我国西南地区的稻田CH4排放

稻田CH_4排放的季节变化和水稻的生长过程(水稻高度)有较大的关系,有机肥对稻田CH_4排放有促进作用,沼气发酵肥可以降低稻田的CH_4排放量,水稻品种对稻田CH_4排放有一定影响,垄作是减少稻田CH_4排放的一种重要方法。     

Assessing the dye‐tracer correction factor for documenting the mean velocity of sheet flow over smooth and grassed surfaces

In the investigation of overland flow hydraulics, mean flow velocity (V) is frequently estimated using the measured surface flow velocity (Vs) multiplied by a correction factor, α. In total, 291 tests were performed in a flume with three beds [smooth glass (GL), sandpaper (SD), and plastic grass (GR)] to investigate α under submerged and non‐submerged flows, and Vs was observed using dye‐tracer method whilst V was calculated by the measured water depth and flow rate. For GL with 5.2% slope and 100 < Re < 5000 [Reynolds number (Re)], α ranged from 0.35 to 0.79, with an average of 0.54. For SD with slopes ranging from 2.6% to 25.9% and 300 < Re < 1200, α varied from 0.18 to 0.48 with an average of 0.32. Raindrop impacts decreased α for GL at 5.2% slope, but the effect diminished for SD as the slope increased. The α‐values less than the theoretical value of 0.67 in laminar flows may be attributed to the greater spatial variability in overland flow compared with channel flow. For GR with non‐submerged flows and Re < 4200, α varied inversely with sediment concentration (SC) at 5.2% slope but was only slightly related to SC at steep slopes of 15.6% and 25.9%. The α‐values were approximately 0.8 for turbulent flows and even greater than 1.0 under high flow discharges. This finding may relate to sheet flow disturbance and retarded surface velocity due to the protruding scattered grass stems. For each surface, α varied positively with Re; α was inversely related to slope for SD but positively related to slope for GR. There was a positive relation between h and α for GL and SD but a negative relation for GR, which highlights the importance of flow inundation status to α. The inundation ratio (h/Δ) is a promising indicator for predicting α; thus, further investigations using different submerged and non‐submerged surfaces are required to predict α effectively based on (h/Δ). Copyright © 2015 John Wiley & Sons, Ltd.     

Surface energy balance of Keqicar Glacier,Tianshan Mountains,China, during ablation period

The meteorological data of ablation season in 2005 were recorded by two automatic weather stations on Keqicar Glacier, in the southwest Tianshan Mountains of China. One is operated on the glacier near the equilibrium line with an altitude of 4,265 m (Site A) and another is operated on the glacier ablation area with an altitude of 3,700 m (Site B). These data were used to analyze the meteorological conditions and the surface energy balance (SEB) of Keqicar Glacier. Net radiation was directly measured, and turbulent heat fluxes were calculated using the bulk aerodynamic approach, including stability correction. The ablation value of 0.68 m w.e. derived from four ablation stakes is in close correspondence to the modeled value of 0.71 m w.e. During the observation period, net radiation accounts for 81.4% of the total energy with its value of 63.3 W/m². The rest energy source is provided by the sensible heat flux with a value of 14.4 W/m². Energy is consumed mainly by melting and evaporation, accounting for 69.5% and 29.7% of the total energy with their values of 54.0 and 23.0 W/m², respectively. Radiative energy dominates energy exchanges at the glacier-atmosphere interface, governed by the variation in net shortwave radiation. Net short-wave radiation varies significantly due to the effects of cloudiness and the high albedo caused by solid precipitation. Wind speed influences the turbulent heat fluxes distinctively and sensible heat flux and latent heat flux are much larger in July with high wind speed.     

Dynamic Parameters of Plant Communities Partially Reflect the Soil Quality Improvement in Eco‐Reclamation Area of an Opencast Coal Mine

The influence of soil physicochemical properties and the relationship between the plant community and edaphic factors have been studied through monitoring the community dynamic parameters and analyzing the soil properties from four plant plots at the Pingshuo opencast coal mine eco‐reclamation area. The results are obtained as follows: (1) the law of the quantity variation of total N and available K is affected by the different kinds of plant configuration mode. It is Robinia pseudoacacia + Pinus tabuliformis (SIV) > R. pseudoacacia (SV) > R. pseudoacacia + P. tabuliformis (SI) > R. pseudoacacia + Ulmus pumila + Ailanthus altissima (SIII). The quantity is close to or exceeds the level of the original geomorphology. The average content of available N has the following order: SIV > SI > SIII > SV; the average content of available P SV > SIII > SIV > SI, both are far below the level of the original geomorphology; pH SIV < SIII < SI < SV; bulk density SI < SIV < SV < SIII, moisture content SIV > SIII > SI > SV; in the soil layer of 20–40 cm, except the available P, other physicochemical factors are in accordance with the factors of the surface soil; (2) the population average density, height and diameter at breast height (DBH) have no obvious relevance with the average density of the stumpage; (3) the average density, height, and DBH of R. pseudoacacia are closely related to pH and the content of available N and available P and all the index can be fitted by the equation of linear regression of the edaphic factors mentioned above. The principal component analysis shows that the magnitude of the impacts of three kinds of edaphic factors on the R. pseudoacacia population has the following order: pH > available N > available P. The average density of U. pumila is closely related to the moisture content of the soil. This regression model can be used to direct the cultivation and propagation of R. pseudoacacia and U. pumila population at the mine eco‐reclamation area.     

Growth performance,digestive enzyme activities and serum nonspecific immunity of the red tilapia ( Oreochromis mossambicus × Oreochromis niloticus ) fed diets supplemented with ultrafine powder of Enteromopha prolifera

Journal of Oceanology and Limnology - The present study evaluated effects of ultrafine powder of the green macroalgae Enteromopha prolifera as dietary supplement on growth performance, digestive...     

复方中草药对珍珠龙胆石斑鱼生长、非特异性免疫及消化酶活性的影响

中草药含有多种活性物质,具有抗病助长无残留等特性,在国内外被广泛使用。本试验采用单因素试验设计方法,研究复方中草药（由黄芪、党参、大黄等12种中草药组合而成）不同剂量对珍珠龙胆石斑鱼（Epinephelus lanceolatus ♂×Epinephelus fuscoguttatus♀）生长性能、非特异性免疫及消化酶活性的影响。以初始体质量（19.16±0.25） g,体长为（10.63±0.56） cm的珍珠龙胆石斑鱼为试验对象,在基础饲料中分别添加0、0.4%、0.8%、1.2%、1.6%和2%复方中草药连续饲喂珍珠龙胆28 d。结果显示,该种复方中草药在添加剂量1.6%以内时,能有效降低石斑鱼的饵料系数（P<0.05）,对石斑鱼的增重率和特定生长率影响不显著（P>0.05）,但能显著提高石斑鱼血清中总蛋白含量（TP）、碱性磷酸酶（AKP）、酸性磷酸酶（ACP）以及总超氧化物歧化酶（T-SOD）活性（P<0.05）。对血清中非特异性免疫酶活性影响结果表明,中草药添加剂量在0.8%和1.2%时能很好地提高石斑鱼的免疫能力。石斑鱼肠道中的脂肪酶、胰蛋白酶活性受该种复方中草药的影响显著（P<0.05）,在添加量为1.2%以内显著提高了肠道中脂肪酶活性,胰蛋白酶活性和肠道总蛋白含量,而对淀粉酶活性影响不明显（P>0.05）,中草药对珍珠龙胆石斑鱼肠道消化酶活性的影响在添加剂量为1.2%时尤为明显。综合石斑鱼的生长、非特异性免疫和消化性能结果,认为该种复方中草药的最适添加量为1.2%左右。     

Research on the Application of Time Structure Variation Analysis to the Jiashi-Bachu Earthquake Swarm Sequence

In 1997 - 2003, 27 earthquakes with M≥ 5.0 occurred in the Jiashi-Bachu area of Xinjiang. It was a rare strong earthquake swarm activity. The earthquake swarm has three time segments of activity with different magnitudes in the years 1997, 1998 and 2003. In different time segments, the seismic activity showed strengthenin-qguiet changes in various degrees before earthquakes with M ≥ 5.0. In order to delimitate effectively the precursory meaning of the clustering （strengthening） quiet change in sequence and to seek the time criterion for impending prediction, the nonlinear characteristics of seismic activity have been used to analyze the time structure characteristics of the earthquake swarm sequence, and further to forecast the development tendency of earthquake sequences in the future. Using the sequence catalogue recorded by the Kashi Station, and taking the earthquakes with Ms≥ 5.0 in the sequence as the starting point and the next earthquake with Ms = 5.0 as the end, statistical analysis has been performed on the time structure relations of the earthquake sequence in different stages. The main results are as follows： （1） Before the major earthquakes with M ≥ 5.0 in the swarm sequence, the time variation coefficient （δ-value） has abnormal demonstrations to different degrees. （2） Within 10 days after δ= 1, occurrence of earthquakes with M ≥ 5.0 in the swarm is very possible. （3） The time variation coefficient has three types of change. （4） The change process before earthquakes with M5.0 is similar to that before earthquakes with M6.0, with little difference in the threshold value. In the earthquake swarm sequence, it is difficult to delimitate accurately the attribute of the current sequences （foreshock or aftershock sequence） and to judge the magnitude of the follow-up earthquake by δ-value. We can only make the judgment that earthquakes with M5.0 are likely to occur in the sequence. （5） The critical clustering characteristics of the sequence are hierarchical. Onl     

Material sources of escaped gases from Tianchi volcanic geothermal area, Changbai Mountains

On the basis of the chemical components and stable isotopic compositions of escaped gases from the Tianchi volcanic geothermal area, the material sources of these gases are discussed, presenting that they are mainly derived from the residual mantle-derived magma in the crust; Changbai geothermal area may be directly interlinked with the eruption canal in history; there is a stable reservoir of the geothermal water and the deep-seated gases under the Changbai geothermal area, with water temperature of the reservoir being about (166 ± 9)°C. Project supported by the National Natural Science Foundation of China.