村镇土地利用预警系统设计与实现

土地利用的监测、评价、预警是保证土地资源合理配置的技术依据。该文通过总结土地利用预警研究现状,从耕地保护、建设用地节约集约、生态安全3个方面出发,以村镇为研究主体,提出了土地利用预警研究的总体思路。基于已有研究成果,构建土地利用预警指标体系,研究指标值获取、指标预测预警模型选择和警度区间划定等方法,进行土地利用预警系统功能模块设计及实现。最后对北京市房山区2015年耕地利用情况进行预测预警,得出房山区部分乡镇在2015年将可能出现较为严重的耕地利用警情。结果表明,土地利用预警系统具有动态、实时的监测及预警     

中国土地资源安全评价研究进展及展望

土地资源作为国民经济发展的载体,其安全关乎粮食安全、社会安全、生态安全。对区域土地资源进行安全评价研究,既有利于落实国家土地保护政策,也可为区域生态友好型土地利用模式提供现实参考。近些年来,在土地资源安全理论研究、耕地与粮食安全研究、基于承载力的土地资源安全研究、土地生态安全评价等研究领域均取得显著进展。论文着重分析土地资源安全研究的新进展,对近年来我国土地资源安全研究最新成果及其在国民经济与社会发展中的应用、成效和前景进行评析,对我国土地资源安全研究的发展趋势进行展望,并提出了新时期土地资源安全研究的主要方向和重点领域。     

黑龙江省耕地资源安全预警分析及预警系统的构建

耕地资源安全预警是保护耕地和实现耕地资源可持续利用的有效手段。该文以黑龙江省为研究区,从耕地保护角度,结合研究区的耕地数量、质量和生态环境3个方面,构建耕地资源安全预警指标体系,利用纵比判断法,以研究区1996-2008年耕地资源安全定量评价值为基础数据,确定研究区耕地资源安全度的阈值。应用灰色模型GM(1.1)与BP人工神经网络技术,对黑龙江省2012-2015年耕地资源安全度及变化趋势进行了预测和分析,并构建了耕地资源预警系统框架体系。结果表明,1996-2008年黑龙江省耕地资源安全值呈不规则下降趋势。2012年黑龙江省耕地资源警度为轻警、2013-2015年为中警,警度有上升趋势;2012年耕地质量略有升高,但耕地数量减少幅度较大,2013-2015年,随着耕地数量的增加,耕地质量不断下降,2012-2015年生态环境呈平缓上升趋势。耕地数量与耕地质量不协调发展是黑龙江省耕地资源在预测期主要致警原因,城市化水平、水土流失比率和抗逆指数等是影响黑龙江省耕地资源安全状况的敏感因子。该文为相关预警研究提供参考。     

大城市近郊县域耕地保护预警方法

县域是耕地保护及预警最为合理的研究尺度,综合应用土地利用规划、年度计划和农用地分等定级成果,预测耕地资源“量”与“质”的变化趋势是科学合理地保护耕地的有效手段。该文在单项指标和综合指标2个层次上,从耕地数量、稳定生产能力、易变养分的空间变化和综合4个方面构建了县域耕地保护预警体系,并对北京市顺义区进行了耕地保护预警研究。顺义区耕地保护单项指标预警结果表明,2007、2008年顺义区耕地数量出现轻警,2009、2010年则为无警;耕地稳定生产能力在2007、2009年为中警,2008年为重警,2010年为轻警;而易变养分含量变化的警情则不尽相同。综合指标预警结果表明：2007年顺义区耕地保护出现重警,2008年和2009年为中警,2010年为轻警。研究结果从预警的时间尺度和空间尺度出发,全面考虑了耕地的数量变化和质量变化,并使警情判定与土地管理和农业生产工作相衔接,是进行区域耕地保护预警研究的有效方法。     

中国耕地资源安全预警系统探讨

该文尝试设计和建立中国耕地资源安全预警系统,为耕地资源安全预警技术规范的编制和耕地资源的合理保护利用提供参考。耕地资源安全预警系统包括监测、评价和预警3个组成部分;耕地资源安全的监测、评价和预警指标体系由距离耕地保有量差值、耕地减少率、基本农田减少率、自然质量等别、耕地结构质量、耕地退化面积比重、化肥农药农膜负荷、耕地重金属污染面积比重和耕地水土流失面积比重9个指标构成,各指标的监测周期在1～10 a间;短板效应模型可以作为耕地资源安全预警的综合评价模型。耕地资源预警系统的建立需要借助于多个行政部门的合作。     

黑龙江省耕地资源安全预警及调控研究

本研究从压力、状态、响应三个子系统构建耕地资源安全预警指标体系,结合Matlab编程,采用灰色关联法,引用经济学中敏感度的概念,对2005年以来黑龙江省耕地资源安全进行预警分析,在此基础上进行调控研究。研究结果表明:(1)从各子系统的安全警度来看,2005~2014年,黑龙江省耕地资源安全压力系统的警度经历了"无警-轻警-中警"的变化过程;状态系统警度基本处于"中警"水平,响应系统的警度由"轻警"上升为"中警"。2015~2019年,耕地资源安全压力系统的警度由"中警"转变为"重警",状态系统和响应系统的警度一直维持"中警"水平。(2)2005~2014年,黑龙江省耕地资源安全总体警度呈逐步上升趋势,2015~2019年,黑龙江省耕地资源安全将一直处于"中警"水平,但预警的指标值持续降低,接近"重警"的水平。(3)黑龙江省耕地资源安全需针对城市化水平、水土流失治理、盐碱地治理及防止耕地污染等方面加以调控。     

区域土地资源持续利用的生态安全研究

生态安全是土地资源持续利用的核心和基础,对土地资源持续利用的生态安全概念和内涵进行了探讨,构建了土地持续利用的生态安全研究内容和体系,介绍了土地持续利用的生态安全评价方法,从土地利用方式的改变、土地生态安全预警、土地生态安全维护与管理、土地生态恢复和重建等方面提出了区域土地资源持续利用的生态安全体系构建。     

新郑市耕地生态安全动态预警研究

耕地生态安全预警对改善耕地生态安全水平,保障粮食安全具有重要的意义。以河南省粮食主产区新郑市为研究对象,基于压力、状态、响应(P-S-R)和生态、环境、经济、社会(E-E-E-S)框架模型,构建了耕地生态安全预警指标体系。引入变权理论确定指标权重,运用改进物元可拓模型确定新郑市2001—2010年耕地生态安全预警等级,并采用障碍度模型分析耕地生态安全障碍因子。结果表明:2001—2010年新郑市耕地生态安全水平总体呈现上升趋势,预警等级由Ⅲ级(预警)上升为Ⅳ级(较安全);2009—2010年预警等级虽处于较安全(Ⅳ级),但有下降趋势。制约新郑市耕地生态安全水平的主要障碍因子是地均化肥使用强度、耕地复种指数、人均粮食产量、城市化水平、耕地垦殖率、人口自然增长率、人均水资源量、地均地膜使用强度、第三产业占GDP比重、农业经济比重、未利用土地比重等,这些因子应是今后改善新郑市耕地生态安全的重点。     

内蒙古巴林右旗耕地及耕地后备资源生态安全研究

耕地及耕地后备资源的生态安全问题是当下的热点问题,对于耕地及耕地后备资源生态风险的研究势在必行。本研究首次从小尺度出发,以内蒙古巴林右旗的耕地及耕地后备资源图斑为研究对象,假拟耕地后备资源为耕地,以宜耕资源图斑为微观尺度的生态系统,应用AHP层次分析模型从土地暴露度、立地条件与土壤属性及斑块景观格局三个方面选取评价指标,建立巴林右旗耕地及耕地后备资源生态安全评价指标体系,并通过熵权法对模糊综合评价模型的获取权重过程进行改进,借助地统计学、土壤学和景观生态学的理论方法,对内蒙古巴林右旗耕地及耕地后备资源的生态安全进行评价分析。研究结果表明,耕地图斑面积为91995.49 hm2,耕地后备资源图斑面积为275960.00 hm2,总面积共367978.21 hm2。其中,耕地中有26.59%属于高度风险状态;耕地后备资源中55.09%属于高度风险,二者面积总和占评价总面积的47.97%。巴林右旗土地荒漠化严重,耕地及耕地后备资源生态风险总体处于严重水平,有待于针对性治理。     

生态脆弱地区土地生态环境安全初探

关注并保障生态脆弱地区土地生态环境安全是实现区域土地资源可持续利用的基础。在生态脆弱地区土地生态环境系统因素分析的基础上,提出了区域土地生态环境安全的概念和研究的理论基础。在研究技术与方法上提出了应用RS与GIS—EIS耦合技术进行评价、预警、仿真和优化,从而构成生态脆弱地区土地生态环境安全研究的完整体系。     

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.