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11.
12.
P. Rosenkranz N. Brüggemann H. Papen Z. Xu L. Horváth K. Butterbach-Bahl 《Plant and Soil》2006,286(1-2):301-322
During two intensive field campaigns in summer and autumn 2004 nitrogen (N2O, NO/NO2) and carbon (CO2, CH4) trace gas exchange between soil and the atmosphere was measured in a sessile oak (Quercus petraea (Matt.) Liebl.) forest in Hungary. The climate can be described as continental temperate. Fluxes were measured with a fully automatic measuring system allowing for high temporal resolution. Mean N2O emission rates were 1.5 μg N m−2 h−1 in summer and 3.4 μg N m−2 h−1 in autumn, respectively. Also mean NO emission rates were higher in autumn (8.4 μg N m−2 h−1) as compared to summer (6.0 μg N m−2 h−1). However, as NO2 deposition rates continuously exceeded NO emission rates (−9.7 μg N m−2 h−1 in summer and −18.3 μg N m−2 h−1 in autumn), the forest soil always acted as a net NO
x
sink. The mean value of CO2 fluxes showed only little seasonal differences between summer (81.1 mg C m−2 h−1) and autumn (74.2 mg C m−2 h−1) measurements, likewise CH4uptake (summer: −52.6 μg C m−2 h−1; autumn: −56.5 μg C m−2 h−1). In addition, the microbial soil processes net/gross N mineralization, net/gross nitrification and heterotrophic soil respiration as well as inorganic soil nitrogen concentrations and N2O/CH4 soil air concentrations in different soil depths were determined. The respiratory quotient (ΔCO2 resp ΔO2 resp−1) for the uppermost mineral soil, which is needed for the calculation of gross nitrification via the Barometric Process Separation (BaPS) technique, was 0.8978 ± 0.008. The mean value of gross nitrification rates showed only little seasonal differences between summer (0.99 μg N kg−1 SDW d−1) and autumn measurements (0.89 μg N kg−1 SDW d−1). Gross rates of N mineralization were highest in the organic layer (20.1–137.9 μg N kg−1 SDW d−1) and significantly lower in the uppermost mineral layer (1.3–2.9 μg N kg−1 SDW d−1). Only for the organic layer seasonality in gross N mineralization rates could be demonstrated, with highest mean values in autumn, most likely caused by fresh litter decomposition. Gross mineralization rates of the organic layer were positively correlated with N2O emissions and negatively correlated with CH4 uptake, whereas soil CO2 emissions were positively correlated with heterotrophic respiration in the uppermost mineral soil layer. The most important abiotic factor influencing C and N trace gas fluxes was soil moisture, while the influence of soil temperature on trace gas exchange rates was high only in autumn. 相似文献
13.
Carbon cycling and budget in a forested basin of southwestern Hokkaido,northern Japan 总被引:4,自引:1,他引:4
Hideaki?ShibataEmail author Tsutom?Hiura Yumiko?Tanaka Kentaro?Takagi Takayoshi?Koike 《Ecological Research》2005,20(3):325-331
Quantification of annual carbon sequestration is very important in order to assess the function of forest ecosystems in combatting global climate change and the ecosystem responses to those changes. Annual cycling and budget of carbon in a forested basin was investigated to quantify the carbon sequestration of a cool-temperate deciduous forest ecosystem in the Horonai stream basin, Tomakomai Experimental Forest, northern Japan. Net ecosystem exchange, soil respiration, biomass increment, litterfall, soil-solution chemistry, and stream export were observed in the basin from 1999–2001 as a part of IGBP-TEMA project. We found that 258 g C m–2 year–1 was sequestered annually as net ecosystem exchange (NEE) in the forested basin. Discharge of carbon to the stream was 4 g C m–2 year–1 (about 2% of NEE) and consisted mainly of dissolved inorganic carbon (DIC). About 43% of net ecosystem productivity (NEP) was retained in the vegetation, while about 57% of NEP was sequestered in soil, suggesting that the movement of sequestered carbon from aboveground to belowground vegetation was an important process for net carbon accumulation in soil. The derived organic carbon from aboveground vegetation that moved to the soil mainly accumulated in the solid phase of the soil, with the result that the export of dissolved organic carbon to the stream was smaller than that of dissolved inorganic carbon. Our results indicated that the aboveground and belowground interaction of carbon fluxes was an important process for determining the rate and retention time of the carbon sequestration in a cool-temperate deciduous forest ecosystem in the southwestern part of Hokkaido, northern Japan. 相似文献
14.
Egbert Strauß Andreas Grauer Martina Bartel Roland Klein Ludger Wenzelides Grit Greiser Alexander Muchin Heike Nösel Armin Winter 《European Journal of Wildlife Research》2008,54(1):142-147
The German Wildlife Information System, founded in 2001, is a long-term monitoring program documenting occurrence, number,
and development of game populations throughout Germany. Population numbers are recorded by standardized counting methods in
so-called reference areas. The population densities of the European hare are calculated by spotlight strip censuses in the
reference areas each spring and autumn all across Germany. From 2002 to 2005, the censuses were carried out by local hunters
in 510 to 676 reference areas each year. During these years, the calculated spring densities increased significantly from
11.0 (2002) to 14.5 hares/km2 (2005) nationwide. The overall increase in spring densities was primarily caused by the population rise from spring 2003
to 2004, which correlates with the high net growth rate in 2003. In 2005, the number of counted hares varied between less
than 1 and more than 107 hares/km2 in spring and between 0 and more than 170 hares/km2 in autumn. Because of differing landscapes in Germany, three regions were differentiated. In spring 2005, the average population
densities (median) in East Germany (5.4 hares/km2) and Southwest Germany (14.6 hares/km2) were significantly lower than in Northwest Germany (23.9 hares/km2). These regional differences had been similarly distinct in former years. 相似文献
15.
A. Noormohammadi G.R. Ghorbani M. Alikhani A. Sadeghi-Sefidmazgi H. Rafiee J.K. Drackley 《Animal : an international journal of animal bioscience》2022,16(6):100541
Using corn germ (CG) instead of corn grain could maintain dairy cow performance and might increase the efficiency of human food production. The primary objective of this study was to evaluate the effects of replacing corn grain with CG on the performance, nutrient intake, and digestibility of dairy cows. It also aimed to investigate the effect of CG on the efficiency of human food production in high-producing Holstein dairy cows in early lactation. Nine multiparous Holstein cows with 65.6 ± 8.5 DIM, milk yield of 55.6 ± 4.5 kg/d, and body weight of 611.3 ± 43.3 kg (mean ± SD) were used in a 3 × 3 Latin square design with 21-d periods. Treatments were (1) control treatment (CT, diet contains corn grain), (2) alternative treatment (AT, diet where corn grain was replaced with CG), and (3) balanced treatment (BT, diet where corn grain was replaced with CG but with the same energy content as CT). Control and balanced diets were isoenergetic (6.61 MJ/kg of DM); however, AT had higher energy (6.77 MJ/kg of DM). Treatments had no effect on dry and organic matter intake. NDF intake, however, was higher in CG diets compared with CT (P = 0.0001). Total-tract digestibility of DM tended to be reduced (P = 0.08), and OM digestibility was reduced (P = 0.05) by the inclusion of CG in diets. Whole and energy-corrected milk production were greater in AT compared with CT and BT (P < 0.05). Milk yield was similar in cows fed CT and BT. Treatments had no effect on milk composition or feed efficiency. Diet CT, when compared with CG diets, had lower efficiency in terms of human-edible feed conversion efficiency (HeFCE) and net food production (P < 0.05). Diet BT had greater HeFCE and net production of human-edible CP than AT (P < 0.05). Plasma BHBA, non-esterified fatty acids, and glucose concentrations were not affected by treatments, but plasma cholesterol was higher in cows that consumed CG diets (P = 0.04). The results indicate that, in high-producing early lactation dairy cows fed high concentrate diets, net food protein production can be substantially improved without lowering milk production through the reduction of dietary starch from 30.2 to 24.8% by replacing corn grain with CG. 相似文献
16.
Summary In pot experiments with barley, mustard, leek, lettuce and spinach, and in a field experiment with 30 cultivars of barley uptakes of K, Mg, Ca, Na and N were studied at varying concentrations and activities of these cations in the soil solution.The sum of macro cations (K, Mg, Ca, Na) in meq per 100 g aerial plant parts were independent of the chemical composition of the soil solution, but dependent on plant species and on the N concentration in the plant.The ratios
of mean net inflows of Mg, Ca and K into plants and corresponding cation activity ratios (aMg/aCa and
) in the soil solution were linearly related and highly correlated under conditions in which growth rate and/or rate of incorporation into new tissues constituted the rate determining step of cation uptake. Consequently, mean net inflows of K, Mg and Ca were independent of ion concentration and ion activity of K, Mg or Ca in the soil solution under the conditions of constant activity ratio.The results agree with the concept that plants have a finite cation uptake capacity, and that plants are in a equilibrium-like state with the activities of K, Mg, and Ca ions in the soil solution. The results indicate that both ratios and content of exchangeable cations should be considered in our evaluation of soil test data. 相似文献
17.
Inamul Hasan Madar Ghazala Sultan Iftikhar Aslam Tayubi Atif Noorul Hasan Bandana Pahi Anjali Rai Pravitha Kasu Sivanandan Tamizhini Loganathan Mahamuda Begum Sneha Rai 《Bioinformation》2021,17(2):348
Alzheimer''s Disease (AD) is one of the most common causes of dementia, mostly affecting the elderly population. Currently, there is no proper diagnostic tool or method available for the detection of AD. The present study used two distinct data sets of AD genes, which could be potential biomarkers in the diagnosis. The differentially expressed genes (DEGs) curated from both datasets were used for machine learning classification, tissue expression annotation and co-expression analysis. Further, CNPY3, GPR84, HIST1H2AB, HIST1H2AE, IFNAR1, LMO3, MYO18A, N4BP2L1, PML, SLC4A4, ST8SIA4, TLE1 and N4BP2L1 were identified as highly significant DEGs and exhibited co-expression with other query genes. Moreover, a tissue expression study found that these genes are also expressed in the brain tissue. In addition to the earlier studies for marker gene identification, we have considered a different set of machine learning classifiers to improve the accuracy rate from the analysis. Amongst all the six classification algorithms, J48 emerged as the best classifier, which could be used for differentiating healthy and diseased samples. SMO/SVM and Logit Boost further followed J48 to achieve the classification accuracy. 相似文献
18.
不同氮素营养条件下内生真菌感染对黑麦草光合和蒸腾速率及生物量的影响 总被引:2,自引:0,他引:2
以黑麦草(Lolium perenne L)为实验材料,研究在不同氮素营养条件下内生真菌(Neotyphodium lolii)感染对其光合特性及生物量的影响.结果表明:1)整个实验中,内生真菌感染对黑麦草净光合速率、蒸腾速率以及水分利用效率均无显著影响,但在中氮和高氮水平时,感染种群的净同化累积值有超过非感染种群的趋势;2)在本实验的第一处理期和第二处理期,内生真菌感染对黑麦草绿色部分的干物质产量无显著影响,但在第三处理期感染种群的绿色部分的干物质产量显著高于非感染种群. 相似文献
19.
研究了参棚透光率与西洋参叶片净光合速率之间的关系.结果表明,西洋参叶片光饱和点、净光合速率及其日变型均随参棚透光率的不同,存在一定的差异.4年生西洋参叶片在12%、30%、42%3种透光率下(气温29.0℃左右),光饱和点分别为171.0、323.0和429.0μmol·m-2·s-1,净光合速率最大值为6.54mg·dm-2·h-1(CO2),出现在透光率为30%的参棚下;3年生西洋参在透光率不超过25.8%的参棚下,叶片净光合速率日变化呈单峰型,透光率大于25.8%时,呈双峰型,参叶“光合午休”现象明显.单相关分析表明,光量子通量密度是影响西洋参净光合速率的主要因子;回归分析结果表明,各影响因子对参叶净光合速率的综合影响显著. 相似文献
20.