Airborne small-footprint discrete-return LiDAR data in the assessment of boreal mire surface patterns, vegetation, and habitats     

Ilkka Korpela  Markku Koskinen  Harri Vasander  Markus Holopainen  Kari Minkkinen 《Forest Ecology and Management》2009,258(7):1549-1566

Boreal mires encompass high diversity in species and habitats, many of which are endangered. In Finland, extensive use of peatlands has resulted in habitat fragmentation. A need for accurate and cost-efficient vegetation mapping and monitoring of habitat changes exists in mire conservation, restoration and peatland forestry. LiDAR is an emerging and excellent tool for probing the geometry of vegetation and terrain. Modern systems measure the backscattered signal accurately and also provide radiometric information. Experiments were carried out in a complex minerotrophic–ombrotrophic eccentric raised bog in southern Finland (61°47′N, 24.18′E). First, we tested discrete-return LiDAR for the modeling of mire surface patterns and the detection of hummocks and hollows, as well as the effect of mire plants on the Z accuracy of the surface echoes. Secondly, the response of different mire vegetation samples in LiDAR intensity was examined. Thirdly, we tested area-based geometric and radiometric features in supervised classification of mire habitats to discover the meaningful variables. The vertical accuracy of LiDAR in mire surface modeling was high: 0.05–0.10 m. A binary hummock-hollow model that was estimated from a LiDAR-based elevation model matched flawlessly in aerial images and had moderate explanatory power in habitat classification trials. The intensity of LiDAR in open-mire vegetation was mainly influenced by the surface moisture, and separation of vegetation classes spanning from ombrotrophic to mesotrophic vegetation proved to be difficult. Area-based features that characterize the height distribution of LiDAR points in the canopy were the strongest explanatory variables in the classification of 21 diverse mire site types. Actual qualifying differences in the ground flora were unattainable in the LiDAR data, which resulted in inferior accuracy in the characterization of ecohydrological conditions and nutrient level of open mires and sparsely forested wet sites. Mire habitat classification accuracy with LiDAR surpassed earlier results with optical data. The results suggested that LiDAR constitutes an efficient aid for monitoring applications. We propose the co-use of images and LiDAR for enhanced mapping of open mires and tree species. In situ calibration and validation procedures are required until invariant geometric and radiometric features are discovered.  相似文献   

Bimembrane diffusion probe for continuous recording of dissolved and entrapped bubble gas concentrations in peat     

Mikhail Mastepanov  Torben R. Christensen 《Soil biology & biochemistry》2008,40(12):2992-3003

Peatlands are significant sources of the important greenhouse gas CH₄ and generally known as sinks for atmospheric CO₂ through peat accumulation. Accurate measurements of the subsurface concentrations of these gases are of pivotal importance for experimental studies improving our understanding of the dynamics and controls on the exchanges of these gases between peat soils and the atmosphere. In this paper we first briefly outline examples of different probe-based techniques for the determination of subsurface gas concentrations and thereafter we document the development and testing of two different membrane probe systems. Finally we discuss a few applications of the probes and show some results obtained by testing them in the laboratory.  相似文献   

Peat1蛋白及其3个缺失突变体的表达与热稳定性分析（英文）     

LI Ming-yong  QIU De-wen  ZENG Hong-mei  YANG Xiu-fen Institute of Plant Protection  CAAS  Beijing 《（《农业科学与技术》）编辑部》2008,(1)

[Objective] The research aimed to reveal the functions of NAC and UBA domains in Peat1's thermal stability.[Method] Fusion expression vectors of Peat1 protein and the 3 deletion mutants were constructed.The recombinant plasmids were induced by IPTG and the target proteins(Peat1,Peat1-△CD99,Peat1-△ND49 and Peat1-△ND108)were expressed obtained by AKTA and its thermal stability was analyzed.[Result] The research found that 3 deletion mutants have good thermal stability like Peat1.[Conclusion] The research demonstrated that the coexistence of NAC or UBA domains is not necessary to thermal stability of Peat1 protein,and they may give the protein particular stability structure seperately.  相似文献   

烤烟漂浮育苗草炭替代基质研究   总被引：12，自引：8，他引：12  

吴涛  晋艳  杨宇虹  杨焕文  杨丽萍 《中国农学通报》2007,23(1):194-194

用褐煤、腐熟玉米秸秆和腐殖土来完全替代基质配方中的草炭,形成7个替代基质配方。采用配方对比育苗试验方法,研究了替代基质中褐煤和秸秆混配比例对基质理化性状、出苗率、成苗率和烟苗成苗素质的影响,结果表明：秸秆添加比例＞50%而褐煤比例≤10%时,基质部分理化性状与成品基质对照差异较大,育苗试验结果表现为出苗率下降、出苗整齐度降低、出苗期延长,成苗时苗数不足,烟苗成苗素质较差。而当基质中秸秆比例≤50%且褐煤比例＞10%时,二者混配比例对基质理化性状、出苗率、成苗率和烟苗成苗素质的影响较小,基质上述指标与ck较为接近;秸秆+褐煤比例为45%+30%和35%+40%的二个替代处理在本试验所观察和测定的指标中与对照差异较小,基本具备了作为烟草漂浮育苗基质的条件;笔者试验还验证了该型基质替代基质中草炭的可行性。  相似文献   

有机栽培基质在矮牵牛育苗及栽培中的应用研究   总被引：5，自引：2，他引：3  

翟春峰  杨秋生  孙守如  王吉庆 《河南农业科学》2007,(10):77-80

以河南农业大学研制的基质为原料,成熟的草炭配方为对照,梦幻系列矮牵牛为供试品种,通过与不同辅料配比,对不同的有机发酵基质进行筛选。结果表明:在所用基质中,B基质的综合性状优于其他基质,特别是以B基质为主的处理T8,可以代替草炭的成熟基质配比。B基质的发酵配方比为:玉米秸秆粉碎料100kg+花生壳粉碎料65kg+烘干鸡粪20kg+中温发酵菌0.3%+水220kg;处理T8的配比为,B基质∶过磷酸钙∶蛭石=21∶1∶2。  相似文献   

从泥炭中提取腐殖酸的工艺及其结构研究   总被引：1，自引：0，他引：1  

牛育华  李仲谨  余丽丽  郝明德  朱雷 《安徽农业科学》2009,37(35)

探讨了不同预处理方法对从泥炭中提取腐殖酸效果的影响,同时也考察了碱提取液及其酸析液对提取结果的影响。结果表明,采用硝酸对试验样品进行预处理提取率最佳,通空气氧化和超声处理对提取率有益,但是提升效果不明显。碱溶分析表明,若投加0.1mol/L的Na4P2O4与碱液混合,腐殖酸的提取率会得到显著提升,且随着碱浓度的增大而增加,碱溶效果表现为:Na4P2O4+KOH>Na4P2O4+NaOH>KOH>NaOH>Na2CO3;酸析时,当CH+<2 mol/L时,HCl与H2SO4效果相当,且随着酸度的增加提取率增大,当C+>2 mol/L时,HCl优于稀HSO,这是由于硫酸将腐殖酸部分氧化,造成提取率降低。  相似文献   

Physical properties of peat soils under different land use options          下载免费PDF全文

P. Mustamo  M. Hyvärinen  A.‐K. Ronkanen  B. Kløve 《Soil Use and Management》2016,32(3):400-410

Pristine peat soils are characterized by large porosity, low density and large water and organic matter contents. Drainage and management practices change peat properties by oxidation, compaction and mineral matter additions. This study examined differences in physical properties (hydraulic conductivity, water retention curve, bulk density, porosity, von Post degree of decomposition) in soil profiles of two peatland forests, a cultivated peatland, a peat extraction area and two pristine mires originally within the same peatland area. Soil hydraulic conductivity of the drained sites (median hydraulic conductivities: 3.3 × 10^?5 m/s, 2.9 × 10^?8 m/s and 8.5 × 10^?8 m/s for the forests, the cultivated site and the peat extraction area, respectively) was predicted better by land use option than by soil physical parameters. Detailed physical measurements were accompanied by monitoring of the water levels between drains. The model ‘DRAINMOD’ was used to assess the hydrology and the rapid fluctuations seen in groundwater depths. Hydraulic conductivity values needed to match the simulation of observed depth to groundwater data were an order of magnitude greater than those determined in field measurements, suggesting that macropore flow was an important pathway at the study sites. The rapid response of depth to groundwater during rainfall events indicated a small effective porosity and this was supported by the small measured values of drainable porosity. This study highlighted the potential role of land use and macropore flow in controlling water table fluctuation and related processes in peat soils.  相似文献   

提高沙地含水量的研究   总被引：2，自引：0，他引：2  

姚洪林  高挨树 《干旱区资源与环境》1992,6(2):73-79

本文根据干旱地区降水稀少,水资源短缺的特点,对牧草、蔬菜等进行了一系列施用不同比例与组合的保水剂,用以提高植物的抗旱能力。试验资料表明,效果是好的。  相似文献   

根区不同改土模式对葡萄根系生长的影响   总被引：4，自引：0，他引：4  

秦玲等 《中国农学通报》2005,21(7):270-270

利用草炭对葡萄根区进行改良,比较研究了传统混合和局部改土方式对葡萄根系形态、生物量、冠根比、根系活力和根系激素状况的影响。结果表明:草炭可有效提高根系干物重、根系活力以及根系Zip、IAA和GA的含量,降低根系ABA含量。不同改土模式对葡萄根系的影响不同,局部改土一定程度提高根系干重和根系活力,并有效促进了地上和根系的平衡生长。  相似文献   

国内外泥炭腐殖化度及对其古气候意义研究的对比分析     

周莹 《安徽农业科学》2014,(28):10046-10048

以年代标尺为线索,总结了国内外对泥炭腐殖化度的研究区域及内容,并对其指示的古气候意义进行了对比分析,提出泥炭腐殖化度的古气候指示意义虽因地域的差异而不同,但仍是指示古气候环境水热变化的重要指标.  相似文献