Impact of tree species on nutrient stocks in the forest floors of a temperate forest ecosystem

To investigate the effect of silvicultural methods on forest floor C, N and elements stocks an experiment was carried out by sampling the forest floors of a 100-120-years-old species including beech, Norway spruce and mixed beech-spruce at the Solling forest, Germany. While the stocks of carbon and nitrogen in the forest floors of pure beech and spruce were significantly influenced by species specific differences of litter quality (p < 0.001), no significant differences were detected between pure and mixed species stands. Forest floor mass, some elements concentrations and C/nutrient ratios were significantly affected by tree species differences, while no clear dependency between pH and site specific effects was found among pure stands. Acid element concentrations in the forest floors of pure spruce were remarkably higher than the values obtained at beech stand, while the stocks were to some extent modified in mixed silviculture. The base-pump effect of beech significantly controlled variation between mono cultures on calcium stocks, while the acidifying effect of spruce in mixtures resulted in modification of Ca stocks of forest floors. The status of other nutrient elements at mixed species cultures due to variation in nutritional properties and composition of litter compared to pure species were between the range of values observed in mono cultures.     

木论自然保护区森林土壤的理化特性

按木论自然保护区森林植被分布状况及相应海拔高度设置代表性的土壤剖面（0-80 cm土层）,按国颁标准采集样品与测定土壤理化特性。结果表明：（1）土壤容重为0.86-1.38 g.cm-3;土壤总孔隙度为27.66%-44.14%,其中土壤非毛管孔隙度为4.98%-13.22%;土壤通气度为4.67%-13.08%。（2）土壤pH值为6.03-7.45;有机质含量为13.9-120.3g.kg-1;全N为0.81-3.74 g.kg-1;全P为0.21-0.78 g.kg-1;全K为11.62-22.54 g.kg-1。以上表明,广西木论自然保护区森林土壤疏松、通气性能良好;土壤中N、P、K主要养分含量丰富。     

Satellite images as a tool to identify accelerated atrazine mineralization in soils

Microflora adaptation to atrazine (6-chloro-N²-ethyl-N⁴-isopropyl-1,3,5-triazine-2,4-diamine) mineralization due to its frequent use on the same soil has been clearly demonstrated. Studies show accelerated herbicide mineralization with mineralization percentages reaching up to 60% of the applied atrazine in a few days, which results in decreased weed control efficiency. Frequently, atrazine doses are increased to circumvent low efficiency, although this solution does not solve accelerated atrazine mineralization. The identification of soils with accelerated atrazine mineralization to guide selection of adequate management strategies and achieve good atrazine performance in adapted soils is critical. The present research assessed accelerated atrazine mineralization recognition on the basis of previous years maize (Zea mays L.) cropping as an indicator of atrazine use identified using satellite images. Three years of crop sequences were monitored by visual interpretation of Landsat satellite images. Bands 3, 4, and 5 were evaluated and corresponded, respectively, to red, near infrared, and mid-infrared. Vegetation was distinguished by selecting the R:4 G:5 B:3 color composition. Prior to assessment, atrazine behavior was evaluated in soils with high (S_H) and low (S_L) atrazine mineralization capacity. ¹⁴C-ring-labeled atrazine distribution between extractable, non-extractable, and mineralized soil culture fractions was subject to monitoring. Atrazine mineralization was determined by soil laboratory incubation. These included some soils of known past use and others with history predicted by satellite imagery. Topsoil (0-10 cm) samples were extracted according to two soil sampling strategies: Type A sampling (designated site A) consisted of 25 topsoil samples with known history, and type B sampling (designated site B) comprised 20 topsoil samples from history inferred via satellite imagery.Atrazine mineralization was monitored for 23 days under laboratory conditions. Soil ¹⁴C applied mineralization ranged from 0.3-73.0% and 0.2-30.0% in sites A and B, respectively. These broad ranges were closely related to maize presence/absence in the crop rotation at both sites. Following three straight growing seasons of maize, atrazine mineralization capacity reached a plateau in site A soils, with similar results observed in site B soils. This pattern suggests that satellite image information will be of utility to soil managers in selecting strategies to improve atrazine efficiency, including simultaneous fertilization, post-emergence atrazine applications, and choice of maize hybrids based on canopy architecture and weed competitiveness.     

Net ecosystem production and carbon dioxide fluxes in the Scheldt estuarine plume

Background  

A time series of 4 consecutive years of measurements of the partial pressure of CO₂ (pCO₂) in the Scheldt estuarine plume is used here to estimate net ecosystem production (NEP).     

The relationship between the rate of melatonin excretion and sleep consolidation for locomotive engineers in natural sleep settings

Background  

The aim of the study was to examine the role that melatonin production plays in the regulation of sleep consolidation in a population of shiftworkers working and sleeping in their natural environments.     

福州市森林旅游资源现状及森林生态旅游可持续发展探析

对福州市森林旅游资源现状和特点进行阐述,分析当前福州地区森林旅游开发、利用过程中存在的生态环境问题,提出福州地区森林生态旅游业可持续发展的几点建议。     

植物生物刺激剂对茶树重要酶系统和生化成份的调节

研究表明植物生物刺激剂(Plant biostimulants)茉莉酸酯、水杨酸、氨基丁酸、超敏蛋白、油菜素内酯、甲壳素对茶树新梢重要酶系统和主要生化成分的生成有一定调控作用。每一种植物生物刺激剂可以上调1-3种酶的活性,茉莉酸酯处理上调过氧化物酶(POD)、超氧化物歧化酶(SOD)活性,水杨酸处理上调多酚氧化酶(PPO)、过氧化物酶(POD)、超氧化物歧化酶(SOD)活性,β-氨基丁酸处理过氧化氢酶(CAT)活性升高,超敏蛋白处理CAT,SOD活性上升,甲壳素处理PPO活性上升,但在上述物质作用下苯丙氨酸解氨酶(PAL)活性有所下降或基本不变。施用植物生物刺激剂后儿茶素含量升高,EGCG尤为明显,一般增加45.66%-107.2%。茉莉酸酯、水杨酸处理新梢氨基酸总量提高29.18%-33.61%,甲壳素处理后氨基酸总量下降5.72%,而氨基丁酸处理的总氨基酸减少了51.28%,但氨基丁酸处理的样品精氨酸增加了42.78%。本试验条件下茉莉酸处理后挥发物总量微有增加(+2.11%),水杨酸处理总量减少22.72%,其它处理减少3.79%-13.43%。但单一组分里青叶醇及其酯类(2-H...     

Voles,trees, and woody debris structures as habitat: Balancing forest crop protection and biodiversity

Relatively homogeneous early successional habitats develop after clearcutting and wildfire that voles of the genera Microtus and Myodes may colonize and generate population fluctuations. In these habitats, vole populations may reach pest status by their feeding on newly planted tree seedlings. Strategic management of excess woody debris into piles and windrows helps diversify new clearcuts by enhancing populations of forest-floor small mammals, including voles, and some of their predators.This study tested the hypotheses (H) that (H₁) abundance of voles and incidence of feeding damage to tree seedlings will be higher in windrow than dispersed (conventional) sites of woody debris, and (H₂) there will be a gradient of damage with the highest incidence immediately adjacent to windrows. A third hypothesis (H₃) predicts that feeding damage to trees will increase in relation to windrow size. Microtus voles and red-backed voles (Myodes gapperi) were live-trapped for three years (2010–2012) in replicated sites with woody debris dispersed and in windrows at three study areas in the southern interior of British Columbia, Canada. Incidence of feeding damage and mortality to tree seedlings by voles was measured in all sites. Mean abundance of M. gapperi, Microtus, and total voles were all significantly (P ≤ 0.04) higher (up to 3.4 times) in windrow than dispersed sites, and hence the abundance part of H₁ was supported. Mean annual percentage of trees damaged by voles was significantly (P ≤ 0.03) higher in windrow than dispersed sites over the two winters and for cumulative incidence of damage, and hence the tree damage part of H₁ was supported. Mortality of trees followed this pattern but was not formally significant. Trees planted immediately adjacent to a windrow had significantly (P < 0.01) greater feeding damage than seedlings planted further away, and hence H₂ was supported. There were significant linear relationships between mean percentage of trees killed (r = 0.67; P < 0.01) and mean number of total voles, and also with mean volume of woody debris per meter length of windrow (r = 0.98; P < 0.01). Thus, H₃ was also supported. To minimize overall mortality of trees, it is likely worthwhile to not plant trees near windrows. Slightly reduced stocking (<5% net forest area) and potential loss of some trees to voles need to be balanced alongside biodiversity and conservation considerations provided by woody debris structures.     

永定县林权制度改革后林业经营方式的变化

林权制度改革对提高林农的生产积极性及提高林农收入具有积极的作用。通过分析永定县林权制度改革后林业经营方式的变化，探讨了其改革成效及存在问题，并提出了解决对策。     

茶园人工生态群落系统生态功能研究

根据生态学原理，采用定点定位方法对茶园人工生态群落系统生态功能的优良性，系统的能值和蒸散力以及光效能与生物信息进行了研究。结果表明：茶园人工生态群落系统具有良好的生态功能。具体表现为茶园人工生态群落系统光效能、土壤肥力能值、系统蒸散力、系统有益生物信息较纯茶园分别提高40．8％．55．34％、76．34％、16．07％，系统有益生物信息量大幅度增加，抑制了病虫的发生。     

20世纪40年代以来中国大面积种植大豆品种的系谱分析

根据种植面积筛选出20世纪40年代以来我国东北和黄淮海地区大面积种植的大豆品种113份,通过系谱分析,归纳出大面积种植品种的直接亲本和祖先亲本.结果表明,大面积种植品种比普通品种拥有更多的祖先亲本,遗传基础更丰富;新近育成的大面积种植品种比早期育成的大面积种植品种遗传基础更丰富;黄淮海地区大面积种植品种比东北地区大面积种植品种的遗传基础更为丰富.以大面积种植品种作为“平台亲本”培育的新品种更容易在生产上种植应用,更有希望成为新的大面积种植品种.各生态区间的种质交流还有待于进一步加强.     

Life strategies and spatial arrangement of grasses in a Mediterranean ecosystem in Greece

The temporal and spatial distribution, and the life strategies, of fifteen grass species in a Mediterranean evergreen sclerophyllous formation at Petralona (Chalkidiki, Greece) were studied in order to identify the relationships between species, and among species and the environment, which allows for the coexistence of species. The grass species were grouped into (i) early annual species that were characterized by early germination and a relatively long growth period; they did not need excessive resources and were distributed over the entire site, (ii) late annuals that were characterized by late germination and a short growth period; they required resources within this limited period and were competitive in capturing them and so were confined to the most productive sites of the site and (iii) perennial grasses that were characterized by early germination and vegetative reproduction; they were tolerant to nutrient shortages and hence maintained their distribution on the site. The spatial arrangement of species can be considered as a response to the selective pressures of the seasonal water and resource availability in a Mediterranean environment. This environment posed temporal limitations on the activity of early annual and late annual species, which restricts them in time and space. The perennial species overcame this by being flexible in their resource capture and use, because of their ability to store nutrients.     

2000年浙江茶叶大事回顾

1.全年茶叶量减价增,名优茶持续增长 2000年浙江茶叶生产保持了稳产增值的良好发展势头.全年茶叶生产总的特点是:春茶开采推迟,采摘洪峰集中,大宗茶形势欠佳,名优茶持续增长,有机茶发展迅猛,蒸青茶快速发展,整个茶叶产销形势稳中有升.据业务部门统计,全省茶叶总产量11.0万t,比上年减少6.5%;茶叶总产值22.8亿元,比上年增加1.9%.其中名优茶产量2.8万t,比上年增产13.8%;名优茶产值17.4亿元,比上年增加20.0%;名优茶产量、产值分别占茶叶总产量、总产值的25.4%和76.3%.     

Bovine liver abscesses pus and the status of some important minerals

This research was conducted to determine selenium, copper, zinc, iron, calcium, phosphorous and magnesium concentration in the pus of cow liver abscess. The liver has a large reserve of function and approximately three-quarters of its parenchyma must be rendered inactive before clinical signs of hepatic dysfunction appear. Local suppurative infections of the liver cause significant losses in feedlot and grain-fed cattle because of the frequency ofrumenitis in those cattle leading to hepatic abscess formation. Also we know some minerals that can alter and uphold the specific immunity. At the presence of adequate amount of zinc, the formation of hepatic abscess may reduce. For this reason and to determine the mineral concentration in pus, the present study was designed on 40 slaughtered cattle with liver abscess in Shahrekord district. For measuring the minerals concentration, Potentiometric Stripping Analyzer (PSA), atomic absorption spectrometry were used. Results showed that the concentration of Se, Zn, Fe, Cu, Ca, P and Mg in pus were 0.551A+/-0.046 (mg kg(-1)), 6.41A+/-2.32 (mg kg(-1)), 18.18A+/-14.03 (mg kg(-1)), 6.63A+/-4.83 (mg kg(-1)), 221.8A+/-85.82 (mg kg(-1)), 0.85A+/-0.32 (g kg(-1)) and 40.64A+/-21.72 (mg kg(-1)), respectively. The concentration of mentioned minerals in liver parenchyma's were determined 1.06A+/-0.15 (mg kg(-1)), 82.91A+/-32.22 (mg kg(-1)), 62.29A+/-22.12 (mg kg(-1)), 39.22A+/-28.17 (mg kg(-1)), 0.12A+/-0.04 (g kg(-1)), 1.81A+/-0.56 (g kg(-1)) and 0.15A+/-0.07 (g kg(-1)), respectively. For determining the correlation between mineral concentration in pus and liver parenchyma, Pearson correlation was used at The level of p<0.05. The correlation between pus Fe and Cu and also Ca and Se were significantly positive (pvalue = 0.000228, r = +0.871) and negative (pvalue = 0.0305, r = -0.623), respectively. In liver parenchyma the correlation between Zn and Ca (pvalue = 0.0487, r = 0.535) and also Fe and Cu (pvalue = 0.0317, r = +0.596) were significantly positive.     

优化农业产业结构调整实施重大技术研究项目 --写在农业结构调整2004年大豆项目验收会之中

依据国内大豆农业产业品种、技术、人才及市场四大优势，对国内外大豆农业产业的现状进行了科学地分析，所确定的三个专项课题全面地代表了目前存在的共性和个性问题，抓住了关键技术和创新点，合理地确定了项目合同指标，为全面完成工作任务打下了坚实地基础。     

Non-symbiotic nitrogen fixation in some soils of England and Wales

The acetylene-reduction method was used to estimate the fixation of atmospheric nitrogen by non-symbiotic micro-organisms in soils from England and Wales. Significant fixation was found only in the surface horizon of the soil (0–1 cm) and was much higher in the light than in the dark. The highest rates were found with samples having a well-developed surface film of blue-green algae and were from 6 to 10 g ha^?1 N per h. Generally, rates were very much lower. The addition of fertilizer nitrogen at 100 kg ha^?1 markedly reduced N fixation by blue-green algae.