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1.
柴达木盆地弃耕地恢复与重建试验 总被引：2，自引：0，他引：2
通过在柴达木盆地弃耕地上建植人工草地试验 ,结果表明 ,建植人工草地后 ,土壤中盐分含量显著降低 ,土壤由中重度盐土转变为微盐碱化土壤。土壤中有机质含量增加 ,第一生产力提高 相似文献
2.
为探讨高寒地区生物土壤结皮（Biological Soil Crusts,BSCs）在人工草地演替中的生态作用,揭示其对人工草地植被与土壤养分恢复的影响规律。本研究选择在青海省玛沁县5个建植年限（18,14,11,4,和1年）的人工草地,调查各年限草地中BSCs的分布情况,以及BSCs的特征与植被分布特征和土壤理化性质的关系。结果表明：不同建植年限人工草地中BSCs的类型、盖度、厚度各不相同,较长建植年限人工草地中BSCs的多样性大、种类多,主要包括苔藓、地衣以及藻类,而建植年限短的人工草地中仅分布少量的苔藓,但厚度较大。BSCs盖度与禾本科（Gramineae）植物盖度、密度以及地上生物量显著正相关（P<0.05）,但与植被平均高度以及0~10 cm地下生物量显著负相关（P<0.05）。BSCs能调节pH,对累积土壤养分有明显作用,能显著增加建植年限长（14和18年）的人工草地中表层（0~5 cm）土壤速效养分以及建植年限短（1和4年）的人工草地中的全效养分含量（P<0.05）;在建植年限短的草地中,BSCs可减小（P<0.05）土壤粒径,增加（P<0.05）土壤细颗粒（细砂粒、黏粉粒）含量。本研究揭示,建立人工草地有利于增加BSCs盖度、厚度以及多样性,同时BSCs对人工草地地上生物量的增加和土壤结构和养分的恢复具有重要意义。 相似文献
3.
江河源区不同建植期人工草地土壤养分及微生物量磷和磷酸酶活性研究 总被引：7，自引：3，他引：4
研究了"黑土滩"退化草地上建植的2,4和6龄垂穗披碱草人工草地土壤养分、微生物量磷、中性磷酸酶活性变化以及它们之间的相互关系。结果表明,随建植期的增加,土壤pH值呈现先降低后升高的趋势,人工4龄草地土壤pH值最低,人工6龄草地最高。从时间尺度看,人工2龄草地土壤养分含量、土壤微生物量磷含量和土壤中性磷酸酶活性较"黑土滩"退化草地明显升高,随着建植期的增加,人工4龄草地各测定指标明显下降,而人工6龄草地各测定指标再次升高。4种草地土壤养分含量、微生物量磷含量和中性磷酸酶活性在土壤剖面中均呈现随土壤深度的增加而递减的趋势。相关分析结果表明,土壤微生物量磷与有机碳、全氮、速效氮和速效钾含量之间呈极显著正相关关系,与全磷含量间呈显著正相关关系;土壤中性磷酸酶活性与大多数土壤养分呈显著或极显著正相关关系,其中与土壤有机碳的相关系数最大;土壤微生物量磷与中性磷酸酶活性呈极显著正相关关系。 相似文献
4.
不同建植年限人工草地植物群落和土壤有机碳氮特征 总被引：1，自引：0，他引：1
研究三江源人工草地的植物群落和土壤有机碳氮特征,有助于评价退化草地修复效果。本试验以天然草地和黑土滩作为对照,与建植5,12,19年的人工草地的植物群落土壤有机碳氮特征进行了比较。结果表明：人工草地的建植提高了地上生物量和植物群落盖度;不同草地植物群落组成存在差异。土壤有机碳和土壤全氮含量变化趋势呈现为：天然草地 > 人工草地 > 黑土滩。冗余分析表明,0~10 cm土层的含水量、容重、全氮含量和20~30 cm土层的pH是影响不通建植年限人工草地植物群落的主要因子。建植19年的人工草地植物群落相对稳定,但还未达到恢复为天然草地的状态,应加强人工草地的养分添加和土壤改良。 相似文献
5.
以紫花苜蓿和冰草为材料,在内蒙古多伦县农牧交错区旱作条件下建植单播和混播人工草地,通过建植3年连续的野外调查数据,分析了人工草地的产量、种间竞争、杂草组分比、牧草品质及土壤养分,研究人工草地的结构稳定性和功能稳定性。结果表明,1)建植当年除外,单播及混播人工草地的产量均显著高于天然草地;年际间,单播和混播草地的产量均表现为建植第2年最高,建植当年最低。2)紫花苜蓿和冰草间存在种间竞争,且冰草的竞争力强于紫花苜蓿,影响草地的稳定性。3)建植第1年和第3年杂草受到抑制,仅在建植第2年杂草占据优势,杂草防治应选择在建植第2年进行更加有效。4)混播人工草地显著提升了牧草品质,而单播草地对牧草品质的提升作用并不显著;冰草单播和混播方式均增加了土壤的碳、氮含量,为人工草地的稳定建植提供了营养基础。 相似文献
6.
青海草地早熟禾单播人工草地群落结构特征及土壤理化性质研究 总被引：1，自引：0，他引：1
通过调查大武地区青海草地早熟禾不同龄人工草地群落结构特征和土壤理化性质,分析研究了其群落稳定性.结果表明:6龄建植的单播草地植被群落的总盖度、地上生物量和青海草地早熟禾重要值较4龄低;6龄建植的单播人工草地物种丰富度指数、Shannon-Wiener指数、Pielou指数、Simpson指数及土壤全氮、全磷、速效氮、速效磷含量和土壤含水量均高于4龄单播草地,但差异不明显.从6龄到4龄,单播青海草地早熟禾没有发生明显的退化,而是处于群落演替的暂稳态阶段,符合天然草地的演替规律,说明单一播种青海草地早熟禾有利于人工草地可持续发展. 相似文献
7.
高寒地区不同建植期人工草地群落垂直结构和生产力变化的研究 总被引：4，自引：0，他引：4
对高寒地区不同建植期人工草地群落垂直结构和生产力的变化研究结果表明：（1）随着人工草地建植时间的延长,人工草地群落垂穗披碱草高度异质性逐渐减小.（2） 不同建植期（1999、1998、1997年建植）人工草地垂穗披碱草和群落平均地上生物量均主要分布在0 ～20cm冠层中,约占平均地上生物量的61.03%、90.64%、84.55%和67.47%、92.54%、86.08%.（3） 不同建植期 （1999、1998、1997年建植）人工草地群落平均地下生物量均主要分布在0～10cm土层中,约占地下总生物量的85.97%、81.73%和78.47%.（4） 建植的人工草地如果其组分单一,即物种的丰富度很低时,均匀度增加,物种对环境资源的竞争力和利用率提高,导致土壤资源库中某些营养成分缺乏,草地群落初级生产力因此而降低。 相似文献
8.
以三江源区建植3年、7年、16年和20年的高寒混播禾本科人工草地为研究对象,分析人工草地土壤和植物碳、氮、磷含量及其生态化学计量比对建植年限的响应,对比植物群落和不同功能群碳、氮、磷含量、生态化学计量比及养分的内稳性特征。结果表明：随着建植年限的增加,人工草地0～10 cm、10～20 cm和20～30 cm土层的碳含量、氮含量、碳磷比和氮磷比总体上表现出先升后降的变化趋势,而磷含量和碳氮比分别呈现出升高、降低、再升高和降低、升高、再降低的变化特征,建植7年人工草地土壤碳、氮、磷含量最高。总体上,人工草地植物碳含量、碳氮比、碳磷比和氮磷比按照禾本科植物>植物群落>杂类草的顺序依次递减,氮含量和磷含量则表现为杂类草>植物群落>禾本科植物。随着建植年限的增加,植物群落和杂类草除碳氮比以外的其余指标均有着相似的变化特征,而禾本科植物碳含量、氮含量和碳氮比的变化特征与植物群落和杂类草相比存在一定差异。此外,不论在群落尺度还是功能群尺度,植物氮磷比均在8.0以下,表明人工草地植物的生长主要受氮限制。内稳性模型的拟合结果显示,植物群落和禾本科植物的氮含量和氮磷比表现为绝对稳... 相似文献
9.
为探究不同混播的人工草地建植初期对黑土滩的影响，本研究设置三种混播组合，分别是上繁草组合(垂穗披碱草(Elymus nutans)、同德短芒披碱草(Elymus breviaristatus),SF),下繁草组合(冷地早熟禾(Poa araratica)、中华羊茅(Festuca sinensis)、星星草(Puccinellia tenuiflora),XF),上繁草+下繁草组合(垂穗披碱草、同德短芒披碱草、冷地早熟禾、中华羊茅、星星草，SFXF),研究人工草地建植后植物群落和土壤养分的变化特征，筛选出最佳恢复组合。结果表明，人工草地建植显著增加植物地上生物量(P<0.05),但降低了植物多样性(P<0.05);人工草地建植改善了土壤性质和养分条件，显著增加土壤含水量(P<0.05)和土壤硝态氮含量(P<0.05),显著降低土壤0～20 cm的铵态氮含量(P<0.05);采用主成分分析法对三种人工草地建植组合进行分析排序，得出SFXF为最优恢复组合。 相似文献
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Owen J Slocombe D McMillan I 《The Canadian veterinary journal. La revue veterinaire canadienne》1986,27(9):324-328
In late December 1985, 1485 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1985 and 44% of them responded. Veterinarians reported that 137,300 dogs were blood-tested to check for microfilariae and 1210 dogs were found with heartworm. Another 36 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number diagnosed in 1985 as 1247 (0.91%).
Heartworm was reported from all provinces except Prince Edward Island, Newfoundland and Saskatchewan but most (1126) of the cases were in Ontario. Southwestern Ontario continued to be the primary focus of the infection in Canada. From Quebec, 91 cases were reported mostly from and around Montreal. From Manitoba, 19 cases were reported from Winnipeg and surrounding areas. Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 28% of the cases were observed with clinical signs of heartworm disease and 78% had a history of not having left Canada.
相似文献12.
Slocombe JO McMillan I 《The Canadian veterinary journal. La revue veterinaire canadienne》1989,30(6):504-508
In late November 1988, 1581 small and mixed animal clinics and institutional veterinarians across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1988, and 46% of them responded. Veterinarians reported that 181,577 dogs were blood-tested for heartworm disease and 367 dogs were found with D. immitis microfilariae. Another 60 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number of cases diagnosed in 1988 as 441 (0.24%). 相似文献
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Slocombe JO McMillan I 《The Canadian veterinary journal. La revue veterinaire canadienne》1985,26(10):323-327
In late December 1984, 1853 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1984 and 35% of them responded. Veterinarians reported that 97,794 dogs were blood-tested to check for microfilariae and 1417 dogs (1.45% of those tested) were found with heartworm. Another 34 dogs were amicrofilaremic, but were diagnosed as having heartworm disease, to give the total number diagnosed in 1984 as 1451 (1.48%). Heartworm was reported from all provinces except Prince Edward Island and Newfoundland but most (1310) of the cases were in Ontario. In Quebec, 126 cases were reported mostly from west of Montreal.
Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 27% of the cases were observed with clinical signs of heartworm disease and 72% had a history of not having left Canada. Southwestern Ontario continued to be the primary focus of the infection.
相似文献14.
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Slocombe JO Villeneuve A 《The Canadian veterinary journal. La revue veterinaire canadienne》1993,34(10):630-633
In late November 1991, 1883 clinics in Canada were sent a questionnaire to assess the status of Dirofilaria immitis in dogs in 1991 and there was a 60.0% response. There were 344,031 dogs tested for heart-worm (HW), 627 were found infected and the prevalence of HW infection was 0.18%. There were 417 dogs with HW in Ontario, 116 in Manitoba, 38 in Quebec, 53 in British Columbia, three in Alberta, and one in Nova Scotia. In British Columbia, all of the infected dogs but one were from the Okanagan valley which, as from 1991, is a new focus of infection in Canada. Most dogs with HW had not been on preventive medication in 1990, and the prevalence among dogs tested and unprotected was 0.59%. That prevalence was considerably higher in endemic areas. Companion dogs, over three years of age and maintained primarily outdoors in rural areas, were most frequently infected. One cat was diagnosed with D. immitis and 33 dogs had Dipetalonema reconditium. 相似文献
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In late November 1989, 1732 clinics and institutional veterinarians were sent a questionnaire to assess the status of Dirofilaria immitis, and 51.7% responded. Of 247,716 dogs tested, 394 had D. immitis microfilariae and 51 were amicrofilaremic for a total of 445 cases and heartworm prevalence of 0.17%. Most (408) of these dogs had no preventive medication and the prevalence among dogs tested and unprotected was 1.01%. That prevalence was considerably higher in endemic areas. Thirty-seven dogs with heartworm had preventive medication. Heartworm was most frequent in companion dogs over three years of age maintained outdoors in rural areas. About 75% of the cases had never left Canada, 26% had clinical signs and 125 were not treated.
Heartworm was reported from British Columbia, Manitoba, Ontario, Quebec, Nova Scotia and Newfoundland, but 383 cases were in Ontario. South-western Ontario was the primary focus of infection. There were 33 cases in Quebec and 24 in Manitoba, mainly found in and around Metropolitan Montreal and Winnipeg respectively.
相似文献17.
Slocombe JO McMillan I 《The Canadian veterinary journal. La revue veterinaire canadienne》1988,29(8):641-646
In late November 1987, 1246 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1987, and 50% of them responded. Veterinarians reported that 165,428 dogs were blood tested for heartworm disease and 511 dogs were found with D. immitis microfilariae. Another 78 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number of cases diagnosed in 1987 as 589 (0.35%). 相似文献
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Owen J Slocombe D McMillan I 《The Canadian veterinary journal. La revue veterinaire canadienne》1987,28(8):491-495
In late December 1986, 1224 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1986; 46% of them responded. Veterinarians reported that 150,989 dogs were blood-tested for microfilariae and 869 dogs were found with heartworm. Another 65 dogs were amicrofilaremic but diagnosed with heartworm disease and one was found with heartworm at necropsy to give the total number diagnosed in 1986 as 935 (0.62%).
Heartworm was reported from Manitoba, New Brunswick, Ontario and Quebec, but most (810) of the cases were from Ontario. South-western Ontario continued to be the primary focus of the infection in Canada. There were 103 cases reported from Quebec, mostly from and around Montreal, and 21 cases from Manitoba, from Winnipeg and surrounding areas. Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 33% of the cases were observed with clinical signs of heartworm disease and 81% had a history of not having left Canada.
相似文献19.
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Slocombe JO McMillan I 《The Canadian veterinary journal. La revue veterinaire canadienne》1984,25(9):347-350
In late December 1983, 2 800 veterinarians across Canada were sent a questionnaire in order to assess the status of heartworm disease in Canada in 1983 and 26% of them responded. Veterinarians reported that 59 504 dogs were blood-tested to check for microfilariae and 771 dogs (1.30% of those tested) were found with Dirofilaria immitis. Heartworm disease was diagnosed in all provinces except New Brunswick and Newfoundland but most (733) of the cases were in Ontario.
Heartworm disease was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 31% of the cases were observed with clinical signs of heartworm disease and 64% had a history of not having left Canada. Southwestern Ontario continues to be the focus of the infection and most of the dogs there had not left the province previously.
相似文献