探讨如何提高大树移植的成活率     

杜炜怿 《北京农业》2012,(6):170

据各大城市提供的数据分析,大树移植的成活率仅在50%左右,这个问题日益受到有关专家及园林建设者们的重视。如何提高大树移植的成活率?笔者经过多年的实践,认为,大树移植是一项系统的工程,需要严格的技术要求和具体的养护措施,只有遵循自然生长规律,才能收到较好的成活效果。  相似文献   

树形结构对果树生产能力的影响分析   总被引：1，自引：0，他引：1  

杨飞  卢桂宾  杜俊杰  季兰 《山西林业科技》2012,41(1):46-49

果树树形与结构是影响果树产量的重要因素,笔者结合国内外的研究状况,综述了不同树形结构对光能利用率、营养与生殖、抗逆性、产量品质、实际生产的影响,指出适宜的栽植密度、合理的树形结构是保证果园光照良好,产量和品质提高的重要措施。  相似文献   

Crown development in young Picea abies stands     

《Scandinavian Journal of Forest Research》2012,27(1-4):195-204

A dynamic model of branch length and weight growth was developed for two contrasting sites, both with young stands of spruce. At one site sample trees were obtained from both unfertilised plots and from plots with increased growth rate maintained by annual fertilisation. At the second site unfertilised trees and trees subject to single applications of fertiliser were modelled. A model of the same structure was developed for each site and tested by application at the alternate site. In view of the close agreement between sites, model parameters were calculated based on all data combined. The model is driven by height increment and branch age. The sample trees were mostly open grown so that only a tentative estimate of the effects of between tree competition is given. The limitations of the model are stressed.  相似文献   

Effect of Water and Rice Straw Management Practices on Soil Organic Carbon Stocks in a Double-Cropped Paddy Field     

《Communications in Soil Science and Plant Analysis》2012,43(18):2330-2342

ABSTRACT

Water and rice straw (RS) management practices can potentially affect the accumulation of soil organic carbon (SOC) in agricultural soils. Field experiments were conducted in two consecutive rice-growing seasons (wet and dry) to evaluate SOC stocks under different water (continuous flooding [CF], alternate wetting and drying [AWD]) and RS management practices (RS incorporation [RS-I], RS burning [RS-B], without RS incorporation and burning [WRS]) in a double-cropped paddy field. RS-I under AWD had higher volumetric water content than the same RS management under CF at tillering in both growing seasons. Total SOC was significantly higher under AWD at tillering in both wet and dry seasons and after harvesting in the dry season compared with CF. The same trend was also observed for C:N ratio at tillering and after harvesting in the dry season. RS-B plots had lower SOC stocks than RS-I and WRS plots across most of the measuring periods regardless of the growing seasons. SOC stocks were 33.09 and 39.31 Mg/ha at RS-B and RS-I plots, respectively, in the wet season, whereas the respective values were 21.45 and 24.55 Mg/ha in the dry season. Incorporation of RS enhanced SOC stocks under AWD irrigation, especially in the dry season before planting. Soil incorporation of RS in combination with AWD could be a viable option to increase SOC stocks in the double-cropped rice production region as it is strongly linked with soil fertility and productivity. However, the environmental consequences of RS incorporation in irrigated lowland rice production system should be taken into consideration before its recommendation for paddy field on a large scale.  相似文献   

一株高雄山虫草的分子鉴定     

郝芳芳  王秀然  张天柱  刘思阳  王岩  卢天成 《安徽农业科学》2014,(31):10848-10850,10897

[目的]利用生物信息学方法初步探讨虫草属日本拟青霉的分类地位。[方法]提取日本拟青霉的基因组,并利用通用引物ITSL和ITS4采用PCR技术扩增rDNA18S-28S ITS序列。采用Clustalx1.83和MEGA5软件构建系统发育树,生物信息学比较分析确定其分类地位。[结果]PCR扩增产物为603 bp。将日本拟青霉重新命名为雪花高雄山虫草(Cordyceps takaomontana strain JLsnow)。将虫草重新分类,并对该类群及其特征进行了描述。[结论]从分子水平上说明日本拟青霉与其他虫草之间的差异,该研究为虫草属真菌的分类提供新思路。  相似文献   

磷对板栗结实性能及产量的影响   总被引：26，自引：2，他引：24  

黄宏文  周德勇 《园艺学报》1991,18(1):21-26

试验结果表明,磷对板栗(Castanea mollissima Blume)雌花的形成数量有重要影响,结果母枝含磷量与母枝抽生结果枝数量和着生雌花数量呈显著正相关。板栗结果母枝含磷量比雄花母枝和营养枝分别高5.19％和5.27％。树体磷素含量水平与板栗雌、雄花枝比例和结果枝结栗苞数量也存在密切的相关性。在不同施磷水平下,结果枝粗度与果枝结栗苞数均具有显著的回归关系,但b值差异大。本研究结果在鄂东大别山区进行了大面积施磷肥示范,生产实践证明,施磷肥对板栗具有一致的增产效益。  相似文献   

论乡村林业──中国乡村林业经营模式及其实施措施     

何方  张日清 《经济林研究》1995,(1)

乡村林业从它的生产场地和生产内容上看，是当前在中国农村兴起的庭园经济林的同义语，是农村建设的“绿色致富”工程．乡村林业的实施采用立地经营模式，因地制宜，建立商品基地；大力发展产品加工业，提高经济效益；建设好社会化服务体系，推进乡村林业依靠科技进步，向前发展。  相似文献   

京津冀地区大中城市绿化树种的配置与布局     

齐树亭  王晓宇 《河北林果研究》2003,18(Z1):255-258

京津冀地区大中城市现有的绿化树种,由于受地域、气候、流通和科学技术水平的限制,品种较少.为了改变这种现状,可以结合春季干旱、夏季炎热、冬季寒冷、降水量少且不均匀的气候特点,根据乔灌草混合立体栽种的绿化美化原则,因地制宜地引进一些适合本地环境和气候条件的具有"彩色"常绿"和"香味"特点的美化绿化树种,和本地的传统树种搭配种植,改善目前苗木品种较为单一的现状,达到丰富植物种群和提高观赏效果的目的.根据各种植物对光的补偿点不同的原理,最大限度地创造绿量,让城市生态环境向良性循环的方向发展.  相似文献   

黄土丘陵区流域主要植被类型养分循环特征   总被引：9，自引：1，他引：9  

赵护兵  刘国彬  侯喜禄 《草业学报》2006,15(3):63-69

以黄土丘陵沟壑区典型小流域纸坊沟流域为例,系统研究流域在植被稳定恢复期1种乔木、4种灌木和9种草地植被类型的养分循环平衡特征。结果表明,乔灌植被类型的叶片养分含量明显高于当年的新生枝条,新生枝条则明显高于枝干;乔木植被类型的生物量、氮磷养分累积量明显高于灌木植被类型,灌木植被类型则高于草地植被类型;乔木的氮养分循环速率是0.789,灌木为0.742,草地为1.000;乔木P2O5循环速率是0.881,灌木为0.758,草地为1.000。乔木的氮养分年盈余量是333.0 kg/km2,灌木为508.5 kg/km2,草地为597.0 kg/km2;乔木的P2O5年盈余量是333.0 kg/km2,灌木为423.0 kg/km2,草地为531.0 kg/km2。  相似文献   

鳞毛蕨(Dryopteris filix-mas)天山云杉林种群结构分析   总被引：7，自引：5，他引：7  

刘翠玲  潘存德  梁瀛  刘政新 《干旱区研究》2006,23(1):60-65

以西天山国家自然保护区内1 hm2原始鳞毛蕨(Dryopteris filix-mas)天山云杉纯林临时标准地调查材料为基础,分析鳞毛蕨天山云杉林胸径、树高和年龄结构、种群存活曲线以及基本测树因子之间的相互关系.结果表明:①鳞毛蕨天山云杉纯林种群结构稳定,无论是胸径、树高抑或年龄,均呈现出明显的倒"J"型,属于典型的异龄林林分结构,林木更新良好,在其自维持过程中不断有大量小径木更新补充;②林木株数随胸径、树高和年龄的增大,呈负指数函数或负幂函数递减;③树木胸径和树高随年龄的增大,按理查兹生长曲线递增;④胸径与树高的关系为非线性关系.此外,种群存活曲线总体趋势呈现"凹"型,表明该种群是一个连续更新的种群,在林分生长发育过程主要受到小尺度林冠干扰的影响.  相似文献