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1.
Real-time prediction of soil infiltration characteristics for the management of furrow irrigation 总被引：2，自引：1，他引：2
The spatial and temporal variations commonly found in the infiltration characteristic for surface-irrigated fields are a major physical constraint to achieve higher irrigation application efficiencies. Substantial work has been directed towards developing methods to estimate the infiltration characteristics of soil from irrigation advance data. However, none of the existing methods are entirely suitable for use in real-time control. The greatest limitation is that they are data intensive. A new method that uses a model infiltration curve (MIC) is proposed. In this method a scaling process is used to reduce the amount of data required to predict the infiltration characteristics for each furrow and each irrigation event for a whole field. Data from 44 furrow irrigation events from two different fields were used to evaluate the proposed method. Infiltration characteristics calculated using the proposed method were compared to values calculated from the full advance data using the INFILT computer model. The infiltration curves calculated by the proposed method were of similar shape to the INFILT curves and gave similar values for cumulative infiltration up to the irrigation advance time for each furrow. More importantly the statistical properties of the two sets of infiltration characteristics were similar. This suggests that they would return equivalent estimates of irrigation performance for the two fields and that the proposed method could be suitable for use in real-time control. 相似文献
2.
Infiltration characteristics for border strip irrigation at two sites with swelling clay soils were examined. Volume infiltrated was calculated from flow onto the field monitored with flow meters; depth of water in the soil estimated from soil samples taken before and after irrigation; and the advance profile which was used to calculate the volume infiltrated with time. Volume infiltrated was compared with volume of cracks before irrigation.Linear advance and observed crack closing supported the hypothesis that infiltration approached zero after about 10 min. Volume of cracks was less than 20% of the volume infiltrated. Wetting front was 3–10 times greater than depth of observed surface cracks. There was no significant correlation between intake opportunity time and depth of infiltration, but elevation irregularities were related to infiltration. 相似文献
3.
The irrigation advance problem in irrigation hydraulics has been spread across the engineering and soil science literature over a number of decades. The Lewis–Milne framework has been used extensively, but one problem has been to find a suitable infiltration equation. The infiltration advance solutions of Philip and Farrell, and Collis-George and Freebairn are compared to a new solution based on the linear soil infiltration equation. It is shown that the linear soil solution is able to give similar results to the Philip and Farrell solution at early stages of infiltration when this is valid, and the Collis-George and Freebairn solution at longer times when this is valid. The linear soil infiltration advance solution presented here is the first using physically meaningful parameters which is able to give adequate infiltration and advance behaviour over all time scales. To further test the linear soil concept, we inversely fit irrigation advance data to get the sorptivity, saturated hydraulic conductivity and infiltration rate behaviour of the soil using all three infiltration equations. The linear soil is shown to give the best fit for the infiltration behaviour to the measured results with an average r 2 of 0.98 compared to 0.84 for Philip and Farrell and 0.77 for Collis-George and Freebairn. The linear soil model was also the best fit using other statistical tests such as RMSE and RSR. 相似文献
4.
A simple method for predicting surface irrigation advance trajectories using infiltration parameters and inflow rate as inputs
was developed. The difference between the inflow rate and the sum of infiltration rates over the wetted portion of the field
equals the flow rate available for advance. An average (characteristic) infiltration rate ahead of the wet portion is computed
using a fixed time step. An advance step (for a fixed time step) is calculated from the ratio of the flow rate available for
advance and characteristic infiltration rate. Predictions of advance by the proposed method were compared with field observations,
with the kinematic wave model, and with analytical solutions of Philip and Farrell (1964). In all cases, the method provided
predictions that were in good agreement with field observations, and performed similarly to the kinematic wave model. The
method offers a simple and efficient tool for prediction and evaluation of surface irrigation systems under various soil types
and variable inflow rates. The method is particularly useful for predictions in fields with spatially and temporally variable
intake properties. 相似文献
5.
Cablegation is a simple system for automating surface irrigation in small- and medium-sized fields using a gated pipe. In
this work, a Programmable Logic Control, PLC, was used to develop an adaptive cablegation system capable of establishing the
infiltration equation in real time and then adjusting the irrigation times to the infiltration rate and field geometry. A
controlling program was developed for the on-field determination of the infiltration equation, simulation of advance in each
furrow, and the optimization and management of the irrigation event. The equipment was tested in three experimental stations,
including a Luvissol field organized in contour terraces with furrows of various lengths. The results demonstrate the capability
of the system to adapt the application times to the different furrow lengths and the gradual decrease in the soil infiltration
and to recommend an application depth that optimizes the Application Efficiency. Various improvements were made to this solar-powered
cablegation, resulting in a reliable surface irrigation system capable of unsupervised operation. 相似文献
6.
7.
《Agricultural Water Management》1996,30(2):133-142
A volume-balance technique utilizing irrigation advance and recession functions, numerical integration, and an optimization procedure was developed to determine infiltration parameters. The procedure is simple yet rational and accounts for spatial variability of soil characteristics. The required data are flow rate, the coefficients and exponents of the advance and recession functions, and inflow shut-off time. In a field experiment on a clay loam soil (typical of southern Alberta) at the Lethbridge Research Centre, infiltration rates estimated by this technique were similar and in close agreement with those measured with a ring infiltrometer. Except for two border strips, there were no significant mean differences between simulated (Is) and measured (Im) infiltration rates. In the two non-conforming border strips, field measured infiltration rates were higher than those simulated with the volume balance approach, most likely due mainly to spatial variability of soil characteristics and partly to lateral flow which occasionally occurs when measuring infiltration with a ring infiltrometer. 相似文献
8.
Knowledge of the soil infiltration parameters is necessary for efficient furrow irrigation. A method is proposed for the
determination of the parameters in the Kostiakov-Lewis infiltration equation from measurements of the furrow irrigation advance
and inflow. The method employs a volume balance model using optimisation to minimise the error between the predicted and measured
advance and differs from existing approaches in that only advance data and inflow rates are required. The average cross sectional
area of the furrow and the final infiltration rate are treated as fitted parameters and need not be measured. A simple but
effective optimisation algorithm is developed which allows for the solution of the four parameters without user input. The
speed and simplicity of the optimisation may lead to application in real-time control of furrow irrigation.
Received: 16 August 1995 相似文献
9.
根据精细灌溉的要求,采用零惯量模型和土壤入渗理论,开发建立了可进行畦灌水流运动模拟、灌水质量评价、灌水技术参数优化、利用灌溉试验资料率定糙率和入渗参数等功能的畦灌决策计算机服务系统,该系统可为灌区技术人员确定畦灌技术参数、指导灌水实践提供决策服务,也可作为科研人员研究节水灌溉的一种技术工具。 相似文献
10.
Management and control of surface irrigation, in particular furrow irrigation, is limited by spatio-temporal soil infiltration
variability as well as the high cost and time associated with collecting intensive field data for estimation of the infiltration
characteristics. Recent work has proposed scaling the commonly used infiltration function by using a model infiltration curve
and a single advance point for every other furrow in an irrigation event. Scaling factors were calculated for a series of
furrows at two sites and at four points down the length of the field (0.25 L, 0.5 L, 0.75 L and L). Differences in the value of the scaling factor with distance were found to be a function of the shape of the advance curves.
It is concluded that use of points early in the advance results in a substantial loss of accuracy and should be avoided. The
scaling factor was also strongly correlated with the furrow-wetted perimeter suggesting that the scaling is an appropriate
way of both predicting and accommodating the effect of the hydraulic variability. 相似文献
11.
12.
Albert J. Clemmens 《Agricultural Water Management》1982,5(2):159-170
The infiltration characteristics of a soil are important to the design, evaluation and management of border irrigation systems. The use and verification of border irrigation models also rely heavily on infiltration. This paper presents a technique for determining infiltration when detailed information is available on the total infiltrated volume during the irrigation which can be obtained from measurements of inflow, outflow, and water depths on the border strip. The method uses a volume balance at progressive times and is an extension of earlier work. Data from this method were used as input to the zone-inertia border irrigation model and good agreement was found between measured and computed values of advance, recession, runoff rates and volumes, and surface water depths. 相似文献
13.
In order to improve the irrigation efficiencies of small farms employing cavity wells for their water supply, an experimental study was conducted at the Central Soil Salinity Research Institute, Karnal. The cavity wells of the Karnal region do not have any discharge regulating devices for improving the irrigation efficiencies. The only way of improving these efficiencies is by designing an efficient irrigation layout, so that uniform water application is accomplished. The present study involves field determination of the opportunity time at each point along the border from advance and recession curves and computing the depth of cumulative infiltration from the infiltration rate curve. The irrigation efficiencies are also calculated from soil moisture measurements made before and after each irrigation.The results of this study show that a realistic field assessment of the irrigated border efficiencies is obtained through a soil moisture measurement procedure. The procedure, based on opportunity time and infiltration, overestimates the irrigation efficiencies due to the empirical nature of the infiltration equation. For small farms, with a limited discharge of 10 l/s, an irrigation layout of borders of 50–70 m in length and 6–8 m in width is recommended. 相似文献
14.
《灌溉排水学报》2019,(11)
【目的】准确获取阿克苏河下游区灌溉入渗补给系数,对该区灌溉入渗补给系数的影响因素进行分析,为绿洲带高强度人工灌溉模式下地表水地下水转化机理研究,提高研究区地下水数值模拟精度提供基础。【方法】选取阿克苏下游区不同灌溉制度、包气带厚度、土壤结构下代表性点进行野外取样及室内灌溉试验,并结合Hydrus-1d进行包气带水流数值模拟,通过改变灌溉制度、包气带厚度,应用Hydrus-1d模型计算该土壤结构下的灌溉入渗补给系数变化。在模型计算结果的基础上,首先分析灌溉制度、包气带厚度与灌溉入渗补给系数的关系;其后重点利用模型计算结合数理统计的方法分析土壤结构中影响灌溉入渗补给系数的主要因素。【结果】研究区内滴灌条件下灌溉入渗补给系数的范围为0.320～0.474;畦灌条件下灌溉入渗补给系数的范围为0.408～0.561,即不同灌溉制度下灌溉入渗补给系数不同;而伴随包气带厚度增大,灌溉入渗补给系数也随之减小;土壤结构对灌溉入渗补给的主要影响因素为土壤渗透系数、土壤体积质量、土壤初始含水率。【结论】根据室内试验结合数值模型计算出不同灌溉制度下的灌溉入渗补给系数变化范围,得出灌溉入渗补给系数的影响因素为灌溉制度、包气带厚度和反映土壤结构的土壤渗透系数、土壤体积质量及土壤初始含水率,为干旱区下游区灌溉入渗补给系数选取及后续研究提供理论依据。 相似文献
15.
Because of the spatial and temporal variabilities of the advance infiltration process, furrow irrigation investigations should not be limited to a single furrow irrigation event when using a modelling approach. The paper deals with the development and application of simulation of furrow irrigation practices (SOFIP), a model used to analyse furrow irrigation practices that take into account spatial and temporal variabilities of the advance infiltration process. SOFIP can be used to compare alternative furrow irrigation management strategies and find options that mitigate local deep-percolation risks while ensuring a crop yield level that is acceptable to the farmer. The model is comprised of three distinct modelling elements. The first element is RAIEOPT, a hydraulic model that predicts the advance infiltration process. Infiltration prediction in RAIEOPT depends on a soil moisture deficit parameter. PILOTE, a crop model, which is designed to simulate soil water balance and predict yield values, updates the soil moisture parameter. This parameter is an input of a parameter generator (PG), the third model component, which in turn provides RAIEOPT with the data required to simulate irrigation at the scale of an N-furrow set. The study of sources of variability and their impact on irrigation advance, based on field observations, allowed us to build a robust PG. Model applications show that irrigation practices must account for inter-furrow advance variability when optimising furrow irrigation systems. The impact of advance variability on deep percolation and crop yield losses depends on both climatic conditions and irrigation practices. 相似文献
16.
A moving control volume approach was used to model the advance phase of a furrow irrigation system whereas a fixed control volume was used to model the nearly stationary phase and the runoff rate. The resulting finite-difference equations of the kinematic-wave model were linearized and explicit algebraic expressions were obtained for computation of advance and runoff rate. The solutions for the advance increment and the runoff rate were compared with the nonlinear scheme, the zero-inertia model, and a set of field data. A close agreement was found between the models and the field data. Assuming a constant infiltration rate, a differential equation was derived to estimate the error between the kinematic-wave model and the zero-inertia model in predicting the flow cross-sectional area along the field length. The differential equation and two dimensionless terms were used to define the limits for use of the kinematic-wave model in furrow irrigation. 相似文献
17.
土壤入渗特性和田面糙率的变异性对沟灌性能的影响 总被引：2，自引：0，他引：2
以杨凌区粘壤土和砂壤土区域进行的大田沟灌试验为基础,在假定各灌水沟内部土壤入渗特性和糙率均一的条件下,重点分析各灌水沟之间土壤入渗参数和田面糙率的不同组合对沟灌水流运动过程和灌水质量的影响,结果表明土壤入渗特性的变异性对沟灌水流推进过程和灌水质量指标影响较大,在模拟时必须充分考虑;而田面糙率的变异性对沟灌水流推进过程和灌水质量指标影响较小,可采用田块糙率均值代替各灌水沟的糙率。经实例验证,水流推进过程相对误差为7.28%,灌水效率、灌水均匀度和储水效率模拟值与实测值误差分别为5.74%、6.18%和4.07%,结果表明其模拟效果较好。 相似文献
18.
19.
The capability of hydrodynamic, zero-inertia, kinematic-wave and volume-balance models to predict advance and recession phases in furrow irrigation were compared against two sets of field data, providing a wide range of soil conditions and field slopes. The input parameters required for each model were studied, and a simple sensitivity analysis was performed for field slope, furrow geometry, roughness coefficient, infiltration constants, time step, and discharge. The accuracy of the models' predictions depends on the precision of the measurements and the estimation of the input parameters. Excellent prediction of the advance and recession phases were obtained with hydrodynamic, zero-inertia and kinematic-wave models. Those models therefore are preferred in design and management in furrow irrigation. 相似文献