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1.
准确量化分析地气之间的物质和能量交换对于水资源管理和农业可持续发展是十分重要的。能量平衡闭合是评估观测数据准确性和分析地表能量平衡的一个重要的评价指数。本研究利用开路涡度相关系统和全要素自动气象站对华北平原典型冬小麦农田生态系统2013—2014年度的能量通量及常规气象要素进行了连续观测,分析了冬小麦农田各能量通量的日变化和年变化特征,计算冬小麦在4个生育时期(出苗期、越冬期、拔节期和灌浆期)的能量闭合和波文比。结果表明:在日尺度上,选取的4个生育时期净辐射和各能量分量的日变化趋势均为单峰二次曲线,净辐射、显热通量和潜热通量的峰值出现在12:00—13:00,土壤热通量的峰值出现在14:00—15:00。在年尺度上,净辐射和潜热通量的变化趋势较为一致,均在越冬期达到最低值114.51 W·m~(-2)和13.47 W·m~(-2),而在灌浆期达到最大值327.02 W·m~(-2)和116.56 W·m~(-2)。选取的4个生育时期的代表性观测日期能量闭合良好,能量闭合率分别为0.49、0.77、0.81和0.76。4个生育时期内波文比值日变化趋势均呈倒"U"型,出苗期波文比在14:00达到最大值2.12;越冬期、拔节期和灌浆期在10:00左右达到最大值,分别为1.48、0.31和0.58。本文的定量化结果可为华北平原农田生态系统水热通量等研究提供依据。 相似文献
2.
不同水分条件麦田能量与CO2通量变化特征研究 总被引：6，自引：1，他引：6
试验观测不同水分处理冬小麦田能量平衡各分量、反射率和CO2 通量日变化及日际变化特征结果表明 ,小麦拔节期麦田地表反射率平均值约为 0 .18,不同水分处理农田潜热通量和显热通量均有明显差异 ,晴朗天气冬小麦冠层顶部CO2 通量日变化呈抛物线形 ,麦田主要表现为CO2 的汇。 相似文献
3.
以华北平原冬小麦农田尺度为研究对象,采用涡度相关技术,研究冬小麦灌浆期瞬态CO2通量日变化特征及其与农田热量平衡各分量的关系。结果表明,非水分胁迫下CO2通量日变化(负值表示通量指向冠层)为U型,群体净光合速率最高值为-1.2~-1.4mg/m2.s,夜间瞬态CO2通量呈非稳定变化,最高值达0.4~0.54mg/m2.s。白天时段内CO2通量与净辐射、潜热通量呈高度相关,8:00~15:30时段内CO2和水汽通量呈同步日变化趋势,水分利用效率处于稳定状态,瞬态水分利用效率基本维持在0.012~0.014g(CO2)/g(H2O)范围内;但早晨和傍晚时段内水分利用效率变化较大。 相似文献
4.
干旱区膜下滴灌向日葵农田蒸散发特征 总被引：1，自引：0，他引：1
膜下滴灌是中国西北干旱区农业的新兴节水灌溉模式,定量分析膜下滴灌农田蒸散发特征并对比分析其与普通灌溉农田蒸散发的差异,对认识和优化干旱区节水滴灌技术有重要意义。本文以新疆天山北坡三工河流域绿洲向日葵农田为研究对象,基于2016年作物生育期观测数据,利用波文比-能量平衡法、地理探测器及通径分析方法对作物不同生育期农田蒸散发特征进行了定量分析,并与普通灌溉农田进行了比较。结果表明：1）膜下滴灌农田日均蒸散量在作物开花期最高,成熟期次之,苗期最小;随着作物的生长发育,净辐射通量与日蒸散发的相关性逐渐降低;日均蒸散量在各阶段的变化特征与普通灌溉相同,但每个阶段的日均蒸散量均小于普通灌溉农田。2）膜下滴灌农田日内净辐射通量在开花期最高,成熟期次之,苗期最小;日内湍流通量方面,苗期潜热通量与显热通量相当,开花期潜热通量明显高于显热通量,而成熟期潜热通量小于显热通量;而普通灌溉农田在3个时期的潜热通量均高于显热通量。3）温度、湿度与风速是影响膜下滴灌向日葵农田蒸散发的主导因子,湿度的下限决定了蒸散发下限,风速与气温的上限决定了蒸散发的上限;风向对蒸散发的作用不明显。膜下滴灌向日葵农田具有独特蒸散发特征,与普通灌溉农田相比,全生育期节水量超过300 mm。 相似文献
5.
冬小麦冠层温度及其影响因素探析 总被引：12，自引：0，他引：12
采用涡度相关法测定冬小麦农田潜热通量和显热通量 ,研究农田热量平衡各分量及风速对冠层温度和冠层 大气温差的影响结果表明 ,净辐射通量是影响冠层温度高低的主要能量因子 ,二者呈极显著线性相关关系 (α =0 .0 1) ,潜热通量、显热通量和土壤热通量对冠层温度的影响与天气状况有关 ,风速变化对冠层温度的影响作用不显著 ,而与冠层 大气温差间有较好的负相关关系 相似文献
6.
冬小麦调亏灌溉制度田间试验研究初报 总被引：4，自引：1，他引：3
大田试验结果表明,拔节期为冬小麦水分最敏感的生育时期,其次为孕穗期和抽穗～开花期,而返青～起身期充分供水则造成冬小麦明显减产。拔节期最大调亏程度为0～50cm土层土壤含水量≥田间持水量的65%,过小则导致明显减产;孕穗～抽穗期、抽穗～灌浆前期最大调亏程度为0～80cm和0～100cm土层土壤含水量≥田间持水量的60%;灌浆后期最大调亏程度为0～100cm土层土壤含水量≥田间持水量的50%,由此建立了冬小麦调亏灌溉制度。 相似文献
7.
自然条件下半干旱雨养春小麦生育后期旗叶光合的气孔和非气孔限制 总被引：4，自引：1，他引：4
为探究半干旱地区雨养春小麦旗叶的光合作用限制因素、不同生育期差异及其适应策略,分析了大田条件下春小麦旗叶在抽穗期和灌浆期光合生理特征的动态变化规律,探讨了自然条件下光合作用的气孔与非气孔限制特征。结果表明:净光合速率日变化趋势在抽穗期和灌浆期分别为单峰型和双峰型,峰值相当,为18.5μmol(CO2)·m-2·s-1左右。气孔导度具有与净光合作用几乎相似的日变化规律,胞间CO2浓度大致为上午下降、下午回升。胞间CO2浓度变化除受光合作用消耗和气孔限制共同作用外,下午时段叶肉导度增大,也影响胞间CO2浓度变化。在抽穗期和灌浆期,春小麦旗叶光合作用速率与气孔导度相关性十分显著,相关系数分别达0.916(P=0.000)和0.945(P=0.000)。并且2个生育期均出现明显的光合气孔限制,抽穗期达0.64,灌浆期为0.53。其中,抽穗期气孔导度对饱和水汽压差响应十分敏感,下午出现较为明显的气孔限制;灌浆期中午出现较为明显的光合"午休"现象,其主要原因是半干旱区较大饱和水汽压差和强烈辐射致使气孔关闭,气孔限制达到极大值,并且非气孔限制因素也较为突出。抽穗期至灌浆期,由于气孔对饱和水汽压差敏感性的下降以及"午休"策略,光合气孔限制逐渐减小,是春小麦在半干旱地区维持较高光合速率和保证产量的重要自适应机制。 相似文献
8.
半干旱风沙草原区草地潜热通量的特征 总被引：6，自引：1，他引：5
半干旱风沙草原区是北方的主要生态系统类型,对调节局地和全球气候具有重要意义.蒸散作为热量和水量平衡的重要分量,是该生态系统水分损失的主要途径,在水分平衡中占有重要地位.本文利用开路涡度相关系统和常规气象梯度观测系统对科尔沁半干旱风沙草原2007年9月1日-26日的蒸散量和微气象条件进行了观测,根据观测得到数据分析了观测系统的能量平衡闭合状况,探讨了潜热通量与气象因子之间的关系.结果表明,观测系统的能量平衡闭合度为82.7%,处于国内外同类观测闭合度范围的中上水平.30min的潜热通量与净辐射数据之间呈线性相关关系,潜热通量日变化特点是白天高于夜间,中午时刻最高,净辐射与潜热通量每日峰值同时出现,温度、饱和差的峰值比潜热通量峰值滞后2～3h,潜热通量峰值时刻的空气相对湿度处于一日内最低,此季潜热通量平均日总量为5.44MJ*m-2,相当于2.21mm蒸散量,潜热日总量与净辐射日总量呈指数关系. 相似文献
9.
采用涡度相关法,于2010年和2011年对江汉平原水稻-油菜连作田冠层CO2通量进行周年观测,研究该系统CO2源、汇的季节和日变化规律。结果表明,CO2通量的日变化特征明显,各生育期平均CO2通量日变化幅度较大。将观测期通量数据插值后得到CO2净交换通量(NEE)的逐日变化过程,油菜收割后闲置期-中稻移栽期、分蘖期、拔节-抽穗期、乳熟期的平均NEE分别为1.63、-11.86、-20.61、-4.65g.m-2.d-1;水稻收割后的闲置期、油菜苗期-现蕾期、抽薹期、开花期、绿熟期平均NEE值分别为2.18、0.43、-5.00、-11.70、-13.91g.m-2.d-1。全年稻-油连作农田生态系统净CO2吸收量为19.26 t.hm-2。 相似文献
10.
SiB2(simple biosphere model Version 2)是用来模拟生态系统通量较为理想的国外模型,为了探讨其在我国黄河灌区的适用性及利用遥感数据驱动模型的可行性,并用其来研究该地区农田能量收支情况,以位山灌区为研究试点,利用位山实验站1a左右的观测数据对模型进行了验证分析,模拟结果表明:SiB2模型能够较好地模拟位山试验站农田的能量通量、CO2通量及地表温度,净辐射、潜热通量、感热通量、CO2通量与地表温度的模拟值与观测值吻合较好,线性相关系数R分别为0.988,0.714,0.607,0.677与0.933,其中净辐射模拟效果最好,感热通量偏差较大。另外,利用遥感MODIS LAI数据驱动SiB2模型表明,除净辐射外,模拟效果很差,因此在站点尺度遥感LAI(叶面积指数,leaf area index)产品不适合驱动SiB2模型。 相似文献
11.
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
12.
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
13.
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
14.
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
15.
《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
16.
《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
17.
《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
18.
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
19.
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
20.
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