生物有机肥对苹果腐烂病防控效应研究

为了探明生物有机肥对苹果腐烂病和病疤愈合能力的影响,以甘肃陇东黄土高原区盛果期富士苹果为试材,通过连续3年施用生物有机肥试验,比较研究了果园土壤中分别施用生物有机肥2.5 kg/株(处理A)、5 kg/株(处理B)和7.5 kg/株(处理C)对苹果腐烂病病情指数、发病率和病疤愈合能力的影响。结果表明:连续2年、3年施用生物有机肥后,2.5 kg/株(处理A)能够显著降低苹果腐烂病的发生程度;不论施用生物有机肥1年、2年还是3年,5 kg/株(处理B)和7.5 kg/株(处理C)均能有效防控苹果腐烂病的发生;5 kg/株(处理B)和7.5 kg/株(处理C)在降低苹果腐烂病病情指数和发生率及提高病疤愈合能力方面均显著优于2.5 kg/株(处理A);但5 kg/株(处理B)和7.5 kg/株(处理C)二者之间,各项试验指标均无显著差异。从降低苹果腐烂病发生程度、促进病疤愈合能力、减少经济投入综合考虑,5 kg/株(处理B)是比较理想的生物有机肥施用水平。     

不同施肥量对油茶6年生幼林营养生长的影响

在广西巴马县选取6年生的油茶人工林为研究对象,连续3年开展不同施肥量(0.25kg/株、0.50kg/株、0.75kg/株、1.00kg/株、1.25kg/株和不施肥)对油茶中幼林树高、地径、冠幅的影响研究。试验共设6个处理,分别是处理1(0.25kg/株)、处理2(0.50kg/株)、处理3(0.75kg/株)、处理4(1.00kg/株)、处理5(1.25kg/株)和处理CK(不施肥)。结果表明,各施肥处理对油茶中幼林的树高、地径、冠幅增长表现不一致。其中,处理CK对各营养生长指标的影响效果最小;施肥量为1.00kg/株的处理对油茶树高生长的促进效果最大;施肥量为0.50kg/株的处理对油茶地径、冠幅生长的促进效果最大。综合考虑施肥成本和生长情况,以0.50kg/株的施肥量对油茶人工幼林营养生长的促进效果最佳。     

有机肥和覆盖处理对果品质及贮藏性的影响

不同有机肥(豆饼、猪粪、鸡粪、绿肥)、地面覆盖(生草覆盖、地膜覆盖)处理对果实品质的影响。试验结果表明:有机肥处理能提高果可溶性固形物(TSS)、总糖、总酸含量和固酸比以及果实耐贮性,有机肥处理中以豆饼施用效果最明显;猪粪、鸡粪其次;豆饼、猪粪和鸡粪还能有效减少果面黑斑和果肉木栓化。覆盖处理中以地膜覆盖提高果实品质的效果较明显,但对果实的耐贮性影响不大。有机肥提高品质和耐贮性的效果较覆盖处理好。     

有机肥和覆盖处理对（木柰）果品质及贮藏性的影响

不同有机肥（豆饼、猪粪、鸡粪、绿肥）、地面覆盖（生草覆盖、地膜覆盖）处理对（木柰）果实品质的影响。试验结果表明：有机肥处理能提高（木柰）果可溶性固形物（TSS）、总糖、总酸含量和固酸比以及果实耐贮性，有机肥处理中以豆饼施用效果最明显；猪粪、鸡粪其次；豆饼、猪粪和鸡粪还能有效减少果面黑斑和果肉木栓化。覆盖处理中以地膜覆盖提高果实品质的效果较明显，但对果实的耐贮性影响不大。有机肥提高（木柰）品质和耐贮性的效果较覆盖处理好。     

不同有机肥对3种俄罗斯醋栗的生长影响研究

选用猪粪、鸡粪、羊粪等不同有机肥,对黑穗、白穗、金穗3种俄罗斯醋栗进行施肥试验,结果表明:施加有机肥对于俄罗斯醋栗的生长无显著影响;与其他试验处理相比较,施加1kg猪粪的黑穗醋栗长势较好,可做为本地区俄罗斯醋栗栽培的优选方案。     

赤霉素多效唑及摘心对薄壳山核桃容器苗生长的影响

用不同浓度赤霉素和多效唑溶液分别喷施薄壳山核桃容器苗叶面;用不同浓度赤霉素溶液涂抹薄壳山核桃容器苗茎基部;在薄壳山核桃容器苗生长旺季初期分3个时期进行摘心试验。结果表明,叶面喷施不同浓度赤霉素溶液能显著促进薄壳山核桃容器苗的株高生长,但对增粗生长无显著影响。不同溶度赤霉素溶液涂抹薄壳山核桃容器苗茎基部、不同浓度多效唑溶液喷施薄壳山核桃容器苗叶面及不同时期摘心处理,都能显著促进薄壳山核桃的增粗生长。以600 mg/L的赤霉素溶液涂抹茎基部对苗木生长效果最好,以300 mg/L的多效唑溶液喷施叶面、6月18日摘心对苗木的增粗效果最佳。     

山核桃投产林林下套种绿肥效应

为增加山核桃投产林林下植被覆盖度、提高林地水土保持效果,增加土壤肥力,2008—2009年开展了山核桃林下套种1年生黑麦草、多年生黑麦草、白三叶、红三叶以及紫花苜蓿等5种绿肥,对其生物量、土壤有机质、林下昆虫多样性、果实产量和品质的影响进行研究(清耕为对照)。结果表明:(1)林下套种绿肥显著增加林下植被生物量,以1年生黑麦草效果为好,鲜质量和干质量分别达到55 000和9 420 kg/hm2,套种白三叶使土壤有机质增加了2.3 g/kg;(2)林下套种绿肥有利于增加害虫天敌数量和减少害虫密度,其中主要害虫山核桃蚜虫、山核桃花蕾蛆等害虫密度分别降低了57.14%和36.45%;(3)林下套种绿肥显著提高山核桃产量,套种平均产量为821.55kg/hm2,较对照增加12.46%,套种后果品品质也明显提高;(4)综合评价5种套种绿肥的效果后认为,山核桃林下以套种白三叶、1年生黑麦草和多年生黑麦草较好。     

配比施肥对薄壳山核桃幼苗生长和生理特性的影响

【目的】探究不同氮磷钾配比施肥对薄壳山核桃幼苗生理生长的影响,以期找出适合薄壳山核桃幼苗生长的一套施肥方案。【方法】以薄壳山核桃一年生品种‘马罕’(Mahan)嫁接苗为试验材料,采用土壤盆栽试验,根据L9(34)正交试验设计,进行3因子(N、P、K)3水平(N,4 g/株;P,2 g/株;K,1 g/株。N,6 g/株;P,3 g/株;K,3 g/株。N,8 g/株;P,4 g/株;K,5 g/株)配比施肥试验,以不施肥为对照,研究不同处理对薄壳山核桃幼苗生长(苗高、地径、生物量)及生理特性(可溶性糖、可溶性蛋白质、谷氨酰胺合成酶和硝酸还原酶)的影响。【结果】氮(N)、磷(P)、钾(K)对薄壳山核桃的生长指标影响效应为N K P;氮肥对苗高影响显著,平均高出对照(CK)39.13%;氮肥对地径也有显著影响,平均高出对照26.01%;氮肥和钾肥对幼苗地上生物量和地下生物量的影响显著,分别平均高出对照9.32%和45.27%。氮和磷对可溶性蛋白影响显著,平均高出对照19.25%;氮、磷、钾均对可溶性糖有显著影响,平均高出对照15.19%;氮对谷氨酰胺合成酶影响显著,平均高出对照72.79%;氮对硝酸还原酶也具有显著影响,平均高出对照32.1%。【结论】合理的配比施肥能够显著促进薄壳山核桃幼苗生长,同时也提高了主要碳氮代谢物的含量和关键酶的活性。     

施肥对雷竹光合特性及笋产量与品质的影响

在闽北开展雷竹施肥试验，设置4种施肥处理：不施肥对照(处理1)，施用氮磷钾复合肥(375kg/667m²，处理2)，施用有机肥(腐熟的鸡粪5t/667m²，处理3)，施用有机肥与氮磷钾复合肥(腐熟的鸡粪3t/667m²和氮磷钾复合肥150kg/667m²，处理4)，分析不同施肥处理对雷竹叶片光合色素含量、光合特性、竹林生长、笋产量和品质等的影响，筛选出适合闽北雷竹经营的优化施肥方案。结果表明：不同施肥处理对雷竹叶片光合色素含量的影响未达到显著差异水平，但对竹林的光合特性、生长量、笋产量和笋营养物质含量均产生显著性差异影响；光合特性指标表现最优的是处理3和处理4，竹林生长效果最好的为处理2和处理4，竹笋产量和笋品质表现最优的是处理4和处理3。综合分析认为，最优施肥方案为处理4，即施用有机肥(腐熟的鸡粪)3t/667m²+氮磷钾复合肥150kg/667m²，该施肥处理可有效提升雷竹光合作用效率、促进竹林生长、增加竹笋产量及提高竹笋营养价值。     

不同措施对皖南地区薄壳山核桃育苗的影响

为探索播种时间、裸根苗套袋及拉枝角度对皖南地区薄壳山核桃苗木生长的影响,以不同品种和树龄的薄壳山核桃为试验材料,对比不同播种时间、裸根苗整株套袋处理、拉枝角度等处理中薄壳山核桃的生长量、成活率、结果短枝数量。结果表明:(1)冬播覆膜对种子出苗率无显著影响,对幼苗生长量有显著影响,冬播覆膜措施下的1年生苗地径比春播粗2.18 mm,苗高比春播高38.5 cm;(2)薄壳山核桃裸根苗移栽整株套袋处理的成活率与对照组间存在显著差异,整株套袋提高了裸根苗移栽的成活率;(3)薄壳山核桃拉枝角度为45°时与拉枝角度65°、85°和105°处理的平均结果短枝数均存在显著差异,拉枝角度在85°时结果短枝数最多。即薄壳山核桃冬播生长量比春播生长量大,裸根苗移栽套袋处理的成活率增加,拉枝角度处于85°短枝数最多。     

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.