撒施石灰石粉对橡胶树细根空间分布及季节动态的影响

土壤酸化对橡胶树细根生长具有严重影响。为了解橡胶树细根生长对土壤酸度改变的响应,本研究在热研7-33-97未开割(7 a)、开割5 a、开割10 a共3个胶园选取样树,采用撒施石灰石粉的方式进行土壤酸度改良,并用土钻法观测橡胶树根系对土壤酸度改变的响应。结果显示:同一割龄胶园中土壤酸化改良植株(改良组)与对照植株(对照组)相比,其细根生物总量显著增加,且均符合开割5 a胶园的最高,开割10 a胶园的最低这一规律。酸性土壤改良后橡胶树细根在垂直与水平方向生物量均有所增加,分布规律无明显改变。不同割龄胶园改良组与对照组中橡胶树细根年内变化趋势均为单峰型,峰值出现在当年7~9月,年变化规律无明显改变。本研究结果表明,胶园酸性土壤经施用石灰石粉后橡胶树的细根生长量提高,有利于橡胶树从土壤中吸收更多的水分和养分,从而改善橡胶树的生长和提高其产量。     

增加种源树种促进侧柏林演替技术及短期效果

根据徐州市云龙山侧柏林的现状及社会发展需要,制订了人工促进侧柏纯林演替的目标、原则,确定了间伐抚育和林窗开设的标准,提出了种源树种及其配置方式和栽植、管护技术方案.林分改造后各树种生长良好,植物多样性显著增加,景观质量明显改善,风景林的效能已初步形成.     

河北省石灰岩矿区自然生态环境特征探究

基于石灰岩矿区先天脆弱的自然环境,石灰岩矿区开采带来的生态问题趋于严峻。作者通过对河北省石灰岩矿区分布区域的自然生态环境进行分析,得出不同地域的石灰岩矿区生态环境特征,从而为石灰岩矿区后期的生态恢复与治理工程提供基础性资料。     

石灰岩特有植物圆叶乌桕土壤与叶片化学元素含量特征

对石灰岩特有植物圆叶乌桕与同属的乌桕、山乌桕叶片及其生长地土壤化学元素进行测定,比较三者化学成分特征,分析了圆叶乌桕在广东石灰岩地区的环境适应特点.结果表明:圆叶乌桕生长地的有机质、全N及全P含量均高于乌桕、山乌桕生长地,N素和P素有效率较低,速效N仅占全N含量的6.88％,速效P仅占全P的4.77％,全K含量偏低,但圆叶乌桕生长地速效K含量(151.8 mg· kg-1)达到土壤速效K含量对应的适量K(125～155 mg·kg-)水平等级,属适量K型土壤,交换性Ca及交换性Mg含量均高于乌桕、山乌桕生长地,微量元素含量排序为Mn＞ Pb ＞Cr＞ Zn＞ Ni＞ Fe＞ Cd＞ Cu,全Pb、全Zn及全Cu含量均未超过国家规定的3级标准.圆叶乌桕叶片Ca含量(25.24 g·kg-1)、Cd含量(0.45 mg· kg-1)高于乌桕、山乌相.土壤中植物营养元素含量较低的元素如K、Fe和Cu在圆叶乌桕叶片中的生物吸收系数较高,而土壤中含量较高的元素如N、Ca、P、Mg、Mn和Zn在其叶片中生物吸收系数较低.在高温干旱的胁迫下,圆叶乌桕叶片会吸收一定量的Ca,提高抗逆性.圆叶乌桕的化学元素特征反映了它对石灰岩生境的适应性较强.     

Uptake of lead by coen from roadside soil samples

Abstract

The uptake of Pb by young, greenhouse grown corn plants from roadside soil samples was found to be not only dependent upon the total amount of Pb in the soil, but also upon the amount of Pb in the soil relative to the soils capacity to sorb Pb. This is in agreement with the uptake of Pb by corn grown on soils amended with PbCl₂, although plant accumulation of Pb from roadside soils was much less than from PbCl₂ amended soils at comparable Pb concentrations. The use of crushed limestone as a road building material which results in high soil pH values next to the roadside is probably responsible for the reduced plant availability of Pb in the roadside soils.     

Regeneration niches of Norway spruce (<Emphasis Type="Italic">Picea abies</Emphasis> [L.] Karst.) saplings in small canopy gaps in mixed mountain forests of the Bavarian Limestone Alps

Natural regeneration measurements are the main silvicultural objective in overaged protective forests of the Bavarian Limestone Alps. While manifold problems with these stands, especially the impact of browsing, are widely recognised, the regeneration niches of Norway spruce (Picea abies [L.] Karst.) are insufficiently known. The purpose of this study was to determine favourable combinations of site factors for the development of spruce in small, unfenced canopy gaps, located on Aposerido-Fagetum caricetosum albae forest sites. We recorded the occurrence of spruce saplings (as dependent variable) and of six site factors (as independent variables) on 480 0.5 m²-subplots. In addition, we estimated the coverage of six acid adapted plant species to determine correlations with the humus depth. A binary logistic regression analysis was used to predict the probability of the occurrence of a spruce sapling in dependency of the different site factors. Supported by other studies, we assumed that the supply of solar radiation was adequate for the sufficient regeneration of spruce within the canopy gaps. Other site factors significantly determined the regeneration niches of spruce saplings. More spruce saplings were found near hindrances and on rough surfaces than would be expected from a random occurrence of saplings. These microsite types may have characteristics, especially protection against snow gliding that promotes spruce establishment. A calculated “hindrance index”, which accounted for the number, and the distance of surrounding hindrances might be a good specific value to describe the influence of hindrances on steep slopes. The sapling establishment decreased on thin humus layers. Our assumption for the sites was that thick organic layers might represent a good seedbed for spruce. Decayed dead wood was scarce, but was exceedingly favoured by spruce saplings. Results obtained suggest that the natural regeneration establishment of spruce on steep slopes can be successfully influenced by site factors which inhibit the influence of snow gliding. According to a “positive microsite” concept, we recommend for artificial regeneration measurements with spruce, microsites close to hindrances (e.g. stumps, downed trees) and Vaccinium myrtillus as a predictor for thick, acid humus layers.     

Optimum stand density of Chinese pine forests in Taihang limestone mountains, Shanxi Province

lntroductionChinesepine(Pinust8blaeformNisoneofthemostimportanttreespeciesforafforestationandwidelyspreadinTaihanglimestonemountains,ShanxiProvince.Ittakes85%ofthetotaIareaofpIantations.ChinespineplantationsplantedaremainIyforpurposeofsoiIandwaterconservationandtimber.TheinvestigationofChinesepinepIantationsmadelastdecadeshowedthat,accordingtotheirsitecondition,theexistingstandsdidnotmeettheappro-priatedensity.Standsstructureisuniform.Waterlossandsoilerosionareserious,andsoiffertilitygetd…     

皖东石灰岩山地次生林演替趋势与树种的生理特性分析

本文在研究分析琅琊山天然森林群落演替趋势、榆科树种生理生态特性以及皖东石灰岩地区立地分类的基础上 ,探讨了皖东石灰岩山地的适宜造林树种 ,从而为加速北亚热带石灰岩山地的绿化提供理论依据。研究结果表明 ,青檀、榉树、琅琊榆、醉翁榆等榆科树种 ,由于在生理上对高钙、干旱的石灰岩生境有较好适应性 ,同时在群落演替过程中具有相对稳定性 ,因而是皖东石灰岩山地造林绿化的适宜树种     

南方石灰岩土壤发生特性和系统分类研究

目前中国逐渐从土壤发生分类过渡到系统分类,与同地带其他土壤相比,石灰岩土壤由于其本身发育的特异性,在系统分类中需衡量的属性更为复杂。笔者总结分析中国南方石灰岩土壤发育特性,综述其主要诊断层和诊断特性,提出未来南方石灰岩土壤分类需进一步加深了解石灰岩地区地质演变及生态环境过程,运用多技术综合分类对比检索、检验土壤分类系统。同时,由于岩溶区“人多土少”,土地利用强度较大,尤其应加强人为土诊断特性和现象的精细辨识,最终为推动石灰岩土壤的系统分类研究和岩溶生态系统土壤可持续利用提供理论基础。     

毕节石灰岩地区土地利用动态变化分析

以毕节石灰岩地区为研究对象,采用1992、2000、2008年的遥感影像和1∶5万地形图提取不同年份的土地利用信息。在宏观方面以土地利用类型面积变化率方法揭示了不同时期各类型面积变化状况,数据显示各类型变化率逐渐减少,说明土地利用结构趋于稳定;在微观方面以土地利用动态变化和内部转移矩阵表现土地利用变化程度和方向,各类型动态变化的比例整体上趋于减少,说明土地利用类型内部流转性降低,整体上趋于平衡。