无公害苹果生产技术规程

1园地选择与规划1.1园地选择无公害苹果园地的环境条件应符合NY 5013的规定,其他按NY/T441-2001中的3.1规定执行。建园时选择阳光充足,有灌溉条件的中性或微酸性土壤,地下水位2m以上。平地建园应选择地势较高,便于排水的地块;山地建园选择坡度5~10度为宜。坡度大时应修筑水土保     

美国扁桃栽培技术要点

美国扁桃喜光、耐旱、耐贫瘠、适应性强、好栽易管。干旱的西北、华北地区适宜栽培。1　园址选择向阳的平地、坡地、山地均可建园。平地建园要求地下水位较低 ,坡地、山地建园要选择阳坡 ,坡地要修成梯田 ,山地要挖围山转。2　定植时间与密度美国扁桃定植分为秋季定植和春季定植 ,秋季定植在落叶后封冻前进行。长城内外在农历小雪前定植 ,即 1 1月中旬 ,定植后埋土防寒。春季定植在土壤解冻后进行。株行距 :平地 5m× 3m ,坡地、山地 4m× 3m ,即每 667m2 栽培 44株、5 6株。3　品种选择与配置授粉树选择优良品种、配置好的授粉树是扁桃建园…     

核桃园幼树管理技术

一、建园 （一）园址的选择：山地要避开岗、梁，选择坡面的中下部位，以阳坡或半阳坡为好；平地要排水良好，光照充足，土层厚度1．5m以上，质地疏松，PH值6．5～8之间，地下水位在2m以下，最好具备良好的灌溉条件。年平均气温不低于8～12度，最低气温不低于-25度，无霜期120天以上。     

美国扁桃栽培要点

美国扁桃喜光、耐旱、耐贫瘠、适应性强、好栽易管,干旱的西北、华北地区适宜栽培。1　园址选择向阳的平地、坡地、山地均可建园,平地建园要求地下水位较低,坡地、山地建园要选择阳坡,坡地要修成梯田,山地要挖围山转。2　定植时间与密度扁桃定植分为秋季定植和春季定植,秋季定植在落叶后封冻前进行。长城内外在农历小雪前定植,即1 1月中旬,定植后埋土防寒。春季定植在土壤解决冻后进行。株行距:平地5m×3m ,坡地、山地4m×3m ,即每6 6 7m2 栽培4 4株、5 6株。3　品种选择与配置授粉树这是扁桃建园及发展成败的关键。可选择浓泊尔为主栽品种,…     

退耕还林工程发展广丰天桂梨产业的现状与对策分析

天桂梨是江西省上饶市广丰区科技人员选育出的地方名产,在上饶地区经济林产业中的地位与作用越来越突出。该文分析了近年来天桂梨在退耕还林工程中的产业发展现状,并剖析了产业发展中存在的问题,提出了天桂梨在退耕还林中产业的发展目标、对策与措施,为广丰天桂梨产业的健康可持续发展提供决策参考。     

如何使南方早熟梨优质丰产

南方早熟梨因其成熟期早,营养物质丰富,肉质细嫩,口感松脆,香甜,多汁,经济价值高,而深受广大果农的欢迎。近年来,在浙南地区引种栽培较多,种植热潮高涨。笔者经过多年栽培探索,总结出一套南方早熟梨早结优质丰产栽培技术,现介绍如下:1.品种选择:早熟梨因原产地不同,各品种对气候和土壤的适应性也存在差异。根据南方高温、高湿的气候特点,建园时,宜选择优质、丰产和适应性强的品种。如翠冠、脆绿、清香、西子绿、七月酥、新世纪等良种。2.选地建园:园地的选择和规划。选择土层深厚,耕作层达50~10厘米深的平地、缓坡地、丘陵地,以土质疏松、排…     

大果水晶梨引种及丰产栽培

大果水晶梨是韩国新世界育种园从新高梨枝条芽变中选育的新品种.其果实圆形,晶莹光亮,外观诱人,并有适应性强、抗寒、抗旱、耐瘠薄、抗病性强、丰产性和早果性好之特点.鉴于我县用于生产的梨新品种数量少,为适应农业结构调整的需要,于2002年从陕西杨陵引种,2002～2005年在庄浪县北部川区栽植水晶梨267 hm^2,获得良好经济效益.现将丰产栽培技术介绍如下.     

红酥脆梨的无公害栽培

红酥脆梨是郑州果树研究所以日本幸水梨做母本,用我国民间红梨品种--火把梨为父本,通过人工杂交培育而成的一个晚熟红色梨优良品种.通过几年多点引种观察,该品种表现品质优良、着色好、外观美丽、早果丰产、抗逆性抗病性强,适应性、耐贮性和加工性均表现较好,即可作为晚熟鲜食良种栽培,也可作制汁加工良种发展,具有广阔的市场前景和开发潜力.其无公害栽培技术如下:     

大扁杏丰产栽培管理技术

大扁杏是我国“三北”地区特有的经济树种之一。它适应性强，经济价值高（一般10～15年生杏园每亩年收入近千元）.杏仁除含有多种营养成分外，还含有抗癌物质维生素B17，广泛应用于食品、医药等工业，是外贸出口产品，深受外商欢迎。栽植大扁杏是“三北”地区人民脱贫致富的一个重要门路。其丰产栽培技术如下。一、选好园地搞好规划大扁杏园应选在背风向阳、坡度15°以下、土质疏松、土层深厚、地下水位1～2m、排水良好的地方。园地要搞好规划。小区面积一般30～50亩，主路6～8m宽，支路4～6m。无论山地杏园或平地杏园的四周都要栽防护林。…     

无公害果品综合生产技术

1园地选择无公害果园以沙土或沙壤土为佳,选择空气清新、水质纯净、土壤未受污染、地势平坦、光照充足、土壤肥沃、排灌条件良好的地块为宜。要远离城区和公路、铁路、没有工矿等污染源,生态环境条件良好的地区。选择好地块后要深翻改土,增施有机肥料,合理灌水。     

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.     

Decomposition and nutrient loss from prunings of different contour hedgerow species in tea plantations in the sloping highlands of Sri Lanka

Contour hedgerows of multipurpose tree species in the sloping tea lands of Sri Lanka are expected to reduce soil erosion and also add significant amounts of plant nutrients to the soil via periodic prunings. The objective of this experiment was to characterize the biomass decomposition pattern and quantify the amount of nutrients added through prunings of six tree species (Calliandra calothyrsus, Senna spectabilis, Euphatorium innulifolium, Flemingia congesta, Gliricidia sepium and Tithonia diversifolia) currently being used in hedgerows associated with tea. Withered leaf and stem prunings (50 g) were enclosed in 2-mm litter bags, placed at 5-cm depth and retrieved after one, three, six, nine and 12 weeks. Loss of initial dry weight, N, P and K was measured. Single exponential decay function adequately described both dry weight and nutrient loss. Tree species differed significantly in their rate of breakdown with decomposition constants (k) varying from 0.0299 to 0.2006 week⁻¹ for leaves and from 0.0225 to 0.0633 week⁻¹ for stems. Gliricidia showed the highest k for leaves with the rest in the following descending order: Senna > Tithonia ≥ Euphatorium > Calliandra > Flemingia. A similar pattern was observed for loss of all nutrients with Calliandra and Flemingia always having lower k values than the rest. Although N immobilization was not observed, immobilization of P and K was observed during the first week of incubation in some species, particularly in stem prunings. Annual biomass of prunings differed significantly between tree species in the following descending order: Calliandra > Senna > Flemingia > Tithonia > Gliricidia > Euphatorium. Calliandra added the greatest amount of nutrients annually to the soil with Euphatorium adding the least. Calliandra prunings provided the annual total K requirement and 49% of the N requirement of mature tea. However, none of the species provided more than 5% of the P requirement. It is concluded that among the tree species tested, Calliandra and Flemingia are the most suitable for contour hedgerows in tea plantations of this agroclimatic region because of their higher soil nutrient enrichment capacity and slower decomposition rates which would minimize leaching losses. This revised version was published online in June 2006 with corrections to the Cover Date.     

Effects of Seed Weight and Seed Type on Early Seedling Growth of Pinus sylvestris under Harsh and Optimal Conditions

The effects of seed weight and seed type on seedling growth of Pinus sylvestris (L.) were studied by seeding individually weighed orchard and stand seed in different mixtures under harsh (direct seeding in field) and optimal (seeding in nursery) conditions. In the nursery experiment an increase in the seed weight from 3 to 7 mg increased the seedling height by 10-27% and total weight by 27-113%, and decreased the height/diameter ratio by 5-6% after 2 yrs. With elimination of seed weight effects, orchard seedlings were 2% taller than stand seedlings in year 2. Without elimination of seed weight effects, orchard seedlings were 7-13% taller. In the field experiment an increase in the seed weight from 3 to 7 mg increased seedling height by 18-65%, stem volume by 81-274% and the number of top-buds by 23-34% in year 5. After elimination of seed weight effects, orchard seedlings were 7-13% taller than stand seedlings and without elimination of seed weight effects 20-21% taller after 5 yrs. Even after elimination of both seed weight and genetic effects orchard seedlings were 3-9% larger than stand seedlings in the field experiment. In conclusion, the influence of seed weight and seed type on growth traits and slenderness is highly significant and the influence seems to be greater in harsh conditions.     

Growth of Phlebiopsis gigantea in wood of seven conifer species

Heterobasidion parviporum and Heterobasidion annosum are widely distributed root‐rot fungi that infect conifers throughout Europe. Infection of conifer stumps by spores of these pathogens can be controlled by treating fresh stumps with a competing non‐pathogenic fungus, Phlebiopsis gigantea. In this study, growth of three Latvian strains of P. gigantea and the biological control agent ‘Rotstop’ strain was evaluated in stem pieces of Norway spruce, Scots pine, lodgepole pine, Douglas‐fir, Weymouth pine, Siberian larch and Sitka spruce. The growth rates of one H. parviporum and one H. annosum isolate were also measured in the same stem pieces. The growth rate of P. gigantea varied greatly in wood of different conifer species. It was higher in the three pine species, lower in Norway spruce and lowest in Sitka spruce and Siberian larch, and in Douglas‐fir, this fungus did not grow. The largest area of wood occupied by P. gigantea was in lodgepole pine. Growth of Latvian isolates of P. gigantea in the wood of Pinus and Picea species was comparable to that of the Rotstop isolate. Consequently, stump treatment with local P. gigantea isolates should be recommended. However, our results suggest that Douglas‐fir stump treatment against Heterobasidion by P. gigantea may be ineffective and other stump treatment methods should be considered.     

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.     

Potential to harness superior nutritional qualities of exotic baobabs if local adaptation can be conferred through grafting

Baobab leaves form an important part of the local diet in Sahel countries and elsewhere in Africa. Existing leaf nutritional data and agroforestry performance information are based solely on Adansonia digitata L., the baobab of continental Africa. The introduction potential of Adansonia species from the center of diversity in Madagascar and from Australia remains untapped. To assess this potential, the mineral contents and B₁ and B₂ vitamin levels of dried baobab leaves were determined for five-year old trees of A. digitata, A. gibbosa (A. Cunn.) Guymer ex D. Baum, A. rubrostipa Jum. & H. Perrier (syn. A. fony Baill.), A. perrieri Capuron and A. za Baill. grown in an introduction trial in Mali. Nutritional data were evaluated against survival and vigor to identify promising germplasm. Leaf vitamin and crude protein contents were highest in the Madagascar species, especially A. rubrostipa (B₁ 88 mg 100 g⁻¹, B₂ 187 mg 100 g⁻¹, protein 20.7% dry weight). However, the local species far outperformed the introductions in survival, tree height, basal diameter and resistance to termites. We suggest grafting as a way of harnessing the vigor of well-adapted local baobab varieties to the superior nutritional profiles of A. rubrostipa and others. Cross-species grafting tests in Adansonia were successful, thus creating new agroforestry possibilities with different scion/rootstock combinations.     

Modelling of adequate pretwist for obtaining straight timber

Abstract

Wood in general and wooden studs in particular are often distorted owing to uneven shrinkage during the drying process in the sawmill. Twist is often the most detrimental of all types of distortion, and it is caused by spiral grain in combination with variations in moisture content. For sawmills, the objective is to produce dried, straight boards, and one method of dealing with boards with excessive spiral grain is to sort them out and then dry them in a pretwisted position to obtain straight boards after drying. A model using the finite element (FE) method for the simulation of drying twist distortions was first calibrated against laboratory experiments in which boards were dried with and without restraints and pretwists. After the calibration, the FE results were compared with industrial test results for boards that were dried without restraints or with restraints with zero pretwist, i.e. straight restraints. The FE model used an elastic–ideally plastic material model to obtain permanent deformations. The calibration was to set the yield stresses so that there was a good match between FE results and results from the laboratory experiments. The comparison between the industrial test results and the FE results showed that the FE model is capable of realistic simulations of drying boards with and without restraints and presumably also pretwists.     

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。