共查询到20条相似文献，搜索用时 359 毫秒
1.
干旱区地下水主要补给来源为河水入渗,评价干旱区地下水资源量需要准确计算河床的参数,包括垂向河床渗透系数(K)和垂向河水入渗速率(V)。本文描述了一种简化后的渗水仪和干旱区河床垂向渗透系数的计算公式,将该方法应用于新疆南部昆仑山北麓,测定了干旱区河流的河床参数。结果表明:此方法能够有效地测定干旱区河床垂向渗透系数,18个试验点的垂向河床渗透系数在0.864~14.832 m·d~(-1)。根据试验结果总结了干旱区河水垂向入渗速率与河水深度的关系,提出了一个用于描述干旱区河流河水入渗速率与河水深度关系的经验方程,表明河水垂向入渗速率(V)与河水深度(M)正相关,(河水入渗速率的增长率((dV)/(dM))与河水深度负相关,当河水深度很大时,河水入渗速率的增长率趋于0。 相似文献
2.
采用水头下降竖管法对2011年11月-2014年11月渭河陕西段的5个区域河床垂向渗透系数(Kv)进行计算,分析其变化规律并试图通过沉积物的物理化学性质揭示Kv值变化的机制。结果表明:1)渭河草滩段河床的Kv值大于其它4个点位;2)草滩段Kv值具有较为强的时间变异,其它4个点位Kv值在较小范围内变动即趋于稳定;3)2013年5月以后各点位的Kv值比较接近;4)河水温度差异对Kv值的时空变化有一定的影响;5)河床沉积物的类型差异是Kv值变化的主要影响因素;6)不同类型的河床沉积物对Kv值的影响机制存在差异,但Kv值均与沉积物的孔隙率(n)和不均匀系数(Cu)相关。 相似文献
3.
以双膜覆盖栽培技术为研究基础，通过探索不同揭膜方式对棉花生长发育、产量及品质的影响，提出一种新型的地膜覆盖及揭膜方式，以期有效解决残膜污染问题。田间自然条件下，设置5个处理，即膜侧播种+双膜覆盖+苗后头水前揭膜(T1)、膜侧播种+双膜覆盖+苗后揭上膜(T2)、裸播(T3)、膜下播种+单膜覆盖+苗后揭膜(T4)、膜下播种+双膜覆盖+苗后揭上膜(CK),测定棉花农艺性状、生育期、成铃、产量及品质指标，进而分析处理间差异。结果表明：T1处理对棉花株高影响不显著，T2和T4处理对株高影响较小，而T3处理则导致株高显著降低，对棉花生长具有抑制作用；T1、T4和CK处理可以显著降低杂草数量，T2和T3处理对杂草数量的控制力度相对较弱；揭膜方式的变化对棉株生育期天数及产量形成的空间分布具有一定影响；T3处理会显著降低棉... 相似文献
4.
为明晰塔里木河的水文过程,实现水资源的优化配置,采用颗粒分析法,分析塔里木河上中游河床沉积物渗透系数的时空变化特点,并借助达西定律确定了不同来水情景下4个河段的渗漏水量。结果表明:1塔里木河河床沉积物土壤颗粒的粒径0.000 5~0.5 mm,砂类土的比重为83%,因此,Sauerbrei公式用于该河流河道渗透系数的计算。2河床沉积物渗透系数与水温的变化具有一致性,段2、段4、段1和段3的年均渗透系数分别为115.3m·d~(-1)、74.5 m·d~(-1)、71.4 m·d~(-1)、45.2 m·d~(-1),呈逐渐减小趋势。3在12.5%、50%和87.5%的3个来水频率下,河段耗水量、渗漏水量及单位河长渗漏水量均呈现递减趋势;上中游总渗漏水量分别为10.85×108m3、9.94×108m3、9.13×108m3,水量渗漏集中在5—10月。4在同一来水频率下,河段渗漏水量依次为:段1段4段2段3,而单位河长渗漏水量为:段1段4段3段2。验证结果表明,渗漏水量计算结果与定量分离结果误差仅为2%,故渗漏水量及渗透系数计算结果合理。该研究可为实现塔里木河生态引水工程的合理布局和生态保护提供科学依据和技术支撑。 相似文献
5.
为改善蠋蝽在室内继代饲养过程中品质退化问题，提高该虫规模化繁殖效率。本研究以田间大纱笼作为半自然条件，对室内连续繁殖10代的蠋蝽4龄若虫进行复壮，并在室内条件下测定了复壮与未复壮蠋蝽交叉配对（♀田×♂田、♀田×♂室、♂田×♀室、♀室×♂室）后的雌雄成虫寿命、繁殖能力、F1代发育历期及存活率等生物学特性。结果表明，复壮未对蠋蝽雌雄成虫寿命产生显著影响，但对其生殖力及F1代适应性等方面影响显著。♀室×♂田配对组的蠋蝽产卵量最高、产卵前期最短、产卵期最长；相较于雌虫未复壮组（♀室×♂田、♀室×♂室），雌虫复壮组（♀田×♂田、♀田×♂室）的产卵量减少、产卵前期延长；雌雄虫未复壮组（♀室×♂室）无明显偏雌或雄性现象，而雌雄虫均复壮或其中一方复壮组（♀田×♂田、♀田×♂室、♀室×♂田）均出现明显偏雌性；相较于雌雄虫未复壮组，♀田×♂田的F1代由卵到成虫的发育期显著延长、成虫存活率下降。本研究表明，在室内条件下，以田间大纱笼作为半自然条件复壮的蠋蝽繁殖能力提高，但未复壮蠋蝽的F1代适应性更强。 相似文献
6.
利用和田绿洲空气质量日报数据和同期的常规气象资料，分析了2015年1月1日至2017年12月31日该区的空气质量特征，探讨了气象条件和空气质量之间的相互关系。结果表明：和田绿洲近3 a平均环境空气质量指数（AQI）为199，达到空气质量中度污染标准，污染天数占总日数的78.1%。其中，春季空气质量最差，以严重污染为主；其次是夏季，以轻度和严重污染为主；再次是秋季和冬季，以轻度污染为主。PM10、PM2.5浓度年平均分别为332 μg·m-3和100
μg·m-3，超标率为75.7%和49.5%，其余污染物超标率在3%以下，其中PM10浓度春季最大，夏、秋季其次，冬季最小；PM2.5浓度春季最大，夏、冬季其次，秋季最小；SO2、NO2、CO浓度冬季最大，春、秋季次之，夏季最小；O3浓度夏季最大，春、秋季次之，冬季最小。除降水量外，AQI与其余气象因子均呈极显著相关；除平均气温与PM2.5、相对湿度与CO、降水与SO2、PM10、O3、PM2.5无相关外，其余气象因子对污染物浓度 均有显著影响；能见度与AQI和各类污染物浓度均为极显著相关。随着能见度的上升，AQI下降，在同样能见度条件下，AQI在沙尘多发期的夏半年高于沙尘少发期的冬半年；不管在沙尘多发期还是少发期，随着能见度的转好，SO2、PM10、CO、PM2.5污染物浓度呈减少趋势，O3浓度呈增多趋势，NO2浓度无明显的规律，而且PM10、O3、PM2.5浓度夏半年高于冬半年，SO2、CO、NO2浓度冬半年高于夏半年。在沙尘天气期间，最低能见度小于1 km的浓浮尘和沙尘暴天气AQI相互接近，最低能见度在1～3.5 km的浮尘和扬沙天气AQI相互接近，当最低能见度大于3.5 km时，浮尘天气的AQI高于扬沙天气的AQI；PM10、PM2.5浓度随着最低能见度升高而变小，其他污染物浓度虽然随着最低能见度的变化有一定的差别，但规律不明显。 相似文献
7.
以‘陇藜4号’为试验材料，采用根管土柱栽培的方式，研究了不同程度盐碱胁迫(S1:轻度盐碱胁迫；S2:中度盐碱胁迫；S3:重度盐碱胁迫)条件下土壤调理剂PAM施用深度(PAM0-10:距地表0～10 cm; PAM10-20:距地表10～20 cm; PAM20-30:距地表20～30 cm; PAM0-30:距地表0～30 cm)对藜麦根系生长、叶片渗透调节物质含量、植株生物量及产量的影响。结果表明：在PAM施用深度为0～10 cm时，轻度盐胁迫处理藜麦的根长、生物量及产量指标较对照组(S0:不加入盐碱和PAM)分别高出35.71%、15.48%和4.60%,表明藜麦具有较强的耐盐能力。当盐碱胁迫增加到一定程度(S2和S3处理)时，藜麦的形态指标有显著下降趋势，与对照组处理相比重度盐胁迫藜麦的根长、生物量下降幅度最大，平均分别下降了53.72%和62.99%,但在同等重度盐碱胁迫程度时，PAM0-10处理能够缓解盐碱对藜麦生长产生的胁迫作用，与对照组相比藜麦的根长和生物量分别降... 相似文献
8.
模拟干旱胁迫下冬小麦胚芽鞘长度变化及与抗旱性的关系研究 总被引：5，自引：0，他引：5
以6个抗旱性不同的冬小麦品种(系)为材料,通过不同浓度的PEG-6000渗透溶液模拟干旱胁迫处理,研究了小麦苗期的胚芽鞘长度、苗高、主胚根长等性状,并与其在大田及防雨棚控水条件下的产量构成和抗旱性的关系进行分析.结果表明,在不同浓度的PEG-600 0渗透溶液干旱胁迫处理下,小麦苗期胚芽鞘长度在品种间差异显著;产量的抗旱指数与苗期不同干旱胁迫处理下的胚芽鞘长度的相关性分析表明,小麦的胚芽鞘长度与其抗旱指数呈极显著正相关(相关系数为0.9600),抗旱性强的品种胚芽鞘较长,抗旱性弱的品种胚芽鞘较短.在不同程度的干旱胁迫处理下,各品种的胚芽鞘长度变化趋势大致相同 ,因此利用胚芽鞘长度可以在早期对小麦的抗旱性进行鉴选. 相似文献
9.
渭河陕西段潜流带污染特征及其对河水的影响 总被引：1，自引：0，他引：1
河流潜流带沉积物间隙水是影响河流水质的重要因素,为探究其污染物迁移转化对河水的影响,通过现场采样和室内实验测试分析,2013年6月和12月对渭河陕西段4个研究点沉积物中含水率、有机质(OM)的特征和总氮(TN)、总磷(TP)在沉积物中的垂直变化规律进行分析,并分别对TN、TP、有机质在沉积物、间隙水和河水的迁移转化进行相关性分析。结果表明：① 有机质含量在垂直方向上大体呈现随深度增加而波动下降的趋势,但眉县在12月的10 cm以下反而随深度增加而上升;② 沉积物中TP、TN在夏季的平均含量分别为18.55 mg·kg-1和13.52 mg·kg-1,在冬季的平均含量分别为6.48 mg·kg-1和2.91 mg·kg-1,含量偏高,属严重污染,且夏季污染程度高于冬季。沉积物、间隙水和河水TP、TN含量的比较表明,三者之间存在“汇”与“源”的关系,沉积物间隙水TP、TN含量高于河水TP、TN含量,具有向河水释放的趋势;③ 相关性分析表明,间隙水与河水中的TP、TN和有机质存在显著相关性,而和沉积物中的TP、TN相关性不明显,夏季各介质氮磷间的相关性较冬季显著。 相似文献
10.
为探究内蒙古田间影响燕麦叶斑病的因素，采用正交试验设计对燕麦品种、播期、种植密度、施氮量、施磷量和灌水量6个因素及其组合于2009—2011年进行连续3年的重复试验，运用逐步回归法对3年试验数据进行分析，探讨不同因素及其组合对燕麦叶斑病的影响。正交方差和分析表明，播期和品种是影响燕麦叶斑病的主要因素，方差贡献率分别为78.69%和12.20%；而施氮量、施磷量和灌水量对燕麦叶斑病发生程度均无显著影响。拟合分析获得燕麦叶斑病发生程度与播期(x2)、品种(x1)和种植密度(x3)之间的非线性回归方程为y=51.99-6.45x2-0.39x1x3，表明适当推迟播期、选择抗性较高的燕麦品种且相对密植可减轻燕麦叶斑病的发生程度。 相似文献
11.
采用Pearson相关分析法研究负水头供液下不同淋洗时间和淋洗量处理下温室番茄日耗液量与空气相对湿度、气温和太阳辐射强度等环境因子的相关关系,采用通径分析原理分析各环境因子对番茄日耗液量的直接作用和间接作用,并建立了多元回归模型。结果表明:番茄日耗液量与各环境因子均呈显著线性相关(P0.05),其中与日平均太阳辐射强度和日最高太阳辐射强度的正相关性最强;与日最高相对湿度的负相关最强。日平均太阳辐射强度是番茄日耗液量的主要决策因子,决策系数为45.7%,日有效积温是主要限制因子,决策系数为-459.6%。番茄日耗液量模拟值与实测值的回归系数平方值为0.965。建立的多元线性回归模型可较好地预测番茄日耗液量。 相似文献
12.
北方冬小麦品种(系)节水抗旱性研究 总被引：1，自引：0，他引：1
本研究选取中国北方不同生态型冬小麦品种(系)进行产量、收获指数、WUE、抗旱指数、冠层温度等指标和一些农艺性状的测定与分析,以评价参试品种的节水抗旱性。随着灌水量的增加,参试品种的产量均有不同程度的增加,由于参试品种对水分的敏感度不同,产量增加幅度也不尽相同。充分灌溉、自然降水与干旱胁迫处理洛旱6号产量均最高,分别为6 316.20 kg·hm~(-2)、2 538.75 kg·hm~(-2)、1 119.75 kg·hm~(-2)。充分灌溉处理周麦24对水分最为敏感,产量较自然降水处理增加44.12%;自然降水处理开麦20对水分最敏感,产量较干旱胁迫处理增加201.47%。通过产量、抗旱指数与灌浆期的冠层温度的相关性研究,发现产量与灌浆期的冠层温度呈极显著的负相关,与灌浆中期的冠层温度相关系数最高为-0.908。抗旱指数与灌浆后期的冠层温度呈极显著的负相关,相关系数-0.453,与灌浆前期和灌浆中期的冠层温度呈显著负相关,相关系数分别为-0.342、-0.366。 相似文献
13.
IBN ALI Zouheira 《干旱区科学》2017,9(2):244-255
In arid and semi-arid areas, artificial recharge is a key technology in groundwater resources management, and a reliable estimate of artificial recharge is necessary to its sustainable development. Several methods are available to estimate the artificial recharge; however, most of them require field data or model parameters, thus limiting their applications. To overcome this limitation, we presented an analytical method to estimate the artificial recharge through monitoring the water release by piezometer and analysing the controlling factors of the artificial recharge from a hill dam in Tunisia. A total of 97 measurements of water flow in the streambed recorded from 4 gauging stations were analysed. Results indicated that the average infiltration velocity ranged from 0.043 to 0.127 m/d and the infiltration index varied from 7.6 to 11.8 L/(s·km). Pearson's correlation coefficient analysis shows that the infiltration index, the stream gradient, the thickness of unsaturated zone, the number of infiltration pond, the stream geometry, and the water flow rate were found to be the main factors in determining the infiltration. The high correlation coefficients(0.908 for the number of infiltration pond and 0.999 for the stream geometry) mean that the number of infiltration pond and the stream geometry are the most influential factors. Time variations of groundwater level were used to analyze the recharge effects on the piezometry of aquifer. The analysis showed that during the artificial recharge, the water table increased at a rate of 5 mm/d and that the increase was limited to the area surrounding the recharge site. Based on the results of the study, building infiltration ponds along streambed and improving the potential of rainwater harvesting over the study area are recommended. 相似文献
14.
将土壤供水头压力控制为负值,测定了垂直入渗、毛管上升和水平入渗3种情况下的土壤吸水过程.发现随供水吸力的增加,垂直入渗、毛管上升和水平入渗过程中湿润峰前进速度和入渗速度的相对差异变小.将入渗速率等于潜在蒸发速率时的湿润厚度定义为临界湿润厚度,计算了潜在蒸散宰为5 mm/d时不同负水头下壤土的临界湿润厚度;确认了垂直、毛管和水平入渗下湿润峰位置与入渗量的关系,将湿润蜂位置-累计入渗量曲线的斜率,印巴湿润土体内入渗水分所占的容积百分数定义为湿润系数,提供了所测壤土的湿润系数-负水头曲线;建立了负水头供水过程中土壤含水量空间分布模型;观察到湿润锋含水量与供水吸力闸的依赖关系. 相似文献
15.
敌草快的水解动力学研究 总被引：2，自引：1，他引：2
研究了敌草快于25℃下在去离子水、河水和地下水3种水体不同pH值(pH 5、7、9)条件下的水解动力学以及pH为9时不同温度(10、25、35℃)条件下的水解行为。结果表明,敌草快的水解动力学属于一级反应,且其在去离子水中的水解速率与其在河水和地下水中的相似;敌草快在酸性和中性条件下比较稳定,不易水解,而在碱性条件下水解较快;温度升高有利于水解反应,水解活化能为25.89 kJ/mol,活化熵为-191.81 J/mol·K,温度效应系数为1.52。 相似文献
16.
Shunjun HU 《干旱区科学》2017,9(1):27-37
A knowledge of soil permeability is essential to evaluate hydrologic characteristics of soil, such as water storage and water movement, and soil permeability coefficient is an important parameter that reflects soil permeability. In order to confirm the acceptability of the one-dimensional horizontal infiltration method(one-D method) for simultaneously determining both the saturated and unsaturated permeability coefficients of loamy sand, we first measured the cumulative infiltration and the wetting front distance under various infiltration heads through a series of one-dimensional horizontal infiltration experiments, and then analyzed the relationships of the cumulative horizontal infiltration with the wetting front distance and the square root of infiltration time. We finally compared the permeability results from Gardner model based on the one-D method with the results from other two commonly-used methods(i.e., constant head method and van Genuchten model) to evaluate the acceptability and applicability of the one-D method. The results showed that there was a robust linear relationship between the cumulative horizontal infiltration and the wetting front distance, suggesting that it is more appropriate to take the soil moisture content after infiltration in the entire wetted zone as the average soil moisture content than as the saturated soil moisture content. The results also showed that there was a robust linear relationship between the cumulative horizontal infiltration and the square root of infiltration time, suggesting that the Philip infiltration formula can better reflect the characteristics of cumulative horizontal infiltration under different infiltration heads. The following two facts indicate that it is feasible to use the one-D method for simultaneously determining the saturated and unsaturated permeability coefficients of loamy sand. First, the saturated permeability coefficient(prescribed in the Gardner model) of loamy sand obtained from the one-D method well agreed with the value obtained from the constant head method. Second, the relationship of unsaturated permeability coefficient with soil water suction for loamy sand calculated using Gardner model based on the one-D method was nearly identical with the same relationship calculated using van Genuchten model. 相似文献
17.
R. J. HANCE 《Weed Research》1965,5(2):108-114
Summary. A series of adsorption experiments was carried out in order to determine if there was significant competition for adsorption sites between diuron and water. Adsorption of diuron was much lower on hydrophilic materials such as cellulose, chitin, aluminium oxide and a soil mineral fraction than on the less hydrophilic ion exchange resins, lignin, carbon and a soil organic fraction. Methylation with methanolic HCL or diazomethane increased adsorption by the soil organic material, but methylation with dimethyl sulphate did not.
The soil mineral fraction adsorbed considerably more diuron from petroleum spirit solution than from aqueous solution, but the organic matter preparation adsorbed more from aqueous than from petroleum solution.
It was concluded that there is competition between water and diuron for adsorption sites and that diuron is a more effective competitor at soil organic matter surfaces than at soil mineral matter surfaces.
Observations sur la relation entre l'adsorption du diuron el la nature de l'adsorbant 相似文献
The soil mineral fraction adsorbed considerably more diuron from petroleum spirit solution than from aqueous solution, but the organic matter preparation adsorbed more from aqueous than from petroleum solution.
It was concluded that there is competition between water and diuron for adsorption sites and that diuron is a more effective competitor at soil organic matter surfaces than at soil mineral matter surfaces.
Observations sur la relation entre l'adsorption du diuron el la nature de l'adsorbant 相似文献
18.
基于Jensen模型的内蒙古河套灌区春玉米水分生产函数研究 总被引：2，自引：0，他引：2
为了系统分析玉米整个生育期不同时期水分亏缺对产量的影响,适时开展灌溉影响评估,基于Jensen模型和水量平衡方程,利用水分试验数据和历史观测资料研究了河套灌区玉米水分敏感指数、玉米需水量和最高产量,建立了需水量和水分敏感指数时间变化方程,包括三项式和Logisitic两种形式,在旬尺度上二者的模拟结果十分接近;通过回代和实例检验,估算产量与实测产量有较好的一致性,回代结果的相关系数在0.92以上,相对误差小于15%的样本占到80%;实例检验的相关系数在0.63~0.69之间,相对误差低于20%的样本占到80%~100%,模拟效果基本符合实际。 相似文献
19.
Naohiro Takahashi Nobuyoshi Mikami Hirohiko Yamada Junshi Miyamoto 《Pest management science》1985,16(2):119-131
The photodegradation of fenpropathrin [(RS)-α-cyano-3-phenoxybenzyl 2,2,3,3-tetramethylcyclopropanecarboxylate] ( I ), in water, on soil and on plant foliage, was investigated using 14C-preparations labelled separately at the cyano group, cyclopropyl-C1 or in the benzyl ring. On exposure to sunlight, I was photodecomposed with initial half-lives of >6 weeks in distilled water, 6.0 weeks in humic acid aqueous solution, 2.7 weeks in river water, 1.6 weeks in sea water and 0.5 of a day in 2% aqueous acetone. A triplet photosensitiser, acetone, together with naturally occurring substances in river and sea water, including humic acid, enhanced the photodegradation of I . On three kinds of soil, I was rapidly photodegraded with initial half-lives of 1–5 days, whereas it was fairly photostable on a mandarin orange leaf. The photoreactions involved were: decarboxylation, hydration of the cyano group to carboxamide, cleavage of the ester or the diphenyl ether linkage, hydrolysis of the carboxamide group to carboxyl, and hydroxylation at either or both of the gem dimethyl groups. The predominant reactions in water were decarboxylation, ester bond cleavage and photo-induced evolution of [14C] carbon dioxide from the [14C] cyano label; on soil, hydration or ester bond cleavage predominated. The hydration was also of importance in river and sea water. Decarboxylation did not occur on soil and plant foliage. 相似文献
20.
Elgala Abdelmonem M. Abd-Elrahman Shaimaa H. Saudy Hani S. Nossier Mona I. 《Gesunde Pflanzen》2022,74(2):457-465
Seeking for safe and cheap alternatives to provide the nutrient requirements of crops remains the most significant alternative for obtaining healthy and economical products. Thus, the present study aimed to assess the efficiency of aqueous water hyacinth shoot extract as a source of nutrients to feed tomato plants. Therefore, the effects of three fertilization treatments (without foliar spraying, commercial synthetic solution and natural solution of water hyacinth shoot extract) on the nutritional status and biomass yield of tomato were investigated. The experiment was designed in a randomized complete block design with three replicates. At different growth stages, several macro- and micronutrients, in addition to the final yield at harvest, were estimated. The results showed that at all growth stages of tomato (vegetative, flowering, fruiting and maturity), the natural solution of water hyacinth caused the maximum increases in phosphorus, iron, zinc, manganese, and selenium. However, the differences between the natural solution of water hyacinth and synthetic solution in nitrogen and potassium at the vegetative stage, phosphorus at the flowering and the fruiting stages, and manganese and selenium at the maturity stage were not significant. The increases in fresh and dry weights and fruit yield of tomato plants owing to the natural solution of water hyacinth application were 37.5, 56.8 and 72.2%, respectively, over the control. Natural organic solution of water hyacinth application increased the net return of tomato cultivation by approximately 1.84 and 1.63 times compared with the conventional practice (control) and synthetic chemical solution, respectively. It could be concluded that exploiting the natural organic solution of water hyacinth achieves several profits in agriculture via fertilization programs by enhancing the income of tomato farmers. Accordingly, it is recommended to benefit from the wastes of water hyacinth plants that are annually removed from the Nile River and other waterways.
相似文献