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1.
全球主要粮食作物产量变化及其气象灾害风险评估 总被引：3，自引：6，他引：3
随着粮食全球化趋势和中国粮食安全战略调整,准确了解中国和国外主要粮食作物生产状况、产量变化及其气象灾害风险水平,对于气候变化背景下保障中国粮食安全和国家"农业走出去"战略实施具有重要意义。该文以全球主要粮食生产国粮食产量资料为基本资料,通过作物气象产量分离对全球主要粮食作物的产量变化进行了研究;用新构建的减产概率系数pc和平均减产率d、减产率变异系数v定义了综合气象灾害风险指数Pw,根据Pw≤2.0、2.0Pw≤4.0和Pw4.0将全球粮食主产区划分为气象灾害低风险区、中风险区和高风险区。研究结果显示,法国、德国和中国的小麦、美国、巴西、阿根廷的玉米和大豆、中国和越南的水稻产量水平在近50多年提升迅速,但区域差异明显。加拿大和澳大利亚小麦、美国玉米、巴西和阿根廷大豆的Pw超过4.0,为气象灾害高风险区;俄罗斯和中国小麦、巴西和阿根廷玉米、美国和中国大豆、印度水稻的Pw介于2.0和4.0,为中风险区;美国、德国、法国和印度小麦、中国玉米、中国、越南和泰国水稻的Pw小于2.0,为低风险区。文中方法能够直观评估全球粮食产区粮食生产水平和综合气象灾害风险,对宏观了解和认识国内外粮食生产状况具有借鉴意义。 相似文献
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磷钾硼锌肥对百合、白术产量和养分吸收的影响 总被引：1，自引：0，他引：1
在田间试验条件下研究了不同营养元素对百合、白术产量和养分吸收的影响。两年结果表明,在河沙土和灰泥土上,施用磷、钾、硼和锌肥的百合产量分别平均增产5.1%、33.5%、22.3%、16.3%和16.2%、12.5%、2.1%、6.1%,在灰泥土上,白术产量分别平均增产8.6%、34.6%、9.1%、5.8%,百合施用钾、硼和锌肥的增产效果大于白术,而白术施磷的增产效果大于百合。施磷肥能促进百合和白术对氮、磷、钾和硼的吸收,而降低对锌的吸收;施钾、硼和锌肥能增进百合和白术的氮、磷、钾、硼和锌养分的吸收量。百合和白术吸收的养分量表现出钾>磷>锌>硼。百合和白术吸收的氮、磷、钾和锌主要分配在鳞茎和根状茎部分,吸收的硼主要集中在茎叶部分。平衡施肥可提高药用部分(鳞茎和根状茎)的磷、钾和锌养分的分配比率。 相似文献
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重金属Cd、Zn、Cu和Pb复合污染对土壤生物活性的影响 总被引：6，自引：0，他引：6
通过野外土样采集及室内培养试验(25℃),研究了云南东川铜矿区土壤酶和微生物特征,以及模拟重金属Cd、Zn、Cu、Pb复合污染对土壤微生物和酶活性的影响。结果表明,矿区土壤(距矿口0~800 m)重金属污染严重,Pb、Cd、Zn、Cu全量和有效含量是对照土壤(距矿口10 000 m)的3.7~141.0倍和2.2~773.2倍;距矿口越近,土壤有机质、有效氮、有效磷和速效钾含量及土壤pH亦越低,土壤酶活性和土壤微生物数量、微生物生物量碳和氮受到的抑制程度也显著增强。与对照土壤相比,距矿口0~800 m的土壤蔗糖酶、脲酶、酸性磷酸酶、过氧化氢酶和脱氢酶活性分别降低25.5%~47.3%、22.6%~74.2%、30.9%~83.1%、16.7%~69.1%和34.6%~92.3%;细菌、放线菌和真菌数量分别较对照下降30.5%~80.1%、8.1%~49.9%和3.3%~8.3%。土壤酶中的酸性磷酸酶和过氧化氢酶,土壤微生物中的细菌对重金属污染较为敏感。恒温(25℃)培养试验中,低量的Cd、Zn、Cu、Pb复合污染刺激了土壤酶活性和细菌、真菌、放线菌、微生物生物量碳和氮的数量,但高量的Cu、Zn、Pb、Cd复合污染使土壤酶活性、细菌、真菌、放线菌、微生物生物量碳和氮均显著下降。重金属Cd、Zn、Cu、Pb之间存在着一定的协同或拮抗作用,Cd、Zn、Cu和Pb之间在微生物生物量碳和氮上表现出明显的协同效应,Pb与Cd、Zn、Cu对细菌数量的复合效应机制为拮抗效应,Cd、Zn、Cu和Pb对真菌数量和放线菌数量的复合效应机制表现为协同效应和拮抗效应并存。 相似文献
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规模化奶牛场育成牛和泌乳牛产排污系数的测算 总被引：15，自引：1，他引：14
为了给奶牛场环境工程设施的设计提供基础参数,并为畜禽养殖业环境污染的防治提供科学依据,对黑龙江省规模化奶牛场育成牛和泌乳牛的产污系数和排污系数进行了测算。结果表明:每头育成牛粪便、尿液、化学需氧量(COD)、氮、磷、铜和锌的产污系数分别为15.77kg/d、7.23L/d、2132.49g/d、112.82g/d、50.28g/d、96.04mg/d和461.89mg/d;每头泌乳牛粪便、尿液、COD、氮、磷、铜和锌的产污系数分别为33.47kg/d、16.34L/d、4265.58g/d、270.88g/d、182.99g/d、196.34mg/d和979.09mg/d;每头育成牛COD、氮、磷、铜和锌的排污系数分别为540.39g/d、34.34g/d、13.29g/d、18.37mg/d和91.06mg/d;每头泌乳牛COD、氮、磷、铜和锌的排污系数分别为1000.58g/d、85.29g/d、59.65g/d、39.64mg/d和213.31mg/d;育成牛和泌乳牛的粪便收集率分别为73.31%和69.93%;黑龙江省规模化奶牛场所产生的污染物大约有20%～30%排放到环境中。 相似文献
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以富士、金冠苹果树为试材,分析了同一花序不同部位的果实重量,Ca、Mg、K含量和果柄结构的变化,以期探讨果柄发育和幼果Ca、Mg、K吸收之间的关系及其在幼果脱落中的作用。结果表明,随幼果的发育,单个幼果重量和Ca、Mg、K含量呈增加趋势;与发育不正常的边果相比,发育正常的中心果和边果的鲜重、干重、果柄直径、维管束数目、木质部厚度、韧皮部维管束面积和单果Ca、Mg、K总含量较高,而以干重为单位的果柄Ca、Mg含量较低。相关分析表明,苹果幼果的单果重和Ca、Mg、K含量与果柄的直径、维管束数目、木质部厚度、韧皮部维管束面积呈显著正相关,说明幼果发育与Ca、Mg、K吸收和果柄结构密切相关,Ca、Mg、K吸收率低和果柄发育不良可能是导致落果的重要原因。 相似文献
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现代农业生产方式与技术体系对生态环境的影响 总被引：4，自引：1，他引：4
现代农业是一种发达、先进、高效的新型农业生产方式和产业体系,是世界农业发展之所向。建设和发展现代农业是大幅度提高农产品产量、产值与质量,增强农业素质、效益和竞争力,抗御自然灾害与市场风险能力,保障农产品有效供给和全球粮食安全的根本途径。但现代农业也绝非是完美无瑕和万能的,其对农业农村生态环境的影响和破坏更是显而易见和难以避免的,乃至一定程度地障碍、制约或威胁农业的持续发展。文章深入分析和阐释了现代农业集约化、专业化、化学化、水利化、机械化、设施化和生物化等生产方式和产业技术体系对农业农村生态环境产生的诸多负面影响和危害,并指出应正确看待、理性认识、深入探究和积极应对系列相关问题,力促和确保现代农业的健康、科学、可持续发展,人与自然的和谐共荣以及资源节药型、环境友好型社会建设和生态文明建设的顺利推进。 相似文献
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W-OH是一种以水为固化剂的亲水性聚氨酯改性复合材料,可广泛用于荒漠化防治和水土保持,具有优异的抗风蚀和水蚀性能.为研究W-OH与砂土的固结体抗水流冲击效果,采用模拟水流冲击试验,研究在W-OH质量分数(3％、4％、5％、6％和7％)、坡度(0°、15°、30°、45°和60°)和水流冲击速度(4、5、6、7、8、9和... 相似文献
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动态显示玉米的生长、发育和产量形成过程,有利栽培管理。本研究主要目的是建立一个基于生长模拟模型的可视化系统,从而反映玉米生长、发育和产量形成的实时动态。有关玉米生长、发育和产量形成的基本算法与品种、环境和生产水平密切相关,其主要来自于现有文献和研究数据。基于生长模型的逐日输出,耦合玉米种子、根、茎、叶和穗等的形态建成和生长规则,从而建立了玉米形态变化的数学模型。通过计算机图形学、Visual C＋＋和OpenGL,本文建立了基于生长模拟模型和三维动画技术的玉米可视化模型系统,其能基本反映玉米生长、发育和产量形成规律,并具有结构简单、界面友好和图像真实等优点。 相似文献
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基于PMF模型的准东煤矿周围土壤重金属污染及来源解析 总被引：4，自引：1，他引：3
为了解准东煤矿区周围土壤的污染状况及来源,在准东露天矿区采集47个表层土壤样本,测定其中Zn、Cu、Pb、Cr、Hg和As 6种重金属元素的含量。运用统计学方法、地累计指数(geoaccumulation index,I_(geo))和潜在风险指数(potential ecological risk index,PER)对研究区土壤重金属污染程度和生态风险态势进行评价,采用正矩阵分解模型(positive matrix factorization,PMF)解析重金属污染源。结果表明:1)研究区土壤Zn、Cu、Pb、Cr、Hg和As含量均超出新疆土壤环境质量背景值,超标率分别为2.1%、14.9%、4.3%、68.1%、68.1%和95.8%,其中As含量的均值分别超过国家土壤质量Ⅰ级和Ⅱ级标准(GB15618-1995)的2.1和1.3倍;2)Hg的地累积指数和潜在生态风险指数呈极高污染和高风险态势,Zn、Cu和Pb处于未污染和低风险状态。研究区综合潜在生态风险指数介于50.09～1 038.47之间,差异明显,均值为180.22,21%和11%土壤采样点呈现出较高和高风险水平;3)PMF模型结果显示:研究区土壤Hg主要受到燃煤活动的影响;Pb的积累主要与交通运输有关,As的积累主要与大气沉降和工业排放有关,工业排放是Cr的主要污染源,Zn和Cu的积累主要与土壤成土母质等自然因素有关。燃煤、交通运输、大气降尘、工业排放和自然因素5种来源的贡献率分别为20.79%,16.83%,16.83%和27.72%和17.82%。 相似文献
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Wyss W. -S. Yim 《Water, air, and soil pollution》1996,92(1-2):181-190
Given the evidence from past experience, the coastal city of Hong Kong would be vulnerable to a variety of hazards that could be exacerbated by climatic change, including potential increases in typhoons, landslides, floods (both storm surges and rainstorms), and droughts, as well as the threat of future sea level rise. The greatest death tolls in the past have been inflicted during typhoon-induced storm surges. During two unnamed typhoons, in 1906 and 1937, the death tolls were 10,000 and 11,000, respectively. In contrast, death tolls associated with landslides and other hazards were relatively small. Under a climatic change scenario of an increase in frequency and severity of typhoons and rainstorms, and rising sea level, the vulnerable areas of Hong Kong can be identified. The shift in development from hillslope areas to coastal land reclamations over the last 25 years is a matter of concern. Although the hillslopes are susceptible to landslides during rainstorms, virtually all landslides can be traced to some important anthropogenic causes and are preventable with appropriate measures. In the coming decades, the low-lying areas created through coastal land reclamations could be susceptible to flooding during storm surges and rainstorms and as the sea level rises. These areas are also where there is high density urban and industrial development, and the vulnerability is the greatest. High seawalls to protect the reclaimed areas from storm surge flooding and sea level rise may increase the risk of rainstorm flooding To reduce vulnerability, a combination of better monitoring, planning, protection, maintenance, and warning is proposed for adaptation. Monitoring is needed not only to detect future sea level changes but also to identify areas with the greatest risk. 相似文献
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K. Chatterjea 《Land Degradation \u0026amp; Development》1998,9(2):143-157
The characteristically short, intense rainstorms of Singapore occur throughout the year. The impact of such rainstorms on runoff and sediment generation from bare and grass-covered slopes of urban Singapore is examined through observations made on an experimental plot for a representative sample of natural rainstorms. While the responses of the bare surfaces to the incoming rainfall are instantaneous and significant (runoff: up to 91 per cent of total rainfall), irrespective of the dimension of the rainfall, the grass-covered slopes respond more slowly and gently (runoff: 4·8 per cent–17 per cent of the total rainfall). The sediment generating potential under the two types of landcover is closely linked to the short-term intensities of the incoming rainfall, particularly on bare surfaces where high-intensity rainstorms of less than 10 minute duration are capable of generating measurable sediment and runoff. The sediment discharge from the bare surfaces during the long construction period is not only controlled by the episodic heavy storms, but also to a considerable extent by the more frequent, low-magnitude rainstorms, which contribute to a more sustained sediment movement. With a higher frequency of occurrence, such short-duration, high-intensity rainstorms have a significant impact on the sediment and runoff generation potential of the extensive bare surfaces at the construction sites in urban Singapore. © 1998 John Wiley & Sons, Ltd. 相似文献
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以罗玉沟流域实测水文泥沙数据和洪水调查资料为基础,分析几场造成极强烈侵蚀的典型特大暴雨的雨、洪、沙特性。结果表明：典型暴雨面雨量离差系数为0．15—0．74,不均匀系数为0．37—0．90,极端降雨比值系数为1．3-188．8,暴雨中心最大10min、最大30min和最大60min降雨量分别占次降雨总量的19％-29％、35％-73％和60％-100％;次暴雨洪量超过年径流量的30％,径流系数0．20—0．49,洪峰流量模数为4．07—9．34m^3／（s·km^2）,洪水总历时6—96h,上涨历时15—80min;次洪输沙量超过年输沙量的60％,次洪输沙模数为0．71-1．40万m^3／km^2,最大含沙量高达774kg／m^3,且沙峰多超前于洪峰10—20min,沙量过程线的消退明显滞后于流量过程线,最大含沙量出现时的流量较最大流量偏小40％-50％;历次暴雨的雨、洪、沙特性差异主要受暴雨时空分布特征和下垫面条件控制,水土保持措施具有明显的滞洪减沙效应。 相似文献
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S. V. Budnik 《Eurasian Soil Science》2007,40(2):187-194
Problems regarding the relationship and effect of shear stress components (hydraulic and viscous shear stresses) on erosion in overland flows were considered. Empirical relationships were proposed for calculating the viscous shear stresses in the overland flows upon rainstorms. 相似文献
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The effect of sludge and sludge compost as a mulch for dissipating raindrop impact and maintaining a relatively high percolation rate was studied using a Paleudalf from South Africa. Three kg soil were packed in perforated boxes in a making a two cm layer, and subjected to five consecutive simulated rainstorms during a period of 26 days. A 4-day incubation was allowed between the first 4 storms and 10 days before the 5th storm. The soil was amended with either a dry waste activated sludge or a sludge compost at a rate equivalent to 45 Mg ha−1. The amendments (<2-mm) were applied either on the surface or mixed with the whole soil. The application of both sludge and sludge compost reduced the final percolation rate (FPR) compared with the unamended control. The effect of the consecutive rainstorms on the average FPR from all the treatments was as follows: FPR after 1st storm 2nd3rd4th>5th. The effect of amendment on average FPR from all storms was: control>sludge mixed with the soil>surface-applied sludge>sludge compost mixed with the soil≥ surface-applied sludge compost. The decrease of FPR was not related to the electrical conductivity or clay concentration of the leachates. The main chemical species that appeared in the leachates from the treated soils, and persisted throughout the five rainstorms, were ammonium and sulfate. Other ions, such as calcium and magnesium, were present in high concentrations in the leachate during the first storm but at low concentrations in subsequent storms. Nitrate concentrations were high during the first and fifth storms. It is suggested that the adverse effect of the amendments resulted from mechanical and microbial clogging of soil pores. 相似文献
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坡面水土流失比尺模型相似性的试验研究 总被引：7，自引：3，他引：7
通过不同比尺的系列模型试验,为坡面水土流失的比尺模型相似性研究,提供了原型和模型的降雨-产沙资料。试验结果表明,坡面产沙浓度随时间的变化有较强的紊动性,因此建议采用经验回归的方法率定降雨产沙的比尺关系;原型和模型的侵蚀产沙量都与雨强成幂函数相关,其雨强系数随模型几何比尺的增大而减小,而雨强指数的大小与坡面几何尺度的大小无关。 相似文献
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汉江上游近50a来降水变化与暴雨洪水发生规律 总被引：6，自引：1，他引：5
使用EOF分解、滑动平均和线性回归趋势分析,对汉江上游流域1960—2009年逐月及全年降水量变化进行时空分析。结果表明,汉江上游在近50a来,年降水量在总体上呈现出减少的趋势。各月份降水量变化以4月和9月降水量减幅最大,而6月和8月降水量则有所增加。1980—1988年是汉江上游流域气候转型期。由于大气环流形势发生变化,春季和秋季西南季风环流减弱,夏季东南季风环流增强。西南季风在6—7月中旬和9月通常会在汉江上游造成暴雨洪水,该阶段降水量的减少,可能会导致洪水发生几率减小。东南季风在7月下旬和8月会在汉江上游造成暴雨洪水,此期间季风的增强,可能会使该阶段暴雨洪水的发生几率增大。这些结果对于指导汉江上游水资源水能源开发和防洪减灾具有重要的意义。 相似文献
19.
汶川地震震后降雨滑坡的类型、活动特征及发展趋势 总被引：1，自引：0，他引：1
汶川地震造成许多山体的整体性破坏,部分山体后缘出现裂缝,岩土体在主震作用下产生损伤,边坡稳定性大大降低,在降雨激发作用下极易产生新的滑坡灾害。在分析汶川震后滑坡发育条件变化和降雨滑坡现场调查的基础上,将震后降雨诱发滑坡分为5种类型。震后降雨滑坡的活动特征主要体现在以小型的塌滑最为典型且数量多,沿河道两岸广泛发育,且震区滑坡发生与降雨在时间上具有较强的对应关系,滑坡发生滞后时间短,在强暴雨条件下多为群发型滑坡。从震后降雨滑坡发展趋势来看,初期主要以中小型的滑塌为主,随着时间的推移,小型滑塌数量将逐渐减少,大型、特大型滑坡发生的数量可能会有一定程度的增加。 相似文献
20.
《国际水土保持研究(英文)》2022,10(2):228-239
Investigations of the formation mechanisms of flood peaks in small catchments facilitate flood prediction and disaster prevention under extreme rainstorms. However, there have been few studies on the responses of flood peaks to land use landscape patterns using field surveys during extreme rainstorm events. Based on field data from 17 small catchments near the rainstorm center of Typhoon Lekima, 7 landscape indices were chosen. The flood peak and its sensitivity to the land use landscape were investigated by combining remote sensing interpretation and related analysis. The conclusions are as follows: (1) The peak discharge of the small catchment was 2.36–56.50 m3/s, the peak modulus was 8.00–48.89 m3/(s·km2), and the flood index K ranged from 3.61 to 4.55. (2) Under similar rainfall conditions, the flood peak modulus, K and the proportion of sloping cropland had significantly positive correlations (p < 0.05). The flood peak modulus was significantly negatively correlated with the proportion of forest-grassland and terrace (p < 0.05), and K and the proportion of forest-grassland and terraced land exhibited a negative correlation. (3) The flood peak modulus and K were positively correlated with the landscape fragmentation. (4) The sensitivities of small catchments to floods were evaluated to be moderate compared to K values from other studies. The ability of small catchments to cope with extreme rainstorms can be improved by increasing the areas of forest-grassland, and terraces and reducing landscape fragmentation. Our results could be applied to provide a basis for land use planning and support for the response against disasters caused by extreme floods. 相似文献