共查询到20条相似文献，搜索用时 46 毫秒
1.
气候变化对干旱缺水区中尺度流域水文过程的影响 总被引：3，自引：0，他引：3
基于1997-2003年的气象水文资料,选择了黄土高原泾河流域上游,对半分布式生态水文模型SWIM进行了率定和验证,并以流域历史气象条件为基准,固定其它气候因素不变,针对单一气候因素变化(降水或温度)进行了情景模拟,分析、评价了降水和温度对流域径流量、蒸散量和土壤蓄水量各水文过程的影响。结果表明:流域降水量增加(减少),年径流、蒸散及蒸散分量、土壤蓄水量均增加(减少),且降水转化为各水量平衡分量的比例大小依次为径流量(蓝水)>蒸散量(绿水)>土壤蓄水量;流域温度升高,蒸散及其分量随之增加,但径流和土壤蓄水量则随之相应减少。研究结果对于变化环境下的干旱区流域水资源管理具有一定的意义。 相似文献
2.
新疆冬小麦农田蒸散估算模型的研究 总被引：1，自引：0，他引：1
本文在田间试验资料的基础上，综合考虑了影响冬小麦农田蒸散的气象、生物学特性和土壤水分等因素，选用蒸发力、冬小麦的叶面积指数和相对有效土壤湿度建立了新疆冬小麦农田蒸散估算模型，并且检验了该模型的计算效果。 相似文献
3.
砾石覆盖量对夏玉米作物系数及水分利用效率的影响 总被引：1，自引：0，他引：1
为评价半湿润易旱地区砾石覆盖对土壤贮水量、作物生长与产量及水分利用效率的影响,利用杨凌地区夏玉米2014年实测数据及气象数据,基于Penman-Monteith公式计算了砾石不同覆盖量下全生育期内参考作物蒸发蒸腾量,并根据FAO推荐的分段单值平均法,计算夏玉米各生育期作物系数,以及砾石不同覆盖量下作物水分利用效率。结果表明:砾石覆盖的保水效果主要体现在作物生长初期,拔节期最大砾石覆盖处理0~200 cm土壤贮水量较对照增大12.8%,后期由于冠层覆盖影响其效果减弱;夏玉米全生育期作物系数与覆盖量呈线性关系;覆盖量越大,不同生育阶段的作物系数也相应增加;叶面积和株高与作物系数有着较好的回归关系,可以对生育期内的玉米蒸散量进行预报;砾石覆盖可以缩短夏玉米生育期的天数,最大可缩短19 d;砾石覆盖能促进作物生长,提高作物产量,且在该试验覆盖量范围内,覆盖量越大,增产增效越明显,随覆盖量增加,各处理分别较对照提高4.65%~38.17%;作物水分利用效率随覆盖量的增大分别较对照提高2.94%~32.99%。 相似文献
4.
塔里木盆地水面蒸发量的实验研究 总被引：10，自引：0，他引：10
本文根据阿克苏水平衡站 1 999年至 2 0 0 2年非冻结期 ( 4月至 1 0月 ) 2 0 m2蒸发池水面蒸发量及常规气象观测资料 ,探讨了水面蒸发量与气象要素的关系 ,并用灰色关联度分析法分析了各气象要素对水面蒸发的影响程度 ,建立了计算水面蒸发量的经验公式 ,结果表明( 1 )气象要素对 2 0 m2蒸发池旬平均水面蒸发量的影响程度从大到小的排列顺序为饱和水汽压差、气温、风速、水面温度、相对湿度差、气压、空气饱和差、实际水汽压 ;( 2 ) 2 0 m2蒸发池旬平均水面蒸发量与饱和水汽压差、空气湿度饱和差、气温、水面温度、风速、水汽压成正比关系 ;而与气压、相对湿度成反比关系 ;( 3)所有回归方程都达到极显著水平 ,可供塔里木盆地缺测资料地区选用。 相似文献
5.
北方干旱寒冷地区羊草生育期蒸散量变化规律研究 总被引：2，自引：2，他引：0
基于2005-2006两个不同水文年对羊草、拂子茅、冰草构成的羊草群落生育期生境中气象因子及生理因子野外观测试验数据,用联合国粮农组织FAO-56分册中最新双作物系数法计算分析了羊草群落生育期不同降雨条件的需水量。模拟计算的蒸腾、蒸发量与实际观测值间进行了拟合相关图、拟合优度参数法的有效性检验。用羊草生育期生理特性、冠层结构变化、气象要素和根系层土壤含水率变化对计算结果进行了分析,得出生育期各生长阶段蒸散量和日平均蒸散强度及其它们的变化规律。 相似文献
6.
利用田间水量平衡方程,本文对塔克拉玛干沙漠腹地人工草坪水分蒸散进行了初步研究。蒸散总量数据显示,部分覆盖(60％)>全裸地>全覆盖(100％)。从日变化数据来看,植物蒸腾由于能消耗更深层次的水分,其强度的减弱要迟于土壤蒸发。由于特殊的自然条件与灌溉方式,本区草坪的蒸散具有自己的特点,部分覆盖草坪的蒸散量最大。水量平衡分析的数据则表明,渗漏水占灌溉水量中相当大的部分,这说明,提高土壤表层的持水能力,可以有效地提高水分利用效率。 相似文献
7.
北疆春小麦蒸散规律及蒸散量估算研究 总被引：4，自引：1，他引：4
通过对2002～2003年北疆春小麦田试验数据的分析结果表明,北疆春小麦全生育期蒸散量在410～430mm左右,蒸散强度为4.11～4.14mm,蒸散量和蒸散强度均在抽穗～乳熟期达到最大,平均棵间蒸发占总蒸散量的比例为38.3%～42.0%。叶面积指数与蒸散强度关系极为密切,可用复合曲线方程来描述二者的关系。通过采用Penman-Montieth模式配合单值平均作物系数和水分胁迫系数估算农田蒸散量的方法,对当地春小麦田的日蒸散量进行估算,精确度检验结果表明该方法是切实可行的。 相似文献
8.
箭杆杨林地蒸散的研究 总被引：3，自引：0，他引：3
本文运用１９９２－１９９４年新疆莫索湾沙漠站的试验资料，分析了箭杆杨林地蒸散与气象因子之间的关系，并且依据Ｐｅｎｍａｎ的可能蒸散与相对有效土壤湿度建立了箭杆杨林地蒸散量估算模型。 相似文献
9.
塔里木灌区棉田蒸散与棵间蒸发变化规律 总被引：2，自引：0，他引：2
为了给塔里木灌区棉花合理灌溉提供科学理论依据,根据新疆阿克苏农田生态系统国家野外科学观测研究站监测的地面沟灌棉田土壤水分、降水量、灌水量等资料,采用水量平衡原理计算了棉田蒸散量,采用自制的Micro-Lysimeters测定了棉田棵间蒸发,分析了棉田蒸散和棵间蒸发的变化规律及其影响因子,结果表明,棉田蒸散强度与棵间蒸发强度从苗期、蕾期、花铃期逐渐增大,到花铃期达到最大,吐絮期、收获期逐渐减小;棵间蒸发占棉田蒸散量的比例从苗期、蕾期、花铃期逐渐减小,到花铃期达到最小,吐絮期、收获期又逐渐增大,棉花生育期内棵间蒸发占蒸散量的比例为16.49％.棉花相对棵间蒸发强度与表层土壤含水量关系密切,随着表层土壤含水量的增大相对棵间蒸发强度增强. 相似文献
10.
11.
农业生产活动对黄土高原丘陵沟壑区坡地土壤水分动态的影响 总被引：1，自引：1，他引：0
通过在坡度为20°耕地和荒草坡面对降水、土壤水密集观测,结合模拟降雨实验,从降雨入渗、蒸散发等过程分析讨论了影响黄土高原丘陵沟壑区坡地土壤水分动态的主要因素。结果表明:1)降雨入渗量△S主要受控于雨强和降雨量,坡耕地的入渗量随着雨强增加而衰减的速度快于荒坡,坡耕地有利于中等雨强大雨的下渗,雨强增大时两坡面的降雨转化率逐渐接近,且植被的再分配作用凸显,甚至使短历时暴雨时坡耕地的入渗速度低于荒坡,长历时的大、暴雨或连续降雨利于深层入渗,坡面耕作或在裸地上种植冰草后降雨转化率增约50%;2)7月～10月上旬为土壤水补给期,土壤水分在枯水年及平水年处于负平衡,在丰水年获得补给,最终以蒸散发消耗;3)荒地主要耗水层在20cm,耕地土壤水分活跃层及作物主要耗水层延伸至30cm。总体上,农作物增大蒸散发量、增加土壤水分利用深度,农业生产活动对减少降雨径流、增加土壤水资源量、强化水分小循环有重要作用。 相似文献
12.
人类胁迫对松嫩平原土壤盐渍化的灰色关联分析 总被引：8，自引：3，他引：8
在广泛搜集资料和实地土壤采样调查的基础上,系统分析人为干扰下松嫩平原水盐运动规律及土壤盐渍化过程。利用灰色关联分析方法对该区50年的资料进行定量分析,探讨人为因素引起的松嫩平原水土环境的空间结构变化与土壤盐渍化的耦合关系。研究结果表明植被退化和流域内流化是松嫩平原盐渍化形成与演化的直接原因;短时期内人为因素对土壤盐渍化面积变化影响显著,其贡献率大于气候因子变化对盐渍化面积的影响。 相似文献
13.
Rangelands are an important ecosystem in the western US, and herbage and livestock production are important issues throughout the western states. Making stocking rate decisions early in the growing season is difficult because of high variation in annual herbage production. In this study, regression analysis was used to relate herbage biomass to monthly and growing season predicator variables (rainfall, actual evapotranspiration, and soil moisture) using data collected from fifteen Wyoming rangeland sites. Both predictor and response variables were scaled before regression to correct for different physical and environmental conditions between sites. Growing season precipitation was the strongest predictor of herbage biomass production (r2 = 0.79), followed by growing season actual evapotranspiration (r2 = 0.69), and growing season profile-average soil water content (r2 = 0.59). April profile-average (0–90 cm) and April surface (0–30 cm) soil moisture also predicted herbage biomass (r2 = 0.53–0.54), indicating that early growing season soil moisture can be used to inform stocking rate and grazing management decisions as it provides information at the onset of the growing season. 相似文献
14.
零通量面法计算土壤水分腾发量研究 总被引：1，自引：0，他引：1
土壤水分腾发量的确定是土壤水分运动研究的难点问题。零通量面法是利用零通量面存在时段计算土壤水分腾发量的方法。在计算时段内,根据零通量面发育状态不同可分为零通量面稳定条件下的计算公式和零通量面移动条件下的计算公式。选择不同水位埋深、不同作物类型的土壤剖面对计算公式进行了验证,结果表明,零通量面法计算土壤水分腾发量精度较高,简单易行。本方法适用于计算潜水埋深在3~10 m的干旱半干旱的平原地区计算土壤水分腾发量。 相似文献
15.
Variations in climate are widely recognized as central factors governing the competitive balance in mixed‐species plant communities. In agricultural systems, highly variable patterns of crop yield reduction as a function of weed density have been documented across sites and among years at the same site for several crop–weed combinations. This variation is typically attributed to contrasting environmental conditions. Despite broad acknowledgement of their importance, experimental and temporal limitations have constrained the investigation and systematic understanding of environmental controls on the dynamics of competition. For several well‐studied crop–weed associations, aggregating historical data from similar competition experiments provides an opportunity to explore interference relationships over an array of conditions. In this study, 19 site‐years of maize –Abutilon theophrasti (velvetleaf) data were compiled and the weather characterized (i.e. average ambient temperature and moisture regime) for discrete portions of each growing season. These features were then related to patterns of maize yield loss from A. theophrasti interference at high weed densities. Results of this analysis suggest that temperatures following establishment, together with the presence or absence of water stress during the maize crop's exponential growth phase, account for over 60% of the observed variation in relative yield loss. 相似文献
16.
Bailey SW 《Pest management science》2004,60(2):158-162
A herbicide degradation model, using real weather data for the period 1980-2001, has been used to estimate the change in persistence of autumn-applied isoproturon over this period. The results suggest that soil residues fell to the minimum for weed control on average approximately 30 days earlier over the last 5 years of this period than in the first 5 years, equivalent to a reduction of approximately 25% in the duration of weed control. This decline in persistence is attributed to increasing soil temperature. The results are discussed in relation to recent observations and predictions on climate change. The relevance of the findings to other pesticides and future weed control is considered. 相似文献
17.
In this study,we analyzed the hydrological and meteorological data from the Syr Darya River Basin during the period of 1930–2015 to investigate variations in river runoff and the impacts of climate change and human activities on river runoff.The Syr Darya River,which is supplied by snow and glacier meltwater upstream,is an important freshwater source for Central Asia,as nearly half of the population is concentrated in this area.River runoff in this arid region is sensitive to climate change and human activities.Therefore,estimation of the climatic and hydrological changes and the quantification of the impacts of climate change and human activities on river runoff are of great concern and important for regional water resources management.The long-term trends of hydrological time series from the selected 11 hydrological stations in the Syr Darya River Basin were examined by non-parametric methods,including the Pettitt change point test and Mann-Kendall trend tests.It was found that 8 out of 11 hydrological stations showed significant downward trends in river runof f.Change of river runoff variations occurred in the year around 1960.Moreover,during the study period(1930–2015),annual mean temperature,annual precipitation,and annual potential evapotranspiration in the river basin increased substantially.We employed hydrological sensitivity method to evaluate the impacts of climate change and human activities on river runoff based on precipitation and potential evapotranspiration.It was estimated that human activities accounted for over 82.6%–98.7%of the reduction in river runoff,mainly owing to water withdrawal for irrigation purpose.The observed variations in river runoff can subsequently lead to adverse ecological consequences from an ecological and regional water resources management perspective. 相似文献
18.
Evapotranspiration of an oasis-desert transition zone in the middle stream of Heihe River,Northwest China 总被引：1，自引：0，他引：1
As a main component in water balance, evapotranspiration is of great importance for water saving and irrigation-measure making, especially in arid or semiarid regions. Although studies of evapotranspiration have been conducted for a long time, studies concentrated on oasis-desert transition zone are very limited. On the basis of the meteorological data and other parameters(e.g. leaf area index(LAI)) of an oasis-desert transition zone in the middle stream of Heihe River from 2005 to 2011, this paper calculated both reference(ET0) and actual evapotranspiration(ETc) using FAO56 Penman-Monteith and Penman-Monteith models, respectively. In combination with pan evaporation(Ep) measured by E601 pan evaporator, four aspects were analyzed:(1) ET0 was firstly verified by Ep;(2) Characteristics of ET0 and ETc were compared, while the influencing factors were also analyzed;(3) Since meteorological data are often unavailable for estimating ET0 through FAO56 Penman-Monteith model in this region, pan evaporation coefficient(Kp) is very important when using observed Ep to predict ET0. Under this circumstance, an empirical formula of Kp was put forward for this region;(4) Crop coefficient(Kc), an important index to reflect evapotranspiration, was also analyzed. Results show that mean annual values of ET0 and ETc were 840 and 221 mm, respectively. On the daily bases, ET0 and ETc were 2.3 and 0.6 mm/d, respectively. The annual tendency of ET0 and ETc was very similar, but their amplitude was obviously different. The differences among ET0 and ETc were mainly attributed to the different meteorological variables and leaf area index. The calculated Kc was about 0.25 and showed little variation during the growing season, indicating that available water(e.g. precipitation and irrigation) of about 221 mm/a was required to keep the water balance in this region. The results provide an comprehensive analysis of evapotranspiration for an oasis-desert transition zone in the middle stream of Heihe River, which was seldom reported before. 相似文献
19.
全球变暖对鄂尔多斯地区水文情势影响的初步分析 总被引：2，自引：0，他引：2
傅国斌 《干旱区资源与环境》1994,8(1):53-61
本文在分析鄂尔多斯地区历史时期（全新世高温期、千年尺度、近四十年）气候冷暖与干湿情景的基础上，着重讨论了未来全球变暖对区域水文情势的影响。 相似文献
20.
通过对黄土高原腹地甘肃合水MJY全新世土壤剖面磁化率、全铁、TOC、Rb、Sr和Rb/Sr等气候代用指标的测定分析,揭示了与全新世环境变化相对应的成壤过程,并在此基础上,阐明黄土高原中部地区环境资源变化对人类活动的影响。认为全新世早期,黄土高原中部地区气候比较温和干燥,风尘堆积速率降低,地表植被以草本为主,并有一定的生物风化成壤作用,土壤发育表现为边沉积边成壤;全新世中期,气候温暖湿润,地表植被发育,生物风化成壤作用大于风尘堆积作用,随着沉积和成壤的继续,土壤层深厚,形成古土壤层(S0);全新世晚期,气候开始恶化,干旱少雨,植被退化,沙尘暴频繁发生,风尘堆积作用大于风化成壤作用,土壤退化形成的现代黄土层(L0)覆盖了土壤(S0)使之成为埋藏古土壤。在寺洼文化时期(3250—2520 a B.P.),由于气候干旱使环境资源恶化,土壤退化严重,土地资源利用方式和文化形态从原始的农耕文化转向游牧类型文化。 相似文献