毛竹林不同施肥方式效果比较

对毛竹林采用不同的施肥方式,分析其对立竹质量、竹林产量以及竹蔸的影响,结果表明:伐桩施肥与沟施、穴施相比肥料损失少,施肥见效快,并能加速竹蔸腐烂,具有显著的促进生长效应.     

果树施肥十注意

1注意施肥后灌水时间要根据肥料特性而定 施肥后灌水时间的早晚对肥效的影响很大。施肥后有及时灌水和延迟灌水之分。及时灌水的肥料有氨态氮肥和农家肥（人粪尿、骡马粪、猪粪、饼肥等）。氨水和碳酸氢铵是速效氮肥,极易挥发,因此,氨水和碳酸氢铵必须沟施覆土并及时浇水。硫酸铵和氯化铵易被作物吸收,施用后灌水使肥料与土壤密接,能尽快发挥肥效。农家肥含有大量的微生物,这些微生物必须在充足水分的条件下繁殖、分解有机质而释放大量的养分。因此,施用农家肥后也要及时浇水。而施用尿素却要延迟灌水。因尿素中酰胺态氮不能被果树利用,须在尿酶的作用下转化为碳酸氢铵后才能被吸收,如果浇水过早,酰胺态氮易随水流失而浪费。所以,施尿素后应延迟5—7d浇水。     

毛竹林不同施肥方式比较

通过毛竹林不同施肥方式对立竹质量、竹林产量以及竹蔸的影响试验，结果表明：伐桩施肥与沟施、穴施相比肥料损失少，输送迅速，并能加速竹蔸腐烂，具有显著的生长效应，是毛竹林一种较好的施肥方式。     

毛竹伐桩快速腐烂技术试验研究

竹伐桩在自然状态下腐烂速度极度级慢，为加快其腐烂速度，增加土地有利用空间，试用尿素、碳酸氢铵、食盐、草甘磷等肥料或农药，木霉、果胶霉等生物菌类单种或组合施于竹桩内腔。结果表明：这些物质都能有效提高竹桩糜烂速度，但提高速率有差别。使用草甘磷与碳酸氢铵、食盐的混合处理是本试验中农药和化肥组合中的最佳组合，它在处理后2年可达到自然状态的6年，腐烂速度提高了3倍。单用果胶霉、木霉处理腐烂速度也可以提高3倍；毛竹桩先加入碳酸氢铵后覆土，再加入一定量的果胶霉、木霉，其处理后23个月竹桩的腐烂程度相当于自然状态下的6年程度，糜烂速度可提高3倍以上。     

在竹蒲头内施化肥的方法好

竹子砍伐后的伐桩俗称竹蒲头。毛竹砍伐后留在林地的竹蒲头,一般要10年左右方会烂掉。据我们调查,一亩毛竹林有10%的林地被竹蒲头所占据,严重影响出笋、成竹。为了加速竹蒲头腐烂及改进竹林施肥方法,我们在竹蒲头内进行了施尿素试验。试验表明,在竹蒲头内施尿素不易流失,也不会被杂草夺走,但竹子能吸收,因此出笋多、产量高;同时,能加速竹蒲头的腐烂,有利于竹林的再生产。在开花竹林中对竹蒲头内灌尿素,还可抑制竹林开花或使开花竹林在2—5年内复壮。所以,在竹蒲头内施化肥是一种值得推     

德清县大面积毛竹林试行免耕施肥

德清县林业科技人员,根据该县大部分竹林地山高坡陡、土层较浅、大暴雨频繁等情况,于1988年开展毛竹免耕施肥试验,对下届出笋的毛竹山,分别采用每竹眉形施、竹蒲头打洞施和开水平沟施等办法,每亩施碳酸氢铵70～80kg,次年对早期笋每亩再施尿素15kg。边试验边示范推广,三年来全县共施肥3.2万亩,施碳酸氢铵1315t,尿素61t。据统计,在试验林     

不同施肥方法对毛竹笋产量影响的对比试验

在标准地调查的基础上,采用不同施肥方法,对毛竹笋产量的影响进行了对比试验,结果表明:在相同条件下(如:立地条件、肥料品种、施肥量等),沟施结合伐桩施肥的方法效果最好;沟施的方法次之;伐桩施肥的方法第三;撒施的方法效果最差。可见采用沟施结合伐桩施肥的方法可较大地提高毛竹笋的产量。     

闽中毛竹林伐桩施肥的应用评述

为了提高闽中毛竹林的集约管理水平,文章指出了未能实施大面积施肥管理的主要原因:投入资金不足、认识不足、劳动力不足、运输不便、土壤坚硬、鞭根妨碍。伐桩施肥具有提高肥效、减少成本、节约劳动力、加速伐桩腐烂、防止水土流失、运输方便、见效快等优点。因此认为推广应用伐桩施肥,是解决目前闽中毛竹林大面积施肥问题的良好技术措施。     

毛竹林内竹蔸分布及其促腐情况的调查分析

通过对不同竹山的调查,结果显示竹蔸的平均半径为0.29m,单个竹蔸面积平均为0.265m2,竹林内竹蔸占林地面积比例达10.4%。对毛竹伐桩进行施肥,有利于毛竹蔸的腐烂,并能提高竹林的经济效益。     

不同施肥方法对毛竹笋产量影响的对比试验

在标准地调查的基础上，采用不同施肥方法，对毛竹笋产量的影响进行了对比试验，结果表明：在相同条件下（如：立地条件、肥料品种、施肥量等），沟施结合伐桩施肥的方法效果最好；沟施的方法次之；伐桩施肥的方法第三；撒施的方法效果最差。可见采用沟施结合伐桩施肥的方法可较大地提高毛竹笋的产量。     

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.