共查询到18条相似文献，搜索用时 140 毫秒
1.
以室外试验为基础,应用饱和-非饱和土壤水分运移理论,利用Hydrus软件对甘肃黑方台包气带水分运移规律进行数值模拟,分析土壤剖面不同深度处含水量变化规律,将模拟结果与实测结果进行对比分析,并将拟合参数应用到两种不同的介质中。结果表明：（1）土壤含水率呈峰谷波动变化;（2）均质黄土层和上覆5 cm厚的粉质壤土的黄土层中,土壤水分入渗率和潜水蒸发率均随潜水埋深的增加而减少,在潜水埋深300 cm以下时,两种介质的土壤水分入渗率趋于同一值,含粉质壤土的潜水蒸发率小于均质黄土的潜水蒸发率。表明该含水量的变化具有时空特征,土壤水分入渗率、潜水蒸发率随着潜水埋深变化,其规律整体相似,这对研究滑坡水分分布具有重要意义。 相似文献
2.
以室外试验为基础,应用饱和-非饱和土壤水分运移理论,利用Hydrus软件对甘肃黑方台包气带水分运移规律进行数值模拟,分析土壤剖面不同深度处含水量变化规律,将模拟结果与实测结果进行对比分析,并将拟合参数应用到两种不同的介质中。结果表明:(1)土壤含水率呈峰谷波动变化;(2)均质黄土层和上覆5 cm厚的粉质壤土的黄土层中,土壤水分入渗率和潜水蒸发率均随潜水埋深的增加而减少,在潜水埋深300 cm以下时,两种介质的土壤水分入渗率趋于同一值,含粉质壤土的潜水蒸发率小于均质黄土的潜水蒸发率。表明该含水量的变化具有时空特征,土壤水分入渗率、潜水蒸发率随着潜水埋深变化,其规律整体相似,这对研究滑坡水分分布具有重要意义。 相似文献
3.
不同湿润比下滴灌土壤入渗特性模拟试验研究 总被引：2，自引：0，他引：2
为了研究滴头流量和设计湿润比对土壤水分运移规律及湿润体特性的影响,前期利用粘壤土进行试验研究,然后依据非饱和土壤水动力学理论和滴灌条件下土壤水分运移特征,建立了土壤水分运动模型,利用HYDRUS-3D对不同湿润比下滴灌土壤入渗模型进行求解。通过所建模型,对11个观测点的模拟结果与实测结果进行了对比,得出灌水结束时各观测点模拟与实测含水率的相对误差均小于10%,实测与模拟湿润比的相对误差为4.75%~11.78%。利用所建模型对不同情景下湿润体运移规律进行了模拟,获得了湿润体特征变化规律:滴头流量主要影响水平湿润锋的运移距离,而设计湿润比对垂直湿润锋运移距离的影响较大;滴头流量相同时,设计湿润比越大,湿润体内平均含水率越大,高含水区(含水率0.410 cm~3·cm~(-3))半径也越大;设计湿润比相同时,湿润体内含水率高于0.410 cm~3·cm~(-3)的湿润半径随流量增大而增大。 相似文献
4.
《干旱区研究》2021,38(3):682-694
河套灌区杭锦后旗各质地盐渍土壤的水分入渗性能、温度及含盐量不同,使土壤改良效果存在差异。为研究"沙穴"种植番茄对不同土质的土壤水分、温度、盐分的迁移规律,通过在土柱中填装3种典型土质(砂壤土、粉壤土、黏壤土),同时布设沙穴,探索在滴灌条件下种植加工番茄以改良不同土壤质地的可行性。结果表明:沙穴种植对不同土质的水热盐迁移影响不同,沙穴种植能显著改善黏壤土土壤水分入渗性能,提高根系层土壤的湿润区面积及含水率,在深度20～40 cm相对增加了24.15%,但降低了砂壤土和粉壤土的保水性,土壤剖面含水率呈上干下湿的特点;沙穴种植可显著提高作物生长初期黏壤土的温度(P0.05),平均增温3.64℃,有利于初期幼苗生长发育,但对原状砂壤土和粉壤土的温度变化不显著,生育后期土壤温度随着气温变化均呈下降趋势;沙穴种植对土壤盐分具有淋洗作用,在深度20 cm处,粉壤土和黏壤土的盐分淋洗效果显著(P0.05),平均相对脱盐率达23.28%和56.29%。综合分析沙穴种植对不同土质盐渍土土壤水热盐迁移规律,得出在杭锦后旗3种典型盐渍土中,黏壤土是最适宜沙穴改良方式的土质。 相似文献
5.
滴灌条件下水分入渗与再分布是评价滴灌灌溉效率的重要内容,通过Hydrus3D模型模拟单点源和点源交汇情况下水分入渗及其再分布过程,并利用田间试验实测资料进行验证。结果表明:采用Hydrus3D软件建立的模型可较好地模拟单点源水分入渗、水平湿润锋扩散过程及土壤剖面水分的分布情况,水平湿润锋距离的模拟值和实测值的误差在灌水结束时达到最大,且滴头流量越大,误差亦越明显,其中最大绝对误差为4.6 cm,最大相对误差达0.167,R2在0.95以上,F检验P值大于0.05,且RMSE在2.1以内;模型模拟的土壤体积含水量分布和实测值基本一致,模拟值和实测值的R2在0.90以上,F检验P值大于0.05,RMSE均小于0.07;湿润范围模拟结果和实测结果的吻合度较高。灌水结束后20 h,模拟土壤剖面含水量的分布情况与实测值基本一致,模拟值和实测值R2在0.575~0.652之间,F检验P值大于0.05,RMSE在0.013左右,双点源交汇区整个剖面模拟值和实测值R2为0.526以上,F检验P值大于0.05,RMSE均小于0.01,模拟结果较好,说明Hydrus3D模型可模拟土壤水分再分布情况。 相似文献
6.
肥液浓度对膜孔单向交汇入渗NO-3-N运移特性的影响 总被引：1，自引：0，他引：1
通过室内入渗试验,研究了不同浓度的膜孔肥液单向交汇入渗NO3--N的分布特性。研究表明,不同肥液浓度的膜孔入渗湿润体膜孔中心和交汇界面中心垂向土壤NO3--N的浓度锋运移距离与土壤水分运动的湿润锋一致;肥液浓度越大,相同入渗时间的NO3--N浓度锋运移距离越大,土壤NO3--N浓度最大值越大,相同深度处土壤NO3--N浓度也越大。建立了肥液交汇入渗湿润体膜孔中心和交汇界面中心垂向土壤NO3--N浓度分布特征与湿润体深度之间的分段函数模型,经实测资料验证表明,该模型精度较高。入渗供水过程中,NO3--N浓度锋运移距离和浓度最大值随时间的延长而增大;再分布过程中,NO3--N浓度前锋运移距离随时间延长而增大,而NO3--N浓度最大值逐渐减小。 相似文献
7.
针对土壤盐分较重的砂壤土确定土壤水分扩散率D（θ）的问题,采用室内非稳定流水平土柱法对新疆石河子121团灌区膜下滴灌棉田不同粒径砂壤土水分扩散率及土壤盐分运移进行了研究。结果表明：粒径为1.0~2.0 mm的砂壤土水分扩散率最大,而且变化比较迅速,其次是0.5~1.0 mm的砂壤土,最小的是<0.5 mm的砂壤土,随着土壤粒径的减小,土壤水分扩散率逐渐降低;随着土壤含盐率的增大土壤水分扩散率减少。得出以土壤体积含水率为变量而且还考虑土壤含盐率的综合通用模式,该通用模式较为符合实际情况,并能够较好地反映同一容重、相同水平距离情况下粒径不同时含盐砂壤土的土壤水分扩散率的变化。 相似文献
8.
通过室内膜孔肥液自由入渗试验,观测分析不同入渗时间和再分布过程中铵态氮运移和分布特性,结果表明:在肥液自由入渗过程中,铵态氮锋面运移滞后于土壤水分锋面,但土壤铵态氮含量和土壤含水率以膜孔为中心向外逐渐减小;在再分布初期,土壤铵态氮锋面和土壤水分锋面运移一致,土壤铵态氮含量和含水率以膜孔为中心向外逐渐减小,减小的速度变慢,但随着再分布时间延长,土壤铵态氮开始硝化成硝态氮,铵态氮含量减小,硝态氮含量增加。 相似文献
9.
基于HYDRUS-1D的不同质地土壤入渗过程数值模拟 总被引：1，自引：0，他引：1
基于HYDRUS-1D软件,对不同土质(淤泥、粉砂壤土、砂质粘壤土)的灌溉方案进行了系统的数值实验,模拟灌溉结束时及灌溉结束24 h之后的土壤剖面含水量和土壤湿润锋的变化情况。结果表明:在不产生径流的情况下,灌溉结束24 h后土壤的含水量分布和湿润深度只与土壤种类和灌溉量有关,与灌溉速度无关;对透水性较好的土质,灌溉水分重分布明显,以粉砂壤土灌溉速率0.7 cm·h~(-1)和灌溉时间3 h为例,灌溉结束时和灌溉24 h后土壤湿润深度分别为9.2 cm和20.6 cm,有55.3%的灌溉水参加了水分重分布;土壤湿润深度与灌溉量之间存在线性关系,拟合直线的斜率介于5.15(淤泥)和5.95(砂质黏壤土)之间。 相似文献
10.
垄作沟灌技术具有显著的节水增产作用,但在春小麦种植中应用尚缺乏参数设计方面的理论支撑。本研究采用粉砂质粘壤土与粘土两种典型土壤实测水分运动参数和HYDRUS软件,模拟了梯形灌水沟不同垄宽情况下的土壤水分运动和停水后水分再分布,研究了不同灌水量时湿润锋推进过程和水分再分布后的湿润体变化,分析了设计灌水定额下适宜作物生长湿润体范围,提出了粉砂质粘壤土和粘土宜采用的合理垄宽为20～50 cm和20～35 cm,这一结果为干旱区春小麦垄作沟灌技术推广提供了技术支撑。 相似文献
11.
Petri dish bioassays, based on root response of corn grown in soil or in perlite, were used to study the activity, adsorption,
mobility and field persistence of sulfosulfuron in a silty clay loam and a sandy loam soil. Both bioassays indicated that
activity of sulfosulfuron increased with increasing herbicide concentration, and to a slightly greater degree in sandy loam
soil than in silty clay loam soil. More sulfosulfuron was adsorbed on the sandy loam (not biologically available) than on
the silty clay loam soil. Consequently, slightly greater amounts of sulfosulfuron were leached through the silty clay loam
than through the sandy loam soil. Biologically available sulfosulfuron was not detected at depths below 40 cm after application
in sandy loam, but this was not the case for the silty clay loam soil. In 2002, all sulfosulfuron rates showed field persistence
of less than 5 months. On the other hand, in 2003, biologically available sulfosulfuron was detected in the 0–10-cm soil depth
150 days after application.
http://www.phytoparasitica.org posting May 6, 2004. 相似文献
12.
Laboratory studies on the formation of bound residues and on the degradation of the triazole fungicide propiconazole were conducted in two different soils. Soils treated with 14C-propiconazole were incubated at 22 degrees C and extracted exhaustively with a solvent at each sampling date until no further propiconazole was extracted. The solvent-extractable residues were used to measure propiconazole remaining in the soil, and the extracted soils were used to investigate bound residues of propiconazole. Mineralization of propiconazole was investigated by measuring [14C]carbon dioxide evolved from the soil samples. Formation of bound residues of propiconazole was higher in silty clay loam soil than in sandy loam soil, giving approximately 38 and 23% of the applied 14C, respectively. In contrast, the rates of degradation and mineralization of propiconazole were lower in silty clay loam soil than in sandy loam soil. Decreased extractability of the 14C residues with incubation time was observed with increased formation of bound residues. When the propiconazole remaining in the solvent-extractable residues was quantitatively measured by high-pressure liquid chromatographic analysis, the half-life value in sandy loam soil was about 315 days, while the half-life in silty clay loam soil exceeded the duration of the 1 year experimental period. Increased formation of bound residues was observed as propiconazole degraded with incubation time, suggesting that degradation products are involved in the formation of bound residues. Our study suggests that the formation of bound residues of propiconazole contributes to the persistence of this fungicide in soil. 相似文献
13.
Willy Dejonckheere Walter Steurbaut Guy Melkebeke Ren H. Kips 《Pest management science》1983,14(2):99-107
The leaching of aldicarb and thiofanox in soils (sandy loam, silt loam and sandy clay loam), and their uptake by sugarbeet plants were studied. Three irrigation levels were maintained: half, normal and double dose. The residues were determined as the sum of the insecticidal metabolites (parent compound + sulphoxide+ sulphone) for both pesticides. Leaching was greatly influenced by the amount of water added and the soil type. Under normal conditions, leaching seemed to proceed very slowly, keeping the chemicals available for uptake by the root systems for a long time. The concentration of insecticide in the leaves was highest in beets grown on sandy loam and lowest in those grown on sandy clay loam. The quantity of irrigation did not influence the residue concentration in the leaves greatly, although its influence was obvious on the total residue present (μg per plant). Increasing the water dose always resulted in a higher total residue, and a greater plant weight. The breakdown in the soils was directly related to the water dose. The experiments show that thiofanox was more stable than aldicarb and was taken up by sugarbeet to a greater extent. 相似文献
14.
为了解雨水集聚深层入渗(RWCI)系统土壤水分的入渗规律,设置不同灌水量(10 L、21 L和36 L)和RWCI设计坑深(40 cm和60 cm)的室内土箱试验,观测不同灌水量与不同水头变化情况土壤含水率变化和土壤湿润锋在径向和垂直方向上运移过程,依据非饱和土壤水动力学理论,建立HYDRUS-2D变水头边界条件土壤水分二维入渗模型。通过与实测数据对比,结果表明模型模拟值和实测值具有较好一致性:垂向湿润锋相对均方差(R_E)、平均绝对误差(MAE)和纳什系数(NE)分别为0.019、0.011 cm和0.994,径向湿润锋R_E、MAE和NE分别为0.018、0.851 cm和0.977,土壤含水率R_E、MAE和NE分别为0.188、0.016 cm~3·cm~(-3)和0.916。相比于设计深度为40 cm的RWCI系统, 60 cm RWCI系统在不同灌水量下能够更有效地增加果树根系分布层的土壤含水率,增加土壤水分入渗深度;相同灌水量下RWCI系统设计深度的径向湿润锋分布间无明显差异,而垂直方向的分布具有明显差异;RWCI系统在相同的设计深度下,随着灌水量增大湿润锋在垂向与径向的运移距离差异逐渐增大。 相似文献
15.
Shenghai PU 《干旱区科学》2019,11(5):740-753
Biochar addition can improve the physical and hydraulic characteristics of sandy soil. This study investigated the effects of biochar on water holding capacity and water movement in sandy soil under drip irrigation. By indoor simulation experiments, the effects of biochar application at five levels (0%, 1%, 2%, 4%and 6%) on the soil water retention curve, infiltration characteristics of drip irrigation and water distribution were tested and analyzed. The results showed thatbiochar addition rate was positively correlated with water holding capacity of sandy soil and soil available water. Within the same infiltration time, with an increasing amount of added biochar, the diffusion distance of the horizontal wetting front (HWF) tended to decrease, but the infiltration distance of vertical wetting front (VWF) initially declined and then rose. The features of wetted bodies changed from "broad-shallow" to "narrow-deep" type. The relationship between the transport distance of HWF and VWF and the infiltration time was described by a power function. At the same distance from the point source, the larger was the amount of added biochar, the higher was the soil water content. Biochar had a great influence on the water content of the layer with biochar (0-200mm) and had some effects at 200-250mm without biochar; but had less influence on the soil water content deeper than 250mm. For the application rate of biochar of 4%, most water was retained within 0-250mm soil layer. However, when biochar application amount was high (6%), it would be helpful for water infiltration. During the improvement of sandy soil, biochar application rate of 4% in the plow layer had the best effect. 相似文献
16.
为缓解无灌溉丘陵区土壤季节性干旱问题,以岩棉为供试材料,通过室内模拟结合野外林地试验,研究了岩棉对不同质地土壤的增水潜力、岩棉水分扩散能力、岩棉材料对不同坡位土壤水分保蓄能力以及对山核桃林地土壤水分保蓄和油菜生长的影响,以期探索出一种新型实用的土壤水分保蓄技术。室内模拟试验结果表明,供试岩棉最大容积持水量为64.64%;分析了岩棉应用于松砂土、砂壤土、中壤土和轻粘土等4种不同质地土壤的保水潜力,土壤最大容积有效含水量分别增加54.02%、50.67%、41.41%和50.31%。将吸水饱和岩棉埋入风干土壤中,水分在垂直和水平方向均有扩散作用,并在一定时间内达到相对稳定状态。距岩棉垂直方向和水平方向5 cm处最高土壤含水量分别为27.89%和20.67%,10 cm处土壤最高含水量分别为13.13%和13.00%,由此建议,岩棉埋设位置距离根系不宜太远。林地试验表明,岩棉对红豆杉林地不同坡位土壤均能充分发挥水分保蓄作用,持续晴天无雨时,红豆杉林地上、下坡位土壤含水量顺序为岩棉附近岩棉地植物根附近无岩棉地(对照)。久旱和雨后山核桃林地岩棉附近土壤含水量比无岩棉地分别提高29.19%和23.39%(P0.05);油菜生长宽度范围为80 cm,岩棉保水影响范围是岩棉自身宽度的5倍之多;与无岩棉对照相比,埋设岩棉处油菜植株(开花期)的地茎、株高、叶面积和单株鲜重等指标分别提高了58.63%、62.85%、65.66%和44.51%(P0.05)。在土壤中合理使用岩棉材料是解决无灌溉丘陵区土壤季节性干旱问题的有效措施之一。 相似文献
17.
土壤底墒与苗期灌溉量对玉米出苗和苗期生长发育的影响 总被引：4，自引：3，他引：4
采用二次回归正交设计方法,进行了土壤底墒和苗期灌溉量对玉米出苗和苗期生长发育影响的盆栽试验研究,分别建立了苗期株高、总干重与土壤底墒、灌溉量关系回归模型。研究结果表明,土壤底墒显著影响玉米出苗率,玉米出苗率最高时的壤土和沙土底墒分别为20.6%和13.6%;土壤底墒和苗期灌溉量的交互作用对株高和单株干物质重量具有相互协同效应和替代效应;玉米苗期株高和总干重最大时的壤土底墒均为15.1%,最佳灌溉量分别为86.7 mm和91.7 mm;玉米苗期株高和总干重最大时的沙土底墒分别为12%和13%,最佳灌溉量均为76 mm。 相似文献
18.
农田土壤入渗特性研究 总被引：3，自引：0，他引：3
以陕西杨凌一级阶地砂壤土和三级阶地粘壤土所选典型田块的双环入渗试验为基础,对不同土壤质地条件下的土壤入渗特性进行了研究。结果表明：两种土壤质地条件下描述其入渗过程的最优入渗公式为修正Kostiakov公式;土壤入渗试验合理的设计观测时间一级阶地砂壤土条件下不应小于90 min,三级阶地粘壤土条件下不应小于120 min;根据各入渗参数的最大相关距离,计算了典型田块入渗试验的合理测点数,一级阶地砂壤土和三级阶地粘壤土试验田块均为42个测点;可在一定程度上借助稳定入渗率f0的变异特征描述土壤入渗性能和衡量土壤入渗能力,但同时还应考虑入渗参数k的空间变异特征。 相似文献