不同玉米品种水分利用效率的研究

选用5个玉米杂交种为试材,探讨了苗期生长发育和水分利用效率的关系。结果表明,GWUE、产量和耗水量在品种间的差异显著,在3种供水条件下,郑单958是高GWUE品种,具有高产中耗水的特性,鲁单981是低GWUE的品种,是低产高耗水品种,而四单19的GWUE是在干旱胁迫下最具增长潜力的品种,具有稳产节水的特性。     

Effects of predation and intraspecific interactions on habitat use and foraging by brown trout in artificial streams

Abstract— We studied habitat use, foraging rates and behavior of 10 cm and 12 cm long brown trout, Salmo trutta , at two densities, 1.5 and 3.0 fish. m⁻², in artificial streams that contained either the amphipod, Gammarus pulex , alone or G. pulex together with the piscivore, northern pike, Esox lucius. Gammarus were stocked in and largely restricted to the pools at a density of 128 Gammurus. m⁻² . pool⁻¹ Large trout (12 cm) used pools more and riffles less when small trout (10 cm) were present than when small trout were absent. Small trout consumed fewer Gammarus when together with large trout than when alone, but showed no difference in habitat use in the presence and abscnce of large trout. Habitat use and number of Gammarus consumed per trout were not affected by trout density for either size-class when alone. For both size-classes of trout, use of pools and foraging rates were higher in the absence than in the presence of pike, and pike primarily resided in the pools. The number of aggressive interactions by both size-classes of trout decreased when pike was present. Our results indicate that for habitats that differ in food resources and predation risk, size structure may affect habitat use and foraging by brown trout.     

麝香可持续利用的探讨

笔者根据文献资料结合自己的研究,从麝香的重要作用,麝香来源,天然麝香与人工麝香的比较,野生麝资源状况和发展麝资源等几个方面对麝香资源与应用进行了概述,针对麝香长期供不应求,直接影响医疗用药的问题,根据我国50多年的人工养麝经验,指出人工养麝是保护野生麝资源和实现天然麝香可持续利用的有效途径,并就我国人工养麝概况,人工养麝发展存在的问题,突破人工养麝的瓶颈问题,实现产业化养麝保障麝香可持续利用方面进行了系统总结与探讨。     

森林生态系统中植物养分利用效率(NUE)的研究

植物养分利用效率(NUE)是整个生态系统研究中的重要参数,反映植物对所处环境的适应能力。该文从植物NUE的概念出发,对森林生态系统中植物NUE的格局分布、引起植物NUE差异的生化基础,以及影响植物NUE因素等研究进行了综述,并对今后森林生态系统中植物NUE的研究进行展望。     

施肥对普陀樟苗木生长及养分吸收利用的影响

为了解不同施肥水平对普陀樟Cinnamomum japonicum var.chenii苗木生长及养分吸收利用情况的影响,设置了3个水平的田间试验,即不施肥(ck),常规施肥(T50,50 g·m-2)和增量施肥(T100,100 g·m-2),于2012年6月至9月观测苗高和地径,定期采集分析土壤和植物样品。结果表明:普陀樟苗木的苗高、地径、根部和茎部生物量均随施肥量的增加而增加(P<0.05);而叶生物量和总生物量在6月时随施肥量增加而升高(P<0.05),到9月时则呈先升后降的趋势(P<0.05)。苗木体内养分质量分数和单株养分含量随施肥量的增加而增加(P<0.05),不同处理均以叶片养分质量分数最高;养分吸收及利用率随着施肥的增加而降低(P<0.05),T50和T100处理各元素的吸收利用效率均为氮>磷>钾。到试验结束时,T50处理土壤养分质量分数与试验开始时持平,T100处理钾积累,ck引起钾亏缺。从移栽成活来看,T50苗木体内养分积累,有利于移栽成活,保持土壤养分平衡;而T100养分浪费。综合判断,普陀樟苗木最适需养量应为50 g·m-2到100 g·m-2,且较接近50 g·m-2。     

An unholy disease in the Holy Land: The history of anthrax between the Jordan River and the Mediterranean Sea (1909–2012)

The history of recorded cases of anthrax in human beings and animals from 1909 to 2012 in the area between the Jordan River and the Mediterranean Sea is reviewed. The disease was endemic until the middle of the 20th century, but the incidence decreased thereafter, with only sporadic cases from the 1980s onwards. Human cases have not been diagnosed in the region since 1984 and the number of episodes of animal disease has reduced to less than one per year. This decline is mostly due to the disruption of the infective cycle by improved veterinary control, including vaccination, treatment and outbreak management. A policy of reactive vaccination for 10 years of affected herds and herds grazing in their proximity has been applied. No new outbreaks have been observed in such herds after the cessation of vaccination, despite continued grazing on the same sites, so it is assumed that spore survival in such areas is shorter than 10 years. This is independent of the soil composition, which is calcareous throughout most of the relevant area. However, reemergence of anthrax, even after decades, has occurred following disturbance and heavy rainfall.     

Cascading effects of introduced Nile perch (Lates niloticus) on the foraging ecology of Nile tilapia (Oreochromis niloticus)

Abstract –  Nile tilapia ( Oreochromis niloticus L.) is the dominant of the introduced tilapiines in many East African lakes and has flourished in the presence of introduced Nile perch ( Lates niloticus L.). We explored the hypothesis that O. niloticus exhibits increased omnivory in response to a decline in abundance of haplochromine cichlids. First, we quantified variation in habitat use and diet of O. niloticus in Lake Nabugabo, Uganda. Second, we compared the diet of O. niloticus in lakes with (Nabugabo, Victoria) and without (Mburo, Wamala, Nyamusingiri, Kyasanduka) introduced Nile perch. In Lake Nabugabo, a higher level of phytoplanktivory was observed in small juveniles than in larger fish and in wetland ecotone areas where haplochromines were most abundant. An omnivorous diet dominated by detritus and invertebrates was recorded for O. niloticus in lakes Nabugabo and Victoria, while a predominantly herbivorous diet was characteristic of O. niloticus in lakes without Nile perch. Availability of a broad food base in lakes where inshore insectivores have been reduced may explain the increased omnivory recorded in lakes Nabugabo and Victoria.     

休闲期覆膜与施氮量对旱地小麦水氮利用效率和籽粒产量的影响

为探寻旱地小麦休闲期覆盖下的适宜施氮量,在旱地小麦休闲期覆盖与不覆盖条件下,分别设置75、150和225kg·hm-2三个施氮量,分析了休闲期覆盖配施氮肥对旱地小麦水氮利用效率和籽粒产量的影响。结果表明,休闲期覆盖显著提高播种至孕穗期0~300cm土壤蓄水量,其中播种期土壤水分增加70~81mm,其蓄水保墒效果可延续至孕穗期,进而提高了小麦产量和水分利用效率。休闲期覆盖促进了小麦植株对氮素的吸收和积累,增加了植株花前氮素转运量、花后氮素积累量以及籽粒氮素积累量,提高了氮素收获指数和氮素生产效率。休闲期覆盖配施氮素150kg·hm-2时,蓄水、增产和水分高效利用、氮素积累与转运的效果最好。     

Developing scoring functions for soil quality to assess land suitability for irrigated wheat in Southern Algeria

Efficient land-use management could be optimized through appropriate advice regarding land suitability and achieving a reasonable yield while preserving soil and environmental conditions. The main objective of this study was to determine and define those locations capable of wheat cultivation with irrigation in the municipality of N’goussa (Southern Algeria). Expert opinion (EO) method was used for selecting minimum soil data set (MDS_-EO), where six influencing soil properties (sand, pH, salinity, organic matter, gypsum and lime) and other three key parameters (slope, land use/land cover, and proximity to roads and electricity network) were considered important for irrigated wheat cultivation in the study area. Indicators were weighted according to principal component analysis (PCA) loadings and summed. PCA revealed that the selected nine indicators are appropriate for accounting 73.63% of the total variance. Two maps of land suitability were created here (expressed as a soil quality index within a range from 0 to 1) from multivariate analysis and already known standard scoring functions (SSFs) by using two data sets (pure and scored). The distribution of soil quality index (IQI) showed that above 70% of the land was moderately (MS) to highly suitable (HS) for irrigated wheat. The estimation accuracy of soil quality classes has been evaluated using random forests (RF), having as a dependent variable the final class of land suitability used in each map. It was determined that estimation accuracy could reach 60% (pure data set) and 65% (scored data set) at 0.5 cut-off value for soil quality classes. Final prioritizing according to ranks of sensitivity index (SI) and efficiency ratio (ER) showed that IQI obtained from scored data set is the most suitable approach in soil quality assessment of arid areas. Therefore, it could be applied in southern Algeria for land management, integrated planning and environmental assessments.     

基于InVEST模型的祁连山国家公园碳储量时空分布研究

[目的] 研究祁连山国家公园碳储量及其时空分布,分析土地利用变化对陆地生态系统碳储量的影响,为提升国家公园生态价值、调整生态工程及土地管理政策提供科学依据。[方法] 结合土地利用变化动态指数和土地转移矩阵分析国家公园生态破坏和生态恢复前后的土地利用变化,然后基于InVEST模型Carbon模块,以土地利用遥感影像和碳密度为模型运行数据,计算土地利用变化导致的碳储量变化。[结果] ①祁连山国家公园1980,1990,2000,2010,2018年的碳储量分别为9.07×10⁸,9.07×10⁸,9.07×10⁸,9.16×10⁸,9.17×10⁸ t,呈现“先减后增”的趋势,累计增加9.86×10⁶ t。②碳储量空间分布与土地利用类型有一定联系。碳储量较高的地区主要集中在公园东段和中段东侧,以林地为主;碳储量较低的地区主要集中公园西段和中段西侧,以未利用地为主。③1980—2018年生态正向演变下的土地利用变化（耕地、草地和未利用地转为林地,耕地和未利用地转为草地,未利用地转为水域）是国家公园碳储量增加的主要原因。[结论] 巩固实施生态工程,着重保护草地资源、调整土地管理政策等方式能够有效促进生态系统正向演变,优化土地利用结构,有利于祁连山国家公园陆地生态碳储量的增加。