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1.
为提高季节性冻土区冬、春季储水灌溉的灌水质量和效果,在季节性冻土区冻融期间进行了大田冻融土壤的系列入渗试验,获取了自然冻融条件下的大量土壤入渗试验数据,拟合得到了不同冻融条件下的Philip入渗模型参数,建立了入渗模型参数与土壤基本理化参数间的BP神经网络的预报模型,实现了基于土壤体积含水率、黏粒含量、土壤密度、土壤温度以及灌溉用水水温等基本理化参数对Philip入渗模型参数稳渗率A、吸渗率S的预报。所得到的预测值与实测值之间相对误差的平均值控制在7%以内。研究表明,利用冻融土壤条件下土壤常规理化参数对Philip入渗模型参数进行预报是可行的,可为季节性冻融土壤灌溉技术参数的确定提供有力支撑。 相似文献
2.
《中国农村水利水电》2016,(2)
为提高季节性冻土区冬季储水灌溉的灌水质量和效果,基于冬季冻土期的大量田间冻土入渗试验样本,建立了基于BP神经网络模型的Kostiakov三参数入渗模型参数的预测模型,实现了利用土壤基本理化参数地表土壤容重、含水率及冻结土壤特有参数冻土层厚度、灌溉水温、土壤温度对入渗模型参数的预报。通过BP神经网络对数据样本和入渗参数进行的非线性逼近训练和误差分析,得到其平均相对误差都小于5%,在可接受范围内。这表明基于基本理化参数及特有影响参数建立的Kostiakov土壤入渗经验模型的三参数预报模型是可行的。研究结果对于冬季冻融土壤灌溉技术参数的确定有重要的支撑作用。 相似文献
3.
为满足季节性冻土地区越冬期间储水灌溉管理的需求,基于山西省汾河灌区季节性冻土的冬季大田土壤水分入渗试验,得到了120组Philip入渗模型参数实测样本,借助MATLAB软件,建立了以土壤温度、有机质质量分数、土壤含水率、土壤体积质量、物理性黏粒量为输入因子、以Philip入渗模型参数吸渗率和稳渗率为输出因子的多元非线性传输函数模型,并用实测资料对该模型进行了精度检验。结果表明,预测参数的相对误差均小于11%,预报精度在可接受范围之内。 相似文献
4.
《中国农村水利水电》2017,(7)
为改良和改善盐碱地提供土壤入渗参数技术支撑,基于在山西省北部盐碱地进行的野外系列入渗试验,获取了累积入渗量与入渗历时的数据样本,并计算回归了kostiakov二参数入渗模型的入渗系数k与入渗指数α,建立了盐碱土壤基本理化参数与入渗参数之间的数据样本,利用BP神经网络的方法,建立了以土壤含水率、容重、质地、有机质、全盐量以及p H为输入变量,kostiakov入渗参数为输出变量的预报模型。结果表明:盐碱地土壤条件下,以土壤基本理化参数为输入变量,kostiakov入渗模型参数为输出变量的BP预报是可行的,入渗系数k的相对平均误差为0.29%、入渗指数α的相对平均误差为1.28%,以及根据两个入渗参数计算得到90 min累积入渗量的相对平均误差为2.37%,对所建立的模型进行检验时,以上三个参数检验误差的平均值均能控制在3%以下,确定所建立的BP预测模型能获得较好的效果。 相似文献
5.
冻融土壤Kostiakov入渗模型参数的非线性预报模型 总被引：1，自引：0，他引：1
《节水灌溉》2015,(11)
在山西汾河灌区季节性冻土区进行了3个越冬期的大田冻结土壤水分入渗试验,获取了Kostiakov冻结土壤二参数入渗模型参数的实测大样本,建立了各个土壤水分入渗参数与土壤理化参数间的非线性关系模型;通过MATLAB软件,实现了Kostiakov二参数入渗模型系数的求解。研究表明:用常规土壤理化参数土壤含水率、密度、物理性黏粒含量、土壤温度和有机质含量作为非线性预报模型的输入参数实现对入渗参数的预测是可行的,所建立的非线性关系模型高度相关,预测参数的实测值与预测值的相对误差可控制在10%以下。因此,用土壤常规理化参数对冻融土壤的水分入渗参数进行非线性预报是可行的,可为季节性冻土区冬季储水灌溉提供技术支撑。 相似文献
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农田耕作土壤田间持水率的BP预测模型 总被引：1，自引：0，他引：1
为了合理确定疏松黄土的灌溉制度,基于黄土高原区农田耕作层土壤田间持水率的测试资料,建立了以土壤理化参数包括土壤体积质量、黏粒量、粉粒量、有机质量为输入变量,田间持水率为输出变量的BP预测模型。结果表明,预测值和实测值的相对误差控制在7%以内,在可接受的范围,表明利用土壤基本理化参数预报农田耕作土壤的田间持水率是可行的。研究结果可为黄土高原区耕作农田土壤水分调控和灌溉管理提供支撑。 相似文献
8.
Philip入渗模型参数的非线性预报模型 总被引：1，自引：0，他引：1
利用黄土高原区大田耕作土壤的水分入渗试验过程资料,拟合了Philip入渗模型参数,建立了以土壤体积含水率、干密度、粉、黏粒含量和有机质含量等土壤理化参数为输入变量,Philip入渗模型参数为输出变量的土壤传递函数,通过对函数的分析、检验,建立了土壤入渗参数S和A的多元非线性预测模型;在此基础上,运用灰色关联分析理论,将各输入变量进行了灰色排序。研究表明:用土壤体积含水率、干密度、粉粒含量、黏粒含量和有机质含量作为预报模型的输入参数可实现对入渗参数的预测,预测参数实测值与预测值之间的相对误差可控制在8%以下,所建立的非线性预测模型高度相关。 相似文献
9.
基于黄土高原区大田耕作土壤的水分入渗试验,建立了Kostiakov二参数入渗模型参数的BP神经网络预测,实现了以土壤基本理化参数为输入变量,Kostiakov二参数模型参数为输出变量的BP预测方法,并分别对二参数模型中的入渗系数k、入渗指数α以及90min累积入渗量H进行了预测值与实测值的精度比较,结果显示对入渗系数k实现BP预测的平均相对误差为6.082 3%,入渗指数α的平均相对误差为1.045 9%,90min累积入渗量H的平均相对误差为4.973 5%,三者的平均相对误差值均在7%以下,预测精度较高,预测效果较好,表明以土壤基本理化参数为输入变量的BP神经网络预测是可行的。研究结果为获取准确的入渗参数提供技术手段,进而为提高农业灌溉水管理水平和灌水效率提供支撑。 相似文献
10.
以山西地区黄土高原区土壤为研究对象,通过实施大量大田耕作土壤水分入渗试验,获取了Kostiakov二参数入渗模型参数的实测大样本,建立了各个土壤水分入渗参数与土壤理化参数间的非线性关系模型;通过MATLAB软件,实现了Kostiakov入渗模型系数的求解。结果表明,常规土壤理化参数土壤含水率、体积质量、粉粒、砂粒和有机质质量分数作为非线性预报模型的输入参数是合理的,所建立的非线性关系模型高度相关,预测参数的实测值与预测值的相对误差可控制在8%以下。因此,用土壤常规理化参数对土壤水分入渗参数进行非线性预报是可行的。 相似文献
11.
Overland water and salt flows in a set of rice paddies 总被引：1，自引：0，他引：1
E. Playn O. Prez-Coveta A. Martínez-Cob J. Herrero P. García-Navarro B. Latorre P. Brufau J. Garcs 《Agricultural Water Management》2008,95(6):645-658
Cultivation of paddy rice in semiarid areas of the world faces problems related to water scarcity. This paper aims at characterizing water use in a set of paddies located in the central Ebro basin of Spain using experimentation and computer simulation. A commercial field with six interconnected paddies, with a total area of 5.31 ha, was instrumented to measure discharge and water quality at the inflow and at the runoff outlet. The soil was classified as a Typic Calcixerept, and was characterized by a mild salinity (2.5 dS m−1) and an infiltration rate of 5.8 mm day−1. The evolution of flow depth at all paddies was recorded. Data from the 2002 rice-growing season was elaborated using a mass balance approach to estimate the infiltration rate and the evolution of discharge between paddies. Seasonal crop evapotranspiration, estimated with the surface renewal method, was 731 mm (5.1 mm day−1), very similar to that of other summer cereals grown in the area, like corn. The irrigation input was 1874 mm, deep percolation was 830 mm and surface runoff was 372 mm. Irrigation efficiency was estimated as 41%. The quality of surface runoff water was slightly degraded due to evapoconcentration and to the contact with the soil. During the period 2001–2003, the electrical conductivity of surface runoff water was 54% higher than that of irrigation water. However, the runoff water was suitable for irrigation. A mechanistic mass balance model of inter-paddy water flow permitted to conclude that improvements in irrigation efficiency cannot be easily obtained in the experimental conditions. Since deep percolation losses more than double surface runoff losses, a reduction in irrigation discharge would not have much room for efficiency improvement. Simulations also showed that rice irrigation performance was not negatively affected by the fluctuating inflow hydrograph. These hydrographs are typical of turnouts located at the tail end of tertiary irrigation ditches. In fact, these are the sites where rice has been historically cultivated in the study area, since local soils are often saline-sodic and can only grow paddy rice taking advantage of the low salinity of the irrigation water. The low infiltration rate characteristic of these saline-sodic soils (an experimental value of 3.2 mm day−1 was obtained) combined with a reduced irrigation discharge resulted in a simulated irrigation efficiency of 60%. Paddy rice irrigation efficiency can attain reasonable values in the local saline-sodic soils, where the infiltration rate is clearly smaller than the average daily rice evapotranspiration. 相似文献
12.
瓦房店市是我国重要的水果生产基地,在国内水果生产领域占有重要地位。随着水果市场化的不断深入,如何满足和适应国内外市场需求成为瓦房店市水果生产的关键问题。从瓦房店市水果生产实际出发,阐述了实施水果生产标准化的必要性,提出了发展水果生产标准化的具体措施。 相似文献
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对引进的谷子新品种金谷子耐旱TG118进行品种比较试验和多点试种。结果表明：该品种抗旱、耐瘠、适应性强,稳产、高产、抗病抗风抗倒伏强,品质优良,粮草兼用,种植简单,省工易管;一般产量在6000kg/hm2以上,比当地主栽品种增产20%以上。最高产量达9450kg/hm2,适于在辽西北地区推广应用。 相似文献
14.
对《种子法》存在问题的探讨 总被引：1，自引：0，他引：1
李鹏 《农业机械化与电气化》2011,(6):129-130
《种子法》是我国种植业第一部法律。自实施以来,为依法加强种子管理提供了有力的法律支撑,促进我国种子产业发生翻天覆地的变化。但随着依法管理工作的深入和种子产业的快速发展,《种子法》及配套规章的一些问题逐步显现出来。对《种子法》及配套规章存在的问题进行深入分析,对需要进一步补充的章节以及需要调整的内容进行深入探讨,以求更加完善和明确。 相似文献
15.
About 30 years have passed since the Government of Egypt embarked on implementing a series of large scale drainage projects. At present, about 3.8 million acres have been provided with drainage systems on the basis of systematic pre-drainage investigations and designs. The target is to provide drains in approximately 6.4 million acres in the Nile Valley and Delta.The implementation of the subsurface drainage system is carried out by the public sector and private contractors under direct supervision of governmental regional departments. The implementation process depends on many factors related to the drainage material, machinery, manpower, site requirements, farmers and organizations involved. Problems and constraints are sometimes challenging, however, the annual rate of implementation has gradually increased to 170,000 acre/year.This paper discusses the different aspects involved in the implementation process of drainage systems. The development in materials, machinery and construction technologies will be reviewed. Institutional and management factors are going to be also considered. 相似文献
16.
在新世纪,面对机遇和挑战,党的十六大把“社会更加和谐”作为全面建设更高水平的小康社会的一个重要目标。中国人素有社会和谐的理想;西方人自古也向往社会和谐;借鉴东西方两种和谐社会思想的经验、教训,构建社会主义和谐社会理论。 相似文献
17.
Gunter Wriedt Marijn van der Velde Alberto Aloe Fayçal Bouraoui 《Agricultural Water Management》2009,96(5):771-789
We present a pan-European irrigation map based on regional European statistics, a European land use map and a global irrigation map. The map provides spatial information on the distribution of irrigated areas per crop type which allows determining irrigated areas at the level of spatial modelling units. The map is a requirement for a European scale assessment of the impacts of irrigated agriculture on water resources based on spatially distributed modelling of crop growth and water balance. The irrigation map was compiled in a two step procedure. First, irrigated areas were distributed to potentially irrigated crops at a regional level (European statistical regions NUTS3), combining Farm Structure Survey (FSS) data on irrigated area, crop-specific irrigated area for crops whenever available, and total crop area. Second, crop-specific irrigated area was distributed within each statistical region based on the crop distribution given in our land use map. A global map of irrigated areas with a 5′ resolution was used to further constrain the distribution within each NUTS3 based on the density of irrigated areas. The constrained distribution of irrigated areas as taken from statistics to a high resolution dataset enables us to estimate irrigated areas for various spatial entities, including administrative, natural and artificial units, providing a reasonable input scenario for large-scale distributed modelling applications. The dataset bridges a gap between global datasets and detailed regional data on the distribution of irrigated areas and provides information for various assessments and modelling applications. 相似文献
18.
在介绍粉质仪和拉伸仪结构和原理的基础上,探讨了粉质曲线中吸水率、形成时间、稳定时间、弱化度和评价值等指标与面粉品质的关系,以及如何根据拉伸曲线中面团最大拉伸阻力、延伸度和拉伸曲线面积等指标来评价面团品质,并结合生产实际,概述了粉质仪和拉伸仪在面粉生产中的作用。 相似文献
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车辆ABS控制算法的研究及探讨 总被引：1，自引：0，他引：1
对现代汽车的ABS控制算法作了一些简单的介绍,同时指出了它们的一些缺陷,相应地提出了几种对ABS的其它控制方法并加以探讨,其中着重论述了ABS门限值控制算法中参考车速的确定方法和基于附着系数的控制算法。 相似文献