控释肥对苹果产量和品质的影响

为了探讨苹果(Malus pumila)产量和果实品质对控释肥的响应机制,以苹果专用控释肥(20-10-15)为试材,设置不同的控释肥施用深度和施用量处理,研究控释肥对苹果产量和果实品质的影响。结果表明:在施肥量相同的情况下,控释肥效果较好,且施肥深度为20cm效果最好,单果质量、单株产量、可溶性固形物含量、可溶性糖含量、维生素C含量均为最高,分别为248.8g、76.3kg、14.8%、15.3%、17.5%。在施肥深度相同的情况下,控释肥施用量为2.5kg/株时效果最好,单果重量、单株产量、可溶性固形物含量、可溶性糖含量、维生素C含量均为最高,分别为分别为252.7g、78.2kg、15.9%、15.9%、19.8mg/kg和56.8。根据研究结果,控释肥和普通肥料相比,控释肥在提高苹果产量和品质方面优于普通肥料。     

4种肥料对蝴蝶兰生长的影响

调查Ｈｙｐｏｎｅｘ(ＮＰＫ比例6.5∶4.5∶19,下同)、Ｍａｇａｍｐ-Ｋ(6∶40∶6)、有机液体肥料(5∶4∶6)和大豆复合肥(8∶14∶12)等4种肥料对蝴蝶兰生长的影响。结果表明,施用Ｈｙｐｏｎｅｘ后叶面积增加。未观察到施用Ｈｙｐｏｎｅｘ、Ｍａｇａｍｐ-Ｋ和大豆复合肥之后三者间叶与根的数量以及根的总长有明显的不同。与其他肥料相比,施用有机液体肥料后,植株生长量减少。施用Ｈｙｐｏｎｅｘ和Ｍａｇａｍｐ-Ｋ后,根与叶部中的ＮＰＫ浓度高。果糖和葡萄糖含量不受施肥影响,但施用Ｍａｇａｍｐ-Ｋ后蔗糖含量较高。有机液体肥料使蔗糖含量降低4…     

控释肥在巨桉穴盘育苗上的应用

研究控释肥与普通复合肥在穴盘巨桉育苗上的应用,结果表明基质中一次性添加控释肥料基本上能满足巨桉整个生长期对养分的需求,施用控释肥苗木株高、地径、生物量、根系、质量指数等生长指标明显较普通复合肥料好;采用控释肥料育苗仅需90d,比普通复合肥育苗缩短了60d;B处理施肥成本最低,比其它处理节约了20.00%~50.21%,因此B处理即每立方基质中添加3kg控释肥最合理。     

不同施肥处理对宜昌楠苗木生长及光合生理影响

以宜昌楠2 a生的苗木为试材,采用N、P、K、NP、NK、PK、NPK和CK 8种施肥配方处理,研究其在不同施肥配方处理下形态特征和叶片光合生理的变化.结果表明:(1)NPK平衡施用具有明显促进宜昌楠生长的作用.N肥能使叶色变的深绿,叶面积增大;P肥能促使地下和地上部加快生长;K肥提高光合作用的强度,增强作物抗逆、抗病能力.K能促进N肥的吸收和利用.(2)施用NPK、NP、P、NK、PK肥宜昌楠苗木的净光合速率较高;施用NPK、P、NK、N、NP、PK肥宜昌楠苗木的蒸腾速率较高;施用NPK、NK、N、P肥使宜昌楠苗木的气孔导度上升;施用K、P、NK肥对宜昌楠苗木的胞间CO2浓度影响较大.     

氮、磷、钾对银杏叶黄酮含量与营养生长的效应

通过正交试验，利用营养液盆栽法研究了N，P，K3种大量元素对银杏叶黄酮含量和营养生长的影响。结果表明，处理间叶黄酮含量差异极显著，3种元素对黄酮含量效应大小依次为N，K，P。营养液中N，K，P的质量浓度分别为0．21，0．18，0．7g/L对提高叶黄酮含量的效果最优。银杏新梢的增粗生长，3种元素不同配比间存在极显著差异；N，P对新梢粗生长的主效明显，营养液中N和P的质量浓度以0．28g/L和0．12g/L对新梢粗生长效果最好。     

油茶轻基质容器苗木缓控专用肥研究

为了了解缓控肥对油茶轻基质容器苗生长的影响情况,以研发促进容器苗生长的缓控专用肥,以优良无性系长林4#为试验材料,采用单因素完全随机试验设计,设置如下7个缓控肥配方——(1)14︰14︰14+TE+B.3~6M、(2)15︰25︰20+TE+B.3~6M、(3)18︰18︰10+TE+B.4~6M、(4)20︰8︰10+TE+B.3~6M、(5)20︰10︰15+TE+B.4~6M、(6)17︰11︰12+TE+B.3~6M、(7)25︰5︰6+TE+B.3~6M,每个供试肥料配方处理下又各设置了0.2、0.3、0.4、0.5 g/株4个施肥量处理,就不同缓控肥配方及其不同施用量处理对1年生油茶轻基质容器苗生长状况的影响情况进行了试验、观测与分析。结果表明:7个供试肥料配方均能促进苗木地径、苗高的生长及苗木叶片数量的增加,其中配方(3)的效果最优,配方(2)和配方(7)的效果均较优;各配方的最佳施肥量为0.4~0.5 g/株,即基质量为2.5~3.0 kg/m3。     

硅酸钠胁迫下三角枫和滇润楠苗木生理生化变化的研究

分别用0(ck)、2、4、6、8、10 g/L的硅酸钠溶液处理1～2年生三角枫(Acer buergerianum)苗木和滇润楠(Machilus yunnanensis)苗木,对硅酸钠胁迫下苗木进行研究.结果表明:在0～6 g/L硅酸钠浓度范围内,随着浓度的增加,2种苗木膜透性(MP)、丙二醛(MDA)、超氧化物歧化酶(SOD)、过氧化物酶(POD)的含量均有不同程度的降低,可溶性糖(SS)、可溶性蛋白(SP)、叶绿素a、叶绿素b、叶绿素均有不同程度的升高;在6～10g/L硅酸钠浓度范围内,随着浓度的增加,MP、MDA、SOD、POD的含量均有不同程度的升高,SS、SP、叶绿素a、叶绿素b、叶绿素则有不同程度的降低,而类胡萝卜素的含量在0～10 g/L范围内随硅酸钠浓度的增加总是保持在-个水平含量上,没有显著差异.说明在一定的硅酸钠浓度范围内,可以促进苗木的生长,保护苗木细胞不受伤害;相反,高浓度的硅酸钠对苗木的生长起到危害作用.     

配方施肥对枸杞品质及产量的影响

为了解大量元素肥及微量元素肥对枸杞外观品质及产量的影响,采用正交试验设计L16(43×24),选用大量元素肥N、P、K和微量元素肥Fe、Zn、Mo、B,对3年生枸杞(宁杞1号)进行大田配方施肥试验,测定其果实大小、百粒质量及产量指标,以确定枸杞的最佳施肥配方。结果表明:不同的配方施肥组合的果实大小、百粒质量及产量均比CK增加,其最大值分别比CK增加了18.08%、38.42%、80.83%,最佳施肥水平组合为N3P2K3Fe1Zn2Mo1B1。即大量元素肥料的施肥量为:尿素217 g/株、过磷酸钙417 g/株、硫酸钾313 g/株,微量元素肥料以施入Zn肥10 g/株为好。     

N、P、K对杉木幼苗生长量的影响

开展了施用N、P、K肥对杉木幼苗期生长量影响的研究。结果表明:施肥能显著促进杉木幼苗苗高和地径的生长,但需N、P、K肥配合施,单施N肥的效果较N、P、K配施的效果差,单施N肥和N、P、K肥配施的处理间达到极显著差异。不同施肥处理对杉木苗木的苗高和地径生长的影响也达到极显著差异。此试验最为合理的施肥配方是:N 1.5 g、P 5 g、K 1.5 g,苗高比对照高出38.8%,地径比对照高出46%,可在生产中推广使用。表现最差的施肥配方是N 1.5 g,苗高比对照高出17.4%,地径比对照高出20.0%。     

白花油茶苗木生长对叶面施肥的响应

选用尿素和磷酸二氢钾对云南山区油茶苗木进行叶面喷肥,采用两因素三水平[2因素选用尿素(C)和磷酸二氢钾(K),3水平选高、中、低3个量],9个处理,3次重复的3×3设计,以拉丁方排列设置27个小区进行田间试验,研究叶面喷肥对白花油茶苗木成活率、生长量(包括苗高、地径、冠幅)和生长进程的影响。结果表明,(1)白花油茶苗木的苗高、地径、冠幅对叶面喷肥的响应均符合二元二次回归方程及产量反应曲面,说明叶面喷施尿素和磷酸二氢钾对白花油茶苗木具有一定的作用,这种作用均呈现出钟形曲面模式。(2)对白花油茶苗木生长量的二元二次回归方程进行单因素、双因素和全因素模拟的结果表明,尿素与磷酸二氢钾配合喷施的效果比单施尿素或单施磷酸二氢钾的效果要好。(3)交互试验中,C用量分别为2.846g/L、2.667g/L和2.589g/L,K用量分别为1.736g/L、2.071g/L和0.975g/L,两者配比分别为1︰0.609、1︰0.777和1︰0.377时,苗高、地径和冠幅生长可以达到理论最高增量。(4)等产线图指出,对苗木的苗高、地径和冠幅增长具有促进作用的C肥合理施用量分别为0-1.797g/L、0-2.071g/L和0-1.016g/L,K肥用量合理施用量分别为0-2.888g/L、0-2.666g/L和0-2.593g/L。     

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.