福建省沿海防护林体系工程建设的现状及对策

沿海防护林体系工程是抵御海啸、风暴等自然灾害的绿色屏障。福建省沿海地域辽阔,居全国之首,沿海防护林体系工程建设具有重要的生态、社会和经济效益。本文在分析沿海防护林体系建设现状的基础上,就目前福建沿海防护林体系建设中发现的问题,从可持续发展的角度,提出了沿海防护林体系工程建设的对策。     

迁安县治山改沙生态效益分析

研究和分析了半山半沙地区建设生态农业、实施工程措施和生物措施取得的成效，阐明了山区修建“围山转”水平沟和沙区营造速生丰产林、护岸林及农田防护林等配套生态工程建设是治山改沙的有效途径，可充分利用自然资源，改善生态环境，生态、经济和社会效益显著。     

长江流域防护林体系工程建设30年回顾与展望

通过对长江流域防护林体系工程建设30年历程的回顾,明晰我国针对大江大河的流域性工程治理的发展脉络,总结植树造林等生物措施防治水土流失的技术体系和综合治理模式,将取得的成功经验和典范成果推广至其他地区,并展望我国流域性防护林建设的未来发展方向。长江流域防护林体系工程建设以生物措施治理水土流失为主要方式,在长江全流域大力推进生态建设,增加绿色资源,扩大生态容量,取得了十分明显的生态、经济和社会效益。同时存在工程建设难度越来越大、工程建设投资支持力度不够、投资项目过少等问题。未来长江流域仍有大面积可造林地需要绿化,工程建设任务还很重,工程建设空间还很大,流域生态治理仍然任重道远。     

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。     

内蒙古赤峰地区防护林体系建设质量及效益考察报告

30多年来赤峰市林业建设的发展,特别是党的十一届三中全会以后,在“三北”防护林体系建设第一期工程中取得显著成就,其生态效益、经济效益和社会效益之大,令人鼓舞。赤峰市的实践进一步证明了三北防护林体系建设的必要性、迫切性和可能性,并展示了林业建设在改善生态条件促进生态系统向良性循环发展的前景。赤峰市林业建设的经验应当推广,值得借鉴。     

加强流域生态经济防护林体系建设

本文从世界农林业发展的现状及实际效果出发,结合“三北”防护体体系工程实践的分析,论述了流域生态经济防护林体系建设在流域治理与开发中的重要作用。     

前言

本期所刊载的论文是国家“八五”重点科技专题“毛乌素沙地生态经济型防护林体系模式研究”（专题合同编号为:85-019-02-07）中第一、第二两个子专题:“毛乌素沙地生态经济型防护林体系结构研究”与“毛乌素沙地生态经济型防护林体系效益研究”的主要研究的内容。     

罗源县沿海防护林生态网络体系的建设

在论述罗源县沿海防护林体系建设现状与存在问题的基础上，按照建设绿色海峡西岸的要求，根据生态功能与绿化美化相结合的原则，提出了罗源县沿海防护林体系建设内容和技术措施，并进行了效益评价。     

多方法结合的盐碱地防护林构建技术探讨——以盐城某地生态防护林为例

本文以盐城市滨海地区生态防护林营造为例，探究沿海地区盐碱地造林技术体系的构建，按照“先降盐后造林”的思路，重点从盐碱地改良、造林和抚育管理等方面进行探讨，实现了盐碱地造林工程全过程的技术探究，有效提升了盐碱地造林成活率，达到改善生态环境、防治水土流失、促进生态文明建设的目的。     

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。     

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。     

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.     

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.     

Properties of anaerobically digested and composted municipal solid waste assessed by linking soil mesofauna dynamics and nitrogen modelling

We have studied the effect of anaerobically digested (ADMSW) and composted municipal solid waste (CMSW) on mineralization and foodweb dynamics to verify the hypothesis that ADMSW would immobilize N right after addition to soil in contrast to addition with CMSW. Another hypothesis was that the mesofauna (enchytraeids and microarthropods) would stimulate N release from the decomposer community. We measured excretion of -N and urea-N from the mesofauna and hypothesized that enchytraeids would release urea. ADMSW and CMSW were amended to pots with sandy loam and barley. The pots were divided into treatments with or without mesofauna. Mesofauna, plant N and biomass, soil N and ergosterol (fungal biomass) were measured over a 113-day period of four equidistant samplings. Soil respiration, N mineralization and N release by the mesofauna were modelled from concurrent studies. ADMSW- and CMSW-treated soils initially (<20 days) immobilized N. The amendments did not increase plant growth substantially, and this was probably due to N-limitation in the early stages of plant growth. Enchytraeid abundance was about three times higher in ADMSW- than CMSW-treated soils, indicating that ADMSW contained more labile compounds, bacteria, and microfauna. The mesofauna did not affect N-content, but the cumulated -N excreted by the mesofauna was estimated to be substantial and about one-fifth of total plant N in ADMSW. An explanation for this discrepancy might be that in the absence of the mesofauna, other members of the detrivore and microbivore community performed the mesofauna’s function. Neither enchytraeids nor microarthropods excreted urea.     

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,     

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,     

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.     

Assessing the effectiveness of conservation measures: Resolving the “wicked” problem of the Steller sea lion

“Wicked” problems are those that are complex and that change when solutions are applied. Many conflicts in conservation fall into this category. The study approached the problem of how to constrain the apparent wickedness of a problem in the conservation management of a species by using simple empirical indicators to carry out iterative assessment of the risk to a population and to document how this risk evolves in relation to the addition of new data and the implementation of management actions. Effects of high levels of uncertainty within data and also concerning population structure were examined through stochastic simulation and by exploration of scenarios. Historical trends in the example used, the Steller sea lion, showed rapid declines in abundance in some regions during the 1980s. The current total population is 130,000-150,000 Steller sea lions through Alaska and British Columbia and this number has been stable since about 1990 in spite of regional differences in population dynamics. Regional differences in the sequence of changes in the number of pups and non-pups, suggested that an internal re-distribution of juveniles could have happened between 1980 and 1990. Current productivity also appears close to the long-term mean. Stochastic population projection using various scenarios showed that, based upon this history, the risk of extinction for the population has declined and is below reasonable thresholds for considering the population to be endangered. The trends in risk suggest that management actions taken since 1990 have probably been effective. Consequently, the conservation management objectives for the Steller sea lion are probably being met. The approach provides a mechanism, based upon experience and scenario analysis, for exploring future policy options and may help to constrain the debate amongst stakeholders about the cost-benefit trade-offs associated with different options.     

Soil-profile distribution of primary and secondary plant-available nutrients under conventional and no tillage

Nutrient distributions under no tillage (NT) compared with conventional disk-and-bed tillage (CT) management in the warm, humid region of the southeastern USA need to be assessed so that future placement, quantity, and type of fertilizers can be altered, if necessary, to efficiently match crop demands. We determined soil-profile distributions of pH, N, P, S, K, Ca, Mg, Na, Zn, Fe, Mn, and Cu to a depth of 0.9 m at the end of 8.5 years of continuous CT and NT management on a Weswood silty clay loam (fine, mixed, thermic Fluventic Ustochrept) in southcentral Texas. Most dramatic changes occurred within the 0–0.05 m depth, where soil under NT had lower pH, Fe, and Cu than under CT, but greater P, K, Zn, and Mn. Greater P and K under NT than under CT also occurred below the till-zone (0.15–0.3 m). At a depth of 0–0.3 m, soil under NT contained greater amounts of extractable P, K, Zn, Fe, Mn, and Cu than under CT. Nitrogen fertilization had little effect on nutrient distributions, except resulting in greater extractable K at 0–0.05 m and greater nitrate at 0–0.15 m. Few changes in soil-profile distributions were observed for extractable S, Ca, Mg, and Na. Long-term continuous use of NT on this fine-textured, high-fertility (except for N) soil had no apparent adverse effects on nutrient distributions relative to CT, but enhanced conservation and availability of P, K, Zn, Fe, Mn, and Cu near the soil surface where crop roots proliferate.