抚顺地区橡实生物能源开发利用对策

抚顺橡实资源非常丰富,据统计,抚顺地区柞树总面积33万hm2,蓄积2519万m3,每年橡子产量可达20万t。橡实营养丰富,橡实开发利用的前景十分广阔。对橡仁、橡壳进行综合利用,可以生产出淀粉、色素及一系列副产品,同时还可以将橡实淀粉加工成生物能源,从而提高产品的科技含量和经济价值。针对抚顺地区橡实资源利用的现状,提出了旨在充分发挥资源优势、扩大利用规模、提高经济效益的开发利用的对策。     

蒙古栎乙醇原料林不同种源橡实成分分析

通过对黑龙江省各种源蒙古栎橡仁淀粉、可溶性糖、粗纤维、单宁、蛋白质、脂肪、灰分和橡壳中糠醛和活性炭等成分含量的比较分析,结果表明:不同种源蒙古栎橡实各物质成分含量存在显著差异,综合比较,初步确定林口、绥阳和桦南等种源橡实中可制乙醇物质含量高,为优良种源。     

蒙古栎乙醇燃料林不同家系橡实商品性状分析

以蒙古栎非粮乙醇燃料林培育为目的,对收集的66株蒙古栎优树的橡仁淀粉、可溶性糖、粗纤维、蛋白质、脂肪、单宁和灰分,橡壳糠醛和活性炭等成分指标进行分析,结果表明:不同家系蒙古栎橡实各项成分指标存在着显著的差异。以可制乙醇物质总量、单宁、脂肪含量、橡壳单位重量可制活性炭重量为主要考核指标对各家系进行聚类分析,初步确定TL-1、HS-1、HS-2、HS-3、HS-4、SY-1、SY-2、SY-3、SY-5、SY-6、SY-6、SY-7、SY-8、SY-9、HN-6和DJC-5为优良家系。     

小陇山林区橡树资源及其开发利用研究

甘肃省小陇山林区橡树种类较多，分布广，资源丰富，是本林区的主要建群树种。橡仁富含淀粉，橡碗富含单宁，可多层次深度开发，其废弃物还可综合利用。通过对小陇山壳斗科栎属植物资源详细的调查，摸清了资源现状及橡树叶、籽、壳、碗产量，提出了橡树资源开发利用对策。     

蒙古栎燃料乙醇原料林不同家系橡实成分分析1）

以蒙古栎燃料乙醇原料林为培育目标,对所收集的33株蒙古栎优树的橡仁淀粉、可溶性糖、粗纤维、蛋白质、脂肪、单宁和灰分等7种成分进行分析,结果表明：不同蒙古栎家系的橡仁成分有明显差别。其中的淀粉含量和可溶性糖含量具有明显的负相关关系。通过此项研究,为蒙古栎乙醇原料林良种选育提供了橡实成分指标选择的基础数据。     

安徽省橡实资源及其开发利用

橡实是泛指除大量栽培种板栗以外的壳斗科Fagaceae植物种子的总称。我省橡实资源丰富，尤其是橡仁含有丰富的营养成分，但大都没有开发利用；作者分析了麻栗、栓皮栎、茅栗、青冈栎等多个树种果仁的淀粉含量与油脂含量，并提出充分发挥该类资源优势、扩大利用规模、提高经济效益的开发利用的对策。     

蒙古栎乙醇原料林不同家系橡实形质指标分析

通过对在黑龙江省所收集的65株蒙古栎优树橡实长、宽、重、橡实壳厚、橡实仁重、千粒重等形质指标和播种品质分析,结果表明:各优树蒙古栎橡实的长、宽、单果重、橡壳厚、仁重、千粒重等形态指标和播种品质指标在95%的水平上都存在着显著的差异。各优树间在蒙古栎橡实形态指标表现出了高纬度、高海拔橡实果小、轻、壳厚。而低纬度、低海拔橡实果大、重、壳薄的变化趋势。所以初步确定HN-3、HN-4、HN-5、HN-6、HN-7、HS-1、HS-2、HS-3、HS-4、DJC-8、SY-1、SY-2、SY-5、SY-8、SY-10、BA-1为优良家系。     

湖南省主要橡子资源综合开发利用的研究

湖南省橡子植物种类较多,资源丰富,在全省均有分布,且多集中于丘陵山区.橡仁富含淀粉,橡碗富含单宁,可多层次深度开发,其废弃物还可综合利用.橡子在无公害天然保健食品的开发方面具有良好的市场前景.目前,湖南省橡子资源一方面利用率极低,一方面原料供应紧张,没有形成规模;现有开发利用手段落后,新产品开发严重不足,经济效益低下.为此,提出了旨在充分发挥资源潜力,扩大利用规模,提高利用效益的开发利用建议.     

橡实淀粉可食用性技术的研究

以单宁含量较高的栓皮栎为原料,对橡实淀粉可食用性进行了研究。结果表明:橡实淀粉经过脱苦和脱色处理后能够达到淀粉的食用标准。比较常规水浸提法、超声波助提法和微波助提法等3种方法对单宁脱出效果的影响表明,超声波辅助水浸提法在45℃下脱苦60 h效果较好;正交试验结果表明超声波辅助脱色法效果最佳,橡实淀粉脱色工艺条件为:超声波频率为82.5 kHz、换水3次、温度45℃、时间7 h。     

马尾松飞播林地土壤微生物的研究

为了探讨湘南丘陵低山区马尾松飞播林地土壤微生物的分布规律和土壤肥力综合评价方法 ,于 2 0 0 0年 12月 2 0日采集到湖南醴陵市大林乡 5个马尾松飞播林标准林地土壤样品和 1个阔叶林地土壤样品 ,分析其土壤微生物的数量及其类群分布规律 .结果表明 :马尾松飞播林地土壤微生物数量 (以干土计 )主要集中在 0～ 2 0 cm的表土层中 ,随土层加深 ,其数量迅速减少 ;在深度为 0～ 60 cm的土层中 ,同一类群的微生物数量变动范围较大 ,其中好气性细菌为 2 .46× 10 5～ 6.48× 10 5个 /g,厌气性细菌为 1.14× 10 3～ 8.8× 10 3个 /g,自生固氮菌为 1.3× 10 2～ 3 .0 1× 10 4个 /g,放线菌为 8.6× 10 3～ 2 .99× 10 4个 /g,真菌为 6.6× 10 3～ 2 .43 5× 10 5个 /g.其中 1号样地微生物数量最多 ,达 2 .45× 10 6个 /g,说明混交林中微生物数量很丰富     

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.     

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.     

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.     

Biogeochemical impacts of clearfelling and reforestation on blanket-peatland streams: II. major ions and dissolved organic carbon

Streams and drains in blanket-peatland forest in western Ireland were sampled weekly over 5 years, 1996–2000, using continuous, depth-proportional passive sampling. Analysis was for pH, alkalinity by Gran titration, anions by IC, metals by ICP, aluminium speciation by loaded-resin exchange, and dissolved organic carbon (DOC) by absorbance at 320 nm.

Effects of felling are identified graphically from two forest drains whose catchments (both about 1 ha) were clearfelled, and partial clearfelling of one larger catchment (somewhat over 1 km²), in summer 1999. Calcium concentrations and alkalinity were increased in the drain- and streamwater from the felled areas. The pH was increased in drains, while in the larger stream, pH range decreased while the mean increased. Phosphorus increased markedly with clearfell, in the absence of recent fertilising, and also increased with fertilising; these results are reported in an accompanying paper. Ammonium-nitrogen concentrations were increased in the two drains with felling, and temporarily decreased in the larger stream. Nitrate increased in some cases. Potassium and manganese concentrations also increased. Concentrations of DOC and organic monomeric aluminium increased gradually, subject to a continuing strong annual cycle. There were no clearfelling effects on concentrations of solphate, suspended solids or inorganic monomeric aluminium. In the two drains (fully clearfelled), concentrations of sodium, chloride and magnesium, and conductivity, were all reduced after felling. Fertilising effects other than for phosphorus were indistinct.

Effects of the combined clearfell–reforestation treatment were testable statistically, using randomised intervention analysis, between two larger streams (1 km²) as a treatment–control comparison. There were statistically significant positive responses in streamwater concentrations of nitrate, potassium, calcium, DOC and aluminium fractions. The implications for management practice depend on whether the loss of nutrients is sustainable for future crop productivity, and whether critical limits and loads of receiving ecosystems are exceeded.     

Effect of Drought on Growth and Mortality of Actively Growing Norway Spruce Container Seedlings Planted in Summer

Survival, root egress and height growth of 13-month-old actively growing Norway spruce ( Picea abies (L.) Karst.) container seedlings exposed to preplanting drying treatments (0, 4, and 8 days) and postplanting drought periods (1, 2, 3, and 4 weeks) were studied in the field between 5 July and 18 August 1999. The mortality of seedlings increased and the height growth and root egress decreased throughout the postplanting drought period. Postplanting performance was also affected by preplanting drying treatments. The results indicate that no risk of excessive mortality and growth restrictions occurs when actively growing seedlings are planted in summer, provided that seedlings are well watered before planting and the drought period does not exceed 3 weeks.     

Rehabilitation of diseased cacao fields in Peru through shade regulation and timing of biocontrol measures

The objective of this case study was to test the effectiveness of biocontrol for the rehabilitation of abandoned, diseased (moniliasis, witches' broom and black pod) cocoa and to develop testable hypotheses regarding the effect of shade and biocontrol timing. Three trial fields differed in their shade regimes. Biocontrol was administered starting either at flowering or pod filling. Disease incidence and yield were compared with cultural control alone. Biocontrol reduced moniliasis from 49% to 25%, independent of the shading regime and application time. Witches' broom was most severe without shade and unaffected by biocontrol. No significant effects on black pod were observed. Although biocontrol increased percentage healthy fruit independent of shading and timing, only the shaded plot with biocontrol from flowering onwards responded with increased yield. Our hypothesis is: 'In the rehabilitation of abandoned cacao, only fields under sustainable shade management and early onset of biocontrol can realise their production potential.' This revised version was published online in June 2006 with corrections to the Cover Date.     

qPCR quantification of Ophiognomonia clavigignenti‐juglandacearum from infected butternut trees under different release treatments

The use of a molecular assay for quantifying conidia of Ophiognomonia clavigignenti‐juglandacearum, the fungal pathogen responsible of butternut canker, was investigated. Purified DNA from conidia collected on glass fibre filters of a passive rain collectors was quantified using a TaqMan real‐time quantitative polymerase chain reaction (qPCR) assay. The qPCR assay could specifically discriminate the target species from all other North American known species of Ophiognomonia, and it was sensitive enough to repeatedly detect one conidium. A linear relationship between numbers of conidia and qPCR C_t values was determined, and used to assess the sporulation of the pathogen under trees that were released to promote their vigour. In total, 977 samples of field‐captured conidia from 49 trees, at two locations, and from two successive growing seasons were analysed. No significant difference of sporulation was observed under control and release treatments. However, our results demonstrated that qPCR assay was reliable for detecting and quantifying O. clavigignenti‐juglandacearum from environmental samples, which will be useful to assess further control methods for this disease.     

The potential of alley cropping in improvement of cultivation systems in the high rainfall areas of Zambia I. Chitemene and Fundikila

Three trials investigating the potential of alley cropping to improve the traditional systems of cultivation, chitemene and fundikila, in the Northern Province of Zambia are described. Flemingia congesta, Tephrosia vogelii, and Sesbania sesban, were grown in association with finger millet, groundnut, cowpea, and maize in various traditional cropping sequences. The indigenous species Tephrosia vogelii and Sesbania sesban were not able to withstand repeated pruning and the long following dry season, and were replaced with Calliandra calothyrsus, and Cassia spectabilis.Over a four year period, there was no benefit by alley cropping with any of the tree species on crop yields, and yields in alley crop treatments even dropped significantly below the control treatments in the fourth year, casting doubt on the potential of alley cropping for sustainable production. There was also no consistent effect on soil chemical characteristics in any of the trials. It was suggested that this lack of beneficial response to alley cropping was due to low tree biomass production low quality of prunings, and an inappropriate cropping sequence. There was no evidence that alley cropping contributed to enhanced nutrient recycling, despite substantial localised pools of soil nutrients, particularly in the chitemene, with which recycling could potentially occur.     

Toxicity of biocide GCSC-BtA on arthropod pests under different temperature conditions

The present research dealt with the toxicity of GCSC-BtA (Germany–China Scientific Cooperation-Bacillus thuringiensis-Abamectin), a new type biocide developed by conjugating a toxin from Bacillus thuringiensis (B.t.) with Abamectin from Streptomyces avermitilis, on arthropod pests under different temperature conditions. The results showed that GCSC-BtA possessed higher toxicity than B.t. crystal, Abamectin or Cypermethrin, with pest mortalities of 97.9, 93.7, 96.4, 82.3 and 96.7% for Tetranychus cinnabarinus (Boisd.) (Acari, Tetranychidae), Frankliniella occidentalis Pergande (Thys., Thripidae), Aphis fabae Scopoli (Hom., Aphididae), Plutella xylostella (L.) (Lep., Plutellidae) and Cameraria ohridella Deschka et Dimić (Lep., Gracillariidae), respectively. Toxicities of GCSC-BtA to T. cinnabarinus and P. xylostella decreased significantly at the older developmental stage with an exception that egg stage had the highest tolerance, in which LC₅₀s of GCSC-BtA were 0.0001, 0.0019 and 0.0708 mg/ml for nymph, adult and egg of T. cinnabarinus, and that 0.0399, 0.2035 and 0.9033 mg/ml for the 2nd instar larvae, 4th instar larvae and egg of P. xylostella, respectively. Also, the biocide was more effective to the lower stage of A. fabae than the higher one with LC₅₀s of 0.0023, 0.0086 and 0.0171 mg/ml against 1st instar nymph, 3rd instar nymph and adult, respectively. In general, toxicity of the new type of biocide was positively related to temperature against all the tested pests, except against T. cinnabarinus, where it was almost similar at the three temperature conditions. GCSC-BtA displayed significantly lower toxicities at 15/20°C than 20/25°C or 25/30°C against F. occidentalis, A. fabae, P. xylostella and C. ohridella. However, no significant difference was found in the toxicities against F. occidentalis, A. fabae and C. ohridella above 20°C, whereas toxicity against P. xylostella increased as temperature raised. Therefore, to achieve higher efficacy in the field, application rate and time should be devised according to these factors.