排序方式： 共有17条查询结果，搜索用时 31 毫秒
1.
Investigation of crop evapotranspiration and irrigation water requirement in the lower Amu Darya River Basin,Central Asia 总被引：1，自引：0，他引：1
Durdiev KHAYDAR CHEN Xi HUANG Yue Makhmudov ILKHOM LIU Tie Ochege FRIDAY Abdullaev FARKHOD Gafforov KHUSEN Omarakunova GULKAIYR 《干旱区科学》2021,13(1):23-39
High water consumption and inefficient irrigation management in the agriculture sector of the middle and lower reaches of the Amu Darya River Basin(ADRB)have significantly influenced the gradual shrinking of the Aral Sea and its ecosystem.In this study,we investigated the crop water consumption in the growing seasons and the irrigation water requirement for different crop types in the lower ADRB during 2004–2017.We applied the FAO Penman–Monteith method to estimate reference evapotranspiration(ET0)based on daily climatic data collected from four meteorological stations.Crop evapotranspiration(ETc)of specific crop types was calculated by the crop coefficient.Then,we analyzed the net irrigation requirement(NIR)based on the effective precipitation with crop water requirements.The results indicated that the lowest monthly ET0 values in the lower ADRB were found in December(18.2 mm)and January(16.0 mm),and the highest monthly ET0 values were found in June and July,with similar values of 211.6 mm.The annual ETc reached to 887.2,1002.1,and 492.0 mm for cotton,rice,and wheat,respectively.The average regional NIR ranged from 514.9 to 715.0 mm in the 10 Irrigation System Management Organizations(UISs)in the study area,while the total required irrigation volume for the whole region ranged from 4.2×109 to 11.6×109 m3 during 2004–2017.The percentages of NIR in SIW(surface irrigation water)ranged from 46.4%to 65.2%during the study period,with the exceptions of the drought years of 2008 and 2011,in which there was a significantly less runoff in the Amu Darya River.This study provides an overview for local water authorities to achieve optimal regional water allocation in the study area. 相似文献
2.
The effects of human activities on the soil cover transformation in the eastern part of Kazakhstan were investigated during the period of 1956-2008.The results of the research for different soil types in Priaralye indicated that there was 643.3×103 hm2 solonchaks,accounting for 38.5 % of the total area(1670.5×103 hm2) in 2008.Vast areas are occupied with dried lakeshore soil(311.1× 103 hm2),sandy soils(147.6×103 hm2) and grey-brown desert soils and solonetzes(146.7×103 hm2).In 2001 the area of solonchak was 755×103 hm2 and decreased to 643.3×103 hm2 in 2008,which due to the shrinkage of the Aral Sea,the areas of marsh and lakeshore solonchaks decreased with the increase of dried bottom of the Aral Sea.The level of soil cover transformation in the modern delta of the Syr-Darya River can be seen from the comparison of the results obtained from the different years in the study area.The area of solonchaks increased by 10×103 hm2 and the area of alluvial-meadow salinizied soils increased by 17.9×103 hm2 during the period of 1956-1969.It means that many non-salinizied soils were transformed into salinizied ones.Striking changes occurred in the structure of soil cover as a result of aridization.So,the researches in1969 significantly determined the areas of hydromorphic soils subjected to desertification(it was not fixed on the map before 1956).Later,these soils were transformed into takyr-like soils.The area of takyr-like soils increased almost by 3 times for 34 years(from 1956 to 1990).The long-term soil researches on soil cover transformation in Priaralye have shown that the tendencies of negative processes(salinization and deflation) are being kept and lead to further soil and eco-environment degradation in the region. 相似文献
3.
以新疆阿拉尔垦区为研究区,选取1961-2013年逐日地面气象要素值,采用Penman-Monteith模型、气候倾向率、Mann-Kendall突变检验和距平相关法,分时段分析了阿拉尔荒漠-绿洲区潜在蒸散量(ET0)变化特征及其影响因素.结果表明:①ET0年际间波动较大,1987年前的减幅[52.4 mm·(10a)-1]高于1987年后的增幅[22.2 mm·(10a)-1],呈“高-低-高”的动态变化,1987年是年ET0突变点.②ET0四季性明显,为“夏＞春＞秋＞冬”的季节变化,1987年前的减幅[12.7 mm· (10a)-1、23.4 mm·(10a)-1、6.6 mm·(10a)-1、9.7mm·(10a)-1]高于1987年后的增幅[0.4 mm· (10a)-1、14.3 mm·(10a)-1、6.4 mm·(10a)-1、1.1 mm·(10a)-1],为“高-低-高”的年际变化,1987年后春季ET0的增幅最大.1987年是四季ET0突变点.③阿拉尔荒漠-绿洲区年ET0的变化主要与日照时数、平均相对湿度和平均风速有关,与气温关系不明显,1987年后年ET0的增加与日照时数的增加有关;季ET0的变化由日照时数、平均相对湿度、平均风速和气温多种气象因子共同作用.1987年后春季ET0的增加与气温的升高和日照时数的增加有关,冬季ET0的增加与平均相对湿度的增大、日照时数的增加和最高气温的降低有关,夏、秋季ET0的增加仅与日照时数的增加有关,与气温、湿度、风速关系不明显. 相似文献
4.
中亚咸海流域的资源和环境问题一直是全球关注的热点。为揭示咸海流域水环境变化及其成因,本文利用2019年中下游流域21个采样点水质数据,通过主成分、聚类和秩次等多元统计分析方法相结合,分析了水体的基础理化属性、氮磷营养元素、其他元素和离子等20种指标的空间分布特征,辨识了该流域主要水质类型、空间分布及成因,探索了不同空间尺度土地覆被类型对水质类型的影响。结果表明:1)电导率、总溶解性固体物质和离子浓度越往河流下游数值越高,其中在咸海最大;不同形态磷元素浓度在阿姆河中游较高,硝态氮浓度在锡尔河较高;碳元素浓度也在阿姆河,特别是阿姆河下游三角洲地区较高。2)所有采样点水体根据水质指标相似性聚类可划分为3种综合性水质类型。第1类型为水质指标浓度均偏低的水体,分布在锡尔河中游和咸海;第2类型为氮磷营养元素浓度偏高的水体,分布在阿姆河中下游;第3类为碳元素和离子浓度均偏高的水体,分布在咸海。第1和2类型水体的元素浓度主要受荒漠地区岩石风化过程控制,阴阳离子来源于硅酸盐岩和蒸发岩的风化;第3类型水体主要受气候干燥导致的蒸发-结晶过程控制,阴阳离子除来源于硅酸盐岩和蒸发岩的风化外,还受碳酸盐岩风化影响。3)当各采样点缓冲区半径从0.5 km增加到10 km时,对第1类型水质浓度变化影响显著的土地覆被类型逐渐从荒地变为水域、灌木、草地和农田与植被混合,其中水域的影响最大;第2类型水质浓度变化与土地覆被类型无显著性关系;对第3类型水质浓度变化影响显著的土地覆被类型从水域变为水域、农田与植被混合等,其中水域的影响最大。因此,咸海流域水质浓度变化与当地干旱缺水和蒸发剧烈等气象条件以及土地覆被类型有密切关系。为改善咸海中下游流域水环境状况,在增加中下游河道流量和咸海的补给,减弱下游和咸海蒸发-结晶作用的同时,还需加大河岸带的植被修复和退耕还林还草,特别是在阿姆河和锡尔河中下游农业区、咸海等地区。 相似文献
5.
Central Asia is located in the hinterland of Eurasia, comprising Kazakhstan, Uzbekistan, Kyrgyzstan, Turkmenistan, and Tajikistan; over 93.00% of the total area is dryland. Temperature rise and human activities have severe impacts on the fragile ecosystems. Since the 1970s, nearly half the great lakes in Central Asia have shrunk and rivers are drying rapidly owing to climate changes and human activities. Water shortage and ecological crisis have attracted extensive international attention. In general, ecosystem services in Central Asia are declining, particularly with respect to biodiversity, water, and soil conservation. Furthermore, the annual average temperature and annual precipitation in Central Asia increased by 0.30°C/decade and 6.9 mm/decade in recent decades, respectively. Temperature rise significantly affected glacier retreat in the Tianshan Mountains and Pamir Mountains, which may intensify water shortage in the 21st century. The increase in precipitation cannot counterbalance the aggravation of water shortage caused by the temperature rise and human activities in Central Asia. The population of Central Asia is growing gradually, and its economy is increasing steadily. Moreover, the agricultural land has not been expended in the last two decades. Thus, water and ecological crises, such as the Aral Sea shrinkage in the 21st century, cannot be attributed to agriculture extension any longer. Unbalanced regional development and water interception/transfer have led to the irrational exploitation of water resources in some watersheds, inducing downstream water shortage and ecological degradation. In addition, accelerated industrialization and urbanization have intensified this process. Therefore, all Central Asian countries must urgently reach a consensus and adopt common measures for water and ecological protection. 相似文献
6.
为揭示平原水库周边无灌溉盐荒地及防风林生长区水盐分布特征,在沙漠绿洲区多浪水库南库区周围布设了地下水监测井和土壤监测点,进行了为期2 a的逐月地下水埋深监测和土壤含水率及含盐量的定点取样测定试验。结果表明:库区周边盐荒地地下水埋深随监测时段变化变幅不大,2 a内均值为1.28 m;不同土壤含水率整体随土层深度增加呈升高趋势,其中60~100 cm的土壤含水率较其他土层波动较大。2 a间盐荒地的土壤含盐量在0.48~8.86 g·kg~(-1)之间变化,不同土壤总盐含量随土层深度增加呈减小的趋势,0~40 cm土层含盐量变化较为明显,具有显著的盐分表聚现象,其中,防风林地土壤含盐量在0~40 cm土层内较天然生态林地明显降低。 相似文献
7.
Yulduz Djumaniyazova Rolf Sommer Nazar Ibragimov Jumanazar Ruzimov John Lamers Paul Vlek 《Field Crops Research》2010
The crop-soil simulation model CropSyst was used to simulate growth, water- and N-uptakes of irrigated winter wheat (Triticum aestivum L. cv. Kupava) in Khorezm, in the dry lands of northwest Uzbekistan, Central Asia. CropSyst was calibrated using the findings of field experiments of 2005/06 and 2006/07 and validated for the 2007/08 season. A relative root mean squared error of 11% proved the accuracy between simulated and observed aboveground biomass and grain yield in 2007/08. Scenario analyses showed that N-leaching was high and ranged from 63 to 106 kg ha−1 when irrigated between 749 and 869 mm during the first two cropping seasons. The simulated N-leaching was lowest and ranged from 7 to 15 kg ha−1 when irrigation was only 148–395 mm during 2007/08. The considerable N losses during leaching and high N-uptakes by wheat together resulted in a negative N-balance even during applications of 180 and 240 kg ha−1 of N-fertilizer. N scarcity in the N-balance was reduced with increasing N-fertilizer amounts and ranged from −29 to −153 kg N ha−1 in 2005/06 and 2006/07. Despite a common shallow groundwater table in the region during some time of the year, scenario analysis revealed that only full irrigation water (580 mm) and N supply according to crop demand (180 kg ha−1) guaranteed high grain yields, unless the water table is permanently shallow to overcome irrigation deficits. Limited irrigation and N application (40% and 55% of ‘optimal’, respectively) in combination with a groundwater table below 3 m resulted in a 55% yield decline. The CropSyst wheat model proved a robust tool for assessing the influence of water and N dynamics under conditions of varying irrigation and shallow groundwater tables. It thus has potential as a decision support not only in northwest Uzbekistan, but also in comparable regions of Central Asia. 相似文献
8.
新疆阿拉尔垦区土壤发生特性及系统分类研究 总被引：2，自引：0，他引：2
通过样地调查和土壤理化性质分析对新疆阿拉尔垦区荒漠植被下的土壤特性进行了研究,结果表明:研究区土壤颗粒组成以砂粒为主,有机质在表层积聚现象明显,土壤氮、磷含量偏低,土壤钾素含量较高.供试土壤的pH呈碱性反应.依照<中国土壤系统分类检索(第三版)>,研究区的土壤类型在系统分类中可归属为3个土纲、3个亚纲、3个土类和4个亚类,其中剖面T-01属于暗沃简育湿润雏形土,剖面T-02属于石灰干旱正常新成土,剖面T-03属于斑纹简育湿润雏形土,剖面T-04属于暗瘠简育正常潜育土. 相似文献
9.
Kayo Matsui Tetsuhiro Watanabe Maira Kussainova Shinya Funakawa 《Arid Land Research and Management》2019,33(1):37-54
Black saxaul (Haloxylon aphyllum) is a native tree species tolerant of aridity and salinity. It is planted to alleviate environmental damage due to the formation of the Aralkum desert and improve vegetation of the Aral Sea region. To investigate the environmental factors that determine seedling mortality and growth after rooting, we focused on soil properties and topographic factors in a study plot. We found that a hard clay layer that was low in hydraulic conductivity underlay accumulated sandy sediments at different depths. The soil in low seedling mortality areas was consistently sandy and low in salinity from the surface to a depth of 100 cm. In areas of high seedling mortality (75–100%), soils with a high content of silt and clay, with high salinity were detected within 100 cm depths. This suggests that accumulated sand sediment over a depth of 100 cm is required for root development. Plant height was positively correlated with depth of the hard clay layer. Significant relationships with plant height were also detected in chemical and physical properties at 80–100 cm such as electric conductivity (ECe), sodium adsorption ratio (SAR), and sand ratio. However, these properties had no significant relationship at 0–20 cm or with the relative elevation of the plot, suggesting that the subsequent growth of seedlings depends more on the sub-soil environment than on-surface conditions. The assessment of sub-soil condition is recommended to make site selection for reforestation much more reliable. 相似文献
10.
Assessing impacts of surge-flow irrigation on water saving and productivity of cotton 总被引：1，自引：0，他引：1
To improve water saving and conservation in irrigated agriculture, a range of field evaluation experiments was carried out with various furrow irrigation treatments in cotton fields to estimate the possibilities of improving furrow irrigation performances under conditions of Central Fergana Valley, Uzbekistan. The research consisted in comparing surge and continuous-flow in long furrows and adopting alternate-furrow irrigation. The best results were achieved with surge-flow irrigation applied to alternate furrows. Field data allowed the calibration of a surface irrigation model that was used to identify alternative management issues. Results identified the need to better adjust inflow rates to soil infiltration conditions, cut-off times to the soil water deficits and improving irrigation scheduling. The best irrigation water productivity (0.61 kg m−3) was achieved with surge-flow on alternate furrows, which reduced irrigation water use by 44% (390 mm) and led to high application efficiency, near 85%. Results demonstrated the possibility for applying deficit irrigation in this region. 相似文献