首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 303 毫秒
1.
华北平原小麦-玉米农田生态系统服务评价   总被引:8,自引:1,他引:7  
本研究于2006 年和2007 年在中国科学院栾城农业生态系统试验站田间试验基础上, 评价了华北平原小麦-玉米农田的初级产品生产、气体调节、土壤有机质累积、水调节和氮素转化等5 项生态系统服务。研究表明, 华北平原小麦-玉米农田初级产品量包括籽粒产量5.04~5.71 t·hm-2·a-1(小麦)和6.69~8.24t·hm-2·a-1(玉米), 秸秆量8.58~9.72 t·hm-2·a-1(小麦)和6.97~8.58 t·hm-2·a-1 (玉米); 农田气体调节包括释放O2 24.99~28.64 t·hm-2·a-1, 固定CO2 34.23~39.22 t·hm-2·a-1, 排放N2O 0.72~1.13 kg·hm-2·a-1, 吸收CH4 3.39~5.70 kg·hm-2·a-1; 农田耕层土壤有机质累积量为1.13~2.39 t·hm-2·a-1; 水资源消耗量为2 890~3 830 m3·hm-2·a-1; 农田土壤氮素几乎都处于亏缺状态, 变化范围为-107.73~5.33 kg(N)·hm-2·a-1, 不施氮肥农田亏缺较多。综合评价发现, 小麦-玉米农田提供生态服务的经济价值为5.48~6.25 万元·hm-2·a-1, 是粮食生产价值的3 倍左右。氮肥施用对农田生态系统服务及其产生福利的影响较为复杂, 这主要是由于施加氮肥明显增加了氮素转化功能导致的经济损失, 而同时可能会增加初级产品生产、气体调节中作物固定CO2 和释放O2 功能的经济价值。尽管目前有关生态系统服务评价研究主要关注生态系统产生的正效应, 但仍有必要对农田产生的负效应做出评价, 以便客观看待农田生态系统价值, 正确认识农田生态系统对人类福利的影响。  相似文献   

2.
丹江上游商洛市畜禽粪便排放量与耕地污染负荷分析   总被引:1,自引:0,他引:1  
南水北调中线上游水源地保护与水质持续安全一直是研究的重点之一。商洛市辖商州区、丹凤县和商南县被规划为丹江流域上游“水源地安全保护区”。掌握该地区畜牧养殖业发展情况、估算畜禽粪便的排放量、分析该地区常用耕地对畜禽粪便及其污染物的消纳能力、评估畜禽粪便可能造成的污染风险等是科学管控畜牧养殖业和有效实施水源地保护的基础性研究。目前,该地区尚无这些方面具体的成果和资料。本研究采用畜禽粪便排泄系数方法,估算了丹江上游流域自上游至下游的商洛市辖商州区、丹凤县、商南县2014—2016年各类畜禽粪便排放量,依据3区县的常年耕地面积分析了畜禽粪便猪粪当量耕地负荷,确定了当前商洛地区畜禽粪便猪粪当量最大适宜耕地负荷标准,并评估了3区县畜禽粪便耕地负荷的污染风险。结果表明:1)商州区、丹凤县和商南县年度平均畜禽粪便排放量猪粪当量分别为5.732×105 t·a-1、9.321×105 t·a-1和1.274×106 t·a-1;其中猪与禽的粪便占到总粪便排放量的68.06%。2)3区县畜禽粪便排放量猪粪当量耕地负荷依次为27.04 t·hm-2·a-1、76.72 t·hm-2·a-1和90.10 t·hm-2·a-1。3)商洛市畜禽粪便排放量猪粪当量最大适宜耕地负荷标准为61.22 t·hm-2·a-1。4)3区县畜禽粪便耕地负荷的污染风险警报级别分别是:商州区为Ⅱ级,稍有污染风险;丹凤县和商南县均为Ⅳ级,有较严重的污染风险。5)商州区、丹凤县和商南县的总氮平均耕地负荷分别为159 kg·hm-2·a-1、450 kg·hm-2·a-1和530 kg·hm-2·a-1,总磷平均耕地负荷分别是51 kg·hm-2·a-1、179kg·hm-2·a-1和199 kg·hm-2·a-1,生化需氧量平均耕地负荷分别为716 kg·hm-2·a-1、2 275 kg·hm-2·a-1和2 595kg·hm-2·a-1,化学需氧量平均耕地负荷分别为768 kg·hm-2·a-1、2 345 kg·hm-2·a-1和2 667 kg·hm-2·a-1,NH3-N平均耕地负荷分别为65 kg·hm-2·a-1、201 kg·hm-2·a-1和232 kg·hm-2·a-1。总之,商洛市商州区、丹凤县和商南县的畜禽养殖总量大,养殖结构不合理;商洛市常用耕地面积相对较少,畜禽粪便的耕地负荷及其污染物负荷均较大,且形成自上游到下游急剧增加的态势;商洛市超量污染物排放会造成氮素和磷素等成分的淋溶和流失,对于南水北调水源地的水质安全构成较大的潜在威胁。  相似文献   

3.
会稽山古香榧群农业文化遗产生态服务价值评价   总被引:3,自引:0,他引:3  
会稽山区是香榧的原产地和主产地, 其千年古香榧群有着悠久的历史、深厚的文化、独特的价值和古老的嫁接技术, 是一种重要的农业文化遗产, 对其生态服务价值进行评价, 有助于人们进一步认识这一重要的农业文化遗产类型, 并针对性地开展保护工作。本文基于文献资料和调查资料, 采用生态系统评估方法, 从供给功能、调节功能、文化功能和支持功能4方面对会稽山区古香榧群的生态服务功能进行了综合评价。研究表明: 会稽山古香榧群提供的综合生态服务功能价值高达86.14万元·hm-2·a-1; 其中林副产品等供给功能价值为36.86万元·hm-2·a -1, 土壤保持、水源涵养、气候调节、固碳释氧、净化环境等调节功能价值为20.78万元·hm-2·a-1, 遗产、旅游、人文、科研等文化功能价值为28.45万元·hm-2·a-1, 生境提供、养分循环等支持功能价值为489元·hm-2·a-1。会稽山古香榧群资源不仅具有经济价值, 是经济林和旅游的重要资源, 能够促进当地经济可持续发展; 还具有生态价值, 有利于水土保持、涵养水源、保护生物多样性等; 同时还具有承继香榧起源与香榧文化发展的文化价值, 将古香榧群资源作为农业文化遗产进行动态保护, 不仅有利于资源的保护与合理利用, 而且能够促进当地经济、环境与文化的协调发展。  相似文献   

4.
姚惠琴  曹景勤  陈碧云 《土壤》1986,18(5):263-264
具有固氮作用的茎瘤豆科植物约有三种,即含羞草亚科素食假含羞草属的素食假含羞草(Neptunia oleracea)[1];蝶形花亚科合萌属的合萌(Aeschynomene indica)[2,3];和具啄田菁(Sesbania rostrata)[4]。  相似文献   

5.
对青狮潭水库太湖新银鱼的月龄生长进行全年连续采样分析 ,用 von Bertalanffy生长方程描述其生长特性 ,得到体长、体重关系式和生长方程 ,经 X2 检验显著服从 ( P<0 .0 5) ,并由此推导出体长和体重的生长速度方程及生长加速度方程。银鱼生长拐点在 4 .8月龄处。建议银鱼最适捕捞期为 1 1月  相似文献   

6.
谭清美  张佳宝  王明珠  赵春生 《土壤》1994,26(6):295-300
本文通过对余江县多年干旱无数和降水系列的统计分析,选择1974年和1978年等为典型干旱年份。通过对典型干旱年份降水过程与稻田需水过程的比较分析,得出:为保证在连续干旱50-70天时作物能正常生长,每公顷稻田需灌水11210米3,全县稻田需灌水2.26×1083;为满足P=95%的抗旱设计保证率,每公顷稻田需灌水10678米3,全县稻田需灌水2.15×1083。提出了稻田节水研究的几个方面。  相似文献   

7.
我国生态农场建设的思考   总被引:2,自引:2,他引:0  
生态农场作为生态农业的落地载体,兼顾生态环境保护与经济社会可持续发展,具有市场灵活性,在带动农户发展专业化、标准化、绿色化生产方面具有明显优势。新形势下,各地已形成了一批各具特色的生态农场典型案例。2016-2017年,作者重点围绕面源污染防控与农业清洁生产,以我国东部15个省市的468家生态农场为研究对象,制定调查问卷开展典型案例调查研究。研究结果表明,90%的农场成立时间在15年以下,生态农场经营者的平均年龄为47.5岁,土地面积在6.6~16.6 hm2的农场占到40%,土地平均租金为11 040元·hm-2·a-1;以公司、合作社和家庭农场为组织形式的农场各占23%、40%和30%;进行了农产品质量认证的农场占到73%;生态农业措施采用率排在前5位的是有机肥/堆肥、人工/机械除草、轮作、清洁田园、杀虫灯/秸秆还田;养殖农场的生态意识较为淡薄,生态措施的采用情况也不乐观。在农场投入方面,种植农场的肥料投入和养殖农场的饲料投入最高,劳动力工资平均在3~4万元·cap.-1·a-1;种植农场收益率为-21%~70%,养殖农场为13%~337%,种养结合农场为-21%~152%;50%的农场获得过农业补贴。从调研结果看,我国生态农场有着良好的发展势头,但还处于初级阶段,缺乏相应的指导。文章在调研的基础上还从技术应用、产业融合、成本收益、销售途径及补贴政策等方面分析了生态农场发展过程中面临的问题和挑战,并提出了相应的对策建议,以期对我国生态农场健康有序发展提供指导。  相似文献   

8.
基于水氮耦合的枸杞灌溉制度优化   总被引:1,自引:0,他引:1  
为明确一定养分条件下枸杞耗水量与产量的关系,于2014年和2015年采用2因素3水平对比试验设计,研究了枸杞耗水量与碱解氮消耗量耦合效应对产量的影响,通过回归的耦合模型对基于树种、树龄、碱解氮消耗量的枸杞灌溉制度进行了优化。结果表明:(1)相同施肥条件时,4年树龄时HW产量最高,为1 335.7 kg/hm2,MW产量次之,为1 174.2 kg/hm2,LW产量最低,为1 066.5 kg/hm2,5年树龄时HW产量为2 463.7 kg/hm2,MW产量最高,为2 556.1 kg/hm2,LW产量最低,为2 394.5 kg/hm2;(2)同一灌水水平条件下2年试验均表现出中施肥水平产量最高,高施肥水平产量次之,低施肥水平产量最低,4年树龄MF产量为2 758.0 kg/hm2,HF产量为2 595.5 kg/hm2,LF产量为2 407.0 kg/hm2,5年树龄MF产量为4 113.9 kg/hm2,HF产量为3 652.3 kg/hm2,LF产量为3 532.1 kg/hm2;(3)耗水量、碱解氮消耗量耦合效应显示,2014年产量随着耗水量的增加而增加,而产量随碱解氮消耗量增加呈"凸"形抛物线趋势变化,2015年产量随耗水量、碱解氮消耗量增加均呈"凸"形抛物线趋势变化。(4)灌溉制度优化发现1年树龄总ETa为166.0~198.8 mm,2年树龄总ETa为194.7~252.5 mm,3年树龄总ETa为196.6~227.2 mm,4年树龄总ETa为173.5~221.6 mm,5年树龄总ETa为179.3~196.6 mm。研究结果可为1~5年树龄"宁杞1号"枸杞获得理想的产量提供灌溉制度优化参考。  相似文献   

9.
草原生态系统土壤-植被组分中氮、磷、钾、钙和镁的循环   总被引:19,自引:0,他引:19  
张小川  蔡蔚祺  徐琪  熊毅 《土壤学报》1990,27(2):140-150
本文研究了内蒙古锡林河流域两种典型草原的生产力、营养元素在生态系统中的分配及其循环.研究表明,除C和N在植物组分中贮量稍高以外,P、K、Ca和Mg的99%以上存于土壤分室中.而植物组分中的营养元素则主要贮存于根系之中.1985年至1986年,羊草草原地上凋落物的形成量为234克·米-2,大针茅草原为88.4克·米-2;同期凋落物的消失量分别为219.6和91.1克·米-2;从活根向死根生物量的年转移量分别为1712和920克·米-2;根系的降解速率分别为0.00355和0.00365克·克-1·天-1.文中给出了诸元素在生态系统中的循环图,讨论了两类草原生态系统中元素循环的特点.  相似文献   

10.
水稻耐盐性的初步研究   总被引:1,自引:0,他引:1  
曾宪修 《土壤》1986,18(6):300-303
实践证明种稻是改良盐碱地的有效措施之一。稻田经常维持一定水层,能抑制表土层返盐,并淡化土壤溶液浓度,既有利于水稻生长又可达到土壤脱盐效果[1];另一方面,水稻本身也有一定的耐盐力[2,3]。  相似文献   

11.
林东年  李德 《水土保持研究》2006,13(3):258-261,264
根据在电白大放鸡渔场开展人工鱼礁投放海域本底调查所获的海洋资源和环境资料及以往有关文献中对该海域的调查资料,对人工鱼礁礁区的生物资源、海水水质、底质等方面进行评价,认为电白大放鸡渔场人工鱼礁礁区滨海旅游基础好,海洋渔业资源种类繁多,浮游生物丰富,水质良好,底质多为沙、粗沙或粉沙黏土为主,具有营造游钓鱼礁,发展海洋(岛)生态旅游与娱乐游钓的得天独厚的自然条件.  相似文献   

12.
A major impediment to the identification of priority areas for marine biodiversity conservation is a fundamental lack of information about the distribution of many marine species. Comprehensive species inventories for many areas currently do not exist, and performing detailed taxonomic surveys is often prohibitively expensive and time-consuming. Accordingly, there is a need to develop simple and reliable rapid-assessment techniques for mapping marine biodiversity. One potential approach is to use ‘surrogates’ that function as proxies for the distribution of other, less easily sampled, ‘cryptic’ biota. Two potential surrogates for predicting arthropod faunal biodiversity on rock subtidal reefs were investigated in this study: (1) macroalgae, and (2) faunal subsets derived by aggregating the arthropod fauna at higher taxonomic levels. Faunal and macroalgal assemblage composition was only weakly correlated across sites reflecting broad faunal responses to changes in algal structural complexity and/or common environmental gradients. This suggests that algal species composition may not be very informative in mapping patterns of faunal species distribution on reefs. Instead, the best surrogates were related (i.e. nested), subsets of the faunal assemblages such as family-level taxon richness which was found to be a good predictor of arthropod species richness at independent test sites.  相似文献   

13.
Natural refuges can play a fundamental role in protecting species from overexploitation but have not been adequately quantified in the marine environment. We quantified the effect of a depth refuge on all fish species in an artisanal coral reef fishery in Zanzibar, Tanzania by comparing changes in fish species richness and relative abundance with depth at five fished and three unfished reefs across the region. Commercial species richness was depleted by 15.1% at shallow depths in fished reefs, but there was no difference between the reefs deeper than seven metres. Non-commercial species were not affected by fishing or depth. Evidence for similar patterns in fish communities in other countries and depth-limitations to artisanal fishing methods imply this effect is widespread. The depth refuge effect could be sustaining coral reef fisheries and should be taken in to account before implementing policies or subsidies that encourage or allow fisheries to exploit deeper waters.  相似文献   

14.
中国常用人工鱼礁流场效应的比较分析   总被引:6,自引:0,他引:6  
不同结构的人工鱼礁在海中会产生不同的流场效应,为了对比分析不同结构人工鱼礁的流场效应差异,该文利用CFX软件,对6类礁型18种中国常用人工鱼礁进行了数值模拟。引入了2种相对评价方法(比礁高和比混凝土体积)和3个评价指标(礁体中垂面上的上升流面积、背涡流面积和上升流高度)。首先分析了评价指标适用的相对评价方法,然后对18种鱼礁进行比较研究,最后从每类礁型分别选出一个礁体为代表研究它们在不同流速下(0.2,0.4,0.6,0.8和1.0 m/s)上升流和背涡流的差异。结果表明:研究上升流和背涡流面积时比混凝土体积法更科学,研究上升流高度时比礁高法更有效;无论上升流还是背涡流,三角型礁的相对面积都为最大,复合型礁次之,框架性礁最小;上升流高度、上升流面积和背涡流面积都不随来流速度变化;最大上升流流速与来流速度呈线性关系,其斜率在不同礁体间存在差异;该研究以期为不同海域不同要求下人工鱼礁的选择和设计提供了参考。  相似文献   

15.
Many species of coral reef fish undertake ontogenetic migrations between seagrass beds, mangroves, and coral reefs. A recent study from the Caribbean found that the availability of mangrove nursery habitat had a striking impact on the community structure and biomass of reef fish in their adult, coral reef habitat. The biomass of several species more than doubled when the reefs were connected to rich mangrove resources (defined as having at least 70 km of fringing Rhizophora mangle within a region of 200 km2). Here, the results of this large-scale empirical study are translated into a series of algorithms for use in natural resource management planning. Four algorithms are described that identify (i) the relative importance of mangrove nursery sites, (ii) the connectivity of individual reefs to mangrove nurseries, (iii) areas of nursery habitat that have an unusually large importance to specific reefs, and (iv) priority sites for mangrove reforestation projects. The algorithms generate a connectivity matrix among mangroves and coral reefs that facilitates the identification of connected corridors of habitats within a dynamic planning environment (e.g., reserve selection algorithms).  相似文献   

16.
Marine reserves are increasingly advocated not only as conservation but also as fisheries management tools to safeguard the decline of coastal fishing resources. Still, conclusive evidence of their functioning is lacking, amongst others due to the influence of spatio-temporal variations in fish populations and habitat heterogeneity which could hamper a sound data interpretation. We conducted a spatial analysis of the benefits of the Medes Island Marine Reserve by combining geostatistical and Geographic Information System (GIS) tools. Concurrently, we analysed effects of trends reflecting habitat heterogeneity and spatial structuring of data on spatial predictions of fish catch per unit effort (CPUE) and length. Predicted spatial patterns showed the complexity and simultaneous action of trend factors leading to mostly non-linear gradients in CPUE and length data. CPUE of total fish and CPUE and length of common pandora (Pagellus erythrinus) increased close to the Integral Reserve due to direct and indirect reserve effects. CPUE and length of striped red mullet (Mullus surmuletus) slightly increased also near the Integral Reserve, but distinct reserve effects could not be identified due to the strong influence of artificial reefs. We conclude that the spatial dimension of the Buffer Zone, where artisanal fisheries are allowed, permits in general protection only for target species, favouring a habitat with no discontinuities from the reserve outwards. Our spatial approach to assess reserve benefits provides major insights into complex systems like coastal marine reserves in the northwestern Mediterranean. In addition, it contributes to a crucial aspect of marine conservation, viz. the decision on the spatial dimension of protected areas.  相似文献   

17.
The role of marine protected areas in conserving fish stocks and their potential influence on adjacent fisheries was studied at Malindi and Watamu Marine National Parks, Kenya (established in 1968). For most species catch per unit effort (CPUE) in traditional Dema traps fished across park boundaries was higher within the parks (up to an order of magnitude). However, a few species (e.g., the seagrass parrotfish, Leptoscarus vaigensis and the whitespotted rabbitfish, Siganus sutor, WSR) had higher seasonal CPUE outside the parks. Potential spillover of fishes from the parks to adjacent fished areas was tested with a logistic “decay” model of density gradients (CPUE) across park borders from fringing and patch reefs. A steep decay in CPUE off the Malindi patch reef suggested little spillover of most species. However, greater spillover was suggested off fringing reefs. Species differences were evident. The two most important commercial species showed different density gradients. Species diversity declined more abruptly off the fringing reefs. We conclude that although spillover of most species from the parks is limited, the most important commercial species exhibits significant spillover to adjacent fisheries and the Parks likely comprise important nursery and growth areas for other species.  相似文献   

18.
Many exotic fresh-water and brackish-water fish species have become established in Florida waters, but the red lionfish is the first entirely marine species that appears to have become established here. We give a detailed account of the initial collections of adult specimens from off St. Augustine and Jacksonville, including data on morphometrics, meristics, and gonad histology. Our review of historical sightings on Florida reefs and of the specimens reported herein suggests that the most plausible vector for the introduction of this fish was aquarium releases. We discuss our reasons for concluding that this species has probably become established in Florida, summarize the potential danger that these venomous fishes pose to the public, and examine the effect of a parasite hosted by the male lionfish. We also consider the potential effect of the red lionfish on marine communities in Florida, but limited information on its biology precludes a detailed assessment.  相似文献   

19.
The productivity, diversity and susceptibility to stress of tropical marine communities are compared with those of temperate marine communities. The question of the i importance of conservation is raised.The applicability of island biogeographical theories in relation to the design of marine reserves is briefly reviewed. It is suggested that the contention that conservation areas should always consist of the largest possible single area is not necessarily correct for the tropical marine environment.Conservation problems of particular habitats within Tanzanian coastal waters are detailed with special reference to the following: coral reefs, rocky intertidal platforms, cliffs, sandy beaches, sandy-muddy tidal flats, seagrass beds, mangroves, estuaries and small islands. The plight of some endangered species is discussed.Conclusions are drawn regarding the present status of marine conservation in Tanzania.  相似文献   

20.
以基于人工鱼礁为构建主体的大亚湾海洋牧场为研究实例,以2007年4月和2009年5月调查数据为基础,研究了海洋牧场在资源养护和提高海域碳汇能力等方面的作用。结果表明,人工鱼礁型海洋牧场建设提高了海域浮游生物和底栖生物的栖息密度以及渔业资源的数量和质量,底栖生物和游泳生物的生物多样性指数增加,渔业资源优势种中的优质经济鱼类的数量增加。根据海域叶绿素浓度的提高进行计算,海洋牧场建设使海域碳汇增加了937.40kgC,相当于3.44tCO2。如果同时考虑通过渔业生物收获从海域中移出碳而增加的海域碳汇能力,则其起到的海域碳增汇能力将更高。本研究的结果表明,海洋牧场是一种环境友好型、可持续发展的低碳渔业生产模式,有利于水生生物资源养护和增殖,也是生物碳汇扩增的科学途径。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号