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青藏高原高寒草甸广大牧区由于交通不便、能源短缺和生活习俗等原因,牛粪依然是当地牧民的主要生活能源来源,长期、大量地捡拾牛粪改变了粪斑的数量和面积,使养分在天然草地上无法回到草地生态系统进行再循环,因而对草地植物群落结构和生物量产生一定影响,从而增加了生态风险。为探讨捡拾牛粪对草地的生态影响,本文以青海省河南县高寒草甸生态系统为研究对象,通过对适度放牧草地上牦牛粪开展为期3年的不捡拾、一半捡拾和全部捡拾3个处理的试验研究,探讨捡拾牛粪对高寒草甸生态系统植物经济功能群落特征和生产力的影响。结果表明:牛粪不捡拾处理的草地生产力显著低于半捡拾和全捡拾处理,植物多样性显著低于半捡拾处理,禾草类优良牧草生物量显著高于半捡拾和全捡拾处理,莎草类优良牧草生物量显著高于全捡拾处理;牛粪半捡拾处理比不捡拾处理草地植被丰富度显著提高31.9%,植物多样性显著增加,群落生产力显著提高9.7%(42.6 g·m~(-2)),优良牧草和可食牧草生物量变化不显著;牛粪完全捡拾比不捡拾处理也显著增加草地植被的丰富度,增幅为10.7%,植物多样性显著增加,群落生产力显著提高4.1%(17.96 g·m~(-2)),但同时毒杂草显著增多,优良牧草和可食性牧草显著减少,牧草适口性变差。捡拾(半捡和全捡)牛粪会使禾草类和莎草类优质牧草生物量显著减少,莎草类在完全捡拾牛粪区生物量极显著减少70%以上;豆科植物生物量显著增加,在完全捡拾牛粪区生物量极显著增加,可达5倍以上;占总生物量74%~79%的杂类草和毒草的生物量也显著增加,且以半捡拾区增量最多。适度的牛粪捡拾可增加植被的丰富度和多样性,也提高了植被的生物量,并可保证牧草的营养品质和适口性。本项研究结果可以为高寒草甸牧区牛粪的适度捡拾和草地生态系统可持续管理提供科学依据。 相似文献
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生草覆盖与植物篱技术防治紫色土坡地土壤侵蚀与养分流失的初步研究 总被引：8，自引：2，他引：8
水土流失与农业面源污染是三峡库区农业生态环境的关键问题之一．研究采用生物治理的方法具有投资少、操作容易和见效快等特点。采用连续定位监测的方法，以常规旱作花生-小麦和黑麦草-大豆（紫粒苋）为对照，分别设置紫花苜蓿多年生牧草、花生-小麦附设香椿生物篱、花生-小麦附设紫花苜蓿生物篱3个处理，连续3年监测各雨次径流、泥沙和泥沙氮磷养分流失量。结果表明，4～9月份是库首地区早坡地土壤侵蚀和泥沙氮磷养分流失的高峰期，不同利用管理方式下，由于植被覆盖和耕作、施肥措施的不同，造成的土壤侵蚀和氮磷养分流失量有明显的差异。与种植季节性牧草和旱坡地常规小麦-花生模式相比，种植多年生牧草和常规小麦-玉米模式附设香椿植物篱．可以有效地减少土壤和泥沙态氮、磷流失。发展饲草-养殖模式的早坡地，选种多年生饲草，既能实现物质、能量多级利用，又能保持水土；常规旱坡地等高设置经济植物篱笆．同样具有显著的生态效益。 相似文献
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为揭示牧草种植改良盐碱地的效果,更好地开发利用后备土地资源。以黄河三角洲滨海盐碱地为研究对象,采用小区试验、野外取样、室内测试相结合的方法,研究了高丹草、甜高粱和墨西哥玉米3种一年生牧草在1个生长期内对黄河三角洲盐碱地土壤物理、化学和酶活性改良效果的动态变化,并依据土壤质量指数综合评价了改良效果。结果表明:(1)土壤含水量、pH和电导率随生长时间增加呈下降趋势,高丹草和墨西哥玉米在生长旺盛期对土壤pH的降低效果最明显,甜高粱在收获期降低pH的效果最好。3种牧草土壤电导率较CK均显著降低,对20—40 cm土层的降低效果优于0—20 cm土层,其中墨西哥玉米效果最好。(2)种植不同牧草对土壤养分含量有明显改善,其中土壤有机质、速效氮、速效磷含量有显著提升,但对土壤速效钾含量影响不大。(3)3种牧草在不同生长期内对土壤酶活性的影响不同,在生长旺盛期土壤酶活性最强,均显著增强土壤过氧化氢酶、蔗糖酶和脲酶的活性,其中甜高粱对过氧化氢酶和蔗糖酶活性影响最大。(4)不同牧草对盐碱土壤改良指标的贡献值存在差异,综合土壤理化性质、养分含量和土壤酶活性作为土壤评价指标,种植不同牧草后土壤质量从高到低依次为甜高粱＞高丹草＞墨西哥玉米＞CK。研究结果可为黄河三角洲地区盐碱地的植物修复技术和筛选及引进国内外具有高效生态经济效益的耐盐植物提供理论依据和重要参考。 相似文献
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不同粮草种植模式对四川紫色丘陵区水土流失的影响 总被引：1，自引：0，他引：1
把饲草作为主要作物引入耕作制,通过3年3重复随机区组定位试验,研究了紫色土丘陵区坡耕地不同粮草种植模式对水土流失的影响。研究表明:夏季牧草在雨季需刈割多次,造成土壤覆盖度急剧降低,栽种夏季牧草后加大了土壤侵蚀。刈割后再生力较强的墨西哥玉米较再生力较差的高丹草有利于减少土壤侵蚀。在冬季小麦预留空行增种禾本科牧草能在夏季残留大量根系,固定泥沙,显著减少土壤侵蚀。因此,从控制土壤侵蚀的角度考虑,在四川紫色丘陵区发展饲草种植,首先应考虑冬季小麦的空行利用,在栽培夏季牧草时应选择再生能力和分蘖力强的牧草品种。 相似文献
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高寒草甸植被生育期耗水量和耗水规律的分析 总被引：7，自引：4，他引：7
用１９９１～１９９３年在高寒草甸地区植被生育期测定的土壤水分资料，联系土壤水分平衡方程，讨论高寒草甸植被生育期的耗水量和耗水规律的特征，结果表明，草甸地区植被生育期５月２０日～９月１５日，３年平均耗水量约为３６１．０ｍｍ；全年牧草地上净初级生物量与耗水量具有一定的相关性；植被生育期内气温、降水的协调配合能提高牧草地上净初级生物量。５～９月，植被耗水量变化量单峰型曲线，３年平均表明，７月耗水量最高，５月最低。 相似文献
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Sanborn试验地建立于1888年,是密西西比河西部建立最早的一个农业试验地.它为长期作物轮作和土壤管理,包括每年的施肥对土壤侵蚀以及这些技术措施的持续性的影响提供了可靠的依据.对各试验小区中连作玉米的、连作梯牧草的和6年一轮玉米、燕麦、小麦、三叶草及2年梯牧草轮作的连续耕作100年后的表土保留情况进行了分析.结果表明,种植100年后的连作玉米小区比6年一轮梯牧草小区保留的表土有明显减少.连作玉米小区保留的表土只相当于梯牧草小区的44%.而轮作小区则相当于梯牧草小区的70%.连作玉米小区耕层的粘土含量比轮作和梯牧草小区有显著增高,而且玉米小区还出现耕层与底层粘土混合的现象.据测产表明,在有侵蚀的小区即使施用大量肥料,其玉米产量仍比无侵蚀小区减产60%.因此,如果要持续长期生产就必须改进条播耕作管理工作. 相似文献
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三种草本植物蒸散量的对比试验研究 总被引：9，自引：1，他引：9
利用盆栽试验,对宁夏南部地区3种主要牧草的蒸散量进行了对比研究,结果表明,在生长季中后期人工牧草苜蓿蒸散量的日平均值为4.15mm,分别比芨芨草和长芒草高出24.34%和29.88%。芨芨草由于植株形体高大,其植物蒸腾耗水量相应也较大,故在生长季内总的蒸散量高于长芒草;然而在生长季末由于植物几乎无蒸腾作用而使其总蒸散量略低于长芒草。3种草本植物的蒸散量与土壤含水量呈高度相关,并在此基础上建立了回归方程。 相似文献
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低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响 总被引：2，自引：2，他引：0
【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。 相似文献
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Aleš Lebeda Ivana Doležalová Eva Křístková Barbora Mieslerová 《Genetic Resources and Crop Evolution》2001,48(2):153-164
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. 相似文献
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Kyle Devey Michael Mucalo Gordon Rajendram Joseph Lane 《Communications in Soil Science and Plant Analysis》2015,46(4):72-80
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. 相似文献
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Thomas Larsen Jesper Luxhøi Jakob Magid Lars Stoumann Jensen Paul Henning Krogh 《Biology and Fertility of Soils》2007,44(1):59-68
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. 相似文献
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《中国生态农业学报》2014,(6)
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, 相似文献
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《中国生态农业学报》2014,(7)
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, 相似文献
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I.L. Boyd 《Biological conservation》2010,143(7):1664-1674
“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. 相似文献
18.
Soil-profile distribution of primary and secondary plant-available nutrients under conventional and no tillage 总被引：1，自引：0，他引：1
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. 相似文献
19.
《中国生态农业学报》2014,(8)
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, 相似文献
20.
M.A. Callaham Jr. J.M. BlairT.C. Todd D.J. KitchenM.R. Whiles 《Soil biology & biochemistry》2003,35(8):1079-1093
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. 相似文献