the basic working principle of the self-priming pump.  相似文献   

19.
【Objective】Snow melting runoff is an important recharge component of arid inland rivers. Seasonal snow cover is very sensitive to environmental change. Therefore, it is of great significance to study and control the key factors affecting seasonal snow accumulation and snow melting process for basin safety and sustainable utilization of water resources under changing environment. 【Method】By observing the physical characteristics of seasonal snow layers under the conditions of sheltered or not (under canopy and open land) in the Urumqi River Basin experimental area on the northern slope of Tianshan Mountains in Xinjiang from November 2017 to February 2018, the differences of physical characteristics of seasonal snow layers were analyzed. 【Result】① the temperature of open land was slightly higher than that of under canopy, and the relative humidity under canopy was higher than that of open land. ②The average depth of snow under canopy was less than that of open land, and the proportion of deep frost layer to coarse snow layer was larger in stratified snow cover. ③The vertical profile of snow density under canopy was basically the same as that under open land. The snow density increased gradually from the new snow layer down to the peak of coarse snow layer (open land) and medium-sized snow layer (under canopy). ④ Snow temperature and liquid water content of layers under canopy and open land increased from new snow layer to deep frost layer. ⑤ The variation trend of snow water equivalence under canopy and open ground was basically the same during observation period. The value of snow water equivalence under open ground was obviously larger than that under canopy. 【Conclusion】Snow surface temperature is a significant factor affecting the liquid water content of snow under canopy and open land. © 2019 Office of Journal of Irrigation and Drainage, Farmland Irrigation Research Institute, Chinese Academy of Agricultural Sciences. All rights reserved.  相似文献   

20.
Eastern Germany is often hit by drought causing income risk for crop farmers. Index-based risk management instruments could help crop farmers to reduce their farm income risk. Such instruments have some important advantages over damage-based insurance, like e.g. less moral hazard and adverse selection. At the same time they typically have a high level of basis risk. Up to now, mainly precipitation-based weather derivatives have been discussed as an appropriate risk management instrument for farmers in Germany. As a potentially more effective alternative, we propose water capacity-based index insurance. In order to show the benefits of a precipitation-based and water capacity-based index insurance, several contract designs are compared. Using a whole farm risk program planning approach, we show that for an average agricultural producer in Eastern Germany water capacity-based index insurance offers greater benefits than precipitation-based index insurance.  相似文献   

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