基于立地类型的油茶树高生长模型

以隆林县森林资源二类调查的油茶（Camellia oleifera）林小班为研究对象,利用主成分分析法划分隆林县油茶林的主要立地类型,然后采用 5 个理论生长方程构建不同立地类型的油茶树高生长模型。结果表明：（1）影响隆林县油茶林分布的主要立地因子为土壤类型、坡度、地貌和坡向,隆林县油茶林的立地类型可划分为 54 种;（2）红壤缓坡低山阴坡、红壤缓坡丘陵阴坡、黄壤缓坡低山阴坡、黄壤缓坡丘陵阴坡、石灰土缓坡低山阳坡以及石灰土平坡低山阳坡立地类型的油茶最优树高生长模型均为Logistic 模型,黄壤缓坡低山阳坡的最优模型为 Korf 模型,石灰土缓坡低山阴坡的最优模型为 Gompertz模型。     

立地条件对油松造林效果的影响

为了探讨我国辽西半干旱地区油松造林适宜的立地条件,开展了不同的坡位、坡向、坡度、土层厚度下油松造林比较试验,结果表明,不同的立地条件可不同程度地影响油松造林后的成活及生长情况,整体来说以坡位为中上坡以上、坡度为20°～30°、土层深厚的阳坡上实施油松造林可取得较好的效果。     

石质山困难立地条件造林综合配套技术试验

石质山地立地条件差,土壤瘠薄干旱,造林难度大,部分地块历经多次造林,均出现成活率和保存率低,造林效果不理想。为解决石质山地的造林困难,真正彻底消灭荒山,湄潭县通过造林综合配套技术试验,选用大穴整地、容器苗造林、覆盖灌草等造林综合配套技术,实行专人管护和割灌抚育,造林成活率和保存率均分别达95%、90%以上,苗木长势良好,造林成效明显。     

Height models for Red Alder (Alnus rubra Bong.) in British Columbia

Interest in managing red alder (Alnus rubra Bong.) for pulp, lumber and improving site quality is increasing. Proper management of this species requires growth and yield information. Height-age and years to breast height models developed for western Washington and northwestern Oregon are being used in British Columbia. It is unknown whether these models are suitable for British Columbia's conditions. Therefore, new models were developed from thirty stem analysis plots established in red alder stands in coastal areas of British Columbia. The sample trees in the plots were intensively sampled by taking sections out of the tree stems and counting the annual growth rings on each section. This led to height-age data for each tree, which was then averaged by age to get plot height-age data. Years to breast height and height-age models were developed from these data and are summarized in this paper. The height-age model was anamorphic, which contrasts with the model previously used in British Columbia. The new years to breast height model provides more resolution than the previous model.     

杨树不同土壤立地条件施肥效应研究

为探索南方型杨树不同土壤立地条件集约栽培途径,在江汉平原选择有代表性的3种土壤立地,进行氮、磷、钾常规肥料不同施肥量及配比施肥试验（1991～1995）。结果表明：氮肥效应普遍显著;单施磷、钾肥效应均不好。平原粘湿土壤还呈显著负效应,只宜单施氮肥;平原冲积上、湖区沉积土立地均以氮＋磷混施效应最佳。优化施肥量：平原粘湿上按400kgN／hm2、平原冲积土按200kgN／hm2＋100kgP2O5／hm2、湖区沉积土按100kgN／hm2＋100kgP2O5／hm2,分别折算成尿素或过磷酸钙施用。5a提高蓄积生长量35％～80％,增值额0．7～1．1万元／hm2。     

Karst rocky desertification in southwestern China: geomorphology,landuse, impact and rehabilitation

Karst rocky desertification is a process of land degradation involving serious soil erosion, extensive exposure of basement rocks, drastic decrease in soil productivity, and the appearance of a desert‐like landscape. It is caused by irrational, intensive land use on a fragile karst geo‐ecological environment. The process is expanding rapidly, and it is daily reducing the living space of residents and is the root of disasters and poverty in the karst areas of southwestern China. The tectonic, geomorphic and environmental background to karst rocky desertification is analysed. Population pressure and the intensive land use that have led to this serious land degradation are described. Although the problem concerns the Chinese Government and some profitable experience in the partial restoration or reconstruction of the ecological environment has been gained, effective remedial action has not been achieved on a large scale. Copyright © 2004 John Wiley & Sons, Ltd.     

两种立地条件下蒜头果叶片形态特征的比较研究

研究了土山区和石山区两种不同立地条件对蒜头果叶片形态解剖的影响。结果表明,石山立地蒜头果叶片面积较小,表皮细胞、角质乳状突起和气孔器等的密度均是石山的较小,但它们的大小均是石山的大于土山的,并分析了这种差异的生理生态学意义。     

Myxobolus erythrophthalmi sp. n. and Myxobolus shaharomae sp. n. (Myxozoa: Myxobolidae) from the internal organs of rudd, Scardinius erythrophthalmus (L.), and bleak, Alburnus alburnus (L.)

During a survey of myxosporean parasites of cyprinid fish in Hungary, infections caused by unknown Myxobolus spp. were found in the internal organs of rudd, Scardinius erythrophthalmus, and bleak, Alburnus alburnus . Small plasmodia developed in blood vessels of the kidney, liver, testes and intestinal wall. The parasites were studied on the basis of spore morphology and by histological and molecular methods. In most cases, plasmodia were surrounded by host tissue without a host reaction; however, in advanced cases, a connective tissue capsule was seen around plasmodia. Spores collected from the two fish species differed from each other and from the known Myxobolus spp. both in their morphology and 18S rDNA sequences. The two species, described as M. erythrophthalmi sp. n. from rudd and M. shaharomae sp. n. from bleak, are characterized by a specific histotropism to blood vessels, while the organ specificity involves the kidney and for the latter species, most internal organs.     

Release and mobility of polycyclic aromatic hydrocarbons and iron‐cyanide complexes in contaminated soil

Export of organic and inorganic pollutants from the unsaturated zone of manufactured gas plant (MGP) sites may endanger groundwater quality. The release and mobility of polycyclic aromatic hydrocarbons (PAH) and iron‐cyanide complexes (FeCN) in soils from a former MGP site were studied in column and batch experiments. The unsaturated column experiment involved two parts. (1) The development of steady‐state effluent concentrations was studied under constant irrigation. (2) Rate‐limited contaminant release was studied by the system's response to flow interruption. Transport data were supplemented by a sequential batch‐desorption experiment. During constant irrigation the initial concentrations of total PAH and FeCN, but also the concentration of dissolved organic carbon (DOC) were higher than the steady state level, indicating that a specific fraction of the DOC and the contaminants was readily mobilized. Cyanide reached a constant effluent concentration after seven pore volumes (pvs), whereas equilibration of effluent PAH took 20 pvs. After flow interruption, rate‐limited release of DOC, PAH, and FeCN was observed by increased effluent concentrations. Comparison of FeCN levels with theoretical equilibrium concentrations indicated that in addition to the dissolution of iron(II)ferrocyanide (Berlin Blue), Fe₄[Fe(CN)₆]₃, other cyanide‐species may control the release and such the mobility of FeCN. This was confirmed by decreasing FeCN concentrations during sequential batch extractions. Due to rate‐limited release, seepage water concentrations of DOC, PAH, and FeCN in alkaline MGP soils are influenced by the flow regime. Experiments performed at continuous irrigation may therefore severely underestimate the release of PAH and FeCN under field conditions. The effect of DOC on the release and mobility of PAH and FeCN under transient conditions has to be further investigated.     

基于形态学的黑背景下收获前棉花图像自动分割技术研究

以棉田实地采集的黑背景下收获前含铃壳棉花图像为样本(7级×9张/级),首先,对原始灰度图二值化以提取中心模板,进一步进行形态学高帽剪切预处理并提取其外围二值模板,两者叠加完成背景分割;试验结果表明:98.4%的含铃壳棉花二值模板图像被准确提取。其次,用形态学低帽剪切预处理后的二值图执行开启运算,以判别棉瓣间的连通性:⑴对于多连通的低品级棉花,直接提取未开启二值图中不超过4个区域的棉瓣二值模板,⑵对于单连通的高品级棉花,重新对原始灰度图二值化并提取最大区域的棉瓣二值模板;实验证明:基于棉瓣面积明显大于铃壳面积的棉瓣抽取算法是健壮的,74.6%的棉瓣二值模板图像被准确提取。