基于“三生”空间的重庆市土地利用演变与城镇化关系研究

[目的] 分析重庆市土地利用时空演变规律,探究土地利用转型及景观格局响应的演变特征与城镇化的关系,为重庆市"三生"土地规划与城镇化可持续发展提供数据支持。[方法] 基于"三生空间"功能分类的视角构建用地分类标准,利用2000,2010,2020年土地遥感影像和夜间灯光数据,采用转移矩阵、相关性分析及回归分析法进行分析。[结果] ①2000-2020年重庆市生产、生态空间总体减少,生活空间持续扩张。2000-2010年,生产、生态空间减少191.87,252.95 km²,生活空间增大446.03 km²;2010-2020年,生产空间面积减少13.76 km²,生态空间减少324.05 km²,生活空间增大314.87 km²。②重庆市生产功能向生活功能转化较为明显。随着城镇化加强,生态空间转向生产空间显著,功能转变明显聚集于重庆市中心区域。③重庆市空间景观破碎度减小,景观复杂度逐渐提高,林草水生态空间占据主导优势。④2000-2010,2010-2020年土地利用面积变化对夜间灯光值的影响存在差异;2000年,城镇生活空间、农村生活空间变化对夜间灯光变化影响起主导作用,而2020年工业生产空间、城镇生活空间变化对夜间灯光变化影响较强。[结论] 重庆市各类空间发生相互转换,利用不同"三生"空间类型变化和城镇化的关系,推动土地规划与城镇化协调发展。     

中国天眼工程周边地区土地利用时空演变与生态环境效应

[目的] 分析FAST （中国天眼）工程周边的贵州省平塘县、惠水县、罗甸县的土地利用类型和空间变化,探讨土地利用变化与生态环境的关系,为FAST工程周边的生态环境保护和改善提供科学参考。[方法] 以2000,2005,2010,2013和2017年5期TM遥感影像数据为基础,运用RS和GIS技术解译遥感影像数据获取惠水县、罗甸县、平塘县“三生”空间的土地利用数据,计算区域生态环境质量指数及其生态贡献率,分析研究区近20 a土地利用功能演变特征及区域生态环境响应状况。[结果] ①FAST周边林地面积比例最大,但呈减少的趋势。研究区土地利用面积表现为：生态用地>生产用地>生活用地,但生活和生产用地面积增加,分别由1 661.74和12.84 km²增加到1 674.07和25.66 km²,生态用地面积则由6 610.55 km²减少到6 590.86 km²。②FAST工程建设加速土地利用类型的转变,促使FAST周边林地生态用地、草地生态用地、农业生产用地、水域生态用地相互转换,其中林地生态用地的转出面积最大,占转出面积的46.14%。③FAST周边的生态环境质量指数由0.471 0下降到0.468 1,生态环境呈现下降的趋势,FAST周边的发展促使高生态环境土地利用转向低生态环境土地利用类型。[结论] FAST周边的生态环境与土地利用变化存在耦合关系,生态环境质量随生态用地向生产、生活用地转变呈现下降趋势。提高FAST周边生态用地质量,有助于FAST工程的安全运行。     

广东省1980-2018年“三生”用地转型对生态环境质量的影响

[目的] 研究基于格网单元的广东省“三生”用地转型对生态环境质量的影响,为区域生态、经济协调发展提供科学依据。[方法] 基于广东省8期土地利用现状遥感监测数据和“三生”土地利用主导功能分类体系,对该区“三生”用地转型特征及生态环境质量进行定量研究。[结果] ①1980—2018年,广东省农业生产用地面积大幅减少,共减少了5 369.61 km²,城镇生活用地、工矿生产用地面积大幅增加,分别增加了4 526.02 km²,2 406.93 km²,农业生产用地和林地生态用地间转换现象明显。②“三生”用地空间转型主要表现为工矿生产用地、林地生态用地中心逐渐靠近广东省几何中心,农业生产用地、城镇生活用地中心逐渐远离几何中心。③广东省生态环境质量指数从1980年0.648 1降至2018年的0.641 4,生态环境质量空间分异明显,呈现“沿海低—内陆高”的分布特点。④Getis-Ord G_i^*指数表明,生态环境质量变化热点区域集中在粤东西北地区,冷点区域多位于珠江三角洲地区。⑤广东省生态环境存在改善和恶化两种趋势。[结论] 建议充分考虑区域自然条件、功能定位以及导致生态环境变化的主导因素,制定土地政策措施,实现土地利用方式创新,更好地推动广东省区域均衡发展。     

额尔齐斯河流域土地利用变化对生态系统服务价值损益时空演变的影响

[目的] 评估土地利用变化与生态系统服务价值损益之间的关联效应,为制定适宜的土地干预政策提供科学依据。[方法] 基于5期额尔齐斯河流域土地利用数据以及CLUE-S模型,量化土地利用变化下流域生态系统服务价值损益时空演变规律。[结果] ①2000—2018年额尔齐斯河流域草地和林地持续地转化为其他土地,耕地面积大幅度增长;到2030年,流域耕地面积的比例将上升4.92%(1 502.48 km²上升到4 070 km²),而林地呈现快速下降趋势,所占比例将下降7.18%(由7 547.26 km²减少到5 424.36 km²)。②额尔齐斯河流域生态系统服务价值由2000年的518.16亿元增长到2018年的1 832.44亿元,到2030年,生态系统服务价值处于波动下降趋势(2030年为1 777.86亿元); ③林地和草地被耕地所占用,导致额尔齐斯河流域生态系统服务价值损失预计达到108.80亿元,依次为：草地转换损失(34.39亿元)>林地转换损失(28.49亿元)>水域转换损失(18.31亿元)。④额尔齐斯河流域生态系统服务价值损益空间分布呈现“北高南低”的发展格局,价值损益在全局和局部上均呈现显著的正向空间自相关。[结论] 人为因素导致大量生态用地被占用,生态系统服务价值下降且损益空间异质性显著,需要进一步采取有效的生态保护与补偿政策推动农牧户生计转型,减小对自然环境的依赖性。     

1990-2015年阿克苏市建设用地的扩展与驱动力

[目的]探讨新疆阿克苏市建设用地扩展特征及其驱动因素和存在的问题,为绿洲城市发展和建设决策提供一定的利用依据。[方法]以1990,2000,2010,2015年的Landsat TM/ETM⁺卫星遥感影像为数据源,借用ENVI进行监督分类,得出阿克苏市4个时间段的建设用地、耕地、林地、水体、未利用地等信息。应用建设用地扩展强度、速度,重心坐标转移、紧凑度、弹性系数等指标,研究阿克苏市建设用地变化规律。[结果]1990年建设用地面积为18.34 km²,2015年建设用地面积为91.61 km²,25 a里总扩展面积为73.24 km²,净增加了1990年的4倍。建设用地扩展中主要占用的土地类型为未利用地和耕地,面积分别为43.84,28.04 km²。建设用地重心坐标向EN,WS,WS方向迁移,靠近交通路线移动。1990-2000年重心坐标移动距离不大,移动距离为243.7 m。2000-2010年移动距离为832.2 m。2000-2015年移动距离最大（为1 568.2 m）,扩展形状为面状和条带状。建设用地外围紧凑度一直呈下降趋势,从1990年的0.201下降到2015年的0.066,城市空间形态越来越复杂。[结论]阿克苏市1990-2015年建设用地不断往外扩展。阿克苏市建设用地扩展速度在研究期间一直高于人口增长速度,而两者之间差距不断扩大,弹性系数为1990-2000年2.3,2010-2015年10.13,城市扩展与人口增长高度不合理。非农业人口因子、经济因子、政策因子、交通因子是引起阿克苏市土地利用变化最主要的驱动因素。     

黄河中游典型支流无定河流域水土流失动态监测

[目的] 探索黄河中游典型的粗泥沙支流无定河的水土流失分布和动态变化特征,为新时期水土保持工作、生态环境建设和流域高质量发展提供科学依据。[方法] 以无定河流域为例,基于1985,1999,2011年3次普查和2019年全国水土流失动态监测成果,提取年度水土流失强度、面积,分析其时空分布及动态变化特征,并采用Mann-kendall检验,基于水文数据,分析1980—2018年流域水沙变化特征。[结果] 2019年无定河流域水土流失面积1.20×10⁴ km²,以水力侵蚀为主,风力侵蚀主要集中分布在流域北部的风沙区。下游干流（白家川—绥德+丁家沟段）、小黑河绥德以上的输沙模数超过流域平均水平的3倍,是主要的泥沙策源地;水土流失面积较1985年减少1.40×10⁴ km²,减幅为53.87%,输沙量和径流量均呈现出减小的趋势,拐点分别出现在2007年和1996年。空间上,风力侵蚀由1985年的集中连片分布转为零星分布,水力侵蚀空间位置分布与1985年相比基本无变化,但干流赵石窑至流域出口段左岸侵蚀强度有所降低。[结论] 无定河流域水土保持工作成效显著,有效遏制了土壤侵蚀,生态环境整体向好。但流域水土流失依旧严重,未来工作中,应结合历史水土保持工作经验,突出工作重点,进一步加强无定河流域水土流失综合治理。     

基于InVEST-PLUS模型的郑州市碳储量时空演变及空间自相关分析

[目的] 陆地生态系统碳储量的主要驱动因素之一是土地利用变化,以“过去—现在—未来”的逻辑,分析河南省郑州市土地利用与碳储量时空演变之间响应关系,为实现城市的生态安全可持续发展提供参考。[方法] 首先基于GIS和InVEST模型,对2005—2020年碳储量时空分布进行定量评估,然后结合PLUS模型,模拟2050年自然发展情景和生态保护情景下土地利用和碳储量时空变化特征;并辅以莫兰指数和热点分析在格网尺度下评估其空间关联程度。[结果] ①2005—2020年,耕地不断调整为建设用地,累计转入1 004.98 km²,致使郑州市土地利用结构发生显著变化,生态保护情景下生态用地减少趋势相对自然发展情景得到较好改善。②受城镇化快速扩张的影响,2005,2020年郑州市碳储量分别为6.59×10⁷,5.67×10⁷ t,15 a间高碳密度地类用地转移,碳储量空间分布呈“西高东低,南北中等,中部低”的特点,自然发展情景和生态保护情景下碳储量变化分别减少了8.27×10⁶ t和1.80×10⁶ t,其中耕地发挥着重要碳汇作用。③碳储量空间分布上具有集聚性,冷热点分布不均,生态保护情景下热点破碎化程度缓和。巩义市和登封市始终为碳储量集聚程度较高区域。[结论] 碳储量时空分布特征与土地利用结构变化密切相关,郑州市未来土地利用规划应适当采取生态保护措施,优化土地利用格局,增强生态系统固碳能力。     

峰丛洼地石漠化区景观格局的形态学特征及空间演变规律

[目的] 探究峰丛洼地石漠化区景观格局的形态学空间分布特征,为揭示峰丛洼地石漠化区景观格局动态变化和生态保护的可持续发展提供理论参考和指导。[方法] 利用形态学空间分析(MSPA)方法对岩溶石漠化景观识别、处理、分类得到核心、环线等互不重叠的7类景观类型,应用景观动态度、景观格局指数、景观转移矩阵和热点分析探究峰丛洼地石漠化区景观格局的形态学时空演变特征。 [结果] ①2000年形态学景观类型分布最广(190.60 km²),2022年分布最少(147.32 km²),在形态学景观类型中核心是研究区内主要的景观类型,2000年面积最大为121.62 km²,2022年面积最少为76.05 km²,主要分布在研究区西北部和南部区域;孤岛在形态学景观类型中面积最小,其面积1990年最少为1.12 km²,2022年最多为3.07 km²,孤岛和分支等景观类型分散分布在各核心之间。 ②研究区形态学景观空间分布趋于分散,且形态学景观多样性、复杂程度和景观破碎化程度增加;研究时段内,形态学景观类型单一动态度分别为0.10,-0.18和-2.13,说明形态学景观面积呈现收缩趋势并且形态学景观类型1990—2000年发育最为剧烈,2000—2010年发育最为平缓。 ③形态学景观类型转移方向主要是核心景观类型转移为边缘和孔隙景观类型,总体来看形态学景观主要转移方向是形态学景观转移为背景,并且背景的转入量大于转出量。高—高聚集区域呈现出向磨合村、老街村和安乐村扩张的趋势,低—低聚集区域呈现出向三光村和老街村扩张的趋势。 [结论] 研究区形态学景观面积处于快速减少阶段且形态学景观类型趋于复杂,核心是主要的形态学景观类型,形态学景观的演变特征主要由核心的变化导致。     

黄河流域景观生态风险分析及预测

[目的] 探究黄河流域近20 a土地利用变化并对2030年土地利用进行预测,分析景观格局指数,揭示生态风险状况,助力黄河流域景观保护修复和规划治理。[方法] 使用FLUS模型,根据2000,2010,2020年土地利用数据,结合社会、经济、地形、气候等因子对该区2030年土地利用状况进行预测,通过景观指数构建景观生态风险指数,并进行深入分析探讨。[结果] ①2000—2020年耕地面积减少12 150 km²,林地面积增加2 514 km²,建设用地面积增加10 620 km²。②黄河流域优势景观为草地和耕地,但优势性逐渐降低,整体景观连通性增加、聚集性减弱,景观多样性呈增长趋势,但整体仍不均衡。③工作区景观生态风险以低、较低风险为主,中风险为辅,共占该区总面积88%以上,各生态风险区在空间上相对稳定,在时间上呈逐步恶化趋势。④预测2030年建设用地面积增速减缓,耕地、草地、未利用地面积继续减少,景观破碎度增加,低、较低生态风险区域增加1.12%,高风险区域增加0.26%,其余风险区域变化较小。[结论] 国家人口增长、城市逐步扩张对土地利用影响巨大,进而导致景观破碎,加之黄河流域环境脆弱,风沙强度大,荒漠化程度高,区域生态风险增高,需要国家更加关注该区域的生态保护和高质量发展。     

生态工程对科尔沁沙地主要生态服务功能的影响

[目的] 研究生态工程实施下科尔沁沙地主要生态服务功能的变化特征,为该区今后生态保护建设提供科学依据。[方法] 运用已有的生态服务评估方法定量评估了2001—2018年科尔沁沙地固碳量、水源涵养及水土保持服务功能的时空变化情况。[结果] ①科尔沁沙地土地利用类型主要以耕地、林地和草地为主,生态工程实施期间,林地、耕地面积分别增加8 448 km²,3 280 km²,草地面积减少12 639 km²; ②科尔沁沙地固碳量稳步增长,林地和耕地的固碳量均增加,草地的固碳量减小,但草地固碳量依然最高; ③科尔沁沙地水源涵养量呈先增加后略微减少的趋势,所有土地类型中林地水源涵养量持续升高; ④科尔沁沙地水土保持量持续上升,约增加1.38×10⁷ t,林地水土保持量增加最显著。受地势的影响,区域水土保持总量呈西高东低的分布特征。[结论] 科尔沁沙地生态工程建设效果良好,创造了显著的生态效益。     

低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响

【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。     

Pasture Vegetation Elemental Analysis by Laser-Induced Breakdown Spectroscopy

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.     

Faculty positions:Center for Agricultural Resources Research,Chinese Academy of Sciences

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,     

Biodiversity and ecogeography of wild Lactuca spp. in some European countries

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.     

Macroinvertebrates in North American tallgrass prairie soils: effects of fire, mowing, and fertilization on density and biomass

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.     

Properties of anaerobically digested and composted municipal solid waste assessed by linking soil mesofauna dynamics and nitrogen modelling

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.     

Faculty positions: Center for Agricultural Resources Research,Chinese Academy of Sciences

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,     

Faculty positions: Center for Agricultural Resources Research,Chinese Academy of Sciences

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,     

Variation in quality parameters between and within 14 Nordic tree fruit and berry species

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.     

Potassium Fixation and Release Characteristics in Rhizosphere and Nonrhizosphere Soils for a Rapeseed–Rice Cropping Sequence

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.