华北平原作物棵间蒸发占蒸散比例及减少棵间蒸发的措施   总被引：23，自引：0，他引：23  

裴冬  张喜英  李坤 《中国农业气象》2000,21(4):33-37

利用棵间小型蒸发器测定了华北平原主要作物冬小麦、夏玉米、大豆、谷子、高梁和棉花生长期间棵间蒸发占蒸散比例随生育期的变化。结果表明,这几种作物在整个生育期中棵间无效耗水大约占总耗水量的１／４～１／３。影响棵间蒸发速率的主要因素除气象条件外,还有土壤表层含水量和作物群体叶面积指数。秸秆覆盖、中耕锄划、调控表层土壤根系分布等可作为减少土壤蒸发的有效措施。  相似文献   

57年来本溪冷凉山区温度降水变化对蒸发的影响     

高巍  詹克荣  吉奇 《安徽农业科学》2010,38(36)

利用草河口1953～2009年月平均气温、降水量、小型蒸发资料,采用线性倾向率、Mann-Kendall(简称M-K)方法对蒸发量进行了趋势分析和突变检测。结果表明,冷凉山区年蒸发量呈现波动性增加趋势,其线性倾向率为30.16 mm/10a;四季的蒸发量均呈增加趋势;年蒸发量随着温度升高呈增加趋势,随着降水增加而呈减少趋势;蒸发最大值出现在5月份,最小值出现在1月份。  相似文献   

用历史资料揭示夏日降水特征     

陈铁  曹乃和  汤建国  张鹏  凌和稳 《安徽农业科学》2009,37(5):2084-2085

应用统计和检验的方法研究江苏省通州市2004～2007年有降水日和无降水日2种条件下,不同季节的日照时数、蒸发量和天文可照时数等要素的综合表现特征。  相似文献   

土壤蒸发,蒸散模型的研究   总被引：4，自引：1，他引：4  

蒋俊明 《四川林业科技》1995,16(4):20-25

本文根据陆地蒸发的机理和过程，提出下垫面蒸发的相似性的理论，并将陆地蒸发分为非限制蒸发和限制蒸发两种类型。然后利用器测法收集的数据资料，建立了土壤蒸发、蒸散的数学模型，为进一步研究土壤水分消退规律和蒸发力的计算提供了依据。  相似文献   

Estimation of evaporation rate from the forest floor using oxygen-18 and deuterium compositions of throughfall and stream water during a non-storm runoff period   总被引：3，自引：0，他引：3  

Tayoko?KubotaEmail author  Yoshio?Tsuboyama 《Journal of Forest Research》2004,9(1):51-59

Rainwater, throughfall, stream water during a non-storm runoff period, and soil water were sampled about every 10 days at six nested basins within the Hitachi Ohta Experimental Watershed in Japan from 1998 to 2001. Basins HA and HB are covered with an 80-year-old artificial forest of Japanese cypress and Japanese cedar. HC and HV are covered with 12-year-old forest of the same species. HO and HX are covered with various aged stands of the same species. The samples were analyzed for the isotopic compositions of ¹⁸O and deuterium (D). The weighted means of ¹⁸O (D) in HA and HB were –7.35 (–46.7) and –7.38 (–46.8), while they were –7.51 (–48.1) and –7.57 (n/a) in HC and HV, respectively. They were –7.50 (–47.6) and –7.41 (–47.1) in HO and HX, respectively. There was a relative difference of 0.2 (1.4) in ¹⁸O (D) between 80-year-old and 12-year-old forest. The stream water during a non-storm runoff period is considered to reflect the effect of evaporation from the forest floor. The evaporation rates from the forest floor were estimated using values in throughfall and stream water using the Rayleigh distillation equation under equilibrium conditions. They were estimated to be 5.5 (9.1), 5.2 (9.0), and 4.9 (8.7)% of annual throughfall in HA, HB, and HX (mature forests), respectively, using ¹⁸O (D), and 4.0 (7.6), 4.1 (8.1), and 3.5 (n/a)% of annual throughfall in HC, HO, and HV (young forests), respectively.  相似文献   

Evapotranspiration components and dual crop coefficients of coffee trees during crop production   总被引：1，自引：0，他引：1  

Danilton Luiz Flumignan  Rogério Teixeira de FariaCássio Egídio Cavenaghi Prete 《Agricultural Water Management》2011,98(5):791-800

Quantifying crop water consumption is essential for many applications in agriculture, such as crop zoning, yield forecast and irrigation management. The objective of this study was to determine evaporation (E), transpiration (T) and dual crop coefficients (Ke and Kcb) of coffee trees during crop production (3rd and 4th year of cultivation), conducted under sprinkler and drip irrigation and no irrigation, in Londrina, Paraná State, Brazil. Crop evapotranspiration (ET) was measured by weighing lysimeters cultivated with plants of cultivar IAPAR 59, E was measured by microlysimeters installed on the lysimeters and T was obtained by the difference between ET and E. The crop coefficient (Kc) was determined for the irrigated treatments as the ratio between ET and the reference evapotranspiration (ETo). Similarly, evaporation coefficient (Ke) and basal crop coefficient (Kcb) were determined as the ratio of E and T, respectively, to the value of ETo, which was estimated by the ASCE Penman-Monteith method on an hourly basis. The values of E and Ke varied due to atmospheric demand and water application method. Those factors, in addition to crop phenology and leaf area evolution, also influenced T and Kcb. Regardless irrigation treatment, the measured values of E represented 35% of ET, while T was 65% of ET. The recommended values of Ke were 0.46 and 0.26 for sprinkler and drip irrigation, respectively. The recommended values of Kcb were 0.52 and 0.82 for sprinkler-irrigated, and 0.5 and 0.65 for drip-irrigated treatments, varying as a function of daily ETo (ETo ≥ or <3 mm day⁻¹, respectively).  相似文献   

沧州市近 40 年蒸发量变化特征分析简   总被引：1，自引：0，他引：1  

许丽景  李海川 《安徽农业科学》2013,(21):9032-9034

利用沧州市气象站1971～2010年期间小型蒸发皿（口径20cm）蒸发量资料,对近40年沧州市蒸发量变化进行统计分析。结果表明,近40年沧州蒸发量变化较大,在年内呈波状分布,蒸发量最大的为6月,最小的为1月;近加年小型蒸发皿蒸发量呈总体下降趋势,蒸发量最大为2273．3min,出现在1972年,最小为1681．4mm,出现在1990年,年最大蒸发量与最小蒸发量相差591．9mm;近40年一年四季中夏季蒸发量最大,变化幅度也最大,春季次之,冬季蒸发量及变化幅度最小;不同季节蒸发量变化趋势不同,蒸发量下降主要在春季和秋季,夏季无明显变化,而冬季蒸发量呈上升趋势;沧州近40年蒸发量年代际变化呈波状变化,整体下降趋势;年代特征明显,20世纪80年代为各年代最高值,平均蒸发量为1958．6mm,高出近40年平均值39．7mm,21世纪以来蒸发量为1880．9mm,为各年代最低值,比平均值低38．0mm。  相似文献   

不同遮荫水平对茶树光合环境及茶叶品质的影响   总被引：21，自引：0，他引：21  

肖润林  王久荣  单武雄  黎星辉  宋同清  汤宇 《中国生态农业学报》2007,15(6):6-11

试验研究了夏秋季80%、61%、37%遮光率遮阳网覆盖处理对茶园生态环境、茶树光合作用特性和茶叶内含成分的影响。结果表明:与露地对照茶园相比,3种遮光率遮荫处理茶园夏秋季气温、叶面温度、地面温度和土壤温度均明显降低;茶园土壤水分含量、茶园空气湿度明显提高。遮荫改善了茶园生态环境,且遮光率越高,效果越明显。与对照茶园比较,80%、61%、37%遮光率遮阳网覆盖处理日平均净光合速率增加了365%、283%和68%;茶叶新梢的叶绿素a含量增加了57.5%、29.3%和15.9%,叶绿素总量增加了52.2%、29.2%和14.3%;茶叶氨基酸含量增加了68.6%、33.5%和2.16%;茶叶茶多酚含量降低了15.3%、12.5%和5.4%。80%遮光率处理1芽2叶新梢制作的茶叶酚氨比达到名优绿茶标准,61%遮光率和37%遮光率处理的茶叶酚氨比也均达到高档绿茶标准,茶叶品质明显优于对照茶园。  相似文献   

蒸发条件下土壤水盐热运移的实验研究   总被引：8，自引：3，他引：5  

邹平  杨劲松  福原辉幸  寺崎宽章  何超 《土壤》2007,39(4):614-620

土壤水盐热的耦合运移研究是土壤水盐运移理论研究的重要组成部分.在模拟蒸发条件下,通过室内土柱实验,对土壤水盐热的迁移做了初步研究.结果表明:地下水位的高低直接影响土壤剖面盐分和水分分布;本实验一直处于稳定蒸发状态,今后需进一步研究不同蒸发条件下土壤水盐热的运移规律.  相似文献   

主要森林植被土壤及枯落物水分蒸发量动态研究     

张德成  殷鸣放  陈宏伟  王炜  王晓峰  王毅峰  丁丽娜  朱学静 《安徽农业科学》2006,34(10):2210-2212

运用固定标准地观测的方法,对辽东山区几种主要森林植被落叶松幼龄林、落叶松中龄林、红松幼龄林、红松中龄林、柞树林、杂木林土壤的枯落物水分蒸发量进行测量。试验表明单位面积上落叶松幼龄林的平均日蒸发量最小,农田的日蒸发量较大。影响单位面积蒸发量的主要因子为地表枯落物量,同时蒸发量又与郁闭度呈弱负相关,地表至20 cm表层土壤的水分蒸发量占总蒸发量的绝大部分,而20 cm以下的土壤失水很少,红松林的土壤水分在20 cm以上的土层有上下交流的现象,而农田的水分上下交流活跃带可深达25 cm。根据布兰尼—尼里德尔公式推算出了辽宁省实验林场邻域范围内的年土壤和枯落物水分蒸发量,表明蒸发量的月份间差异显著,蒸发量冬季较小而在夏季很大。  相似文献