麦积区葡萄种植中土壤NPK施肥精准化研究

葡萄在麦积的种植范围越来越广泛,而施肥的精准化模式对葡萄产业的发展具有重大影响。为给葡萄精准施肥提供了技术支撑,以麦积区为试验区,选择对葡萄种植影响较大的土壤N(氮)、P(磷)、K(钾),结合少量地面调查数据,借助于目标产量法和氮磷钾比例法,对麦积葡萄种植区土壤NPK进行模拟和预测研究。得出如下结论:葡萄园中土壤NPK的差异比较大,施肥随意性较大,比例与国家标准有些偏差;葡萄施肥模拟模型能调整施肥量,并使施肥量和NPK施肥比例达到良好效果。     

甘肃小陇山日本落叶松人工林土壤养分特征分析

在立地条件相对一致的情况下,应用时空互代的方法,探讨了土壤养分的时空变异性特征和动态演化规律。结果表明:土壤养分总体较为丰富,且土壤熟化程度高,但速效N和速效P俱缺。土壤养分含量变异系数较大,为4.0%~61.5%,土壤养分受外界因素影响的空间变异性较为显著,反映了该区土壤性状不均一性。除全P外,其余土壤养分各指标(有机质、全N、全K、速效N、速效P、速效K)天然林都大于人工林。日本落叶松人工林土壤有机质、全N、全P、全K、速效N、速效P、速效K含量在定植后的4~8 a间均呈下降趋势,而在8~26 a间全P、全K、速效N、速效K含量均呈上升趋势,速效P含量呈下降趋势,但总体上地力有所恢复。     

云南三七质量与土壤(N、P、K)的相关性分析

通过对云南三七主要种植区(文山、红河、曲靖、玉溪、普洱、保山)进行土壤和三七采样,并进行了土壤中N、P、K含量和三七皂苷R1、Rb1、Rg1、总皂苷含量检测。应用spss软件分析了土壤中N、P、K含量与三七皂苷R1、Rb1、Rg1、总皂苷含量之间的关系。结果表明:土壤中P、K含量与三七皂苷含量相关性显著,N含量与三七皂苷含量相关性不显著。再一次使用spss软件以三七皂苷含量S为因变量,分别以N、P、K为自变量,进行回归分析,表明皂苷总含量S与土壤P、K之间建立的方程具有显著性。     

秦岭南坡不同海拔土壤肥力的空间分异规律

对秦岭南坡土壤肥力状况、空间分异规律及其与海拔的关系进行研究.结果表明,秦岭南坡土壤肥力指标在整个土壤剖面空间分异范围分别为:土壤pH值5.97～6.89,有机质含量6.6～50.1 g·kg-1,土壤全N含量0.5～3.8 g·kg-1,碱解N含量33.6～257.3 mg·kg-1,速效P含量0.81～5.8 mg·kg-1,速效K含量38.9～262.4 mg·kg-1,粘粒含量11.3%～18.1%,阳离子代换量68.5～310.2 mmol·kg-1;其空间分异程度以速效P、有机质和土壤全N含量较大,土壤粘粒含量和土壤pH值较小;随着土层的加深,土壤pH值、有机质、速效P、土壤粘粒含量和阳离子代换量空间分异程度减小,而土壤全N、碱解N和速效K含量空间分异程度增大.土壤速效K、速效P含量和阳离子代换量水平空间分异程度受海拔的影响较大,而土壤pH值和粘粒含量水平空间分异程度受海拔影响较小.随着海拔的升高,土壤pH值降低,有机质和速效P、K含量增大,土壤肥力空间分异程度减小,这可能与随着海拔升高人为干扰强度降低及林分类型趋向单一有关.     

山核桃溃疡病与营养元素的关系

调查并分析了安徽省宁国市不同种植区山核桃溃疡病与土壤因子、树皮中营养元素等之间的关系,结果表明:山核桃林分中土壤条件与溃疡病的发生与发展的关系十分密切,其感病指数与土壤密度,树皮中P、Fe的含量呈正相关关系;与土层深度,土壤中N、P、K元素的含量和土壤中有机质的含量及树皮中N、K、M g的含量等呈负相关关系。     

不同年龄毛竹营养器官主要养分元素分布及与土壤环境的关系

对福建省永安市不同年龄毛竹营养器官N、P、K、Ca、Mg元素分布进行了研究。结果表明,毛竹不同部位的营养元素含量不同,N、P、Ca、Mg元素平均含量顺序为叶>枝>秆>根;K元素含量的排列顺序为叶>根>枝>秆。叶、枝、秆中主要营养元素的排列顺序为N>K>Mg>Ca>P;根中主要营养元素的排列顺序为K>N>Mg>Ca> P。不同营养器官养分元素含量随年龄增长的变化趋势不同,N、P、Ca、Mg在竹秆与竹根中呈先上升后下降的趋势,竹枝中呈降-升-降的趋势,竹叶中呈"W"型变化,K元素除2年生竹秆中含量较高外,在竹秆、竹根、竹枝中呈下降的趋势。毛竹各器官中有14对元素的相关性达到显著或极显著水平,其中与N元素相关的有8对,与K元素相关的有8对,P元素相关的9对。土壤中有机质、N、P、K的含量对竹秆、竹枝、竹叶中N素含量有重要影响,毛竹营养器官中P、K元素浓度与土壤的主要化学指标之间的相关性未达到显著水平。在土壤养分充足的条件下,竹叶器官中的养分浓度主要由其本身的生理特性决定,与土壤养分浓度相关性不显著。竹叶N、P含量与磷酸酶活性显著相关,与过氧化氢酶极显著相关,土壤酶对土壤中所进行的生物及生物化学过程起着重要的作用,土壤中N、P、K等元素在转化为毛竹可吸收过程中有多种酶的参与。竹秆N与土壤毛管孔隙度和总孔隙度极显著相关,与其他的土壤物理指标相关性不明显。     

湘中丘陵区石栎-青冈栎常绿阔叶林土壤钾含量空间异质性及其影响因子研究

钾(K)是植物生长的必需元素之一,土壤中K含量主要受多种因素的影响。由于森林经营活动和树种组成不同,森林土壤中K含量差异性较大,表现一定的空间异质性。本研究在1hm2石栎-青冈栎常绿阔叶林样地内的10 m×10 m小样地中心位置,分采集0~10、10~20和20~30cm层的土壤样品,测定土壤中K元素含量,用地统计学理论分析土壤K含量空间变异特征,研究土壤K含量与土壤其它养分元素(有机C、N、P)、地形因子(海拔、凸凹度和坡度)和凋落物量之间的关系。结果表明:0~30 cm土壤K含量平均值为28.04 g/kg,为中等变异强度,具有明显的空间异质性。除20~30cm土层中K含量符合线性模型外,0~10\10~20土层和0~30 cm土层K含量符合球状模型分布,各土层土壤K含量具有较强的空间自相关性。0~10、10~20、20~30 cm和0~30 cm土层中K含量的空间自相关变程范围分别为37.51、25.38、39.78和28.92 m,土壤K含量有较小的空间异质性尺度。各土层K含量随地形的变化趋势较为明显,表现为斑块状空间分布,低值出现在中下部的山脊,高值出现在上部山脊和西南角的部分沟谷。土壤K含量与海拔高度、土壤粘粒含量呈显著的正相关,K含量的空间异质性主要受成土母质和地形等结构因素影响。     

3个早熟梨品种矿质元素含量变化及其相关性

为了解早熟梨对N、P、K元素的吸收规律,给合理施肥提供指导,以中梨1号、中梨4号和早酥蜜3个新优早熟梨品种为研究对象,研究果实发育期间,果实、叶片和土壤中N、P、K元素含量的变化规律,并对它们之间N、P、K元素含量的相关性进行分析。结果表明,3个早熟梨品种果实、叶片和土壤中N、P、K元素含量的变化规律基本一致;相关性分析结果相似,3个早熟梨品种土壤与果实和叶片中N、P、K元素含量间均无显著相关性。     

南亚热带不同林龄杉木针阔混交林土壤理化性质分析

森林发育对土壤理化性质有着重要的影响。在南亚热带,以杉木皆伐改造林地3个林龄段（3～5 a、7～9 a和10～11 a）的针阔混交林为研究对象,研究了土壤理化性质的变化特征以及不同理化性质指标之间的相关性。结果表明,土壤容重、总孔隙度、毛管孔隙度随林龄的增加呈上升趋势,而非毛管孔隙度和土壤通气度表现为先升高后降低。土壤pH值、有机质、全N、全P、全K、水解N、速效K随林龄的增加呈现出先降低后升高的趋势,而有效P处于下降的趋势。相关分析表明,不同林龄段针阔混交林的土壤容重主要取决于土壤有机质含量,自然含水量主要取决于毛管孔隙度;土壤有机质含量与全N和水解N相关性最高,土壤中绝大部分N素以有机态存在;而土壤有效P含量主要取决于土壤有机质含量,同时受土壤pH值影响也较大。     

无翼坡垒植物与土壤营养元素及化学计量学特征

为探讨无翼坡垒Hopea exalata土壤、根系和叶片营养元素含量及化学计量特征,以甘什岭省级自然保护区无翼坡垒群落为研究对象,根据物种胸径划分等级,选择幼树(2.5 cm≤DBH 7.5 cm)、小树(7.5 cm≤DBH 12.5 cm)和大树(17.5 cm≤DBH 22.5 cm)3个等级,比较其土壤-根-叶片元素含量及化学计量比的差异,探讨随林龄的变化及相互间的关系。结果表明:1)C、N、P含量表现为叶片根系土壤,土壤全N、全P和全Ca含量以大树最高;随着等级的增长,根系C和Mg含量呈上升趋势,N、P和K含量呈下降趋势;叶片C、P和K含量呈上升趋势,N、Ca和Mg含量呈小幅度下降趋势。2)不同等级土壤C/N、C/K比值以大树最高,叶片中C/N、C/K、Ca/K、Ca/Mg比值显著高于土壤和根系,根系和叶片的N/P、N/K、Ca/K和Ca/Mg均高于土壤。3)不同等级叶片N/P均大于16,表明无翼坡垒植物主要受P限制。PCA分析结果表明,土壤C、全P、全K、全Ca、根系K、Mg、C/K、K/Mg、叶片N、Mg、C/N、C/K、N/K、K/Mg为主要影响因子,土壤全Mg、根系P、Ca、N/P、K/P、叶片Ca、K/P和Ca/K为重要影响因子,反映了无翼坡垒土壤-根-叶C、N、P含量之间以及化学计量比之间也均存在显著相关关系。     

Integration of pines,pastures, and cattle in south Georgia,USA

Agroforestry Systems - Native forages of southern United States are frequently low in nutrients and poorly digestible, while improved pastures are the opposite. Since this area produces rapid...     

乌盟后山干旱半干旱地区沙漠化治理模式探讨

地处阴山以北的乌盟后山地区,土地的风蚀沙化十分严重,北部五旗县80%的耕地遭风蚀危害,10%的草场荒漠化.草场退化,粮食产量下降,农牧业生产长期低而不稳.同时风蚀沙化也危害交通、水利设施和村镇安全.自乌盟实施"进退还"战略以来,在恢复植被、改善生态环境方面上成效显著,但在治理方式上以单一的灌草模式为主,缺乏生物多样性,并由于草种寿命短造成重复建设,为此,本文提出一些治理模式供讨论.     

Gremmeniella abietina,Phacidium infestans,and other causes of damage in alpine,young pine plantations in Norway

Field studies of damage and mortality were carried out through 16 years in six young plantations, mostly of Pinus contorta, but also P. sylvestris and P. sibirica. Differences between pine species, P. contorta provenances, sites, and soil treatments are reported and discussed, as are influences of environment, climatic conditions, snow cover, and nutrient deficiency. Gremmeniella abietina was by far the most important cause of mortality; there were great differences between the sites as to development and seriousness. Other important causes of mortality and damage were Phacidium infestans, elk (Alces alces L.), voles, and snow pressure.     

Extent,pattern, and multifunctionality of treed habitats on farms in Vermont,USA

Agroecosystems can serve as multifunctional landscapes when treed habitats such as woodlots, hedgerows, riparian buffers, windbreaks, and orchards, are conserved on farms. We investigated the extent, pattern, and multifunctionality of on-farm treed habitats for 16 Vermont farms in the Lamoille watershed of the Lake Champlain Basin. The site was selected because the land use pattern is representative of the region, containing a mixture of agriculture and forest in different habitat types. We used a GIS-based approach to delineate treed habitats on farms and conducted semi-structured interviews with farmers to explore their perception of the functions of treed habitats. Through an evaluation of the relationship between farm characteristics and spatial attributes of treed habitats, we found farm size to be an important variable. Larger farms had more land in treed habitats, while the pattern of these habitats was more complex on smaller farms. Average elevation of the farm, an indicator of biophysical conditions, was a stronger predictor of the extent of treed habitats than farm characteristics. From interviews, we found that farmers benefited from alternative forest products, both for direct consumption and sale, including firewood, timber, maple sugar, edible fruits and nuts, and wood crafts. Most farmers also recognized cultural and ecological functions provided by treed habitats. These results have implications for developing policies to promote the conservation of treed habitats, considering the preferences of the landowner or farmer.     

茂名小良桉树营养元素的测定

为研究茂名小良水保站桉树的化学成分,测定了小良5种桉树的8种营养元素的含量,其中K、Ca、Mg、Cu、Fe、Mn、Zn的含量采用火焰原子吸收光谱法进行测定,P含量采用钼酸铵分光光度法测定。结果表明：同一品种桉树同一器官中各营养元素含量比较,四种大量营养元素含量总体表现为K>Ca>Mg>P,四种微量营养元素含量绝大部分植物以Mn含量最高,Cu含量最低;四种大量元素P、K、Ca、Mg含量都表现为叶最大,枝次之,根和干中的含量较小;而四种微量元素Cu、Fe、Mn、Zn在植物各器官含量的高低排序缺乏一致规律;不同种桉树间的营养元素含量差别总体上缺乏一致规律。     

Spatial distribution of heavy metals (Cu,Pb, Zn,and Cd) in sediments of a coastal wetlands in eastern Fujian,China

We investigated the spatial distribution (horizontal and vertical concentrations) of copper (Cu), lead (Pb), zinc (Zn), and cadmium (Cd) in five wetland types (mudflat, aquaculture wetland, water area,...     

Variation in Seed and Seedling Traits of Celtis australis, a Multipurpose Tree, in Central Himalaya, India

Seeds of Celtis australis were collected from 13 different sources, ranging from 550 to 1980 masl, in Central Himalaya, India. Significant (p = 0.05) variations were observed for seed traits among provenances. However, among various characters, seed weight exhibited maximum variation between seed populations compared to other morphological characters. Between provenances, seed weight ranged from 47.8 to 83.1 g/1000 seed, with mean value of 66.9 ± 10.7 g/1000 seed. Significant (p = 0.01) positive correlation was found between morphological characters of seeds including seed weight and elevational range of seed source. For one year old seedlings, average shoot and root growth was 61.1 ± 13.3 and 30.5 ± 5.4 cm, respectively, irrespective of provenance variation. Inter-comparing biomass yield of the seedlings with altitude, average biomass production was 8.4 ± 2.5, 9.4 ± 3.3 and 12.7 ± 1.7 g/plant, respectively, for low (550–1000 masl), middle (1050–1250 masl) and high (1350–1980 masl) altitudinal populations. Significant (p = 0.01) positive correlation between growth performance of seedlings and altitude of the seed source was recorded. Across the provenances, shoots had the highest proportion of total biomass (42.3%), followed by leaves (32.6%) and roots (24.6%). Among various provenances, Badiyargaon, Agroda, Guptakashi, Jakholi, Gajeli, Srinagar and Palampur populations produced heavier seedlings and grew faster compared to seedlings of other sources.     

广州从化市江埔风水林主要群落类型及其多样性初步研究

基于广州从化江埔地区的5个群落类型9个400m^2的样地数据,对该地区风水林的植物群落结构及其物种多样性特征进行了初步研究。结果显示：9个风水林群落样方中,共统计有维管植物96种,隶属于48科。群落类型主要有荷木林、藜蒴林、中华锥林、黄桐林和黄樟林,乔木层常见树种为荷木（SchimaSU—perba）、藜蒴（Castanopsisfissa）、中华锥（Castanopsischinensis）、黄桐（Endospermumchinense）、黄樟（Cinnamo—mumparthenoxylon）等;灌草层以罗伞树（Ardisiaquinquegona）、九节（Psychotriaasiatica）、疏花卫矛（Euonymuslaxiflorus）、华山姜（Alpiniachinensis）、半边旗（Pterissemipinnata）等植物为优势种。乔木层多样性指数从大到小依次为荷木林〉中华锥林〉黄桐林〉黄樟林〉藜蒴林,灌草层多样性指数由大到小依次为中华锥林〉黄桐林〉荷木林〉黄樟林〉藜蒴林。藜蒴林群落乔木层和灌草层种类较单一,生物多样性较低。     

Occurrence of Diplodia corticola,including new oak host records,in Wisconsin,USA

In the United States, diseased oaks (Quercus species) exhibit tip blight, branch and stem cankers, and dieback often attributed to Diplodia species or related fungi. Emergence of Diplodia corticola as a pathogen of European oaks, and reports of this fungus in the eastern and western United States, prompted re‐examination of strains from Wisconsin. These had been obtained in the late 1990s and early 2000s and previously identified only as Diplodia species. Nuclear ribosomal ITS sequences were obtained from the Wisconsin strains and analysed with other sequences from GenBank. Wisconsin strains confirmed as D. corticola were from northern red oak (Q. rubra), black oak (Q. velutina), white oak (Q. alba) and bur oak (Q. macrocarpa). Other strains from oaks in Wisconsin were D. mutila and D. seriata. Wound inoculation of northern red, white and bur oak seedlings with D. corticola in a greenhouse resulted in shoot death and stem lesions, from which the pathogen was reisolated. We conclude that D. corticola has been present in the northcentral United States for at least two decades and report two previously unrecognized hosts of this pathogen: white oak and bur oak. The roles of D. corticola, related fungi and influences of other environmental factors in deterioration of oak health in North America merit additional investigation.     

Diversity,abundance, and structure of tree communities in the Uluguru forests in the Morogoro region,Tanzania

Uluguru forests are globally recognized as important biodiversity hotspots, but anthropogenic pressure threatens their value. This study examined species diver-sity, abundance, and structure of trees i...