枣果外销潜力巨大

枣树栽培在我国已有4000多年历史，品种达700多种，分布很广。目前，枣树栽培在全国有700多万亩，其中秦、晋、豫、冀、鲁五大枣区栽培的枣树占总面积的90％。全国栽培的主导枣树品种为制干和加工品种，鲜食型较少。枣果营养丰富，美味可口，又可人药，枣果的食疗保健功能世人皆知。枣果还是食品加工的重要原料。据有关资料介绍，2000年全国枣果总产约80万吨，占世界总产量的98％。除韩国仅有1．5万亩枣树规模栽培和总产2万吨枣果外，我国几乎是独家生产供应出口国。我国原枣及加工品年出口量9000吨左右，仅占总产量的2％，其中原枣出口约占出口总量的一半。     

枣果外销潜力巨大

枣树栽培在我国已有4000多年历史,品种达700多种,分布很广。目前,枣树栽培在全国有700多万亩,其中秦、晋、豫、冀、鲁五大枣区栽培的枣树占总面积的90％。全国栽培的主导枣树品种为制干和加工品种,鲜食型较少。枣果营养丰富,美味可口,又可入药,枣果的食疗保健功能世人皆知。枣果还是食品加工的重要原料。据有关资料介绍,2000 年全国枣果总产约80万吨,占世界总产量的98％。除韩国仅有1．5万亩枣树规模栽培和总产2万吨枣果外,我国几乎是独家生产供应出口国。我国原枣及加工品年出口量9000吨左右,仅占总产量的2％,其中原枣出口约占出口总量的一半。销往日本、韩国、新加坡和我国港澳地区的原枣及加工成品量占出口总量的80％-90％,原枣的出口主要为制干枣果,鲜食枣果出口量极少。在国际市场上,1吨鲜枣相当于30吨苹果或10吨核桃的售价,货源奇缺,供不应求。天津大港冬枣每公斤售价36美元、香港346元人民币,欧美市场每个枣果售价1美元。事实说明,大力发展鲜食枣果出口的潜力很大,商机不容置疑。     

发展枣业遇良机

枣树原产我国，目前世界上除韩国有1.5万亩枣林，年产2000万公斤枣果外，其他国家还没有规模栽植。我国的枣树栽培面积700万亩，年产鲜枣8亿公斤，占世界总产量的98％，是我国特有的传统出口商品。枣果味美，营养丰富，富含蛋白质和脂肪，还含有钙、铁、磷等矿物质和维生素，具有滋阴补肾、强身健体、软化血管、开胃健脾等多项功能，有“百果之王”的美称。鲜枣维生素C的含量，是柑桔的10倍、香蕉的60倍、苹果的70～80倍，日本人称枣果为“活维生素丸”。枣果除鲜食，还可制干和深加工，其主要名贵品种有河北赞皇的金丝大枣、山东乐陵的金…     

枣树栽培与管理

枣树原产于我国,已有3000多年的栽培历史。枣树易繁殖,抗性强,结果早,经济价值高。枣的营养成分丰富,据调查每百克果肉含维生素C380-600毫克,高于柑桔10倍、苹果80倍。鲜枣含糖25-35%左右。枣可以入药,枣肉含有卢丁,对高血压有疗效。枣木坚硬,纹理细致,是国防或民用良材。枣是我国传统的出口商品,深受国际市场的欢迎。一、枣树的种类及特性枣树品种繁多,主要优良品种有:园铃枣、灰枣、泗洪沙枣、九月寒、冷枣、马枣、义乌枣、团枣等10余种。枣树在我国分布甚广,除了较为严寒地区外,其他地区均有栽培。枣树根系发达,水平根系长10米左右,分布…     

大力发展枣树生产快速培育无毒种苗

枣树是我国特有的经济树种之一。我国的枣树分布在东经76度至124度，北纬23度至42度范围内的平原、沙滩、盐碱地、山丘及高原地带。我国枣树形成两大栽培区。一是北方栽培区，指秦岭、淮河以北地区，主要集中在山东、河北、山西、陕西、河南五省。南方栽培区位于秦岭、淮河以南，包括湘、鄂、浙、粤、苏、川、因等省。枣果营养丰富，是很好的滋补食品，平均含糖率鲜枣为25％～43．9％，干枣50．3％～86．9％。平均每百克鲜枣果内含蛋白质3．3g，脂肪0．3g，钙41mg，磷23mg，铁0．5mg以及各种氨基酸0．4～0．6mg。枣果除含有维生素A、B外，…     

种枣应选好品种

发展枣树生产是振兴陕北黄河沿岸及渭北贫困地区经济的重要途径,现已形成共识。今就我省红枣生产现状作一简要概述。 近几年我省红枣生产有了长足发展 枣原产我国,黄河中游晋陕峡谷是其发源地。枣在我省栽培历史十分悠久,除部分高寒地区外,广为分布,但集中栽培区有三大     

枣果外销 潜力巨大

枣树栽培在我国已有4000多年历史，品种达700多种，分布很广。日前，枣树栽培在全国有700多万亩．其中秦、晋、豫、冀、鲁五大枣区栽培的枣树占总面积的90％。全国栽培的主导枣树品种为制干和加工品种，鲜食型较少。枣果营养丰富，美味可口，又可入药，枣果的食疗保健功能世人皆知。     

甘肃省枣树的科学栽培

<正> 枣(Zizyphus jujuba Mill)原产我国,已有3000多年的栽培历史。枣果营养丰富,是良好的滋补果品,除鲜食、制干外,还可加工成蜜枣、枣酱、枣汁等产品。此外,枣树抗逆性强,可作防风、固沙树种,防止水土流失,是西北地区良好的经济、生态两用树种。 甘肃省枣树分布广且历史悠久,当地品种主要有分布于陇东黄土高原的晋枣、马牙枣、夏枣、天水     

枣树丰产栽培十项技术

枣树具有结果早、适应性强、易繁殖、寿命长等特点,栽培范围极为广泛.大枣营养丰富,还有滋补安神作用,除鲜食外,还可制成干枣、蜜枣、枣糕、枣泥等多种食品.栽培枣树是发展经济致富农民的重要途径.现将栽培管理技术概述如下:     

新疆6个红枣鲜食品种果实生长发育规律调查

正枣为鼠李科枣属,有3 000多年的栽培历史。枣一直与我国古代人们的生活息息相关,既有丰富的营养价值,又在博大精深的传统中医学中大显身手。枣树是我国重要落叶果树种类之一,已被公认为是世界性独有树种,全球所消费枣产品的99%来源于我国。枣树为温带作物,适应性强,素有"铁杆庄稼"之     

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.