首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   14篇
  免费   0篇
  国内免费   8篇
林业   9篇
农学   1篇
基础科学   1篇
  4篇
综合类   3篇
园艺   4篇
  2018年   3篇
  2017年   1篇
  2015年   2篇
  2014年   2篇
  2013年   3篇
  2012年   1篇
  2011年   3篇
  2008年   3篇
  2007年   3篇
  2006年   1篇
排序方式: 共有22条查询结果,搜索用时 0 毫秒
1.
应用地统计学结合地理信息系统研究了广东省东莞市森林表层土壤(0~25 cm)有机质、全氮、全钾、全磷和pH值等5种土壤肥力指标的空间变异规律。研究表明:全磷、全钾、有机质、全氮为中等变异;pH值属于弱变异;全钾、pH值的变异函数曲线的理论模型符合球状模型,有机质、全氮、全磷适用模型为指数模型;全磷、全钾、有机质、pH值具有中等空间相关性,全氮的空间相关性较弱;5种肥力指标的空间自相关范围存在明显差异,变化范围为2218~19297 m。用普通克立格法进行最优内插,得各肥力指标含量分布图,并分析了各土壤肥力指标的分布状态。  相似文献   
2.
林地枯落物持水量的研究已成为森林水文研究的重要方向之一。采用Palsar雷达数据和CBERS CCD光学遥感数据,结合样地调查数据,采用分类和回归树模型对大岭山林场的林地枯落物持水量进行了估测研究。研究结果表明遥感技术可以用于林地枯落物的估测。本研究为今后中国南方开展大面积的林地枯落物持水量提供了一种连续的、可行的和廉价的研究方法。  相似文献   
3.
应用地统计学和地理信息系统(GIS),对广东省东莞市森林土壤有机质(0~1 m)的空间变异性和主要林分土壤有机质含量进行分析,结果表明:东莞市森林土壤有机质属中等变异性;具有中等的空间相关性;空间分布呈东西高、中北低的趋势;主要林分土壤有机质含量由小至大依次为:荔枝林、桉树林、马尾松林、针阔叶混交林、马占相思林、阔叶混交林。  相似文献   
4.
以东莞尾叶桉林、马尾松林、马占相思林和针阔混交人工林为对象,分析林地0~25cm表层土壤Cu、Zn、Pb、cd4种重金属含量,并以广东省土壤背景值为标准,采用单因子污染指数和综合污染指数评价林地土壤重金属的污染状况。结果表明,尾叶桉林和马尾松林以土壤Ph含量最高,其他两种林型以zn含量最高;4种重金属含量高低为Zn〉Pb〉Cu〉Cd,它们的单因子污染指数大小顺序为Pb〉Cu〉Zn〉Cd。4种林型土壤综合污染指数依次为马占相思林〉尾叶桉林〉马尾松林〉针阔混交林。土壤pH值与Zn、cd之间相关性显著,土壤全钾与Zn、Cd间呈极显著正相关。结合主成分分析结果可知,东莞市4种人工林土壤Cd与自然因素有关,土壤Cu主要受人为输入影响;Zn含量高于背景值,受自然与人为因素的共同影响。  相似文献   
5.
东莞市古树名木健康状况初步研究   总被引:7,自引:0,他引:7  
通过对东莞市50株古树进行现场调查和应用PICUS弹性波树木断层画像诊断仪对树木内部健康状况进行检测。结合分析软件对其进行综合分析评估,初步了解东莞市古树名木健康现状,并提出了相应的保护复壮技术措施。  相似文献   
6.
 双色1号’火龙果是从‘红水晶’实生后代群体中选育的新品种。果实近球形,果皮暗红色,平均单果质量350.7 g,最大740.5 g,可食率78.5%,果肉外红内白,肉质软滑,香味独特,可溶性固形物13.5%,可滴定酸0.23%。自花结实能力强,耐贮运,每年开花结果10 ~ 12批次。  相似文献   
7.
Salinization of soil is recognised as one of the most pressing environmental challenges to resolve for the next century. We here conduct a synoptic review of the available research on how salt affects decomposer microbial communities and carbon (C) cycling in soil. After summarizing known physiological responses of microorganisms to salinity, we provide a brief overview and qualification of a selection of widely applied methods to assess microorganisms in soil to date. The dominant approaches to characterise microbial responses to salt exposure have so far been microbial biomass and respiration measurements. We compile datasets from a selection of studies and find that (1) microbial biomass-carbon (C) per C held in soil organic matter shows no consistent pattern with long-term (field gradients) or short-term (laboratory additions) soil salinity level, and (2) respiration per soil organic C is substantially inhibited by higher salt concentrations in soil, and consistently so for both short-term and long-term salinity levels. Patterns that emerge from extra-cellular enzyme assessments are more difficult to generalize, and appear to vary with the enzyme studied, and its context. Growth based assessments of microbial responses to salinization are largely lacking. Relating the established responses of microbial respiration to that of growth could provide an estimate for how the microbial C-use efficiency would be affected by salt exposure. This would be a valuable predictor for changes in soil C sequestration. A few studies have investigated the connection between microbial tolerance to salt and the soil salinity levels, but so far results have not been conclusive. We predict that more systematic inquiries including comprehensive ranges of soil salinities will substantiate a connection between soil salinity and microbial tolerance to salt. This would confirm that salinity has a direct effect on the composition of microbial communities. While salt has been identified as one of the most powerful environmental factors to structure microbial communities in aquatic environments, no up-to-date sequence based assessments currently exist from soil. Filling this gap should be a research priority. Moreover, linking sequencing based assessments of microbial communities to their tolerance to salt would have the potential to yield biomarker sets of microbial sequences. This could provide predictive power for, e.g., the sensitivity of agricultural soils to salt exposure, and, as such, a useful tool for soil resource management. We conclude that salt exposure has a powerful influence on soil microbial communities and processes. In addition to being one of the most pressing agricultural problems to solve, this influence could also be used as an experimental probe to better understand how microorganisms control the biogeochemistry in soil.  相似文献   
8.
古树名木信息查询网站构建——以东莞市建成区为例   总被引:1,自引:0,他引:1  
基于东莞市建成区古树名木的普查信息,利用计算机网络和数据库技术构建古树名木的数据库查询网站。该网站适用性强,使用方便,具有古树名木信息查询、树木区图查询、图片展示、留言本等功能,是宣传古树名木的重要窗口,对东莞市古树名木的保护和管理起到重要作用。  相似文献   
9.
利用全站仪对地形和植被进行定位,结合CAD技术形成数字化地形图,应用GIS技术开发具有W indows风格用户界面的东莞林科园植被管理系统,系统具有查询、检索、统计和打印等功能,极大地提高植被管理的效率,在东莞林科园植被管理过程中发挥巨大的作用。  相似文献   
10.
火龙果新品种‘莞华红’   总被引:1,自引:0,他引:1  
‘莞华红’火龙果是从‘红水晶’火龙果实生后代中选育的新品种。果实近椭圆形至球形,平均单果质量376.7g,最大单果质量823.6g,可食率79.1%,果肉紫红色,可溶性固形物14.5%,可滴定酸0.17%。自交亲和性强,每年开花结果 10~12批次。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号