胶园间种对枯落物、腐殖质和土壤性质的影响

橡胶间种砂仁、咖啡对林地枯落物、腐殖质和土壤性质的影响调查结果表明，作物的间种明显提高了林地枯落物的积累量，橡胶＋砂仁、橡胶＋咖啡、纯橡胶林分别为３６５３．５、２８６１．１、１９３４．３ｋｇ／ｈｍ２；土壤有机质含量随之提高，０～５ｃｍ土层有机质含量分别为４４．３０３、３２．９０５、２６．８４０ｇ／ｋｇ；三种胶园种植模式土壤腐殖质组成均以富里酸为主，间种砂仁、咖啡利于胡敏酸和胡敏素的形成；土壤性状因间种而得到改良，２～５ｍｍ最为良好稳定的多孔性团粒结构含量分别为３０．８９％、１３．６６％和１２．１３％。以橡胶间种砂仁对土壤肥力的提高最为理想。     

橡胶间种砂仁模式下凋落物的特征

文章研究了橡胶＋砂仁胶园间种模式凋落物的年凋落总量和节律、凋落物组成、分解速率、营养元素及养分释放。结果表明：橡胶林下间种砂仁的胶园凋落物具有较多的热带季雨林的特征，总凋落量为７．６５ｔ／ｈｍ２·ａ，与海南岛山地雨林相近；凋落物组分中明显较高的叶含量形成了橡胶＋砂仁模式自己独特的凋落物组分比值；占凋落物总量３９．７％的砂仁枯落物，在胶砂复合生态系统的养分归还上占有十分重要的地位。     

西双版纳砂仁种植模式探讨

简述国内现有的砂仁种植模式,并对主要模式的优缺点进行比较分析,认为热带雨林+砂仁模式对热带雨林物种多样性保护等带来严重的负面影响;各类杂木次生林+砂仁可在一定程度上提高砂仁产量; 杉木+砂仁、橡胶+砂仁种植模式具有改善土壤肥力、促进间种树种生长等优势。西双版纳有着相当数量的次生林、橡胶林、竹林等,把砂仁种植从热带雨林中转移到雨林外种植同样具有很大的资源优势和生产潜力。     

遮放农场橡胶、茶叶、咖啡间作模式调查

德宏州潞西市遮放农场地处北纬24°13′～24°31′,东经98°08′～98°33′,年均温20.5℃,属三类型植胶区。为改变因寒害频繁,胶园经济效益低的状态,该场于1979年开始布置试验,探索橡胶+茶叶、橡胶+咖啡、橡胶+茶叶+咖啡等三种间作模式及其实际效果。经过20多年生产实践,已体现出良好的经济、社会和生态效益,为三类型植胶区橡胶栽培模式提供了宝贵经验和借鉴。我们于2001年11月底对该场三个间作园的胶树存活率、生长量、烂脚以及园地作物产量、产值情况进行调查,现将调查结果整理报道如下:1　间作园基本情况橡胶+茶叶、橡胶+咖啡、橡胶+茶叶…     

橡胶与砂仁间作复合生态系统营养元素循环的研究

橡胶与砂仁间作和纯橡胶林两种林分营养元素净积累、归还及营养元素在植物、土壤之间生物循环的研究结果表明：间种砂仁可明显增加林分植物库中营养元素的含量，间作林中营养元素总积存量达３４４７．０７ｋｇ／ｈｍ２，是纯胶林的２．５３倍；营养元素总归还量每年每公顷为３６３．２６ｋｇ，是纯胶林的１．４４倍，其中Ｎ，Ｐ，Ｋ，Ｃａ，Ｍｇ的年归还量分别是纯胶林的１．９，２．５４，１．４２，１．０５，１．１６倍；间作林中的Ｎ的归还量为最大，纯胶林中以Ｃａ的归还量为最大，两种林分均以Ｐ的归还量为最小。间作林中营养元素的年吸收总量为１０８３．４３ｋｇ／ｈｍ２，是纯胶林的２．１倍。尽管营养元素的循环系数低于纯胶林，但吸收系数却高于纯胶林，可见间种有利于植物对土壤库中营养元素的吸收。     

东风农场橡胶树的营养状况与施肥

橡胶树营养诊断指导施肥是当前国内外橡胶栽培中的一项先进技术，即通过胶树叶片营养水平为依据，制定合理的施肥方案。1990～1994年，东风农场技术站完成了我场8 603.28hm2胶园，1 218个诊断区的橡胶叶片及土壤的营养诊断工作，取得了较完整的技术资料，现结合我场的生产实际，谈谈我场胶园营养状况及施肥对策。1 胶园土壤肥力状况 我场胶园主要分布于海拔600～900m的坝缘阶地、低山丘陵，成土母质主要是以花岗岩、千枚岩及其风化物形成的冲积物。在北热带气候条件的影响下，以热带雨林和季雨林为特征的生物循环与土体不断进行的脱硅富铝化…     

西双版纳探索环境友好型生态胶园建设

2008年,由于利益驱动,云南出现了大面积超海拔上限植胶、超种植坡度、超宜胶范围等违背自然规律的橡胶种植行为,带来了区域性水资源短缺、土壤肥力下降、水土流失、病虫害加剧等问题,生物多样性受到影响。2009年,西双版纳州政府首次提出了建设环境友好型生态胶园构想,并与中科院西双版纳植物园联合开展研究和探索。     

马来西亚小胶园考察报告

<正> 应马来西亚橡胶研究院(RRIM)的邀请,农垦司于1992年5月8日至22日陈盈祥等一行五人对马来西亚小胶园橡胶栽培技术、种植管理、胶园更新、橡胶加工、培训学校和国家对小胶园的有关政策进行了考察。现将考察情况报告如下: (一)马来西亚小胶园的发展概况     

橡胶栽培技术探讨

橡胶产业作为海南省的重要经济农作物,对推动海南的农业发展具有一定的积极作用.介绍了橡胶的生态特征,就品种选择、胶园建设、胶园管理及割胶等方面探讨了橡胶栽培技术.     

橡胶栽培技术探讨

橡胶产业作为海南省的重要经济农作物,对推动海南的农业发展具有一定的积极作用。介绍了橡胶的生态特征,就品种选择、胶园建设、胶园管理及割胶等方面探讨了橡胶栽培技术。     

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.