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1.
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
2.
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
3.
《Agricultural Water Management》1997,34(2):169-185
The infiltration characteristics of a soil vary spatially and temporally, and due to this the available methods for estimating the characteristics in furrow irrigation are either not suitable or have restrictions for their field use. An optimization method based on the volume balance approach, originally developed for estimating infiltration parameters in border irrigation, and using multiple observations of arrival time of the wetting front was modified for furrow irrigation. The method was applied to 13 irrigation events on furrows monitored on a farm in northern New South Wales, Australia. The soil type at the experimental site has a high clay content (up to 67%) and develops cracks when dry. In addition to the optimization method, one-point and two-point methods using observations of arrival time reported in the literature were also used. The accuracy of different methods was evaluated by comparing the calculated total volume of water infiltrated into the furrow with that observed in the field. The optimization method was the most accurate and the one-point and the two-point were the least accurate among three methods considered in the present study. A possible explanation for a poor performance of the one-point and two-point methods might be related to the assumptions made in the derivation of the methods and the unsuitability of the Philip and the Kostiakov infiltration equations used for the field condition in the present study. 相似文献
4.
《Agricultural Water Management》2005,76(1):62-75
A spreadsheet model was developed to evaluate the performance of furrow irrigation that accounts for soil variability and requires few field measurements. The model adjusts an advance trajectory to three (advance distance, advance time) points and, similarly, it adjusts a recession trajectory to three (recession distance, recession time) points. The head of the furrow (distance = 0) is one of the points used to adjust both trajectories. It then calculates the parameters of the infiltration equation using the two-point method (based on the volume balance equation with assumed surface shape parameters). The model gives the option to enter an estimate of the soil infiltration variability in order to account for this variation when calculating irrigation performance indicators. The combination of variance technique was used for this purpose. A set of irrigation performance indicators (distribution uniformity, application efficiency, tail water ratio, deep percolation ratio and deficit coefficient) is calculated, assuming that the infiltrated water follows a normal frequency distribution. To illustrate the evaluation method, it was applied to three irrigation events conducted on a sunflower field, with 234 m long furrows spaced 0.75 m apart. The evaluations were performed in two 3-furrow sets. The application efficiency was satisfactory in the first irrigation, but low in the other two. Uniformity was high in all three irrigations. The performance indicator that was most affected by soil variability was distribution uniformity. Considering soil spatial variability was important for more realistic determination of the infiltrated water distribution, and therefore of the deep percolation, but it had less importance for the determination of the application efficiency, due to the relevance of runoff in our field application. 相似文献
5.
6.
《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
7.
土壤干缩裂缝几何特征对入渗的影响 总被引：3，自引：0，他引：3
通过碘-淀粉染色示踪试验,结合数字图像处理技术,分析了裂缝宽度、深度及表面裂缝面积率3个裂缝表征参数对土壤水分入渗的影响。研究结果表明:大裂缝即实际宽度大于1.25 cm的裂缝,其入渗深度超过45 cm,能够促进土壤水分入渗,为水分运移提供明显的优先通道,随着大裂缝宽度的增加,入渗深度在45~65 cm范围内变化,没有明显的规律,小裂缝对入渗的作用不明显。裂缝深度较小时,土壤水分可看作一维半无限均匀运动,而深度较大的裂缝对入渗的影响显著,土壤水分运移表现出明显的优先流特征。表面裂缝面积率与湿润的土体体积具有良好的正相关关系(r=0.95),建立了一元回归模型,并提出以表面裂缝面积率作为裂缝对入渗影响程度的表征指标,面积率越大,裂缝对入渗的作用越明显。 相似文献
8.
Zero tillage and controlled traffic have been proposed as means for more productive and sustainable irrigated farming. Both
practices affect soil infiltration characteristics and, therefore, should have effects on sprinkler irrigation performance.
This study compared water infiltration and runoff in three sprinkler irrigation tests performed on an alluvial loam soil at
different times during a maize (Zea mays L.)–cotton (Gossypium hirstium L.) rotation under two soil managements: permanent beds with crop residue retention (PB: planting beds maintained unaltered
from year to year) and conventional beds with residues incorporated with tillage (CB: disc and chisel ploughing followed by
rotavator pass and bed forming every year). Traffic was controlled and two types of furrows were distinguished in both tillage
systems: with (+T) and without (−T) wheel traffic. The irrigation tests were performed on maize at full cover, on bare soil
just before cotton sowing and on cotton with 50% ground cover. Infiltration and runoff were affected notably by both traffic
and soil management. The soil under PB infiltrated more water than under CB, and −T furrows more than +T furrows. Considering
the combined treatments, −T furrows in the CB system infiltrated more water than +T furrows in the PB system. A sprinkler
irrigation model for simulating water application and soil infiltration and runoff was formulated. The model was used to analyse
irrigation performance under infiltration characteristic of the CB and PB systems in trafficked and non-trafficked furrows.
Five irrigation performance indicators were used to assess the various combinations of tillage and traffic: Wilkox–Swailes
coefficient of uniformity; application efficiency; deep percolation ratio; tail water ratio; and adequacy. The model was used
to develop operation diagrams and provided guidelines for making irrigation decisions in the new controlled traffic/permanent
bed system and in a standard conventional system. 相似文献
9.
环式入渗仪测量土壤初始入渗率效果试验 总被引：2，自引：0，他引：2
提出一种环式入渗试验装置,可以在入渗进行一段时间后,通过观测初始入渗水在土壤剖面的分布,估量初始入渗的过程。该入渗环为可拆分的两个半环,以便通过观察入渗水分在土壤剖面的分布估计初始入渗特性。论述了环的构成和测量过程与方法。同时用有机玻璃圆管装填土样,对比观察模拟真实一维入渗过程。用采自北京的粉壤土和该试验装置进行土壤入渗试验。试验分为3种入土打击能量:1、2、4 kg铁锤,自1 m高处自由落体打击入渗环入土。土壤干体积容积密度分别为:1.2、1.3、1.4 g/cm3。每次试验均向环内注入2 L水,每组试验进行2次重复。入渗环内土壤湿润土体表明,实际发生的土壤入渗为由环壁向环内土壤的径向入渗和由地表向下垂直入渗构成,环壁与土壤剖面间产生的优先流极大地影响了初始土壤入渗率的测量精度。在初始入渗阶段,由环壁向土体的水平径向入渗宽度和由地表向土体的垂直入渗深度近似相等,垂直入渗深度是水平径向入渗宽度的1.001倍。环式入渗仪测得的土壤初始入渗率为模拟真实一维入渗率的3.3倍。研究结果可为环式入渗仪测量结果的评估提供参考。 相似文献
10.
总结了几种研究喷灌动能对土壤性能影响的方法 :单位面积动能对土壤入渗的影响 ;单位面积动能强度对土壤入渗的影响和不同的水滴撞击地面的角度对土壤入渗的影响。减小水滴打击地面动能的措施主要有 :在满足土壤结构不被破坏的前提下 ,尽量选择较小的喷头和喷嘴 ;减少喷灌强度和增加地表的覆盖度。同时与修整畦田、破除土壤表面的硬壳、以及喷施一定计量的化学物质 (如土壤改良剂 )等农艺措施相结合 ,可以更好的改善土壤结构 ,增加土壤的入渗水量 相似文献
11.
12.
咸淡组合淋洗对土壤水盐分布特征的影响 总被引：2，自引：0，他引：2
为了缓解干旱半干旱地区淡水资源紧缺问题,最大限度地利用浅层地下微咸水,以全部淡水和全部咸水为对照,采用两咸一淡组合淋洗的方法对垂直土柱淋洗后土壤剖面的水、盐分布规律及土壤理化性质的变化进行研究,结果表明在累积入渗量相同的前提下,咸淡组合次序对土壤大孔隙的形成有影响,导致土壤透水性不同,通过入渗进入土壤的总盐量是土壤含盐量的主要影响因素;入渗历时的延长有助于提高土壤剖面脱盐深度,淡-咸-咸的组合次序洗盐效果最好;各种咸淡组合次序均导致20 cm深度处的钠吸附比较初始值增大,尤其是全部咸水入渗会降低土壤的渗透性,有可能导致土壤发生次生盐渍化.该研究为微咸水的田间合理利用提供了依据. 相似文献
13.
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
14.
15.
基于使用远程智能控制系统,研究扬黄灌区土壤水分入渗试验,分析讨论了2种类型土壤,基于不同压力、埋深程度研究土壤水分入渗速度、湿润锋、时间等,并初步总结出不同外界条件下土壤入渗的变化规律,为保持水土、提高土壤水分生产力提供重要的科学依据。研究表明:压力、贴片式滴灌带的埋深程度对土壤累计入渗量和入渗速度的影响都比较明显。土壤累积入渗量随着压力水头的增加而增大,湿润运移距离位移不单单和环境有关系,压力对其的影响也很大。在越强的压力作用下,水的运送速度越快,这样土壤的入渗速度就越快。速度的增大也加快了各个方向的运移速率,从而达到在短时间内入渗大面积的土壤,增大了运移距离。实验结果显示,湿润锋能够在压力为0.2 MPa的情况下达到最大运移距离;埋深程度也同样影响着土壤累积入渗量和土壤的累计入渗速度,经试验测量埋深10 cm土壤入渗量最大,且地表不宜蒸发到。 相似文献
16.
An automated real-time optimisation system for furrow irrigation was developed and tested in this study. The system estimates the soil infiltration characteristics in real time and utilises the data to control the same irrigation event to give optimum performance for the current soil conditions. The main components of the system are as follows: the sensing of flow rate and a single advance time to a point approximately midway down the field, a system for scaling the soil infiltration characteristic and a hydraulic simulation program based on the full hydrodynamic model. A modem is attached to a microcomputer enabling it to receive signals from the flow meter and advance sensor via a radio telemetry system. Sample data from a furrow-irrigated commercial cotton property are used to demonstrate how the system works. The results demonstrate that improvements in on-farm water use efficiency and labour savings are potentially achievable through the use of the system. 相似文献
17.
涌泉根灌土壤湿润体特性试验 总被引：4，自引：0，他引：4
为了进一步探明涌泉根灌土壤湿润体特性的变化规律,通过在陕北山地枣树微灌示范基地进行的大田涌泉根灌入渗试验,研究了不同流量条件下涌泉根灌土壤湿润锋运移距离和水分分布的变化规律,结果表明：湿润体水平扩散半径、向上入渗距离、向下入渗深度等随灌水器流量的增大而增大,且均与入渗时间之间呈显著的幂函数关系,其相关系数均高于0.97.提出了涌泉根灌土壤湿润锋运移距离计算式,经试验验证：湿润锋运移距离预测值和实测值的相对误差均小于5%.在上述研究的基础上,建立了涌泉根灌湿润体内土壤平均含水量的计算式,经试验验证：灌后土壤平均含水量预测值和实测值相对误差均小于8%.根据农田灌水的实际需要,假定在涌泉根灌垂向入渗深度与所设定的计划湿润层相等的条件下,建立了涌泉根灌水平扩散半径与计划湿润层之间的计算式,试验结果表明：水平扩散半径计算值与实测值误差小于10%. 相似文献
18.
多点源滴灌条件下土壤水分运移模拟试验研究 总被引：3，自引：0，他引：3
为了指导密植作物的滴灌系统合理设计,通过室内物理试验模拟了多点源滴灌条件下土壤水分运移过程,重点研究了不同滴头流量下交汇湿润体内的土壤水分时空动态分布规律．多点源滴灌条件下土壤水分运动遵循先点源入渗、再湿润锋交汇和最后形成湿润带的规律．灌水结束时,土壤水分分布呈现湿润体上部复杂、下部相对简单的特征．湿润体上部,在滴头下方存在土壤含水率相对较高的区域,2个滴头之间近地表处存在土壤含水率相对较低的区域;湿润体下部同一深度土层上的含水率有趋于一致的趋势．灌水结束后,由于土壤水分再分布,同一深度土层上含水率差异逐渐减小．灌水量相同条件下,灌水结束时,滴头流量小的入渗深度较大,湿润体内土壤平均含水率较低;灌水结束后,受土壤水分再分配的作用,不同滴头流量下入渗深度的差异较灌水结束时有所减小． 相似文献
19.
Water flow and solute transport in furrow-irrigated fields 总被引：3，自引：0，他引：3
Field-scale solute transport experiments are not easily implemented because of the overwhelming problems of soil heterogeneity and variability in subsurface hydraulic and solute transport properties. In this paper, the results of four field-scale furrow irrigation experiments designed to investigate the effect of flow depth and solute application time on bromide distribution along and below the furrows are presented. One experiment was conducted under free-draining (FD) conditions in which bromide was applied during the entire irrigation event. Three experiments were carried out in blocked-end furrows in which bromide was injected either during the entire irrigation event (100%), the first half of the irrigation (FH), or the second half of the irrigation (SH). The FD experiment was equipped with neutron probe tubes for measuring soil water contents at different times and locations in furrow cross-section whereas soil samples for bromide analysis and gravimetric soil water contents from all the experiments were collected at different depths up to 1.80 m, 5 days after the irrigation at three locations near the inlet, in the middle, and close to the outlet of the furrows. Overland flow depths along the furrows were also recorded using staff gauges at the inlet, middle, and outlet sites every few minutes during the entire irrigation. Results showed substantial non-uniformity in solute movement along the monitored furrows, with the degree of non-uniformity depending upon flow depth and solute application time. Non-uniform distributions were observed especially at the outlet sites, compared with those at the inlet and middle sites. Solute application efficiencies for the FD, 100%, FH, and SH experiments were 50, 100, 64, and 93%, respectively. The effects of flow depth and irrigation/solute application time on soil water contents were more pronounced in the soil surface layers and were found to be relatively minor at deeper depths. Water and solute deep percolation rates also showed dependency to flow depth and solute application/opportunity time and gradually decreased along the furrows. 相似文献
20.
《Agricultural Water Management》1998,38(1):21-32
The effects of supplemental irrigation and irrigation practices on soil water storage and barley crop yield were studied for a crust-forming soil at the University of Jordan Research Station near Al-Muwaqqar village during the 1996/97 growing season. An amount of 0.0, 48.9, 73.3, 122.2 and 167 mm supplemental irrigation water were applied. The 48.9, 73.3 and 122.2 mm applications were applied through surface irrigation into furrows with blocked ends, and the 0.0 and 167 mm applications via sprinkler irrigation. The greatest water infiltration and subsequent soil storage was achieved with the 122.2 mm application followed by the 73.3 mm irrigation, both surface applied. Application efficiency (the fraction of applied water that infiltrated into the soil and stored in the 600 mm soil profile) and soil water storage associated with supplemental blocked furrow irrigation was significantly greater than with supplemental sprinkler irrigation. For arid zone soil, which has little or no structural stability, application of supplemental irrigation water via short, blocked-end furrows prevents runoff and increases the opportunity time for infiltration, thereby increasing the amount of applied water that is infiltrated into the soil and stored in the soil profile. Supplemental irrigation, applied by a low-rate sprinkler system, was not as effective because of the low infiltration rates that resulted from the development of a surface throttle due to dispersion of soil aggregates at the soil surface. The differences in stored water had a significant effect on grain and straw yields of barley. Without supplemental irrigation, barley grain and straw yields were zero in natural rainfall cultivation with a total rainfall of 136.5 mm. Barley yields in the control treatment, with a 167 mm supplemental sprinkler irrigation were low being 0.19 and 1.09 ton/ha of barley grain and straw, respectively. Supplemental irrigation through blocked-end furrows increased barley grain and straw yields significantly compared with supplemental sprinkler irrigation to a maximum of 0.59 and 1.8 ton/ha, respectively. The improvement coming from the increased water storage associated with furrows. Since irrigation water is very limited if available, farmers are encouraged to form such furrows for reducing runoff from rainfall thereby increasing the amount of water available for forage and field crop production. 相似文献