基于土壤水分的农业干旱监测研究进展     

吴泽棉  邱建秀  刘苏峡  莫兴国 《地理科学进展》2020,39(10):1758-1769

土壤水分是评估农业干旱的关键变量。然而长期以来,由于缺乏大范围、高精度、长时间的土壤水分观测数据,基于土壤水分的农业干旱监测在实际应用中受到限制。近年来,随着遥感观测技术的发展,土壤水分数据的时空覆盖度和产品精度显著提升,基于土壤水分的农业干旱监测逐渐吸引更多的关注。论文系统归纳了站点观测与微波遥感观测的土壤水分数据特性,综述了目前基于土壤水分的3种农业干旱监测指标：基于长时间土壤水分序列的干旱指标、基于土壤水分与土壤水力学参数的干旱指标和基于土壤水分等多变量综合的干旱指标。最后,论文从提高土壤水分数据空间分辨率、加强农业干旱机制研究与完善农业干旱监测体系三方面提出基于土壤水分的农业干旱监测所面临的挑战与机遇,以期为未来的相关研究提供参考。  相似文献   

寿光市蔬菜品质与农业地质背景关系   总被引：1，自引：0，他引：1       下载免费PDF全文

王俊兰  曲建民  付恩光  蔡有兄 《山东国土资源》2008,24(3):39-44

根据寿光市蔬菜种植区种植特征,采用对部分茄果类蔬菜、水、土的样品抽样测试、数理统计、相关分析等方法,得出蔬菜的品质与农业地质背景存在一定的相关性,以及土壤有选择蔬菜品种性,蔬菜在品质上有选择农业地质条件性的结论。  相似文献   

浙江省的新构造运动与农用地分布规律     

陆景冈  唐根年  李健 《浙江国土资源》1999,(2)

从地貌和沉积物分析,浙江省新构造运动表现为西南强烈上升,往东北上渐减,至杭州湾两岸转为下沉,此外西北山区上升,海岸带下沉,一些构造盆地内相对下沉,这些情况与莫霍面等深线图的反映十分符合,说明新构造运动的动力来自地壳深层。不同新构造运动性质的区域内,农用地面积比率、农用地内的结构特征明显不同;各地耕地占总面积的百分比,在大河各河段、滨海各岸段、不同位置的海岛、不同盆地的所在区,均是有规律的变化,也都反映了新构造运动的作用。新构造运动还使地表水土流失与农业经济发展的地理分布很有规律。这些都说明作为地球内力重要部分的新构造运动,能强烈影响地表的生态环境。  相似文献   

Multiple cropping intensity in China derived from agro-meteorological observations and MODIS data   总被引：3，自引：0，他引：3  

Huimin Yan  Xiangming Xiao  Heqing Huang  Jiyuan Liu  Jingqing Chen  Xuehong Bai 《中国地理科学(英文版)》2014,24(2):205-219

Double-and triple-cropping in a year have played a very important role in meeting the rising need for food in China.However,the intensified agricultural practices have significantly altered biogeochemical cycles and soil quality.Understanding and mapping cropping intensity in China′s agricultural systems are therefore necessary to better estimate carbon,nitrogen and water fluxes within agro-ecosystems on the national scale.In this study,we investigated the spatial pattern of crop calendar and multiple cropping rotations in China using phenological records from 394 agro-meteorological stations(AMSs)across China.The results from the analysis of in situ field observations were used to develop a new algorithm that identifies the spatial distribution of multiple cropping in China from moderate resolution imaging spectroradiometer(MODIS)time series data with a 500 m spatial resolution and an 8-day temporal resolution.According to the MODIS-derived multiple cropping distribution in 2002,the proportion of cropland cultivated with multiple crops reached 34%in China.Double-cropping accounted for approximately 94.6%and triple-cropping for 5.4%.The results demonstrat that MODIS EVI(Enhanced Vegetation Index)time series data have the capability and potential to delineate the dynamics of double-and triple-cropping practices.The resultant multiple cropping map could be used to evaluate the impacts of agricultural intensification on biogeochemical cycles.  相似文献   

定陶县城乡建设用地增减挂钩工作问题与对策          下载免费PDF全文

张伟  陈娜  王成宝  程永  康学军  陈丕红  杜瑞华 《山东国土资源》2011,27(12):50-52

介绍了定陶县挂钩试点基本情况,针对城乡建设用地增减挂钩工作中存在的过度压缩农村建设用地、资金缺口大、进度迟缓、涉及面小、动态不平衡等问题,提出了适度节约农村建设用地、多渠道筹集资金、构建城乡建设用地增减挂钩督导机制、部门联动机制等对策。  相似文献   

Deep-learning based projection of change in irrigation water-use under RCP 8.5     

Jang Hyun Sung  Jinsoo Kim  Eun-Sung Chung  Young Ryu 《水文研究》2021,35(8):e14315

Stream water-use is essential for both agricultural and hydrological management and yet not many studies have explored its non-stationarity and nonlinearity with meteorological variables. This study proposed a deep-learning based model to estimate agricultural water withdrawal using hydro-meteorological variables, which projected the changes of agricultural water withdrawal influenced by climate change of future. The relationships between meteorological variables and stream water-use rate (WUR) were quantified using a deep belief network (DBN). The influences of precipitation, potential evapotranspiration, and monthly averaged WUR on the performance of the developed DBN model were tested. As a result, this DBN with potential evapotranspiration (PET) provided better performances than precipitation to estimate the WUR. The PET of multi-model scenarios for Representative Concentration Pathways 8.5 would be increased as time goes by, and thus leads to increase WUR estimated by DBN in three basins, located in South Korea during the future period. On the contrary, water availability expected to decrease compared to the current. Therefore, managing water-uses and improving efficiencies can be prepared for the change in agricultural water-use by climate change in the future.  相似文献   

基于决策树的香蕉气候适宜性区划   总被引：3，自引：0，他引：3  

黄永璘  苏永秀  钟仕全  李政  孙涵 《热带气象学报》2012,28(1):140-146

香蕉是华南重要出口水果,开展香蕉气候适宜性区划可为合理利用资源和优化香蕉布局提供科学依据。针对传统气候区划方法过于依赖知识经验、不具学习能力的不足,尝试使用ID3决策树方法进行广西香蕉气候适宜性区划。根据香蕉生长气候需求,选择年平均气温、年降雨量、≥10℃活动积温、年极端最低气温、日平均气温≤8℃连续天数和年平均日照时数等6个气候因子,利用广西90个气象站1971—2000年观测资料,结合台站空间信息建立栅格推算模型,把各个因子推算为l km×l km栅格数据,并根据香蕉区划指标对各个因子进行离散化运算。通过实地考察并结合离散化后的因子栅格数据,获取香蕉气候适宜性样本点,并使用ID3算法建立决策树,结果总体精度达到92.5%。区划结果表明,ID3决策树算法适用于香蕉气候区划。  相似文献   

环渤海地区农田氮素养分收支空间差异研究(英文)     

郭丽英  杨忍  王道龙 《地理学报(英文版)》2012,22(4):761-768

The Bohai Rim region is one the most important bases for commodity grain pro-duction in China.With the rapid pace of agricultural industrialization,nitrogenous fertilizer has been used at an ever increasing rate,which resulted in the trace of accumulative nitrogen in the soil and caused serious environmental problems.In this study we made use of the farm-land nitrogen balance model to assess the spatial difference of farmland nitrogen nutrient budget in the Bohai Rim region in 2008 with the assistance of GIS.Our results indicated that:1) Farmland in this region has a nitrogen surplus totaling 5.0822 million tons,or an average of 288.54 kg/ha.2) In the Bohai Rim region,farmland nitrogen input and farmland nitrogen budget both show a spatial differentiation.Major grain-producing areas have a higher nitrogen input than that of the grazing-farming areas.The main sources of nitrogen input include chemical fertilizer,organic fertilizer,deposition from atmospheric drying and wetting,and biological fixation,which account for 79.47%,9.53%,4.62%,and 3.58% of the total input,respectively.Therefore,chemical fertilizer is the predominant source of nitrogen input to farmland.3) A total of 3.3398 million tons of nitrogen were output from the farmland via har-vested crops and it accounts for 52.36% of the total nitrogen output from farmland in this region.On average,the amount of nitrogen output from unit farmland is equal to 176.65kg/ha.This study has shed light on farmland nitrogen budget and its spatial variation in the study area,may provide scientific evidences for rationalizing the use of chemical fertilizer and managing agricultural operation on the regional scale and is also valuable for improving the economic and ecological efficiency of fertilizer use at the regional scale.  相似文献   

Climate advice and extension practice     

《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2012,112(2):183-193

This article unpacks the problematic relationship between emerging climate change adaptation norms and changes underway in agricultural extension. It is increasingly recognised that in order to apply new knowledge about climate change in rural development practice a more institutional perspective is needed, but there is no clear consensus on what this implies. This article looks at agricultural extension as an example of a meso-level institution that is frequently assumed to be a major potential “implementing partner” in climate adaptation efforts, at the same time as it is also often portrayed as a worst-case example of the obstacles encountered in changing the focus of a path dependent bureaucracy. This article contrasts the perspectives of normative climate adaptation frameworks (exemplified by the 2011 World Resources Report) with what is known about prevailing extension trends and realities. It is suggested that long lists of recommended climate adaptation tasks and technologies may distract from an understanding of the institutional change processes underway within meso-level institutions, wherein the climate agenda would need to be merged with other agendas related to pluralistic, pragmatic, accountable, sustainable and market-oriented rural development.  相似文献   

耕地集约利用对粮食产量变化影响的定量分析——以江苏省为例   总被引：8，自引：0，他引：8  

徐国鑫  金晓斌  宋佳楠  周寅康 《地理研究》2012,31(9):1621-1630

针对粮食生产力影响因素分层结构的特点,构建粮食单产影响因素的多层线性模型,以江苏省为实证案例,定量研究耕地利用集约度及宏观政策因素对粮食单产变化影响及其内在作用机制。研究结果表明:(1)粮食单产的影响因素是多层次的,耕地利用集约度解释了平均粮食单产差异的57.04%,农业政策因素解释了平均粮食单产差异的42.96%;(2)2001～2008年江苏省的粮食单位面积产出总体呈逐年增加的趋势,其中,劳动集约度和资本集约度分别解释了县级平均粮食单产差异的19.50%和5.68%。(3)所选政策变量中,支农支出、科技支出和农业贷款三个变量对市级平均粮食单产具有显著作用。(4)所选政策变量解释了市级粮食单产均值差异的63.21%,市级层次还有36.79%的"背景效应"未得到解释。  相似文献