油茶土壤养分和果实主要经济性状对沼液用量的响应

为给沼液在油茶上的应用提供合理与科学的指导,以6年生油茶林为研究对象,采用随机区组试验设计,设置了5个施不同沼液量的试验组(B_0:0 kg/株,对照组;B_1:10 kg/株;B_2:20 kg/株;B_3:30 kg/株;B_4:40 kg/株),连续2 a观测其对油茶土壤主要养分含量变化情况及对油茶果实产量、含油率的影响。结果表明:施用沼液能够显著增加土壤中有机质、碱解氮、速效磷、速效钾的含量,对土壤肥力改良作用明显。在施沼液2 a后,土壤中碱解氮、速效磷、速效钾的含量均随着沼液用量的增加而逐渐增加,土壤有机质的含量则趋于平稳。5组处理中,以B_4(40 kg/株)处理对土壤养分含量的改善效果最好。在油茶果实方面,施用沼液能有效提高油茶单株鲜果产量,改善油茶果实经济性状。不同沼液用量处理油茶鲜籽含水率、鲜出籽率、种仁含油率、鲜果含油率差异显著。与对照组B_0处理相比,B_3(30 kg/株)处理油茶鲜出籽率提高了56.7%,干出籽率提高了34.72%;B_4处理主要提高了油茶果实含油率,与对照相比,其种仁含油率提高了21.20%,鲜果含油率提高了58.93%。土壤速效养分含量与油茶果实含油率呈显著正相关,其中以土壤速效磷含量与果实含油率相关性最好。因此,施用沼液能够改善土壤速效养分含量,显著提高油茶果实含油率。     

不同施肥量对油茶6年生幼林营养生长的影响

在广西巴马县选取6年生的油茶人工林为研究对象,连续3年开展不同施肥量(0.25kg/株、0.50kg/株、0.75kg/株、1.00kg/株、1.25kg/株和不施肥)对油茶中幼林树高、地径、冠幅的影响研究。试验共设6个处理,分别是处理1(0.25kg/株)、处理2(0.50kg/株)、处理3(0.75kg/株)、处理4(1.00kg/株)、处理5(1.25kg/株)和处理CK(不施肥)。结果表明,各施肥处理对油茶中幼林的树高、地径、冠幅增长表现不一致。其中,处理CK对各营养生长指标的影响效果最小;施肥量为1.00kg/株的处理对油茶树高生长的促进效果最大;施肥量为0.50kg/株的处理对油茶地径、冠幅生长的促进效果最大。综合考虑施肥成本和生长情况,以0.50kg/株的施肥量对油茶人工幼林营养生长的促进效果最佳。     

不同施肥方案对油茶产量和品质的影响

为探究不同施肥方案对油茶及其果实的生长及产量的影响。以都匀市国有平浪林场为试验地点,设置有机肥和复合肥2种肥料处理,0.60、0.80、1.00 kg/(株·a) 3种施肥量,对不同施肥方式下油茶及其果实的生长情况和品质状况进行评估,比较了不同施肥方案对油茶及其果实产量和品质的影响。结果表明：处理组B2油茶及其果实的品质和产量相对较好,其株高、冠幅、地径、产量相较于对照组分别提高了：35.58%、49.46%、56.85%、63.96%;油茶果实的单果尺寸、单果质量、鲜果含油率、种仁含油率、干出仁率、干出籽率相较于对照组分别提高了：35.51%、85.85%、33.98%、32.09%、15.97%、34.17%。试验结果可为油茶的科学施肥提供理论依据。     

不同肥料类型对油茶生长和产量的影响

探究不同肥料类型对油茶树体生长、果实养分含量及其油茶产量的影响,从而选择最佳肥料应用于农林施肥,为提高经济效益奠定基础。本试验设置4个处理,即每年每株施用复合肥、油茶专用复合肥和油茶专用有机肥(0.2 kg、0.3 kg、1 kg)以及空白对照来开展施肥试验。并测定了不同的油茶树体指标、油茶果实养分及油茶果实产量指标来比较和分析不同处理间的差异。研究结果表明:对于油茶树体指标而言,在4个处理中,油茶专用复合肥对油茶树体生长的促进作用最佳;对于油茶果实养分含量而言,施用油茶专用有机肥具有显著促进果实养分含量累积的作用。对于油茶产量而言,油茶专用有机肥比其他处理更能促进果实产量。油茶树体指标、油茶果实养分指标及油茶产量指标间有及其密切的相关性。本试验结果表明:施用油茶专用有机肥在油茶生产与经营上最为有效。     

沼肥施用量对苹果树生长及产量的影响

于2011—2012年,研究以施用沼渣30 kg·株-1为基肥,分别喷施20%、40%、60%、80%的沼液5次的沼肥不同组合对苹果树生长及产量的影响。结果表明:沼肥能显著促进苹果树生长、改善苹果品质、提高苹果产量,其中以施用沼渣30kg·株-1为基肥,60%沼液喷施5次的沼肥组合(处理3)效果最好。处理3在叶面积、百叶鲜重、叶厚度方面,分别比CK(喷施清水)增长31.40%(P0.01)、13.97%(P0.05)、22.08%(P0.01);6月下旬苹果树的外围新梢,比CK增长38.77%(P0.05);在可溶性糖含量、维生素C含量、可溶性固形物、可滴定酸含量、苹果硬度方面,分别比CK提高59.72%、48.82%、38.34%、30.77%、55.56%,差异极显著(P0.01);在单果重、优质果率、产量方面,分别比CK提高34.29%、47.30%、39.02%,差异极显著(P0.01)。     

凤庆县不同树龄核桃生长与产量的比较研究

为摸清凤庆县核桃产量及生长情况,根据县域不同树龄核桃分布情况,选择3个乡镇9个村委会,共45株不同树龄段的核桃标准树开展生长与产量测定。结果表明：4个树龄段核桃各生长指标均差异显著,随树龄的增长,核桃平均冠幅、基径和树高增长,树体架构不断扩大,以<15年核桃树体架构最小,平均冠幅8.12 m、基径13.92 cm、树高6.97 m,>71年树体架构最大,平均冠幅20.84m、基径115.4 cm、树高18.92 m。产量情况则除<15年和16～30年树龄段之间差异不显著外,其余树龄段之间均差异显著;30年以下产量最低,平均单株果实数736～747个、干果产量9.22～10.09 kg/株,31年～70年平均单株果实数4 715个、干果产量67.18 kg/株,>71年产量最高,平均单株果实数量9 045个、干果产量118.60 kg/株。相关性分析表明冠幅、地径、树高、单株果实数量和干果产量等指标间存在极显著正相关关系,随着树龄增长树体架构增大,产量得以提高。基于凤庆县大面积核桃尚未进入丰产稳产期的现状,应进一步加强抚育管理,实现核桃产量的提升。     

沼肥配施复合肥对油茶生长及产量的影响

以8年生油茶林作为研究对象,采用随机区组试验设计,研究沼肥与复合肥不同施肥比例对油茶生长及结实的影响。结果表明:沼肥与复合肥配施能有效促进油茶树高、地径及冠幅面积增长,配施比例不同使油茶生长出现差异,其中处理3油茶树高、冠幅增长量最多,处理2油茶地径增长量最多;沼肥与复合肥配施能有效提高油茶单株冠幅面积产量,改善油茶果实经济性状,其中处理2油茶单株冠幅面积产量、干出籽率、果实干出仁率及种仁含油率高于其他处理;沼肥与复合肥配施能有效提高土壤有机质、速效养分及微量元素含量,其中处理2改善土壤肥力作用明显。综上,油茶成林按3︰1施用沼肥与复合肥,能有效促进油茶生长,提高油茶产量。     

不同覆盖材料对油茶果实及产量的影响

林地覆盖对于促进油茶果实生长、提高油茶果实产量具有重要意义。该研究对稻草覆盖(A1)、无纺布覆盖(A2)、薄膜覆盖(A3)以及无覆盖(CK)等不同处理下的油茶果实生长变化及其产量进行了分析。结果表明:覆盖可以有效促进油茶果高、果径的生长,提高果实体积及果实产量,不同覆盖材料中稻草覆盖对果实生长的影响最大,观察期末的果高、果径、果实体积及果实产量分别比无覆盖高4.7%、9.7%、16.85%和51.8%。     

东莞广宁红花油茶产量及果实性状特征

以广东省樟木头林场60多年生广宁红花油茶Camellia semiserrata人工林为试验材料,采用样地和抽样调查的方法研究广宁红花油茶的生长性状、果实产量、果实经济以及数量性状。结果表明:广宁红花油茶地径、树高、冠幅分别为24.0 cm、7.9 m、5.0 m。每625 m~2的样地保存有广宁红花油茶24～42株,单株间地径、冠幅变异较大,树高变异较小。每667 m~2平均鲜果产量为295.7 kg,单株最大为30.1 kg,最少的无果,变异大。果实鲜出籽率、种子含油率、种仁含油率、鲜果含油率分别为11.8%、36.61%、63.11%、2.88%,每667 m~2可产鲜籽34.6 kg,产油8.5 kg。     

四种低改措施对油茶产量与果实经济性状的影响

针对当前江西油茶老林改造与低效林提质增效的迫切技术需求，在江西省都昌县与丰城市分别设立M1、M2、M3、M4四种综合改造措施试验，结果表明：(1)各改造措施均提高了老油茶林和低效油茶林单果质量与产量。四种措施下老油茶树的单果重增长4.26%～48.07%,低效油茶树的单果重增长3.75%～149.20%;老油茶树的株产增长8.51%～64.27%;低效油茶林株产增长123.76%～329.56%。(2)老油茶林与低效林分别采用M2、M3措施后，果高、果径和果实体积的提升效果最明显；老油茶林的鲜出籽率、干籽含油率、鲜果含油率均在M3措施下达到最高，分别较CK高32.99%、70.10%和80.50%;低效林的鲜出籽率、干籽含油率、鲜果含油率分别在M3、M1、M3措施下达到最高，分别较CK增加34.46%、45.55%和85.98%。(3)油茶老林改造采用M2措施隔株截杆、内膛修剪、树蔸深挖垦复后施有机肥10 kg·株^-1、3月施尿素0.25 kg·株^-1、11月施硼肥0.15kg·株^-1的综合措施；而低效林改造应用M3措施...     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.     

CAD与建筑设计的关系

本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。     

Natural Regeneration in Clear-cuts: Effects of Scarification,Slash Removal and Clear-cut Age

The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided.     

Risk Perception Among Non-industrial Private Forest Owners

Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken.     

Interactions in decomposition and N mineralization between tropical legume residue components

In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.     

Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain

The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization, (2) milk sewage sludge at 40 kg N ha⁻¹ target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha⁻¹. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹); (2) Lolium perenne L. var. Tove (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea (Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m², with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral systems. This revised version was published online in June 2006 with corrections to the Cover Date.