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1.
为深入探究区域城镇化与生态环境协调发展水平,以长江经济带为例,基于城市土地利用效率与生态系统健康视角构建相关理论框架,综合运用SBM-Undesirable模型、VOR模型及耦合协调度模型测算长江经济带城市土地利用效率与生态系统健康,分析两者的耦合协调特征并识别了其协调发展问题区域。结果表明:(1)2005—2018年长江经济带城市土地利用效率年均值达0.746,整体上呈波动式缓慢上升的趋势,空间集聚特征较为显著。生态系统健康得分均值为0.473,整体呈现小幅波动的趋势,地理空间上则呈现显著的南北分异特征;(2)城市土地利用效率与生态系统健康耦合协调度均值在0.611~0.624区间内小幅增长,截至2018年,区域内实现协调发展的市域达92.62%,耦合结果在空间上表现为由“相对随机”向“南高北低”的分布转变;(3)城市土地利用效率与生态系统健康耦合协调问题区域主要存在于长江经济带中下游部分市域,主要原因在于城市土地利用效率或生态系统健康单方面滞后抑制了城市协调发展水平的提升。总体而言,长江经济带城市土地利用与生态系统之间相互影响、相互促进的程度正逐步深化,交互过程中形成的耦合系统基本实现了平稳发展。 相似文献
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[目的] 对淮河生态经济带新型城镇化、经济发展与水生态环境耦合协调关系及驱动因素进行研究,为该区水生态环境的生态建设与环境保护工作提供科学参考。[方法] 以淮河生态经济带作为研究区域,建立评价指标体系,运用耦合模型和面板数据模型,分析2010—2020年区域内三者间耦合协调度时空演变特征及影响因素。[结果] ① 2010—2020年淮河生态经济带新型城镇化、经济发展、水生态环境三系统综合水平均呈上升趋势,三系统耦合度处于高水平,耦合协调度等级不断提升,东部、北部、中西部的三系统变化趋势趋同,耦合协调度发展趋势与全域相似; ②对外开放、经济发展、产业结构、用水效率、政府、科技、人口和教育因素在不同程度上对全域与三地区的耦合协调度产生正负两方面作用。[结论] 在淮河生态经济带应该同时关注城镇化质量的提升,经济高质量发展和水生态环境保护,充分发挥正向因素作用,减少负向因素影响,实现三系统优质耦合协调发展。 相似文献
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[目的]研究2000—2014年浙江省城镇—环境协调发展的动态计量特征,为浙江省制定新型城镇化可持续发展政策提供决策依据。[方法]基于耦合协调度模型,评价城镇化和生态环境的相互影响程度,并将其划分为4种类型,研究了城镇化和生态环境的协调关系。[结果](1)经济、社会、人口城镇化及其综合发展水平和生态环境响应、状态、压力及其综合发展水平均持续增长;协调度稳定增长,由低度协调发展为良好协调、城镇化滞后转变为生态环境滞后。(2)城镇化和生态环境的协调关系可划分为4种类型:良好协调—生态环境滞后、中度协调—生态环境滞后、良好协调—城镇化滞后、中度协调—城镇化滞后。[结论]各城市必须对应各自协调与滞后的现状,做到在保护生态环境的同时,继续加强城镇化建设,以推动二者协同发展。 相似文献
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为探究长江经济带降雨侵蚀力和植被覆盖关系之间的耦合作用及其与土壤侵蚀风险的关系,该研究基于逐日降水数据和逐月NDVI数据,使用日尺度的降雨侵蚀力计算模型和Mann-Kendall趋势检验方法分析了长江经济带月尺度的降雨侵蚀力和NDVI时空演变特征,并通过耦合协调度理论和Pettitt突变点检验识别了降雨侵蚀力与NDVI耦合协调关系的时空变异特征,最后讨论两者之间耦合协调关系变化的原因。结果表明:1)1965—2019年,7—10月长江经济带多年平均降雨侵蚀力在全区空间上分布比较均匀,其他月份多年平均降雨侵蚀力均呈现从东南向西北减少的空间分布格局。东部地区7月和9月的降雨侵蚀力呈现显著增加趋势(P<0.05);2)不同月份NDVI在1999—2019年间显著增加的总面积比例均超过长江经济带总面积30%,NDVI显著减少面积主要在东部地区,该地区土壤侵蚀风险较大;3)降雨侵蚀力与NDVI耦合协调度的多年平均值呈现东高西低的空间分布格局,耦合协调程度整体较低,耦合协调度显著减少的区域主要位于中部和西南部,显著增加的区域主要位于东部;4)长江经济带东部地区面积占比较小的常绿针叶林、常绿阔... 相似文献
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随着新型城镇化战略的实施和生态文明建设的推进,探索城镇化与生态环境的关系并提出协调发展建议十分必要。该研究以江苏省为例,一方面从指标数值视角构建评价体系,测算2000—2020年城镇化与生态环境的耦合协调度,另一方面从空间格局视角构建空间冲突指数,诊断2000—2020年城镇建设用地与生态环境保护重要性的空间冲突。结果表明:1)江苏省城镇化和生态环境水平均提升,苏南整体属于“高度协调—生态环境滞后”类型,苏中和苏北徐州属于“中/高度协调—城镇化滞后”类型,苏北整体属于“基本协调/失调—城镇化滞后/阻碍”类型。2)江苏省城镇建设用地扩张幅度达203.65%,生态环境保护等级高的区域分布在洪泽湖、太湖等水体、低洼平原以及低丘陵地区。空间冲突强度值先下降后上升,并呈现西部大于东部、北部大于南部的空间特征。3)苏南应针对生态短板指标,提升生态环境水平,空间冲突显著的市域应严格规范建设用地扩张。苏中和苏北的城镇化水平仍有待提高,空间冲突显著的市域应合理引导建设用地扩张方向,加强空间管控。该研究融合指标数值和空间格局双重视角的研究结果可以为江苏省及相似区域的城镇化与生态环境协调发展提供参考和决策依... 相似文献
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[目的]研究经济发展与生态环境之间的关系,为长江经济带高质量发展和三峡库区经济与生态协调发展提供政策参考。[方法]以三峡库区重庆段为研究区域,基于脱钩模型对2006—2018年经济与生态环境"脱钩状态"(分为绝对脱钩、相对脱钩、临界状态、耦合状态)进行判定。结合探索性空间数据分析(ESDA)法,运用ArcGIS, OpenGeoDa软件对脱钩状态相关数据进行空间差异及格局演化特征分析。[结果]三峡库区重庆段整体的脱钩系数偏低,空间相关性较弱;在2006—2010年和2014—2018年脱钩系数主要表现出空间正相关,2010—2014年期间主要表现出空间负相关;从局部空间自相关(LISA)图分析得出,研究区各区县之间的脱钩状态显著性较弱;研究区在3个研究时间段的脱钩状态呈现出显著的倒"V"型发展趋势。[结论]2006—2018年来,三峡库区经济发展与生态环境耦合特征波动较大,亟需进一步深入研究并制定相关整治措施。 相似文献
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基于TOPSIS及耦合协调度的湖南省2009-2018年水资源承载力综合评价 总被引:1,自引:1,他引:0
[目的] 评价湖南省水资源承载力,为区域制定水资源、社会经济发展和生态环境协调发展政策提供理论参考。[方法] 通过构建系统耦合协调度模型及综合评价指标体系,分析湖南省2009—2018年水资源—社会经济—生态环境系统耦合协调的时空演变过程。[结果] ① 2009—2018年湖南省及各市州水资源承载力除湘潭市外,均呈上升趋势,同时空间上呈现“U”型特征; ②在时间维度上,耦合协调度呈波动增长态势,耦合协调状态由初级向中级协调转变; ③从空间维度看,耦合协调度呈现:西部>东部>中部的地区差异,但总体由不均衡逐渐转向整体协同发展,其中张家界市耦合协调最好,常德市耦合协调度增长最快,湘潭、衡阳、邵阳等市处于较低水平。[结论] 湖南省水资源承载力与耦合协调发展态势较好,但时空差异显著;可从产业结构优化、节水排污科技投入、资源优势转化、绿色生态农业发展等方面加大政策支持以提高湖南省水资源承载力,实现高质量的可持续发展。 相似文献
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[目的]探究陕西省耕地利用生态效率与城镇化进程的耦合协调关系,为陕西省城镇化开发和耕地保护相关政策制定提供理论依据。[方法]基于陕西省2005—2019年各县域面板数据,建立耕地利用生态效率评价指标体系和城镇化发展水平评价指标体系,测算县域单元耕地利用生态效率及城镇化水平,采用耦合协调度模型探索两者间的耦合协调关系,利用空间自相关方法分析各县域单元耕地利用生态效率和城镇化发展的空间格局演化特征。[结果]2005—2019年陕西省耕地利用生态效率水平由0.765下降至0.684,但整体耕地利用生态效率值相对较高,且县域间存在空间差异性,各区县耕地利用生态效率以团块状聚集,陕北、关中和陕南地区间差异随时间逐渐缩小;2005—2019年陕西省综合城镇化水平提高了198.24%,整体呈“中部高、南北低”的分布态势,关中地区是人口城镇化、经济城镇化、土地城镇化的核心区域,变化速率整体表现为:经济城镇化>人口城镇化>土地城镇化;2005—2019年,陕西省县域单元耕地利用生态效率与城镇化耦合度等级主要处于低水平耦合向拮抗耦合过渡阶段,25%的区县耦合度有所提高;2005—2019年,陕... 相似文献
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[目的]构建宁夏回族自治区固原市原州区生态环境系统和社会经济系统之间的耦合度和耦合协调度模型,以期为区域的协调发展调控提供科学依据。[方法]基于固原市原州区2002—2016年生态环境和社会经济的数据,构建原州区区域生态系统指标评价体系,采用熵值赋权法计算各个评价指标的权重以及综合评价指数,通过建立耦合度、耦合协调度模型和灰色预测度模型,得到并预测该区域生态环境系统和社会经济系统的耦合度和耦合协调度发展趋势以及耦合协调类型。[结果] 2002—2016年,固原市原州区社会经济系统评价指数稳定上升,受生态环境压力的影响,生态系统综合评价指数呈现先下降后波动上升的趋势,前者的发展速度快于后者;耦合度和耦合协调度不断上升,耦合协调类型从经济滞后中度失调型发展为生态环境滞后的濒临失调型;通过模型预测,2017—2025年生态环境系统和社会经济系统之间耦合度及耦合协调度将逐渐升高,耦合协调类型会不断向理想状态发展。[结论]固原市原州区由于经济发展水平快于生态环境建设力度,从而制约了该区域整体的协调发展。因此为实现原州区区域生态系统的可持续发展。还需大力加强对生态环境的建设。 相似文献
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北部湾城市群土地利用碳收支时空分异及碳补偿分区 总被引:1,自引:1,他引:0
[目的] 分析市域空间尺度对城市群碳收支时空格局演变特征及耦合协调关系,构建碳补偿分区评价体系,为实现碳中和目标提供城市群层面的实施策略参考。[方法] 以北部湾城市群为例,在分析2000,2010,2020年研究区土地利用碳收支时空分异及耦合协调度分析的基础上,结合熵权法和TOPSIS法测算2020年15个城市碳补偿贴近度,构建碳补偿综合评价体系并引入三维魔方单元模型初步构建碳补偿等级进行功能分区研究。[结果] ①2000—2020年北部湾城市群碳收支量呈现整体上升状态,市域尺度主体碳排放区域呈现“核心—外围”结构,主体吸收区域呈现“倒钩”状空间格局。②2000—2020年该区城市群碳源、碳汇在分异格局上,除广西区域呈现西北—东南方向,其余地区均呈现东北—西南为主导的方向,空间分布重心稳定。③2000—2020年城市群内部碳源与碳汇坐标均高于0.5,碳排放与碳吸收水平较高,两者具有较高的耦合协调性。[结论] 北部湾城市群的碳收支存在明显的时空异质性,碳排放与碳吸收耦合协调程度较高。为了进一步探索实现“双碳”目标多元化路径,北部湾城市群未来应多方面考虑区域资源能力、碳排放强度和经济发展条件等,从而健全城市群区域间碳补偿体制。 相似文献
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【目的】以富士(Fuji)、 秦冠(Qinguan)嫁接在平邑甜茶(Malus hupehensis Rehd.)上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水(ZZ)、 低氮正常水(DZ)、 正常氮干旱(ZG)、 低氮干旱(DG)。氮素和水分均设置两个水平,分别为正常氮(6 mmol/L NO-3-N)、 低氮(0.3 mmol/LNO-3-N)、 正常供水(保持盆中砂子相对含水量为饱和含水量的80%~85%)、 干旱处理(保持盆中砂子相对含水量为饱和含水量的60%~65%)。【结果】富士和秦冠的生物量(茎和叶)、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水(ZZ)>低氮正常水(DZ)>正常氮干旱(ZG)>低氮干旱(DG),并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水(ZZ)>低氮正常水(DZ)>正常氮干旱(ZG)>低氮干旱(DG); 氮、 钾元素含量在植株各部位的分布顺序依次是叶>根>茎,磷元素则是根>叶>茎;光合氮素利用效率(PNUE)和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水(DZ)处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱(DG)处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。 相似文献
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Kyle Devey Michael Mucalo Gordon Rajendram Joseph Lane 《Communications in Soil Science and Plant Analysis》2015,46(4):72-80
Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing. 相似文献
13.
《中国生态农业学报》2014,(8)
正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology, 相似文献
14.
Aleš Lebeda Ivana Doležalová Eva Křístková Barbora Mieslerová 《Genetic Resources and Crop Evolution》2001,48(2):153-164
Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions. 相似文献
15.
M.A. Callaham Jr. J.M. BlairT.C. Todd D.J. KitchenM.R. Whiles 《Soil biology & biochemistry》2003,35(8):1079-1093
The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils. 相似文献
16.
Grete Skrede Berit Karoline Martinsen Anne-Berit Wold Stein-Erik Birkeland Kjersti Aaby 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(3):193-208
Abstract A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species. 相似文献
17.
Thomas Larsen Jesper Luxhøi Jakob Magid Lars Stoumann Jensen Paul Henning Krogh 《Biology and Fertility of Soils》2007,44(1):59-68
We have studied the effect of anaerobically digested (ADMSW) and composted municipal solid waste (CMSW) on mineralization
and foodweb dynamics to verify the hypothesis that ADMSW would immobilize N right after addition to soil in contrast to addition
with CMSW. Another hypothesis was that the mesofauna (enchytraeids and microarthropods) would stimulate N release from the
decomposer community. We measured excretion of -N and urea-N from the mesofauna and hypothesized that enchytraeids would release urea. ADMSW and CMSW were amended to pots
with sandy loam and barley. The pots were divided into treatments with or without mesofauna. Mesofauna, plant N and biomass,
soil N and ergosterol (fungal biomass) were measured over a 113-day period of four equidistant samplings. Soil respiration,
N mineralization and N release by the mesofauna were modelled from concurrent studies. ADMSW- and CMSW-treated soils initially
(<20 days) immobilized N. The amendments did not increase plant growth substantially, and this was probably due to N-limitation
in the early stages of plant growth. Enchytraeid abundance was about three times higher in ADMSW- than CMSW-treated soils,
indicating that ADMSW contained more labile compounds, bacteria, and microfauna. The mesofauna did not affect N-content, but
the cumulated -N excreted by the mesofauna was estimated to be substantial and about one-fifth of total plant N in ADMSW. An explanation
for this discrepancy might be that in the absence of the mesofauna, other members of the detrivore and microbivore community
performed the mesofauna’s function. Neither enchytraeids nor microarthropods excreted urea. 相似文献
18.
《中国生态农业学报》2014,(7)
正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology, 相似文献
19.
《中国生态农业学报》2014,(6)
正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology, 相似文献
20.
《Communications in Soil Science and Plant Analysis》2012,43(7):865-877
Potassium (K) fixation and release in soil are important factors in the long-term sustainability of a cropping system. Changes in K concentration and characteristics of K fixation and release in rhizosphere and nonrhizosphere soils in the rapeseed (Brassica napus L.)–rice (Oryza sativa L.) rotation were investigated using a rhizobox system. The concentrations of different forms of K in both rhizosphere and nonrhizosphere soils decreased with plants compared to without plants, regardless of K fertilizer application. Potassium uptake by crops mainly came from the rhizosphere soil. In the treatment without K fertilizer (–K), the main form of K supplied by the soil to the crops was 1.0 mol L?1 nitric acid (HNO3) nonextractable K, followed by nonexchangeable K, and then exchangeable K. In the treatment with K fertilizer (+K), the main K forms supplied by the soil to the crops were exchangeable K and nonexchangeable K. The amount and rate of K fixation after one cycle of the rapeseed–rice rotation was greater in rhizosphere soil than in nonrhizosphere soil. The amount and rate of K fixation of soil in the +K treatment were significantly less than in the –K treatment. The cumulative amounts of K released with 1.0 mol L?1 ammonium acetate (NH4OAc) and 1.0 mol L?1 HNO3 extraction increased with the increasing numbers of extractions, but the K-releasing power of soil by successive extraction decreased gradually and finally became almost constant. The release of K was less in rhizosphere soil than in nonrhizosphere soil. The release of K in the +K treatment was similar to that in the –K treatment in rhizosphere soil, but the K release in nonrhizosphere soil was greater with the +K than the –K treatment. Overall, the information obtained in this study will be helpful in formulating more precise K fertilizer recommendations for certain soils. 相似文献