The influence of rainfall distribution and morphological factors on runoff delivery from dryland catchments in SE Spain   总被引：5，自引：1，他引：5  

M.J. Kirkby  L.J. Bracken  J. Shannon 《CATENA》2005,62(2-3):136

A simplified theoretical model of storm runoff has been combined with analysis of rainfall records to improve understanding of dryland runoff processes in the Guadalentin catchment of SE Spain, and in particular the decrease in runoff fraction with increasing slope length or catchment area.Estimates of storm runoff volumes can be made using a simple runoff threshold, SCS Curve Numbers, or infiltration equations. A modified Green–Ampt equation is applied here to give storm runoff estimates for conditions of constant effective rainfall intensity. This can be seen as both an improvement on estimates made using the simple runoff threshold, although with no additional parameters, and a good approximation to the SCS Curve Number family of rainfall–runoff relationships, providing an improved theoretical basis for the Curve Number approach and an explicit means of linking it to existing soils data on infiltration and surface properties. The frequency distribution of intensities is examined to determine an appropriate effective intensity in relation to slope length, with a duration long enough to allow overland flow to reach the slope base. Hydrologically Similar Surfaces (HYSS) are defined by local runoff characteristics, and the linkage to infiltration allows an explicit comparison with routing over land areas of different area, shape and topography. This provides the basis for up-scaling from at-a-point runoff to runoff from larger areas which are mapped as belonging to the same HYSS class, explicitly allowing for their different topography and size, providing an essential step in up-scaling data on fine-scale surface characteristics to the response of catchment areas. Here we focus on the ways in which catchment area or slope length influence runoff production within a given HYSS class.Characteristics which drive catchment response include (1) variations in intensity over time through a storm (2) areal variations in storm volume. For measured rainfall in the upper Guadalentin catchment, SE Spain, the first of these factors is seen to be the most important for catchments of up to 500 km², and a procedure is suggested for deriving effective rainfalls from recorded intensity data. The rainfall data can then be combined with a HYSS analysis of the soil/land use response, and analyses of catchment network morphology and connectivity to forecast the heterogeneous distribution of ephemeral stream runoff.  相似文献   

旱稻日光温室冬季增代研究     

李慧敏  赵凤梧  马俊永  杨建忠  李爱国 《河北北方学院学报(自然科学版)》2003,19(4):1-2

通过8个旱稻(Upland rice)常规种、7个杂种F_1共15个基因型进行日光温室冬季增代研究,在完全自然条件下,所有参试材料11月12日播种,翌年5—6月前均能完成生命周期,达到增代目的。利用日光温室开展就地加代,是缩短育种周期的一项经济可行的措施。但不同基因型之间,温光反应差异较大。从实用角度出发,冬季日光温室可完成夏播旱稻及杂交后代加代,直接用于翌年田间播种。春播旱稻及杂交种,对来年田间直接正常播种及田间材料鉴定有一定的影响。对特殊组合,如以获得种子为目的的材料及不计产量的遗传分析试验,仍可采用。  相似文献   

杉木第一代改良种子园接株产量变异及其构成因素分析   总被引：1，自引：0，他引：1  

詹学齐 《福建林学院学报》1997,(2)

通过杉木第一代改良种子园45个优良无性系调查结果表明：无性系间单株产量达到极显著水准，遗传方差份量占总变异的37．77％，可见杉木种子园产量很大程度上受到遗传性的制约．在参试的45个无性系中，高产无性系占20％，产量占总产的42．02％，单株产量构成的直接因素为单株果量和单果出籽量，间接效应为雌雄花量．  相似文献   

烟草耐黄瓜花叶病品系GAT—2.GAT—4的研究与利用     

邢淑华  姜茱 《山东农业大学学报(自然科学版)》1990,21(2):19-26

  相似文献   

新生代农民工精神文化生活“孤岛化”问题研究*     

金丽馥  王雪 《安徽农业大学学报》2015,(2):87-91，95

新生代农民工在推进社会主义现代化建设进程中发挥着举足轻重的作用,为社会经济的发展作出了巨大贡献,但是他们面临着精神文化生活“孤岛化”问题。常住地政府作为责任主体,应该切实履行职责;城市社区发挥主要平台作用,开展丰富多彩的精神文化活动;用工企业承担自身社会责任,鼓励新生代农民工提高自身素质,自觉融入城市精神文化生活。由此形成社会合力,最大限度满足新生代农民工精神文化需求,让他们充分享受文化发展结果,体面而有尊严地生活。  相似文献   

粳稻杂种F_2代产量性状的相关及选择效果研究     

刘福才  赵一洲  籍平  孙中泰 《北方水稻》2004,(3):3-6

通过对10个粳稻杂交组合F_2代的7个产量性状的相关及遗传进度分析,认为在早期世代对株高、每株穗数、每穗总粒数、穗实粒数及单株谷重的选择具有较好的效果,并要兼顾其它性状的选择。探讨了水稻品种产量构成的选择方向及相关问题。  相似文献   

Correlation studies on 1000-true-seed weight,tuber yield and other morphological traits in potato (Solanum tuberosum L.)     

T. R. Dayal  M. D. Upadhya  S. N. Chaturvedi 《Potato Research》1984,27(2):185-188

Summary Simple phenotypic, genotypic and environmental correlation coefficients were calculated from one year's data for nine characters in F₁ seedlings of 72 crosses and 18 parents of potato (Solanum tuberosum L.). Crosses were made in a line x tester model having 12 female lines and six male testers. The experiment was designed as a randomized block replicated three times at Kufri, Simla (India) during the 1979–80 crop season. Positive phenotypic and genotypic correlations of 1000-TPS weight were found with total tuber yield, number of leaves on the main shoot, number of shoots per plant and harvest index. The results suggest that 1000-TPS weight could be used when attempting to select for yield and other characters in F₁ seedlings. Adapted from a thesis submitted and approved for the degree of Doctor of Philosophy of Agra University.  相似文献   

Assessing crop management options with crop simulation models based on generated weather data     

Afshin Soltani  Gerrit Hoogenboom 《Field Crops Research》2007

The efficient use of crop simulation models is an effective complement to experimental research. Long-term weather data obtained at a specific site are normally required for the application of these crop simulation models to help determine alternate management practices and associated decisions. Stochastic weather generators sometimes are used to complement or substitute historical weather data. The objective of this study was to evaluate the suitability of weather data generated by the weather generators WGEN and SIMMETEO as input for crop simulation models in order to determine the best option(s) among a number of different crop management practices. Five locations across Iran representing different climates were selected. The wheat, maize, and soybean models of the Decision Support System for Agrotechnology Transfer (DSSAT) were applied in this study, using 30 years of observed weather data and 90 years of weather data generated by WGEN and SIMMETEO. Simulated grain yield using either observed weather data or weather data generated by WGEN and SIMMETEO in response to various ‘experimental’ factors, e.g., cultivar selection, planting date, planting density, irrigation threshold, and change in precipitation under irrigated and rainfed conditions were compared. The statistical evaluation was based on t, F, and Kolomogrov-Smirnov (K-S) tests. The average of the percentage rejected tests was 20% and the parameter estimation method had no impact on the number of rejected tests. Irrespective of some significant differences between simulated yield based on observed weather data and those based on weather data generated by WGEN and SIMMETEO, a similar conclusion could be drawn about the best cultivar, planting date, plant density and irrigation threshold and response to changes in the amount of precipitation. Based on the results of this study it can be concluded that for many crop model applications where only relative estimates or determination of the best management option(s) rather than absolute values are required, weather data generated by either WGEN and SIMMETEO are accurate and sufficient.  相似文献   

野生大豆及种间杂交后代抗灰斑病鉴定筛选   总被引：3，自引：0，他引：3  

杨雪峰  齐宁  林红  刘广阳  李宝英 《黑龙江农业科学》2005,(3):17-19

对132份野生大豆及种间杂交创新后代进行抗灰斑病鉴定。鉴定出2级以上抗病种质70份,其中,免疫材料23份,高抗材料27份,抗病材料20份。鉴定结果表明,野生大豆的抗病性强,抗感比例明显高于种间杂交后代和栽培大豆;野生大豆与栽培大豆种间杂交后代的抗感比例低于野生大豆,而明显高于栽培大豆。经过田间生育期调查、考种分析,综合评价鉴定材料的抗病性、农艺性状、产量性状等,筛选出高产抗病品系8个,以供抗病育种利用。  相似文献   

木薯采后生理性变质的研究进展     

赵平娟  孙海彦  黎娟华  卢诚  彭明 《热带作物学报》2013,33(1):35-41

描述了木薯采后生理变质现象，并对其防治策略、发生机理、评估方法等方面的研究结果进行了综述。  相似文献