河南省黄河中游防护林体系建设与对策

在分析建设河南省黄河中游防护林体系的必要性和紧迫性的基础上,依据该区的自然状况及林业建设发展方向,将河南省黄河中游防护林体系建设划分为豫北太行山水源涵养林、水土保持林和经济林区,豫西黄土丘陵水土保持林区,豫西伏牛山北侧水源涵养林和水土保持林区,平原农田堤岸防护林区四大区,分别阐述了各区防护林体系建设的基本构想,并提出了防护林体系建设应采取的对策。     

蓟县黄土梁子小流域防护林现状与发展研究

根据京津地区目前所面临的生态环境问题,特别是京津地区风沙源防沙治沙工程所面临的技术难题,从防护林体系建设出发,以天津蓟县黄土梁子小流域为例,通过对水源涵养林、生态经济林、道路防护林和沟道防护林所组成的防护林体系进行现状分析,探讨了防护林体系所存在的问题,提出了相应的发展对策。     

水土保持规划中生态功能区的划分方法--以三川河流域为例

在某一区域布设水土保持措施时,主要依据该区域生态系统的结构状态和发展趋势、植物群落的层度和演替趋势来确定该区生态平衡的强度或生态脆弱的程度,依据各生态因子的优劣势及相互之间的因果关系寻找人类引导优势因子与改造恶劣因子的途径,从而确定水土保持生态工程建设通过改善恶劣环境因子、保护和开发优势因子、保护和促进植物群落演替,达到合理开发利用环境资源,促进生态环境向良性循环方向发展之目的。本文以三川河流域为例,根据生态功能区的划分原则,将其划分为:土石山天然水源涵养林预防保护区、土石山坡积黄土缓坡丘陵农林经济区、河谷川滩阶地农业经济区、黄土丘陵沟壑水土保持生态环境及生态农业经济重点建设区和黄土丘陵矿产资源开发水土保持监督区。     

东北黑土区和北方土石山区部分地区水土保持三级区划及其水土流失防治措施

按照全国水土保持规划任务分工,松辽委承担东北黑土区(Ⅰ)和北方土石山区(Ⅲ)中辽宁环渤海山地丘陵区(Ⅲ-1)的规划工作。综合分析后提出了水土保持三级区划原则和方法,在全国水土保持一、二级区划的基础上,将东北黑土区和北方土石山区部分地区划分为12个三级区,即大兴安岭山地水源涵养生态维护区、小兴安岭山地丘陵生态维护保土区、三江平原-兴凯湖生态维护农田防护区、长白山山地水源涵养减灾区、长白山山地丘陵水质维护保土区、东北漫川漫岗土壤保持区、松辽平原防沙农田防护区、大兴安岭东南低山丘陵土壤保持区、呼伦贝尔丘陵平原防沙生态维护区、辽河平原人居环境维护农田防护区、辽宁西部丘陵保土拦沙区、辽东半岛人居环境维护减灾区,并提出了各区的水土流失防治途径。     

宾县二龙山流域水土流失现状调查与分析

二龙山流域水土流失面积 11678 2hm2 ,其中强度侵蚀面积 2 12 1 5hm2 ,极强度侵蚀面积为 60 9 9hm2 。根据地形地貌、土壤、植被、降雨以及人口等特点 ,将二龙山流域分为低山丘陵水源涵养林微度水蚀区、丘陵台地农牧密集强度侵蚀区、矿脉沿线冶炼工程影响区、冲积平原景观旅游区等 4个侵蚀区域。分析了各区水土流失状况 ,并提出了防治建议。     

水源涵养林耗水、水文过程及其结构

现代科学技术和经济社会的发展,对水资源需求量和水质都提出新的需求,其数量和质量均严重影响着人们生活和生态环境。水量需求的增加和水环境的恶化,已成为制约社会经济发展的瓶颈因素,改善水资源紧缺和水质问题已成为全球关注的焦点。随着人们对以涵养水源为目的水源涵养林生态技术和工程重视,水源涵养技术研究已成为现代林业生态体系建设的重要组成部分。从水源涵养林耗水规律、水文作用过程、结构与功能三个方面介绍了国内外水源涵养林研究方法,为从事这一领域研究提供可借鉴的参考。     

东大河林区水源涵养林保育区划

植被保育区划是根据植被的自然环境、空间分布、演替趋势、健康状况以及影响因素综合划分的植被保育地域，是有效地保护天然林、促进森林植被进展演替、有效发挥森林生态服务功能、持续控制自然灾害、促进人与自然和谐、提供科学决策依据的方法和技术。利用森林资源规划设计调查的结果，在阐述植被保育区划的目的、原则和方法的基础上，将东大河林区水源涵养林划分为2个Ⅰ级区、6个Ⅱ级区、8个Ⅲ级区和29个Ⅳ级区，并提出了相应的保育措施。     

山西省水土保持功能区生态脆弱性评价

为了解山西省不同水土保持主导功能区生态脆弱性状况,利用全国水土保持区划成果及相关数据,采用主导因子分析、专家评判分析和层次分析相结合的方法,在评价山西省不同行政县（市）生态脆弱度的基础上,分析不同水土保持主导基础功能区生态脆弱性的分布特征,讨论山西省实施水土保持生态建设的重点区域及措施。结果表明：1）山西省不同水土保持主导基础功能区的生态脆弱性具有明显的差别,其脆弱程度表现为拦沙减沙区（强度脆弱）〉土壤保持区（中强度脆弱）〉防风固沙区（中度脆弱）〉蓄水保水区（轻中度脆弱）〉水源涵养区（轻度脆弱）;2）山西省的水土保持生态建设,在土壤保持-中强度脆弱区、拦沙减沙-强度脆弱区和防风固沙-中度脆弱区应以做好综合治理工作为重点;在蓄水保水-轻中度脆弱区和水源涵养-轻度脆弱区应重点做好预防保护和监督工作。     

广州市水土保持分区探讨

为做好与广东省水土保持的工作衔接,根据广州市具体情况和实际需要,在广东省水土保持分区(四级分区)的基础上进一步划分,提出广州市水土保持分区(五级分区),分别为:北部山地丘陵水源涵养生态维护区(Ⅰ区)、中部低山微丘土壤保持水源涵养区(Ⅱ区)、南部冲积平原人居环境水质维护区(Ⅲ区),并提出相应的水土保持防治需求及治理模式。     

调整朝阳市生态建设政策,加大林业投入力度

朝阳市现有水土流失面积16 046.66 km2,占全市总面积的86.5%。分析朝阳市水土流失现状,针对存在的问题,提出应调整朝阳市生态建设政策,加大林业投入力度。治理的重点:将高山远山石质山尽快封起来。以封为主,封、育、种、造相结合,实施生态修复。将所有只有坡面工程没有植树的地段,应尽量营造水土保持林或薪炭林。坡耕地营造农田水土保持林带。沟壑林业措施中,改工程防护为植物防护,沟底营造固沟林、水源涵养林。河滩按《防洪法》制定造林规划,实施河岸滩地防护林。预计到2020年,全市有林达100万hm2,森林覆被率达50%左右,使95%以上的水土流失面积得到治理和控制。     

低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响

【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。     

Pasture Vegetation Elemental Analysis by Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing.     

Faculty positions:Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Macroinvertebrates in North American tallgrass prairie soils: effects of fire, mowing, and fertilization on density and biomass

The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils.     

Variation in quality parameters between and within 14 Nordic tree fruit and berry species

Abstract

A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species.     

Potassium Fixation and Release Characteristics in Rhizosphere and Nonrhizosphere Soils for a Rapeseed–Rice Cropping Sequence

Potassium (K) fixation and release in soil are important factors in the long-term sustainability of a cropping system. Changes in K concentration and characteristics of K fixation and release in rhizosphere and nonrhizosphere soils in the rapeseed (Brassica napus L.)–rice (Oryza sativa L.) rotation were investigated using a rhizobox system. The concentrations of different forms of K in both rhizosphere and nonrhizosphere soils decreased with plants compared to without plants, regardless of K fertilizer application. Potassium uptake by crops mainly came from the rhizosphere soil. In the treatment without K fertilizer (–K), the main form of K supplied by the soil to the crops was 1.0 mol L^?1 nitric acid (HNO₃) nonextractable K, followed by nonexchangeable K, and then exchangeable K. In the treatment with K fertilizer (+K), the main K forms supplied by the soil to the crops were exchangeable K and nonexchangeable K. The amount and rate of K fixation after one cycle of the rapeseed–rice rotation was greater in rhizosphere soil than in nonrhizosphere soil. The amount and rate of K fixation of soil in the +K treatment were significantly less than in the –K treatment. The cumulative amounts of K released with 1.0 mol L^?1 ammonium acetate (NH₄OAc) and 1.0 mol L^?1 HNO₃ extraction increased with the increasing numbers of extractions, but the K-releasing power of soil by successive extraction decreased gradually and finally became almost constant. The release of K was less in rhizosphere soil than in nonrhizosphere soil. The release of K in the +K treatment was similar to that in the –K treatment in rhizosphere soil, but the K release in nonrhizosphere soil was greater with the +K than the –K treatment. Overall, the information obtained in this study will be helpful in formulating more precise K fertilizer recommendations for certain soils.     

Electron donor and pH relationships for biologically enhanced dissolution of chlorinated solvent DNAPL in groundwater

Biologically enhanced dissolution offers a method to speed removal of chlorinated solvent dense non-aqueous-phase liquid (DNAPL) sources such as tetrachloroethene (PCE) and trichoroethene (TCE) from aquifers. Bioremediation is accomplished by adding an electron donor to the source zone where fermentation to intermediates leading to acetic acid and hydrogen results. The hydrogen and possibly acetic acid are used by dehalogenating bacteria to convert PCE and TCE to ethene and hydrochloric acid. Reductive dehalogenation is thus an acid forming process, and sufficient alkalinity must be present to maintain a near neutral pH. The bicarbonate alkalinity required to maintain pH above 6.5 is a function of the electron donor: 800 mg/L of bicarbonate alkalinity is sufficient to achieve about 1.2 mM TCE dechlorination with glucose, 1.7 mM with lactate, and a much higher 3.3 mM with formate. Laboratory studies indicate that in mixed culture, formate can be used as an electron donor for complete conversion to ethene, contrary to pure cultures studies indicating it cannot. Various strategies can be used to add electron donor to an aquifer for DNAPL dehalogenation while minimizing pH problems and excessive electron donor usage, including use of injection-extraction wells, dual recirculation wells, and nested injection-extraction wells.     

Biodiversity and ecogeography of wild Lactuca spp. in some European countries

Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions.     

Increase in auxiliary photoprotective photosynthetic pigments in wheat seedlings induced by Azospirillum brasilense

Inoculation of wheat seedlings with the plant growth-promoting bacterium Azospirillum brasilense Cd was immobilized in alginate microbeads and, without applying any stress, significantly increased the quantity of several photosynthetic pigments, such as chlorophyll a, chlorophyll b, and the auxiliary photoprotective pigments violaxanthin, zeaxanthin, antheroxanthin, lutein, neoxanthin, and β-carotene. This resulted in greener plants with no apparent visible stress. After monitoring the quantity of photosynthetic pigments for 4 weeks, we observed that inoculated plants had higher quantities of pigments in shoot and stem. The greatest difference in the quantity of all pigments between inoculated and noninoculated plants occurred in the first week of growth. Regardless of treatment, the quantity of pigments in stems was three to four times less than the quantity of these pigments in shoots. Application of Azospirillum, either as liquid inoculant or as alginate microbeads, did not alter the positive effect of the bacteria on pigment production or the positive response of the plants towards A. brasilense Cd inoculation.     

Responses of native legume desert trees used for reforestation in the Sonoran Desert to plant growth-promoting microorganisms in screen house

Three slow-growing legume trees used for desert reforestation and urban gardening in the Sonoran Desert of Northwestern Mexico and the Southwestern USA were evaluated whether their growth can be promoted by inoculation with plant growth-promoting bacteria (Azospirillum brasilense and Bacillus pumilus), unidentified arbuscular mycorrhizal (AM) fungi (mainly Glomus sp.), and supplementation with common compost under regular screenhouse cultivation common to these trees in nurseries. Mesquite amargo (Prosopis articulata) and yellow palo verde (Parkinsonia microphylla) had different positive responses to several of the parameters tested while blue palo verde (Parkinsonia florida) did not respond. Survival of all tree species was over 80% and survival of mesquite was almost 100% after 10 months of cultivation. Inoculation with growth-promoting microorganisms induced significant effects on the leaf gas exchange of these trees, measured as transpiration and diffusive resistance, when these trees were cultivated without water restrictions.