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1.
波涌沟灌节水机理与效果的试验分析   总被引:2,自引:1,他引:1  
根据大量的田间入渗及灌水试验资料,分析了波涌沟灌的节水机理并评价了其灌水效果。波涌沟灌的节水性主要是由于在波涌灌溉条件下土壤间歇积水入渗而引起的减渗性,及由此引起的沟道推进流量增大、间歇水流所引起的沟道糙率减小而最终导致推进速度加快。试验分析表明,波涌沟灌较连续沟灌总供水推进速度提高了9%~22%,灌水均匀度提高了18%~23%,灌水定额减小了8.3%~18.2%。  相似文献   

2.
小定额波涌沟灌技术要素的多目标模糊优化模型   总被引:2,自引:0,他引:2  
针对丘陵山区集雨灌溉灌水定额小等特点,利用模糊数学方法,在田间试验的基础上建立了波涌沟灌的多目标模糊优化模型,并求得各灌水技术要素的优化组合:供水时间15 min、停水时间15 min和入沟流量1 L/s。采用该组合技术要素实际灌水试验证明:试验所得各灌水质量指标与模糊优化结果吻合较好,灌溉质量综合效果较好。研究结果为波涌沟灌技术要素的制定提供了多目标模糊优化组合方法,为广大丘陵山区小定额波涌沟灌技术要素的选择提供了多目标模糊优化模型及优化组合方案。  相似文献   

3.
虹吸式波涌管道灌溉技术的初步研究   总被引:1,自引:0,他引:1       下载免费PDF全文
为解决波涌灌溉的关键技术问题,形成所需间歇水流,该文提出了一种新的适合井灌区的节水灌溉技术——虹吸式波涌管灌节水灌溉技术,其根据虹吸原理,利用一套间歇水流发生装置和调节池,可在低压配水管道出口自动形成波涌灌溉所需的间歇水流,实现波涌灌溉。这一技术将波涌灌和低压管道输水灌溉两种先进的节水灌溉技术有机融为一体,充分发挥各自的优势,以获得最佳的节水效果。该文介绍了虹吸式波涌灌溉系统组成和各部分的作用,分析了间歇水流形成原理,通过室内试验验证了这一节水灌溉技术的可行性,为进一步开展田间试验奠定了基础。  相似文献   

4.
土壤间歇入渗水肥耦合特性试验研究   总被引:4,自引:1,他引:3  
为研究肥液浓度对施肥条件下土壤间歇入渗特性的影响,通过不同肥液浓度土壤间歇入渗试验,分析了不同肥液浓度波涌灌溉土壤间歇入渗水肥耦合特性。结果表明:在周期入渗时间相同时,土壤间歇入渗量与间歇入渗率均随肥液浓度的增加而增大,在间歇入渗的的第一周期表现明显,以后各周期这种差异变化随周期数的增加而变缓。同时分析了土壤间歇入渗量随肥液浓度增渗的机理,提出了不同肥液浓度土壤间歇入渗量计算模型,建立了不同肥液浓度土壤间歇入渗参数与清水连续入渗参数的关系,实现了根据清水连续入渗资料与肥液浓度确定波涌灌溉肥液间歇入渗量。实例计算表明,该方法可简单而有效地确定土壤间歇入渗量。  相似文献   

5.
通过波涌灌条件下的室内间歇入渗试验,研究了间歇入渗特性和不同土壤质地、土壤容重及波涌灌循环率等对间歇入渗减渗效果的影响,并与连续入渗进行了对比分析.给出了判断土壤是否适合进行波涌灌的简便方法,为波涌灌技术的进一步研究奠定了基础.  相似文献   

6.
波涌灌溉技术田间适应性分析   总被引:16,自引:5,他引:11  
利用地面灌溉模型对波涌灌溉条件下地表水流及入渗过程进行模拟,在模拟结果与田间实测资料对比基础上,确定适宜的田间灌水参数,即土壤入渗强度、田块规格、田面坡度、入地流量、田间微地形等的变化范围,给出适合于波涌灌水方法应用的田间组合条件,提出波涌灌水技术对壤类土质的田间适应性,为制定波涌灌溉的田间实施方案提供科学的依据  相似文献   

7.
灌施连续与间歇入渗硝态氮运移与土壤含水量的关系   总被引:6,自引:3,他引:3  
通过室内土壤灌施间歇入渗试验,研究了灌施条件下波涌灌溉土壤间歇入渗硝态氮的运移与分布特性,分析了硝态氮分布与土壤含水量的关系,并与灌施条件下土壤连续入渗进行了对比,为进一步研究施肥条件下波涌灌溉土壤间歇入渗溶质运移规律奠定了基础。  相似文献   

8.
陡坡耕地施加PAM侵蚀产沙规律及临界坡长的试验研究   总被引:5,自引:0,他引:5  
PAM(聚丙烯酰胺 )作为一种土壤结构改良剂施用于地表 ,能显著的减小径流和土壤侵蚀量。本研究设计了一系列人工降雨模拟试验 ,定量研究了坡度、坡长、PAM覆盖度、雨强对陡坡耕地土壤侵蚀产沙的影响。试验采用三种雨强 :5 0mmh- 1 、10 0mmh- 1 、15 0mmh- 1 ,四种坡度 :5°、10°、2 0°、2 5° (8 74%、17 63 %、3 6 4%、46 63 % ) ,四种当量坡长 :8m、16m、2 4m、40m ,五种地表处理 :对照、麦草覆盖、三种PAM覆盖度A、B、C(A 相似文献   

9.
聚丙烯酰胺(PAM)对黄土坡地降雨产流产沙过程的影响   总被引:7,自引:1,他引:6  
从防治水土流失和提高降水资源利用率的角度出发,为使PAM能在黄土地区广泛使用,该文通过室内人工模拟降雨和冲刷试验,研究了黄土坡地土壤表层施加PAM对产流产沙过程的影响,分析了产流、径流累计量、泥沙累计量随时间的变化过程,建立了相应的相关关系。比较了不同PAM用量的作用效果及不同土壤对PAM施用效果的影响。试验结果表明,当坡度为15°,雨强1.2 mm/min,降雨历时为30 min时,每平方米土壤表层施加0.8 g PAM后的产流量减少16%,产沙量不到1 kg,减沙率达87.87%;连续冲刷试验结果表明PAM施放在(土娄)土上的效果远优于黄绵土。  相似文献   

10.
[目的]明确不同坡度、容重、含水率、灌水量对辽西褐土沟灌侵蚀产流起始时间的影响,以减少褐土沟灌侵蚀,指导农田灌溉。[方法]采用正交设计进行了室内模拟垄沟冲刷试验,采用4因素3水平的响应曲面分析法建立产流起始时间、侵蚀量的二次多项式数学模型。[结果]产流时间都在20.05s之内,最小的为3.03s;产流起始时间、侵蚀量的二次多项式数学模型决定系数R2分别为0.998 9和0.999 2。[结论]坡度、灌水量、土壤容重、土壤含水率与产流时间呈负相关关系,对产流时间有着显著影响,且灌水量坡度土壤含水率土壤容重;试验中建立的二次多项式数学模型拟合效果良好。通过数值计算,提出不同坡度下满足侵蚀量最小时的灌溉模式。  相似文献   

11.
It is found that the differentiation and degradation of soil depend on surface slope, water flow rate, and furrow length. The development of irrigation erosion on irrigated areas results in the formation of three zones: erosion, stabilization, and accumulation. The high slopes of irrigated plots favor an intense erosion-accumulation process. Depending on the surface slope and the water flow rate, 0.48–19.40 t of soil is washed away from 1 ha. Irrigation erosion affects the density and porosity of soils, and erosion on the slope is enhanced during the differentiation of soil varieties. The texture of soils becomes coarser in the upper erosion region and finer in the aggraded varieties. On the basis of the quantitative assessment of soil erosion rate, the possible losses in dry matter, humus, and essential nutrients are calculated, as well as their removal with water flows.  相似文献   

12.
DOU Chao-Yin  LI Fa-Hu  L. S. WU 《土壤圈》2012,22(5):681-688
The reduction of soil and water losses under furrow irrigation with saline water is important to environmental protection and agricultural production.The objective of this study was to determine the effect of polyacrylamide(PAM)application on soil infiltration and erosion under simulated furrow irrigation with saline water.Polyacrylamide was applied by dissolving it in irrigation water at the rates of 1.5,7.5,and 15.0 mg L-1 or spreading it as a powder on soil surface at the rates of 0.3,1.5,3.0,and 6.0 g m-2,respectively.The effectrolyte concentration of tested irrigation water was 10 and 30 mmolc L-1 and its sodium adsorption ratio(SAR)was 0.5,10.0,and 20.0(mmolc L-1)0.5.Distilled water was used as a control for irrigation water quality.Results indicated that the effectrolyte concentration and SAR generally did not significantly affect soil and water losses after PAM application.Infiltration rate and total infiltration volume decreased with the increase of PAM application rate.Polyacrylamide application in both methods significantly reduced soil erosion,but PAM application rate did not significantly affect it.The solution PAM application was more effective in controlling soil erosion than the powdered PAM application,but the former exerted a greater adverse influence on soil infiltration than the latter.Under the same total amounts,the powdered PAM application resulted in a 38.2%-139.6% greater infiltration volume but a soil mass loss of 1.3-3.4 times greater than the solution PAM application.  相似文献   

13.
膜下滴灌棉花的土壤干旱诊断指标与灌水决策   总被引:20,自引:5,他引:15  
通过利用烘干法和中子仪法对膜下滴灌棉花和常规沟灌棉花的土壤干旱情况进行诊断试验,该文对所选的两种干旱诊断指标—作物适宜土壤含水率和作物缺水指标CWSI的特点进行了研究。试验和分析表明,两种灌水方式下的棉花生长对土壤水分环境的要求是一致的。另外,两种指标所反映出的规律也基本相同。但是,因膜下滴灌棉花的耐旱性弱,受旱风险大,在生产中进行灌水决策时,其干旱诊断指标应比常规灌时灌水量稍大  相似文献   

14.
 Polyacrylamide (PAM) is currently used as an irrigation water additive to significantly reduce the amount of soil erosion that occurs during furrow irrigation of crops. Elevated soil amidase activity specific toward the large PAM polymer has been reported in PAM-treated field soils; the substrate specificity of the induced amidase is uncertain. PAM-treated and untreated soils were assayed for their capacity to hydrolyze the amide bond in carbaryl (Sevin), diphenamid (Dymid), and naphthalene acetamide. Based on results obtained with a soil amidase assay, there was no difference between PAM-treated and untreated soils with respect to the rate of amide bond hydrolysis of any of the agrochemicals tested. It appears that under these assay conditions the PAM-induced soil amidase is not active toward the amide bonds within these molecules. However, carbaryl was hydrolyzed by a different soil amidase. To our knowledge, this is the first soil enzyme assay-based demonstration of the hydrolysis of carbaryl by a soil amidase. Received: 23 June 1999  相似文献   

15.
坡沟系统作为黄土丘陵沟壑区基本的地貌单元,也是黄土高原侵蚀泥沙的主要来源区。植被和梯田作为坡面水土流失治理的主要措施,对于土壤侵蚀控制和生态恢复发挥着重要的作用,定量评估林草、梯田对坡面细沟侵蚀的调控作用以及多措施协同配置问题对于黄土高原水土流失治理和生态保护具有重要意义。为了揭示植被和梯田的格局和配置对坡沟系统细沟侵蚀的协同调控作用,该研究采用人工模拟降雨,结合三维激光扫描技术,分析了坡面4种措施:上坡位植被(措施A)、下坡位植被(措施B)、梯田(措施C)、梯田+植被(措施D)对细沟侵蚀发生和演变过程的影响。结果表明:1)相同植被覆盖度下,下坡位的植被布设细沟最大长度较上坡位的植被布设细沟最大长度减小量更大;2) 第1次降雨中,侵蚀率最大值达到3 500 g/min以上,第2次降雨过程中侵蚀率最大值仅为1 100 g/min以上,在各产流时间内第2次降雨侵蚀率均为第1次降雨侵蚀率的1/3~1/2;3)对于各措施下细沟沟长发育率由大到小表现为措施A(6.55 cm/min)、措施C(5.71 cm/min)、措施B(3.60 cm/min)、措施D(2.69 cm/min);4)梯田与植被同时布设(措施D)对于细沟侵蚀的调控作用优于单一措施(措施B和C),梯田和植被对细沟侵蚀指数细沟侵蚀量、细沟面积、细沟密度产生了协同作用(分别为7.71%、13.76%、7.52%)。研究可为黄土高原坡沟治理措施配置和细沟侵蚀调控提供一定的科学参考依据。  相似文献   

16.
Irrigation-induced soil erosion seriously affects the sustainability of irrigated agriculture. The effects of irrigation water quality and furrow gradient on runoff and soil loss were studied under simulated furrow irrigation in laboratory using a soil collected from an experimental station of China Agricultural University, North China. The experimental treatments were different combinations of irrigation water salt concentrations of 5, 10, 20, and 30 mmolc L-1, sodium adsorption ratios (SAR) of 0.5, 5.0, and 10.0 (mmolc L-1)0.5, and furrow gradients of 1%, 3%, and 5%, with distilled water for irrigation at 3 furrow gradients as controls. The experimental data indicated that total runoff amount, sediment concentration in runoff, and total soil loss amount generally decreased with increasing salt concentration in irrigation water but increased with its sodicity and furrow gradient. The effects of water quality and furrow gradient on soil loss were greater than those on runoff, and the increase of furrow gradient decreased the influence of water quality on soil loss. When the salt concentration increased from 5 to 30 mmolc L-1 at SAR of 10.0 (mmolc L-1)0.5, total runoff amount, sediment concentration, and total soil loss amount decreased by 3.89%, 52.1%, and 53.92%, and 10.57%, 38.86%, and 42.03% at the furrow gradients of 1% and 5%, respectively. However, they respectively increased by 3.37%, 45.34%, and 55.36%, and 3.86%, 10.77%, and 13.91% when SAR increased from 0.5 to 10.0 (mmolc L-1)0.5 at the salt concentration of 5 mmolc L-1. Irrigation water quality and furrow gradient should be comprehensively considered in the planning and management of furrow irrigation practices to decrease soil loss and improve water utilization efficiency.  相似文献   

17.
Numerous studies have been conducted to examine the efficiency of PAM in controlling soil erosion under surface irrigation; however, there are fewer studies that have examined the effect of PAM on soil-water relations. This trickle irrigation laboratory study on a Jordanian clay loam soil addressed the effect of PAM on the spreading of the wetting front. PAM was added to the irrigation water under a trickle irrigation experiment where we irrigated the soil for 30 min. Four PAM concentrations (0.0, 5.0, 10.0, and 20.0 mg l?1) were used to examine its effect on the wetting front propagation in the soil. We also examined the effect of PAM on the soil water content, where we irrigated for 45 min, using two concentrations of PAM, 0.0 and 20.0 mg l?1. The soil water content was measured at depths of 0.0, 5.0, 10.0, 15.0, and 20.0 cm, 4 h, 24 h, and one week after completion of irrigation. PAM's effect on the soil water characteristic curve was studied using PAM concentrations of 0.0, 25, 50, and 100 mg l?1. In this study the spread of the wetting front on the soil surface and in the vertical and horizontal directions inside the soil profile increased when PAM was added to the irrigation water. As the PAM concentration increased the spreading of the wetting front increased. The average wetting front spreading increased in the vertical direction from 7.8 cm when PAM was not used to 8.3, 9.6, and 12.1 cm, for PAM concentrations of 5.0, 10.0, and 20.0 mg l?1, respectively. At the same time the average increase in the horizontal direction was from 18.4 to 18.5, 18.6, and 21.7 cm for PAM concentrations of 0.0, 5.0, 10.0, and 20.0 mg l?1, respectively. The second experiment showed that at a soil depth of 20 cm, volumetric soil water content (θv) was 15.2% when the irrigation water contained 20.0 mg l?1 of PAM compared to 13.9% when no PAM was added to the irrigation water. PAM did not have a significant effect on soil moisture characteristic curve.  相似文献   

18.
灌溉方法对保护地土壤有机氮矿化特性的影响   总被引:6,自引:0,他引:6  
采用Stanford和Smith提出的长期间歇淋洗通气培养法,对连续7a采用渗灌、滴灌和沟灌灌溉,栽培番茄的保护地不同剖面层次土壤的有机氮矿化特点进行了研究。渗灌管为发汗式半软管,埋深为30cm;渗灌、滴灌和沟灌灌水方法及施肥、田间管理同当地农业生产。当20cm深处的土壤水吸力达到40kPa时开始灌水,渗灌和滴灌每次的灌水量是沟灌灌水量的1/2。试验结果表明,土壤矿化氮含量随着土层深度的增加而降低。从累积矿化氮量—时间曲线变化的趋势看,可将保护地土壤0~50cm剖面分为三个层次,其中渗灌与滴灌处理相似,为0~20cm、20~40cm和40~50cm土层,而沟灌处理则为0~30cm、30~40cm和40~50cm土层。保护地不同层次土壤有机氮的矿化可以用Twopool模型表达。比较不同灌溉处理,在0~10cm土层,易矿化有机氮含量(N1)表现为滴灌>沟灌>渗灌,易矿化有机氮矿化速率(k1)常数也以滴灌处理最大,说明滴灌更有利于表层土壤易矿化有机氮的形成。与渗灌和沟灌相比,长期使用滴灌灌溉有利于改善保护地土壤有机氮的品质。  相似文献   

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