农业干旱风险研究进展   总被引：24，自引：2，他引：22  

何斌  武建军  吕爱锋 《地理科学进展》2010,29(5)

农业干旱风险分析是近年来兴起的一个新的研究领域,这一研究不仅是农业旱灾风险管理的基础和前提,也是农业干旱风险区划和灾前损失预评估的理论基础。本文系统阐述了农业旱灾风险的内涵及构成要素、风险分析体系及研究现状,在此基础上指出,依据自然灾害风险分析基本原理,从农业旱灾危害性以及承灾体脆弱性角度系统地建立农业旱灾综合风险分析程序框架和指标体系,尤其是开发针对每一风险要素的、动态的数学模型和指标体系是当前干旱灾害风险时空格局研究的当务之急。  相似文献   

Soil fertility evolution and landscape dynamics in a Mediterranean area: a case study in the Sant Llorenç Natural Park (Barcelona, NE Spain)     

Jordi Nadal  Albert Pèlachs  David Molina  Joan-Manuel Soriano 《Area》2009,41(2):129-138

The cartography of land covers was used to study fertility and soil evolution in a mountainous Mediterranean area during the anthropocene period ( Crutzen P J 2002 Geology of mankind Nature 415 23). The aim was to determine changes in fertility as agricultural lands were abandoned in the 14 000 hectare area that constitutes Sant Llorenç del Munt Natural Park in a pre-coastal Catalan mountain range (north-eastern Iberian Peninsula). The analysis of land covers using vegetation maps, orthorectified images and aerial photography has allowed us to differentiate six vegetation groups: holm-oak wood, pine grove, oak wood, scrub, active agricultural fields and abandoned agricultural fields. The anthropic covers over the past 100 years were subdivided into five categories: active fields and those abandoned over four time periods. Study variables include field shape (concave, convex, flat), orientation (north, south) and slope (ranging from 12º to 24º). The parameters used for the physical-chemical soil analysis included organic material, phosphorous and potassium; fertility was classified based on groups, types and classes. The results indicate that even when the visual appearance of certain landscapes is similar, the edaphic characteristics may be very different. Changes induced by human disturbance share this phenomenon. Therefore, land management should be considered globally, taking into account vegetation, soils and water as interdependent factors, since it is their interaction that produces landscape and most affects its evolution over time.  相似文献   

动静力排水固结法在淤泥质地基处理工程中的应用   总被引：3，自引：0，他引：3  

张丽娟  李彰明  韩江 《岩土力学》2009,30(2):567-571

以广州南沙泰山石化仓储区1期淤泥质地基处理工程为背景,介绍了采用动静力排水固结法处理促淤饱和软黏土地基的基本思想和工艺。该工程施工与现场实时监测相结合,利用孔隙水压力、土体分层沉降和载荷试验等检测指标对加固效果进行了监测和检测。工程实践表明,采取动力即低能量“少击多遍”的强夯施工工艺,辅以填土预压和设置竖向塑料排水板的静力方法来加固淤泥质地基,其效果明显,促淤地基的物理力学性能和抗变形性能显著提高,整体加固效果很好,工后各项指标完全达到或超过预期值。  相似文献   

Elevated sedimentation in lake records linked to agricultural activities in the Ishikari River floodplain,northern Japan     

Young Sang Ahn  Futoshi Nakamura  Toshikazu Kizuka  Yugo Nakamura 《地球表面变化过程与地形》2009,34(12):1650-1660

The purpose of this study was to examine the historical change in sedimentation rates in lakes that have been impacted by river regulation and agricultural activities in the Ishikari River floodplain. We dated sediment cores using caesium‐137 (¹³⁷Cs) dating and tephrochronology, and we estimated sediment sources from ¹³⁷Cs concentrations in the topsoil of representative land covers. We found that, between 1739 and 1963, the distance between the lake and the main river channel and whether or not the lake was connected to the river affected the sedimentation rates. After 1963, agricultural drainage systems were established in the Ishikari River floodplain. The average sedimentation rate before and after the construction of drainage ditches varied between 1–66 and 87–301 mg cm^–2 a^–1, respectively. The increase in the sedimentation rate after 1963 was caused by the construction of a number of drainage networks, as well as extensive cultivation activity and/or fragmentation of the swamp buffers surrounding the lakes. The ¹³⁷Cs activities at the surfaces of the lake as well as the catchment‐derived ¹³⁷Cs contributions and ¹³⁷Cs inventory in the lake profiles were used to examine the sediment influx from the various drainage areas after the establishment of the drainage system. Our results indicate that the majority of the lake sediments were derived from cultivated areas, and therefore the catchment‐derived ¹³⁷Cs contribution in the lakes was strongly correlated with the sedimentation rate. The ¹³⁷Cs inventory across all of the lake profiles was also significantly greater than the atmospheric fallout. We identified a negative correlation between the ¹³⁷Cs lake profile inventory and the sedimentation rate. This is because the sediment originating from the drainage areas contained low ¹³⁷Cs concentrations, which diluted the overall concentration of ¹³⁷Cs in the lake sediment. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

小尺度地形因子对农地土壤质量的影响研究   总被引：3，自引：1，他引：2  

马群  赵庚星  李玉环 《地理与地理信息科学》2009,25(3)

地形差异是土地利用结构和空间分布格局分异的重要影响因子,也是土地质量的重要参评因素.选择泰山东麓多种地貌类型过渡区,利用数字高程模型(DEM)提取研究区坡度、高程等地形因子信息,通过GIS空间分析划分研究区农地土壤质量等级,利用SPSS统计分析高程、坡度等地形因子对土壤质量的影响.结果表明:土壤质量等级随地形变化呈规律性演替,坡度和高程与土壤质量呈极显著相关关系,且坡度对土壤质量的影响大于高程;随着坡度的上升,土壤质量分值呈抛物线趋势,而随着高程的上升,土壤质量呈降低趋势,且各高程段内不同坡度等级土壤质量分值也呈抛物线走势;土壤质量的最高分值位于坡度2°～5°、高程0～150 m的地形部位.  相似文献   

Agricultural Climate Change and Wetland Agriculture Study under the Climate Change in the Sanjiang Plain   总被引：1，自引：0，他引：1  

YAN Minhua  LIU Xingtu  LI Xiujun 《湿地科学》2009,7(1)

With linear curvefitting, Mann-kendall method and Yamamoto method, ≥10 ℃accumulated temperature and precipitation from May to September of 6 meteorological stations (Baoqing, fujin, Jiamusi, Hegang, Jixi and Hulin) from 1978 to 2007 were used to explore 30-year agricultural climate change and trend in the Sanjiang Plain. The results showed that ≥10 ℃ accumulated temperature of the 6 stations have risen by 141.0 ℃ to 287.4 ℃ when estimated by their significant linear trends (n=30, α=0.05) over the last 30 years (1978 to 2007). The rates of warming for the last 30 years range from 4.70 ℃per year to 9.58 ℃ per year. There are not significant linear trends on precipitation from May to September of the 6 stations over the last 30 years. The period of 1978 to 1998 in which ≥10 ℃ accumulated temperature is lower is consistent with that in which there is more precipitation from May to September, and warming and drying period has occurred in the Sanjiang Plain since 1999. Under the background of warming and drying agricultural climate, high yield cultivation of Phragmites australis and establishment of Phragmites australis-fish (crab) symbiosis ecosystem in natural mire are the ways for reasonable use of natural wetland. The area of paddy fields has been increasing from 7.25×104 ha in 1978 to 121.2×104 ha in 2006. It is proposed that paddy field range should not be expanded blindly toward the north in the Sanjiang Plain, and chilling injury forecast and prevention should be pay attention to. In the area that the chilling injury happens frequently, the rotation between rice and other crops should be implemented. Measures, which combine drainage, store and irrigation, should be taken instead of single drainage on comprehensive control of regional low and wet croplands to ensure controlling drought and flood.  相似文献   

Reconstruction of cropland spatial patterns and its spatiotemporal changes over the 20th century on the Songnen Plain,Northeast China   总被引：1，自引：0，他引：1  

Lijuan Zhang  Lanqi Jiang  Xuezhen Zhang 《地理学报(英文版)》2017,27(10):1209-1226

We initially estimated the cropland area at county level using local historical documents for the Songnen Plain (SNP) in the 1910s and 1930s. We then allocated this cropland area to grid cells with a size of 1 km × 1 km, using a range of cultivation possibilities from high to low; this was based on topography and minimum distances to rivers, settlements, and traffic lines. Cropland areas for the 1950s were obtained from the Land Use Map of Northeast China, and map vectorization was performed with ArcGIS technology. Cropland areas for the 1970s, 1980s, 1990s, 2000s, and 2010s were retrieved from Landsat images. We found that the cropland areas were 4.92 × 10⁴ km² and 7.60 × 10⁴ km², accounting for 22.8% and 35.2% of the total area of the SNP in the 1910s and 1930s, respectively, which increased to 13.14 × 10⁴ km², accounting for 60.9% in the 2010s. The cropland increased at a rate of 1.18 × 10⁴ km² per decade from the 1910s to 1970s while it was merely 0.285 × 10⁴ km² per decade from the 1970s to 2010s. From the 1910s to 1930s, new cultivation mainly occurred in the central SNP while, from the 1930s to 1970s, it was mainly over the western and northern parts. This spatially explicit reconstruction could be offered as primary data for studying the effects of changes in human-induced land cover based on climate change over the last century.  相似文献   

澜沧江流域农业灌溉需水的时空变化(英文)   总被引：1，自引：0，他引：1  

顾世祥  何大明  崔远来  李远华 《地理学报(英文版)》2012,22(3):441-450

Based on the data of eight meteorological stations from the 1950s to 2007, current cropping patterns, field water moisture management, we use the Mann-Kendall and the Re-scaled Range Analysis methods to research the changes of humidity and crop irrigation water requirements in the Lancang River Basin. The results show that the annual and dry season average temperatures significantly increased, and the dry season rainfall increased while wet season rainfall decreased. Evaportranspiration (ET0) increased during both dry and wet seasons at all stations except Dali, Jianchuan and Gengma, and the aridity-humidity index decreased at most of the stations. The turning points of weather factors, ET0, the arid-ity-humidity index, paddy irrigation requirements and total agricultural water requirements occurred from the 1960s to the 1990s. The spatial changing tendency of paddy irrigation quota increased with the increase of altitude and latitude, and the correlation coefficients are 0.513 and 0.610, respectively. The maximum value is observed in Weixi, while the minimum in Mengla.  相似文献   

科尔沁沙地2000-2008年农业生产技术效率研究——以通辽市各旗县为例     

葛小东  黄超  叶青 《中国沙漠》2012,32(5):1457-1462

 基于数据包络分析方法对通辽市各旗县2000—2008年农业生产技术效率进行综合评价。结果表明:①通辽市农业生产技术效率整体上较低,但呈逐年上升的趋势。②通辽市各旗县农业生产技术效率的时空差异明显,霍林郭勒和开鲁县的农业生产技术效率表现为先降低后上升;库伦旗和科尔沁左翼中旗农业生产技术效率表现为持续上升;科尔沁左翼后旗、扎鲁特旗和奈曼旗的农业生产技术效率表现为随时间呈现一定波动性;各旗县中奈曼旗年均效率最高。③通辽市农业生产技术效率主要受投入冗余影响,各旗县均存在降水冗余,反映出当地农业生产投入的盲目性。降水的波动性和不确定性导致灌溉用水、耕地面积投入过多,进而影响了各旗县农业生产技术效率。不同旗县在不同年份的投入冗余有所差异,显示农民应对降水变动的措施也具有一定盲目性。建议针对气候的不确定性对农业生产的干扰展开研究,改进农业生产技术。  相似文献   

不同城市化水平地区农户农地收入分析——基于浙江省农户的问卷调查     

宁爱凤  刘友兆 《地域研究与开发》2012,31(3):163-166,176

用SPSS13.0单因素方差分析和均值比较方法,对浙江省不同城市化地区的农户农地收入比重进行比较分析。认为城市化不同,农户农地收入比重不同,城市化程度高的地区农户农地利用经济收入比值的平均值低于城市化程度低的地区,但城市化程度高的地区农户农地收入比值标准差大于城市化低的地区,其中主要原因是城市化不同导致农户兼业时间不同。提出要创造条件促进资源集中型农户兼业化,使农户农地利用经济效率得到提高,缩小城乡收入差距。  相似文献