Microclimate and CO₂ fluxes on continuous fine days in the Xihu desert wetland,China     

QianQian GOU  JianJun QU  ZhiWen HAN 《干旱区科学》2015,7(3):318-327

The Xihu desert wetland is located in an extremely arid area in Dunhuang,Gansu province of Northwest China.The area is home to an unusual geographic and ecological environment that is considered unique,both in China and the world.Microclimate is not only related to topography,but is also affected by the physical properties of underlying ground surfaces.Microclimate and CO2 flux have different characteristics under different underlying surface conditions.However,until now,few studies have investigated the microclimate characteristics and CO2 flux in this area.The eddy covariance technique(ECT) is a widely used and effective method for studying such factors in different ecosystems.Basing on data from continuous fine days obtained in the Dunhuang Xihu desert wetland between September 2012 and September 2013,this paper discussed and compared the characteristics of daily microclimate variations and CO2 fluxes between the two periods.Results from both years showed that there was a level of turbulent mixing and updraft in the area,and that the turbulent momentum flux was controlled by wind shear under good weather conditions.The horizontal wind velocity,friction wind velocity and vertical wind velocity were commendably consistent with each other.Air temperature in the surface layer followed an initial decreasing trend,followed by an increasing then decreasing trend under similar net radiation conditions.With changes in air temperature,the soil temperature in the surface layer follows a more obvious sinusoidal fluctuation than that in the subsoil.Components of ground surface radiation during the two study periods showed typical diurnal variations.The maximum diurnal absorption of CO2 occurred at around 11:00(Beijing time) in the Xihu desert wetland,and the concentrations of CO2 in both periods gradually decreased with time.This area was therefore considered to act as a carbon sink during the two observation periods.  相似文献   

开都河下游灌区不同土地利用类型土壤质地与土壤盐分关系探讨   总被引：1，自引：0，他引：1  

阿斯耶姆·图尔迪  李新国 《干旱地区农业研究》2014,32(6):176-182

通过野外调查,实地测点以及土壤采样分析,以开都河流域下游绿洲为研究区,利用SPSS与DPS等软件对盐分与土壤质地进行ANOVA和多重比较分析。研究结果表明：（1）土壤是以粉粒为主的质地组成。粉粒百分含量分别为0～10 cm层62．65％,10～30 cm层60．31％,30～50 cm层55．93％;0～10 cm、10～30 cm与30～50 cm表层土壤中盐分离子的均值呈现SO42－＞CL－＞Mg2＋＞Ca2＋。（2）四种土地利用类型各粒级机械组成变异系数范围分别为林地8％～62％、耕地4％～37％、园地2％～40％、未利用地15％～52％。变异系数较高;四种土地利用类型总盐的均值从高到低依次为未利用地、耕地、园地和林地。（3）不同土地利用类型粉粒差异明显,均达到显著性水平（ P＜0．05）。（4）土壤粘粒与HCO3－、Cl－、SO42－呈显著性相关（ P＜0．05）;粉粒与HCO3－离子含量呈极显著相关（ P＜0．01）。  相似文献   

渭干河-库车河三角洲绿洲棉花种植面积时空变化特征分析     

买合皮热提·吾拉木  玉苏甫·买买提  满苏尔·沙比提 《干旱地区农业研究》2014,32(3):214-219

利用研究区棉花种植面积和产量相关统计数据,探究研究区棉花种植面积和产量的时空变化特征及单产和面积作用对棉花产量的影响。研究结果表明：(1) 近62年来,研究区的棉花种植面积、棉花产量和单产均呈上升趋势,而且表现出明显的阶段性和波动性,1949—1985年间增长缓慢,1986—2011年增长迅速。(2) 就棉花总产波动来看, 单产的作用占42.04%,面积作用占50.96%,在1949—1985年间单产增加对棉花总产量提高的贡献较大,在1986—2011年间棉花种植面积扩大对棉花总产量提高的贡献较大。(3) 1985年前棉花种植面积较稳定,波动不大,主要靠挤占粮食作物面积来扩大,1986年之后棉花种植面积扩大迅速,主要途径为开荒造地。(4) 棉花市场价格的波动、生产成本的上升、产量的徘徊、生产环境的恶化和品种等直接影响着研究区棉花生产的竞争力和棉农增收。  相似文献   

Effects of cotton field management practices on soil CO2 emission and C balance in an arid region of Northwest China     

QianBing ZHANG  Ling YANG  ZhenZhu XU  YaLi ZHANG  HongHai LUO  Jin WANG  WangFeng ZHANG 《干旱区科学》2014,(4):468-477

Changes in both soil organic C storage and soil respiration in farmland ecosystems may affect atmospheric CO2 concentration and global C cycle. The objective of this field experiment was to study the effects of three crop field management practices on soil CO2 emission and C balance in a cotton field in an arid region of Northwest China. The three management practices were irrigation methods（drip and flood）, stubble managements（stubble-incorporated and stubble-removed） and fertilizer amendments（no fertilizer（CK）, chicken manure（OM）, inorganic N, P and K fertilizer（NPK）, and inorganic fertilizer plus chicken manure（NPK＋OM））. The results showed that within the C pool range, soil CO2 emission during the whole growing season was higher in the drip irrigation treatment than in the corresponding flood irrigation treatment, while soil organic C concentration was larger in the flood irrigation treatment than in the corresponding drip irrigation treatment. Furthermore, soil CO2 emission and organic C concentration were all higher in the stubble-incorporated treatment than in the corresponding stubble-removed treatment, and larger in the NPK＋OM treatment than in the other three fertilizer amendments within the C pool range. The combination of flood irrigation, stubble incorporation and application of either NPK＋OM or OM increased soil organic C concentration in the 0-60 cm soil depth. Calculation of net ecosystem productivity（NEP） under different management practices indicated that the combination of drip irrigation, stubble incorporation and NPK＋OM increased the size of the C pool most, followed by the combination of drip irrigation, stubble incorporation and NPK. In conclusion, management practices have significant impacts on soil CO2 emission, organic C concentration and C balance in cotton fields. Consequently, appropriate management practices, such as the combination of drip irrigation, stubble incorporation, and either NPK＋OM or NPK could increase soil C storage in cotton fie  相似文献   

Interaction between Cd and Pb in the soil-plant system: a case study of an arid oasis soil-cole system   总被引：1，自引：0，他引：1  

ZhuanJun ZHAO  ZhongRen NAN  ZhaoWei WANG  YiMing YANG  Masayuki SHIMIZU 《干旱区科学》2014,6(1):59-68

The Hexi Corridor,our study area,is located in Northwest China and is also the most developed area of oasis farming in arid regions of Northwestern China.However,the rapid development of metallurgy and chemical industries in this region poses a great threat to the accumulation of heavy metals in crops.The objectives of this study are(1)to determine the influence of heavy metals on plant growth;(2)to assess the translocation capability of heavy metals in soil-plant system;and(3)to investigate the interaction between heavy metals.Pot experiments were conducted on cole(Brassica campestris L.)grown in the arid oasis soils singly and jointly treated with cadmium(Cd)and lead(Pb).Nine treatments were applied into the pots.Under the same planting conditions,three scenarios of Cd,Pb and Cd–Pb were designed to compare the interaction between Cd and Pb.The results showed that the response of cole weights to Cd,Pb and Cd–Pb treatments was slight,while Cd and Pb uptakes in cole were more sensitive to the single effects of Cd and Pb concentration in soils from the lower treatment levels.Under the influence of the single Cd,Pb and joint Cd–Pb treatments,Cd concentrations were lower in the cole roots than in the shoots,while for Pb,the results were opposite.Comparison studies revealed that the interaction of Cd and Pb could weaken the cole’s ability to uptake,concentrate and translocate heavy metals in arid oasis soils.  相似文献   

县域绿洲城市经济、社会与环境协调发展评价     

王爱辉    龙海丽    彭健   《水土保持研究》2014,21(3):235-241

县域绿洲城市是干旱区国民经济和社会发展的基石与载体,协调其内部经济、社会与环境之间的关系,对推进干旱区县域绿洲城市全面建成小康社会具有重要的现实与战略意义。文中运用改进熵值法、耦合协调度和协调发展趋势指数模型,对干旱区典型县域绿洲城市乌苏市经济、社会与环境协调发展状况进行评价,并依据评价结果对城市协调发展机理进行分析。结果表明:乌苏市城市综合协调度与经济、社会发展指数总体呈上升趋势,但评价值较低;环境发展指数对城市综合协调度的功效相对较大,但发展趋势指数具有明显的下降趋势;经济与社会发展指数呈显著正相关,经济与环境发展指数呈倒“N”型耦合关系,社会与环境发展指数呈“W”型耦合关系。经济、社会和环境存在着天然的交互胁迫、交互耦合机理,只有三者协同共进,均衡发展,才能真正实现干旱区县域绿洲城市的协调发展。  相似文献   

绿洲灌区小麦水分生产率在不同尺度上的变化   总被引：4，自引：1，他引：3  

胡广录  赵文智 《农业工程学报》2009,25(2):24-30

水分生产率是衡量农业生产水平和农业用水科学性与合理性的综合指标。文章根据民乐县洪水河灌区1995-2006年的气象、灌溉用水量、灌溉面积、作物产量资料,从田间、斗渠、干渠、灌区4个不同尺度分析了小麦灌溉水分生产率年份间的变化情况。结果表明：不同尺度上平均灌溉水分生产率不同,田间尺度为1.414 kg/m3,斗渠尺度为1.013 kg/m3,干渠尺度为1.089 kg/m3,灌区尺度为0.894 kg/m3,并且不同尺度上的灌溉水分生产率在年份间的差异也比较大。2001年洪水河灌区实施了节水灌溉工程,不同尺度上的平均灌溉水分生产率在2001-2006年较1995-2000年有所提高,田间、斗渠、干渠、灌区分别提高了7.9%、19.4%、16.5%、7.4%,说明目前斗渠、干渠尺度上节水力度大,节水效益明显,而灌区尺度还有较大的节水潜力,应成为未来农业节水研究的重点。  相似文献   

阜康MPOED系统生态生产的轴-带-圈层空间结构模式     

周跃志  潘晓玲  何伦志 《干旱区资源与环境》2004,18(4):113-116

在分析阜康绿洲基于的特定生态系统内外部作用关系基础上 ,运用系统理论、景观生态学和区域经济理论与方法 ,研究阜康绿洲环境与发展协调的空间结构模式。提出阜康MPOEDS( mountain,piedmont,oasis,ecotone and desert system)大系统观 ,基于该系统的内部生态与生产水资源轴、生态经济带状与圈层布局结构模式  相似文献   

渭干河--库车河三角洲绿洲近50a来生态环境变化特征及防治对策   总被引：11，自引：1，他引：10  

满苏尔·沙比提  帕尔哈提·艾孜木  玉素浦江·如 《干旱区资源与环境》2004,18(4):13-18

近 5 0年来 ,渭干河—库车河三角洲绿洲地区在人类不合理活动的作用下 ,水文与生态环境发生了一系列变化。1绿洲地表径流总量多年变化有增有减呈现波动性趋势 ,但是水体盐化和含沙量趋势加剧。2绿洲森林面积持续减少 ,其天然屏障作用减弱 ,草地面积减少、退化严重 ,载畜能力大大降低。 3土地退化面积扩大 ,土地沙漠化发展强烈 ,土壤肥力降低 ,生产能力下降。因此 ,进行水资源统筹利用规划与管理 ,统筹兼顾各县的经济发展与生态环境建设对水的需求 ,以生态系统健康发展为原则 ,遵循生态规律来进行土地资源的开发利用 ,开展整个绿洲为单元的生态功能保护与建设是提高绿洲可持续发展能力的根本途径  相似文献   

渭干河-库车河三角洲绿洲土地资源合理利用对策分析   总被引：4，自引：0，他引：4  

满苏尔·沙比提  热合漫·玉苏甫  阿布拉江·苏莱曼 《干旱区资源与环境》2004,18(1):111-116

本文对干旱区内陆河流域下游具有代表性的渭干河—库车河三角洲绿洲土地资源特征和存在的问题进行了详细的分析 ,分析表明 ,土地资源数量大、质量差、利用率低 ,土壤类型多 ;草场面积大、质量差 ;森林覆盖率低、疏林、灌木林比重大 ;土地利用中存在结构不合理 ,特别是林业、畜牧业比重偏低 ,绿肥和饲料作物面积过小 ;土壤次生盐渍化严重、土壤肥力下降 ,经营管理粗放、单产水平不高 ;草场面积锐减 ,森林资源破坏严重 ,保护绿洲的能力下降。在此基础上 ,提出了优化农业用地结构 ,提高土地利用综合效益 ;增加对农业用地开发利用的投入 ,促进农业用地由粗放型向集约型的转变 ;保护和更新胡杨林 ;保护和建设草场 ;大力治理盐碱 ;发展节水灌溉农业 ,提高水资源利用效益 ;扩大绿洲规模 ,加快城市化建设等持续合理利用土地资源的对策。  相似文献