近40a中国北方降水量与蒸发量变化

利用我国北方1951-1990年年降水量、年蒸发量、年平均风速和太阳辐射等资料,计算了干燥度指数,并据其将我国划分为干旱区(D<0.20),半干旱区(0.20～0.50),湿润区(D>0.50)。近40a我国半干旱区降水量和蒸发量发生了巨大变化,区域差异显著,年代际特征明显。东北区和华北区降水量具有减少趋势,西北东部和西南区有增加趋势。至于蒸发量的变化,东北区具有增加趋势,华北区、西北东部和西南区有减少趋势。近40a我国干旱半干旱区降水量与蒸发量均在减小,但降水量的减小速度大于蒸发量,气候在变干。我国气候的干湿变化主要取决于降水量的变化。     

Meteorological impacts on evapotranspiration in different climatic zones of Pakistan

Arid regions are highly vulnerable and sensitive to drought. The crops cultivated in arid zones are at high risk due to the high evapotranspiration and water demands. This study analyzed the changes in seasonal and annual evapotranspiration(ET) during 1951–2016 at 50 meteorological stations located in the extremely arid, arid, and semi-arid zones of Pakistan using the Penman Monteith(PM) method. The results show that ET is highly sensitive and positively correlated to temperature, solar radiation, and wind speed whereas vapor pressure is negatively correlated to ET. The study also identifies the relationship of ET with the meteorological parameters in different climatic zones of Pakistan. The significant trend analysis of precipitation and temperature(maximum and minimum) are conducted at 95% confidence level to determine the behaviors of these parameters in the extremely arid, arid, and semi-arid zones. The mean annual precipitation and annual mean maximum temperature significantly increased by 0.828 mm/a and 0.014℃/a in the arid and extremely arid zones, respectively. The annual mean minimum temperature increased by 0.017℃/a in the extremely arid zone and 0.019℃/a in the arid zone, whereas a significant decrease of 0.007℃/a was observed in the semi-arid zone. This study provides probabilistic future scenarios that would be helpful for policy-makers, agriculturists to plan effective irrigation measures towards the sustainable development in Pakistan.     

短花针茅荒漠草原土壤种子库对不同放牧强度的响应

在内蒙古短花针茅荒漠草原,采用野外随机定点取样与室内萌发相结合的方法,对不同放牧强度下围封草地土壤种子库的密度、垂直结构、多样性、丰富度、均匀度、以及种子库与地上植被的相似性进行了研究。结果表明,在各试验区土壤种子库主要分布在0～20cm土层,占种子库总密度的87%～96%;随着放牧强度的增加,土壤种子库总密度减少,同时地上植被与土壤种子库的相似物种数减少,种子库组成的相异性增加;轻度放牧对土壤种子库中一二年生草本所占比例影响较小,而中度和重度放牧使土壤种子库中一二年生草本所占比例增加;土壤种子库的物种丰富度、多样性、均匀度均随放牧强度的增加而减小。     

放牧和封育条件下科尔沁沙地小叶锦鸡儿群落土壤种子库特征

以科尔沁沙地小叶锦鸡儿群落为研究对象,对比分析了放牧干扰和不同封育年限下土壤种子库特征。结果表明:①放牧和封育样地土壤种子库均以一年生植物为主,物种丰富度没有明显差异;②放牧样地土壤种子库密度为(3 475±519)粒/m2,封育6年和封育12年样地土壤种子库密度分别为(20 241±1 714)粒/m2和(28 777±3 946)粒/m2,显著高于放牧样地;③Shannon-W iener多样性指数、S impson多样性指数和P ielou均匀度指数在放牧样地分别为1.36,0.68和0.56,并随着封育年限的增加而降低;④放牧和封育样地土壤种子库主要分布于0~2 cm的土壤表层,封育样地各层的种子库密度均显著高于放牧样地;⑤放牧和封育样地土壤种子库均为聚集分布,但放牧样地种子库的空间异质性高于封育样地。     

试论旱区的干旱及其防御

本文阐述了旱区所处的地位及干旱对农业的影响;讨论了干旱的形成;分析了我国北方干旱发生的规律;进行了北方旱区湿润状况分类及评价,分别对西北干旱牧区和绿州农业区、东北西部风沙半干旱区、内蒙古中南部、黄土高原北部半干旱地区、华北平原中北部半湿润易旱区的干旱气候特征及干旱的时空分布规律进行了分析。最后从防御干旱的战略对策提出了几点意见。     

围栏封育对新疆蒿类荒漠草地植被及土壤养分的影响

以新疆封育3年的蒿类荒漠草地为对象,研究干旱区封育对草地植被及土壤养分的影响.结果表明:封育后荒漠草地群落的盖度、产量明显增加(P<0.05),分别比对照提高了11.0%,51.6 g/m~2,且盖度、产量的增加主要是由藜科草类引起;荒漠草地80%以上的地下生物量集中在0～40 cm土层中,且封育促进了0～10 cm土层内生物量的增加(P<0.05);与放牧地相比,封育后土壤有机质、全氮、全磷、全钾及速效氮、磷、钾含量均有所提高,且在0～10 cm的土层中差异显著(P<0.01),而pH值略有上升.     

基于潜在蒸散和干燥度指数的河北省农业气候区划

基于Penman-Monteith模型的潜在蒸散和降水量之比计算得到的干燥度指数作为衡量区域干湿状况的重要指标,已成为全球变化研究中的重要气候指标之一.本文利用温度气候带和以干燥度指数划分的干湿气候区作为二级气候区划指标,开展区域尺度的河北省农业气候分区,将河北省农业气候区划分为暖温带半湿润区,冀北中山中温带半湿润偏旱区、太行山暖温带半湿润偏旱区和滨海平原暖温带半湿润偏旱区,冀北高原中温带半干旱区、太行山北段中温带半干旱区和冀中、南平原暖温带半干旱区,中温带半干旱偏旱区.该分区为合理配置农业生产、改进耕作制度以及引入和推广新品种提供气候依据,同时也为相关部门采取应对措施减轻旱涝灾害及其不利影响提供参考.     

1961-2017年青藏高原东北部雨季降水量变化及其贡献度分析

利用53个气象观测站1961—2017年5—9月逐日降水资料,分析了青藏高原东北部雨季降水量的变化特征,以及不同等级降水变化在降水量增量中的相对贡献。结果表明:1961—2017年青藏高原东北部干旱区雨季降水量呈增加趋势,半干旱区和半湿润区降水量的极端性增强。大部分地区的降水强度普遍增加。进一步分析可知,青藏高原东北部雨季降水量变化主要由降水强度的变化引起,同时中雨等级降水增加贡献大于其他等级降水。半湿润区和半干旱区东部降水极端化趋势明显增强。该结果有助于进一步理解和认识青藏高原东北部生态环境变化的气候效应。     

Change features of time-series climate variables from 1962 to 2016 in Inner Mongolia,China

Detecting change features of climate variables in arid/semi-arid areas is essential for understanding related climate change patterns and the driving and evolution mechanism between climate and arid/semi-arid ecosystems.This paper takes Inner Mongolia of China,a unique arid/semi-arid ecosystem,as the study area.We first detected trend features of climate variables using the linear trend analysis method and then detected their trend-shift features using the breaks for additive seasonal and trend method based on the time-series of monthly precipitation and monthly mean temperature datasets from 1962 to 2016.We analyzed the different change features of precipitation and temperature on a regional scale and in different ecological zones to discover the spatial heterogeneity of change features.The results showed that Inner Mongolia has become warmer-wetter during the past 54 years.The regional annual mean temperature increased 0.4°C per decade with a change rate of 56.2%.The regional annual precipitation increased 0.07 mm per decade with a slightly change rate of about 1.7%,but the trend was not statistically significant.The warmer trend was contributed by the same positive trend in each season,while the wetter trend was contributed by the negative trend of the summer precipitation and the positive trend of the other three seasons.The regional monthly precipitation series had a trend-shift pattern with a structural breakpoint in the year 1999,while the regional monthly mean temperature series showed an increasing trend without a periodical trend-shift.After the year 2000,the warmer-wetter trend of the climate in Inner Mongolia was accelerated.The late 20th century was a key period,because the acceleration of the wetter trend in some local zones(I and II)and the alleviation of the warmer trend in some local zones(Ⅶ,Ⅷand IX)occurred simultaneously.Moreover,the change features had a strong spatial heterogeneity,the southeastern and southwestern of Inner Mongolia went through a warmer-drier trend compared with the other areas.The spatio-temporal heterogeneity of the climate change features is a necessary background for various types of research,such as regional climate change,the evolution of arid/semi-arid ecosystems,and the interaction mechanisms between climate and arid/semi-arid ecosystems based on earth-system models in Inner Mongolia.     

西北地区秋季干旱指数的变化特征

利用甘肃、宁夏、青海、新疆4省(区)的137个气象站30年的降水、蒸发资料,确定适合西北地区的干旱指数计算方法,分析中国西北地区秋季降水、蒸发、干旱指数的空间分布、时间演变等特征.结果表明:西北地区秋季平均自然降水从东南到西北依次减少,在甘肃西部、青海西北部、新疆南部有一条东西向的少雨带,是干旱最严重的地方.新疆南部、甘肃西部、青海西部重旱频率最高,平均2年一遇;新疆北部、甘肃南部、青海南部、中旱频率为30%左右,平均3年一遇,轻旱频率30%左右,平均3年一遇.表明西北地区的干旱有明显的地域特征,即新疆中南部、甘肃西部、青海西部为干旱区,新疆北部、甘肃中东部、青海东部和南部为半干旱区.     

旱胁迫对啤酒大麦产量及酿造品质的影响

在武威黄羊镇啤酒大麦试验基地进行了干旱胁迫对甘啤6号生育期、农艺性状、籽粒产量、原麦品质、酿造品质的影响试验研究。结果表明:干旱胁迫下甘啤6号各生育期均提前,成活率降低,分蘖减少,株高、穗长、单株穗数、单株粒数、单株粒重、单穗粒重、穗粒数均降低;干旱胁迫使甘啤6号成穗数、穗粒数、千粒重均降低,导致产量降低,其中对成穗数影响最大,其次为穗粒数,对千粒重影响最小;干旱胁迫使大麦蛋白质含量升高,千粒重、淀粉含量和筛选率均降低,千粒重降幅尤其明显;干旱胁迫使麦芽糖化时间、糖化力、粘度、β-葡聚糖、微粉浸出率、粗细粉差降低,粗粉浸出率、a-氨基氮、可溶性氮、蛋白质、库值升高。     

围栏与不同放牧强度对东祁连山高寒草甸植被和土壤的影响

在东祁连山高寒草地,对围栏7年和不同放牧强度的草地进行了物种数、地上生物量、地下生物量、土壤理化性质等研究。结果表明,围栏7年的高寒草地鲜草产量为425.8 g·m-2,显著高于夏季中牧159.3 g·m-2和夏季重牧91.0 g·m-2,但与冬季轻牧、夏季轻牧差异不显著。围栏条件下的物种数为26.3种·16 m-2,显著低于其他放牧条件下的物种数,但显著高于夏季重牧条件下的物种数23.0种·16 m-2;轻度或重度放牧都会使物种数减少,夏季中牧下的物种数最高(33.5种·16 m-2)。在0~10 cm的表层土壤中,围栏7年的草地根系生物量显著高于其他放牧强度。随着放牧强度的增加,根系生物量在0~10 cm土壤中呈下降趋势,在30~40 cm土壤中则表现为升高趋势。围栏7年的土壤容重低于其他放牧强度下的土壤容重,但差异不显著;夏季重牧的土壤容重显著高于围栏7年和其他放牧强度的土壤容重。随着放牧强度的增加,0~10 cm土壤碱解氮增加,围栏7年草地最低。围栏封育可有效改善和恢复草地植被,但不能长时间禁牧不进行放牧利用。合理的放牧能够维护高寒草甸草地生态系统功能、促进物种丰富度和土壤营养的均衡。     

Influence of non-stationarity and auto-correlation of climatic records on spatio-temporal trend and seasonality analysis in a region with prevailing arid and semi-arid climate,Iran

Trend and stationarity analysis of climatic variables are essential for understanding climate variability and provide useful information about the vulnerability and future changes, especially in arid and semi-arid regions. In this study, various climatic zones of Iran were investigated to assess the relationship between the trend and the stationarity of the climatic variables. The Mann-Kendall test was considered to identify the trend, while the trend free pre-whitening approach was applied for eliminating serial correlation from the time-series. Meanwhile, time series stationarity was tested by Dickey-Fuller and Kwiatkowski-Phillips-Schmidt-Shin tests. The results indicated an increasing trend for mean air temperature series at most of the stations over various climatic zones, however, after eliminating the serial correlation factor, this increasing trend changes to an insignificant decreasing trend at a 95% confidence level. The seasonal mean air temperature trend suggested a significant increase in the majority of the stations. The mean air temperature increased more in northwest towards central parts of Iran that mostly located in arid and semi-arid climatic zones. Precipitation trend reveals an insignificant downward trend in most of the series over various climatic zones; furthermore, most of the stations follow a decreasing trend for seasonal precipitation. Furthermore, spatial patterns of trend and seasonality of precipitation and mean air temperature showed that the northwest parts of Iran and margin areas of the Caspian Sea are more vulnerable to the changing climate with respect to the precipitation shortfalls and warming. Stationarity analysis indicated that the stationarity of climatic series influences on their trend; so that, the series which have significant trends are not static. The findings of this investigation can help planners and policy-makers in various fields related to climatic issues, implementing better management and planning strategies to adapt to climate change and variability over Iran.     

新疆春小麦黑胚发生与产量及加工品质之间的关系

通过多点分析春小麦加工品质、产量表现和小麦黑胚发生的特点,发现干旱区春小麦黑胚发生率受环境的影响比较大,同一品种在不同地区表现结果不同,同时小麦的籽粒加工品质和产量也受环境条件的影响.小麦抽穗至成熟期间低温、多雨的环境条件有利于小麦黑胚病的发生,也有利于产量的提高,但这种环境条件不利于优良品质的形成.黑胚率高的小麦千粒重和容重较高,降落数值较小,发芽的可能性增大,籽粒蛋白质含量较低,面团流变学特性较差,小麦总体加工品质变差.     

河北省冬小麦生产干旱风险分析

利用河北省冬麦区49个气象站1980-2010年的气象资料及其相应的冬小麦产量资料,选取三种干旱指数,根据自然灾害风险分析的基本原理,计算了气候干旱、作物干旱、产量灾损三种风险度,并进行了相应的风险区划,根据区划结果提出了不同风险区的减灾对策.结果表明:(1)冬麦区气候干旱风险以中风险或较高风险区域为主,作物干旱风险则以较高风险区为主,产量灾损低风险区域较大.(2)气候干旱、作物干旱、产量灾损各等级风险区分布无明显相关关系,产量灾损风险与各地的灌溉条件关系密切.(3)产量灾损各风险区应采取不同的减灾对策,高风险区应以防旱为主,采取一系列保墒措施,提高自然水分利用率;较高风险区应以抗旱防旱为主,加强农田水利基本建设,改善灌溉条件;中低风险区应以发展优化灌溉制度为主,实现节水高产.     

干旱气候变化对甘肃省干旱灾害的影响及防旱减灾技术的研究

西北地区干旱气候变化的主要特征,表现在20世纪90年代夏季降水量有明显减少趋势,干旱化趋势主要发生在西北地区东部,干旱连年发生,尤其是甘肃省河东地区.干旱气候的产生带来了严重的干旱灾害,甘肃省90年代的干旱发生最为频繁,干旱灾情最为严重,1995年是干旱最严重的一年,成灾率达45%,其次是2000年,成灾率为35%,伏秋旱连春末初夏旱是造成夏粮严重减产的旱灾类型.干旱气候变化引发干旱化趋势非常明显,应采取综合的技术措施减轻干旱危害,要加强干旱气候与干旱灾害的监测预测和改善生态环境、优化农业结构、提高水资源利用率以及大力开发空中水资源等防御对策.     

不同干扰条件下荒漠区土壤种子库

在内蒙古阿拉善荒漠区选择开垦、轮牧、过牧和禁牧4种不同干扰条件的样区,于2005年4月(春)、7月(夏)和10月(秋)分别对土壤种子库取样,并在实验室条件下进行发芽试验,得出如下结果:(1)4种不同干扰区在春、夏、秋三个季节土壤种子库可萌发种子平均数量分别为,开垦干扰:688粒/m2;轮牧干扰:1328粒/m2;过牧干扰:1488粒/m2;禁牧干扰:944粒/m2;(2)开垦区与禁牧区在4月份(春)、7月份(夏)、10月份(秋)土壤种子库可萌发种子数量呈连续上升趋势,而轮牧区与过牧区则呈先上升后下降趋势;(3)4种不同干扰条件下,开垦区、过牧区和禁牧区在不同深度土层中水分含量均无显著差异;而轮牧区0-5cm与其它三个土层中水分含量出现显著差异,而且0-5cm土壤层的水分含量与种子的萌发数量呈显著正相关。     

锦鸡儿等旱生树种抗旱生理的研究

研究了青海东部干旱半干旱地区常见的１４种旱生树种在多项抗旱生理指标上的特征。通过凋萎系数的测定将参试树种的抗旱程度进行了初步划分。深入研究了多项水分生理指标，并据此进行了主成份二维排序，将参试树种按耐旱特征划分为五个不同的抗旱类型，供各种生态类型区选用。又综合多指标对１４个树种的抗旱顺序进行了综合排序。     

绿洲气候资源和绿洲建设

作者根据绿洲气候资源的两重性论述了绿洲气候生态的巨大潜力与生态环境的脆弱性，并根据我国干旱地区气候变化的趋势，提出了我国绿洲建设的战略构想。     

大豆种质资源抗旱性综合评价

采用抗旱指数与隶属函数相结合的方法,在年降雨量不足40 mm的敦煌市,设干旱胁迫和正常灌水2个处理,考察了12份地方、73份国内育成和38份国外引进共计123份大豆种质与抗旱性相关的株高、分枝数、单株荚数、单株粒数、单株粒重、百粒重、生物产量等7个性状。结果表明:被考察的农艺性状对干旱胁迫的反应程度各异,其中分枝数和百粒重反应迟钝,单株生物量和单株粒重反应敏感;根据抗旱性量度值(D值)的聚类结果,供试的123份材料中筛选出Spry、晋豆21、下台子磨石豆等12份抗旱资源。利用多个农艺性状,采用抗旱指数与隶属函数相结合的方法,综合评估大豆种质的抗旱性是可行的,不仅可以避免单一指标的片面性和不稳定性,而且可以较好地揭示指标与抗旱性的关系。