2种植物源农药烟雾对黄脊竹蝗的防治效果

为试验喷烟施放1.2%烟碱·苦参碱乳油和1.3%苦参碱可溶液对黄脊竹蝗的防治效果，确定其最佳应用浓度及药剂用量，在福建省三明市梅列区的灰竹林中开展喷烟防治试验。试验结果表明：施药后4 d，1.2%烟碱·苦参碱乳油和1.3%苦参碱可溶液2种农药对黄脊竹蝗成虫的防治效果均超过86.7%，最佳应用浓度配比均为农药与烟雾剂的容积比为1：7，药剂最佳用量分别为900 mL/hm²和1 050 mL/hm²。喷烟施放2种植物源农药对黄脊竹蝗成虫的致死作用强、防治效果佳，可在生产中用于防治工作。     

5种植物源农药对黄脊竹蝗毒力及毒饵的制备与防治效果

为揭示5种植物源农药对黄脊竹蝗毒力强度，探寻制备诱杀黄脊竹蝗成虫新型毒饵的方法，采用碳酸铵、碳酸氢铵和氯化铵与5种植物源农药混合制备毒饵，并进行诱杀黄脊竹蝗成虫试验。结果表明：5种农药对黄脊竹蝗均有良好的致死作用，1%苦参·藜芦碱可溶液、1.2%烟碱·苦参碱乳油、0.5%藜芦碱可溶液、1.5%苦参碱可溶液和4%鱼藤酮乳油对黄脊竹蝗跳蝻和成虫的LC₅₀依次为1.527、0.856、1.931、0.927、1.602 mg/L和1.767、0.957、2.176、1.126、1.825 mg/L；碳酸铵、碳酸氢铵和氯化铵水溶液可代替人尿作为引诱剂，其最佳浓度配比为70、80和90 g/L，5种植物源农药可代替化学药剂作为胃毒剂，胃毒剂与引诱剂的体积比：1.2%烟碱·苦参碱乳油和1.5%苦参碱可溶液均为1∶30，1%苦参·藜芦碱可溶液和4%鱼藤酮乳油均为1∶20，0.5%藜芦碱可溶液为1∶15。本研究提出的毒饵制备方法，可广泛用于大量诱杀黄脊竹蝗成虫，可为黄脊竹蝗的无公害防治乃至综合防治提供借鉴。     

5种农药低空喷雾防治黄脊竹蝗成虫效果分析

为确定低空喷雾无公害药剂防治黄脊竹蝗成虫的林间最佳浓度水平和用药量，掌握低空喷雾施药技术，在福建省三明市三元区的毛竹林建立试验区，应用无人机开展低空喷雾防治试验。结果表明：药后7 d，5种农药的防治效果均超过90%，其林间最佳浓度水平（药剂与纯净水的体积比）为：1.5%苦参碱可溶液和1.2%烟碱·苦参碱乳油均为1：1 000；25%阿维·灭幼脲悬浮剂为1：700，1%苦参·藜芦碱可溶液和4%鱼藤酮乳油均为1：600，原药量用为900 mL/hm²。5种农药防治效果良好，可推广应用于防治黄脊竹蝗成虫。     

6种植物源农药防治波纹杂毛虫林间药效分析

为明确6种植物源农药防治波纹杂毛虫的最佳林间配比度和用药量,掌握低空施药技术,在福建省沙县马尾松林建立试验区,开展林间喷雾和喷烟防治试验。结果表明:6种农药的林间喷雾,药后4 d,防治效果均超过90%;最佳林间配比度为:1.3%苦参碱可溶液剂和1.2%烟碱·苦参碱乳油均为1300倍液;1%苦参·藜芦碱可溶液、4%鱼藤酮乳油和0.6%印楝素乳油均为1000倍液,0.5%藜芦碱可溶液为800倍液。2种农药喷烟后3 d,防治效果均超过90%,1.3%苦参碱可溶液和1.2%烟碱·苦参碱乳油与烟雾剂最佳配比度均为1∶9。参试的6种植物源农药可广泛应用于防治波纹杂毛虫幼虫。     

采用林丹烟剂防治黄脊竹蝗试验

黄脊竹蝗是毛竹林的主要害虫之一.为了掌握黄脊竹蝗的防治方法和措施,使用林丹烟剂进行灭虫试验,结果表明在傍晚大气呈逆增,风速在1m·s-1以内时施放,防治效果可达96%以上,因此,此方法可在竹蝗暴发时应用,为黄脊竹蝗综合防治提供科学依据.     

2种植物源药剂对松丽毒蛾幼虫应用效果

为明确1.3%苦参碱可溶液和1.2%烟碱·苦参碱乳油喷烟防治松丽毒蛾幼虫的林间最佳配比和用药量,在三明市三元区岩前镇、莘口镇的马尾松林建立试验区开展林间防治试验。结果表明:药后3 d,施用2种药剂的松丽毒蛾幼虫死亡率达85.6%以上,1.3%苦参碱可溶液和1.2%烟碱·苦参碱乳油2种药剂与烟雾剂最佳配比均为V(药剂)︰V(烟雾剂)=1︰9,林间最佳用药量分别为750 mL/hm^(2)和600 mL/hm^(2)。2种植物源药剂喷烟防治松丽毒蛾幼虫均有良好效果。     

植物源杀虫剂对石竹竹斑蛾幼虫的防治效果

竹斑蛾幼虫取食石竹竹叶,是石竹的主要食叶害虫之一。近年来,受不合理的经营与防治措施影响,竹斑蛾已成为石竹主要食叶害虫,为践行绿色发展理念,筛选出防治竹斑蛾的有效药剂,探讨无公害防治竹斑蛾的路径,2018年在福建省三明市郊国有林场石竹林中采用喷粉技术喷施1.1%苦参碱粉剂,用量22.5 kg/hm^2,采用喷烟技术,施放5%桉油精可溶液、1.2%烟碱·苦参碱乳油和碧绿1%苦参碱,用量均为750 mL/hm^2,开展对竹斑蛾3龄幼虫林间防治试验。结果表明:药后2 d,参试药剂的防治效果均超过90%。表明4种参试药剂均有高效的杀虫效果,可在防治竹斑蛾幼虫为害时应用。     

6种植物源杀虫剂对黄纹竹斑蛾的防治效果

近年来,由于不合理的防治措施,黄纹竹斑蛾已成为危害毛竹叶片的主要害虫。为探索有效控制黄纹竹斑蛾危害的无公害防治措施,试验研究了不同浓度的6种植物源杀虫剂:0.5%藜芦碱可溶性液、1%苦皮藤素可溶液、4%鱼藤酮乳油、1.5%苦参碱可溶液、1.2%烟碱·苦参碱可溶液和1.1%苦参碱粉剂对黄纹竹斑蛾幼虫的防治效果,其中前5种药剂采用喷烟技术施药,后一种药剂采用喷粉技术施药。结果表明:施药后3 d,6种药剂的防治效果均达90%以上;0.5%藜芦碱可溶性液、1%苦皮藤素可溶液和4%鱼藤酮乳油的田间最佳用药浓度是原药与0号柴油容积比为1:40,用药量为1 200 mL/hm²;1.5%苦参碱可溶液、1.2%烟碱·苦参碱可溶液田间最佳用药浓度是原药与0号柴油容积比为1:9,用药量为800 mL/hm²;1.1%苦参碱粉剂田间最佳用药量为22.5 kg/hm²。上述6种植物源杀虫剂均可作为无公害防治黄纹竹斑蛾幼虫的药剂,在黄纹竹斑蛾幼虫危害时施用。     

5种植物源农药防治松丽毒蛾的效果分析

为研究植物源农药及浓度对松丽毒蛾的林间防治效果,于2019年在福建省沙县官庄国有林场的马尾松林分设立试验区,选用0. 6%印楝素乳油等5种植物源农药开展林间喷雾防治松丽毒蛾幼虫试验。结果表明:药后4 d,5种药剂对松丽毒蛾幼虫表现出较好的杀虫效果,0. 6%印楝素乳油、4%鱼藤酮乳油、1%苦参·藜芦碱可溶液、1. 3%苦参碱可溶液和1. 2%烟碱·苦参碱乳油对幼虫的平均死亡率依次为91. 1%、91. 3%、91. 7%、92. 0%和92. 6%,其最适浓度分别为0. 6%印楝素乳油和4%鱼藤酮乳油1000倍液,1%苦参·藜芦碱可溶液1100倍液,1. 2%烟碱·苦参碱乳油和1. 3%苦参碱可溶液1300倍液,在生产防治上可推广应用。     

黄脊竹蝗应急防治技术

通过7年连续观察发现,黄脊竹蝗不断适应气候环境和立地条件的变化,逐步形成一些新的发生特点。文章介绍了查卵挖卵、扑打跳蝻,选用16％灭幼脲增效粉剂防治低龄跳蝻,选用1．2％苦参碱·烟碱乳油药物防治高龄跳蝻和成虫等应急防治技术。     

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.     

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.     

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.     

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。     

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.