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采用小波软阈值去噪方法对信号噪声进行预处理,很大程度地减小了噪声对扰动检测的干扰.利用小波多分辨率分析方法对去噪后的扰动信号进行检测,更精确地提取出了暂态电压扰动信号的特征值.在仿真环境中对去噪前后的电压骤降信号进行检测和比较.结果表明:去噪后的检测结果更接近于原始信号,小波软阈值去噪方法能够提高暂态电压扰动检测的准确性. 相似文献
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温室棚面集雨及自压渗灌对作物生长环境的影响 总被引:1,自引:0,他引:1
利用棚面与地面自然高差,设计了温室棚面雨水集蓄及自压式渗灌系统,并通过对比试验探讨了雨水自压式渗灌和浇灌条件下温室蔬菜生长环境状况。试验结果表明:冬季集雨渗灌与浇灌相比,晴天全天平均相对湿度降低8.5%,阴雨天全天平均相对湿度降低6.5%;室内空气温度比浇灌平均高出1~3℃;表层土壤平均温度比浇灌低0.26℃,但20 cm深度土壤平均温度比浇灌高0.64℃;全生育其渗灌总灌水量为浇灌的40%,收获蔬菜(包青包)平均高度增加4.3 cm。 相似文献
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螺纹环套式新型渗灌毛管水力特性的试验研究 总被引:2,自引:0,他引:2
文章针对渗灌毛管的易堵塞问题,设计了一种螺纹环套式新型渗灌毛管,并对其进行了水力特性的试验研究。结果表明,螺纹环套式渗灌毛管上螺纹式环套防护时沿程出流量均匀,灌水均匀度比较高,并且螺纹高度对出流均匀度的影响不大;渗灌的工作水头与其出流量呈幂函数关系。 相似文献
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寒区温室冬春季因气候制约不能正常生产,严重影响了菜农增收。经过两年实施有机生态型无土栽培渗灌技术生产试验在不采取人工增温条件下,耐寒类蔬菜实现了周年连续生产,茄果类蔬菜冬春季生产期延长75天左右,温室年纯收入提高2.5倍左右。为寒区温室蔬菜种植拓宽了生产途径。 相似文献
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渗灌条件下保护地黄瓜不同生育期适宜灌水定额 总被引:1,自引:0,他引:1
采用保护地黄瓜栽培小区试验的方法,将黄瓜全生育期分为前期、后期两个阶段,按生育阶段控制上、下限对黄瓜进行组合灌溉,通过比较黄瓜产量和水分生产效率,探讨了用节点式渗灌灌溉温室栽培黄瓜灌水定额(灌溉湿润比)的适宜取值范围。结果表明:在砂质粘壤土上,当节点式渗灌管埋深为25 cm、计划湿润层深15~40 cm(厚度25 cm)、灌水控制上限和下限分别定为土壤水吸力6 kPa(田间持水量)和30 kPa时,将计划湿润层湿润比设定为前期0.37~0.38(灌水定额54~56 m3/hm2)、后期0.34~0.37(灌水定额50~55 m3/hm2),并依此进行灌溉,具有较好的高产、优质、节水效果。 相似文献
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以研究地下滴灌土壤水分运动为目的,根据城市道路绿化树木的特点,研制了一种地下渗灌器,并通过室内试验建立了渗灌湿润体的形状与灌水量的关系,这种渗灌器可通过增加水平渗透边界来增加水平湿润范围以适应树木根系的分布,提高灌溉水的利用率。 相似文献
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地下渗灌方法在农业灌溉上的应用研究 总被引:2,自引:0,他引:2
美国用地下渗灌方法进行农业灌溉,已有20多年的历史,取得了很多成功的经验,本文主要介绍美国这项研究的历史,发展现状和用此法进行农业灌溉的具体管理方法。建议在我国进一步加强这方面的研究,为大面积普及此灌溉方法作准备。 相似文献
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Yield and Quality Response of Cucumber to Irrigation and Nitrogen Fertilization Under Subsurface Drip Irrigation in Solar Greenhouse 总被引:4,自引:0,他引:4
The aims of this research were to compare subsurface drip irrigation scheduling and nitrogen fertilization rates in cucumber, and evaluate yield and quality of cucumber fruit, water (WUE), irrigation water (IWUE), and nitrogen use (NUE) efficiencies in the solar greenhouse in Southwest China. The irrigation water amounts were determined based on the 20 cm diameter pan (Ep) placed over the crop canopy, and cucumber plant was subjected to three irrigation water levels (I1, 0.6 Ep; I2, 0.8 Ep; and I3, 1.0 Ep) in interaction with three nitrogen fertilization levels (N1,300 kg ha-1; N2, 450 kg ha-1; and N3, 600 kg ha-1). The results showed that the cucumber fruit yield increased with the improvement of irrigation water. Irrigation water increased yields by increasing the mean weight of the fruits, and also by increasing fruit number. But the highest values of IWUE and WUE were obtained from 12 treatment. NUE significantly decreased with the improvement of N application, but increased by irrigating more water. The quality of cucumber fruit decreased with the improvement irrigation water and nitrogen fertilization. In conclusion, the optimum irrigation level and nitrogen fertilizer application level for cucunber under subsurface drip irrigation in the solar greenhouse in Southwest China were 0.8 Ep and 450 and 600 kg ha-1, respectively. 相似文献
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地下滴灌不同水量与播种方式下苜蓿种子产量构成因素的相关性分析 总被引:3,自引:2,他引:3
[目的]为改变传统苜蓿制种模式中水资源浪费的现状.[方法]实验通过设置不同的水量与播种方式,研究地下滴灌对新牧1号杂花苜蓿种子产量及其构成因素的影响.[结果](1)地下滴灌条件株高随着配水量的增加而增高,株高与单株种子产量呈正相关,R=0.449 420,P<0.01.(2)花序数/枝条(X2)、豆荚数/花序(X3)籽粒数/豆荚(X4)与种子产量呈极显著正相关,相关系数分别为R=0.778 275、R=0.830 400、R=0.925 693,P<0.01.种子产量回归方程为:Y=-2.677+0.025 X2+0.136 X3+1.712 X4.(3)处理组合T3W1(40~80 cm宽窄行播种,灌水量达相对田间持水量65;~80;).[结论]单株种子产量最高为1.17 g,并与其他处理存在极显著性差异(P<0.01). 相似文献
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[目的]分析不同水分处理对紫花苜蓿植株高度与生长速度、产量、耗水量及耗水规律的影响关系.[方法]通过地下滴灌紫花苜蓿在4种不同水分处理(W1:22.5 mm,W2:30 mm,W3:37.5 mm,W4:45 mm)下产量与土壤含水量的观测试验,得到不同水分处理下紫花苜蓿水分利用效率、耗水量及耗水规律.[结果]不同水分处理下紫花苜蓿植株高度与灌水量呈现线性关系,在生育期内不同水分处理对苜蓿植株高度的影响为W4 >W3 >W2 >W1;随着灌水量的增加紫花苜蓿干物质产量呈先升后降的趋势,苜蓿干物质产量与灌水量 存在二维抛物线关系;不同水分处理下紫花苜蓿水分利用效率为W1>W2>W3>W4,从实现紫花苜蓿高产、优质及节水增效的目标出发,紫花苜蓿在地下滴灌条件下,适宜的灌水处理为W3.[结论]不同水分处理下紫花苜蓿耗水量随灌水量的增加而增大,在全生育期的耗水量变化规律是由小到大,再由大到小. 相似文献
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为探讨新疆棉田地下滴灌方式下土壤速效磷空间分布的规律,在棉花不同生育期采用 0.5 mol/L NaHCO3浸提-钼蓝比色法,从水平方向和垂直方向上测定棉田土壤速效磷(Olsen-P).研究分析后认为:垂直方向上,在棉花各生育期土壤速效磷含量的变化呈随着土层深度的增加而减小的趋势;随生育进程的推进,棉田各土层土壤速效磷呈逐渐下降的变化趋势 ;水平方向上,棉田各土层土壤速效磷的变化呈随着与滴灌带距离的增大而缓慢增加的趋势;随棉花生育进程的推进,水平方向土壤速效磷变化为逐渐减少的趋势. 相似文献
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The Potential Contribution of Subsurface Drip Irrigation to Water-Saving Agriculture in the Western USA 总被引:2,自引:0,他引:2
Water shortages within the western USA are resulting in the adoption of water-saving agricultural practices within this region. Among the many possible methods for saving water in agriculture, the adoption of subsurface drip irrigation (SDI) provides a potential solution to the problem of low water use efficiency. Other advantages of SDI include reduced NO3 leaching compared to surface irrigation, higher yields, a dry soil surface for improved weed control, better crop health, and harvest flexibility for many specialty crops. The use of SDI also allows the virtual elimination of crop water stress, the ability to apply water and nutrients to the most active part of the root zone, protection of drip lines from damage due to cultivation and tillage, and the ability to irrigate with wastewater while preventing human contact. Yet, SDI is used only on a minority of cropland in the arid western USA. Reasons for the limited adoption of SDI include the high initial capital investment required, the need for intensive management, and the urbanization that is rapidly consuming farmland in parts of the western USA. The contributions of SDI to increasing yield, quality, and water use efficiency have been demonstrated. The two major barriers to SDI sustainability in arid regions are economics (i.e., paying for the SDI system), including the high cost of installation; and salt accumulation, which requires periodic leaching, specialized tillage methods, or transplanting of seedlings rather than direct-seeding. We will review advances in irrigation management with SDI. 相似文献
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地下滴灌不同灌水量对苜蓿种子产量构成因子的影响 总被引:3,自引:1,他引:2
[目的]研究地下滴灌不同灌水量对新牧1号杂花苜蓿种子产量及其构成因素的影响,为苜蓿种子生产提供理论依据和生产指导.[方法]在60cm等行距苜蓿种子实验地中,每行铺设地下滴灌带,单次灌水量从150到900m3/hm2设置6个不同的处理.[结果]灌水处理不同,单株花序数、每花序小花数、每英果种子数呈显著差异.当灌水总量达3600m3/hm2,单次灌水600m3/hm2时,产量最高,为832.51 kg/hm2.[结论]在苜蓿的现蕾期至结荚期增加灌水次数,能提高种子产量.地下滴灌应用在苜蓿种子生产中能起到节水增产的效果. 相似文献