气象因子对麦田土壤呼吸速率影响的通径分析(英文)

[Objective] The experiment aimed to study the effects of meteorological factors under different weather conditions on soil respiration. [Method] The path analysis was used to analyze meteorological factors which influenced soil respiration of wheat field under different weather condition and at jointing stage. [Result] In sunny day, the correlations between ground temperature at 5 cm, solar radiation, air relative humidity, air temperature and soil respiration were all at significant level while solar radiation and ground temperature at 5 cm were the major factors which influenced soil respiration. In cloudy day, solar radiation was a major factor which influenced soil respiration. [Conclusion] The soil respiration and surplus path coefficient in sunny day were all higher than these in cloudy day, which demonstrated that except influenced by ground temperature, air temperature, solar radiation and air relative humidity, the soil respiration was also influenced by other factors especially biological factor.     

Estimation of Cucumber Evapotranspiration in Solar Greenhouse in Northeast China

The solar greenhouse without heating system has been widely used for vegetable production in Northeast China since the 1980s. The experiment was conducted in the solar greenhouse to study the relationship between evapotranspiration （ET） of cucumber and climatic factors. Reference evapotranspiration （ET0） and pan evaporation （Ep） were applied to determine cucumber evapotranspiration by regression methods. Results showed that the ET of cucumber increased with the increasing of solar radiation, air temperature and vapor pressure. The solar radiation was the most important factor that influences ET among environmental parameters. The determination coefficient （R2） was 0.865 between ET and Ep, higher than that between ET and ET0 （application of a constant vegetation coefficient, R2 = 0.46）. The pan coefficient （kp, determined from the ratio of ET to Ep） and the crop coefficients （kc, determined from the ratio of ET to ET0） showed considerable variability and no obvious systematic pattern could be described throughout the study period. Ep was linearly related to ET and 20 cm pan can be well used to determine the water requirement of cucumber under subsurface drip irrigation in this type of solar greenhouse.     

Spatiotemporal Characteristics of Reference Evapotranspiration and Its Sensitivity Coefficients to Climate Factors in Huang-Huai-Hai Plain,China

Climate change will have important implications in water shore regions,such as Huang-Huai-Hai（3H） plain,where expected warmer and drier conditions might augment crop water demand.Sensitivity analysis is important in understanding the relative importance of climatic variables to the variation in reference evapotranspiration（ET 0）.In this study,the 51-yr ET 0 during winter wheat and summer maize growing season were calculated from a data set of daily climate variables in 40 meteorological stations.Sensitivity maps for key climate variables were estimated according to Kriging method and the spatial pattern of sensitivity coefficients for these key variables was plotted.In addition,the slopes of the linear regression lines for sensitivity coefficients were obtained.Results showed that ET 0 during winter wheat growing season accounted for the largest proportion of annual ET 0,due to its long phenological days,while ET 0 was detected to decrease significantly with the magnitude of 0.5 mm yr-1in summer maize growing season.Solar radiation is considered to be the most sensitive and primarily controlling variable for negative trend in ET 0 for summer maize season,and higher sensitive coefficient value of ET 0 to solar radiation and temperature were detected in east part and southwest part of 3H plain respectively.Relative humidity was demonstrated as the most sensitive factor for ET 0 in winter wheat growing season and declining relativity humidity also primarily controlled a negative trend in ET 0,furthermore the sensitivity coefficient to relative humidity increased from west to southeast.The eight sensitivity centrals were all found located in Shandong Province.These ET 0 along with its sensitivity maps under winter wheat-summer maize rotation system can be applied to predict the agricultural water demand and will assist water resources planning and management for this region.     

宁夏沙坡头人工植被区土壤真菌种群的动态研究(英文)

[Objective] The changes of fungi in different soil layers and sand dunes of artificial vegetation areas in Ningxia Shapotou during different times were studied. [Method]The number of soil fungi in different soil layers at same plot and in same soil layer at different plots were changed significantly.The quantitative distribution of fungi was the most in Cuiliugou but the fewest in quicksand among all soil types.[Result] The quantity of soil fungi in grasslands was varied in different soil layers at the same sample and in the same soil layer at different sample plots. The quantity of fungi from different soil types distributed mostly in Cuiliugou, a natural desert steppe, but little in quicksand. The species and quantity of fungi in CuiLiugou was the most in different types of sand-fixing lands. [Conclusion] The quantity of soil fungi in artificial vegetation areas raises with the increase of sand-fixing ages, The enhancement of vegetation construction and artificial management measures in inland is helpful for improving present situation of desertification.     

黑麦草-白三叶人工草地退化趋势研究(英文)

[Objective] The study aimed to explore the degradation law and trend of artificial grassland. [Method] Taking the ryegrass (Lolium perenne)-white clover (Trifolium repens) artificial grassland in Maiping Township, Guizhou Province as the research object, the grassland vegetation of 40 quadrats from different areas (area around the sheep shed, hilltop, hillside, flatland at the foot of the hill) were analyzed by comparing the dominance and richness index. [Result] Degradation of different degrees appeared in various areas of this artificial grassland. To be specific, the degradation of grassland around the sheep shed was not serious for less consumption by the sheep; however, the areas on the hilltop and hillside degenerated to the grassland types of dallis grass (Paspalum dilatatum Poir.)-Indian lovegrass (Eragrostis pilosa) and dallis grass-cogongrass [Imperata cylindrica (Linn.) Beauv.], respectively, and the area at the foot of the hill degenerated to the grassland type dominated by garland chrysanthemum (Chrysanthemum coronarium L.) and knotgrass (Paspalum distichum L.). [Conclusion] This study provided a basis for grassland improvement as well as the efficient and sustainable utilization of grazing-type artificial grassland in South China.     

Temperature Difference Between the Air and Organs of Rice Plant and Its Relation to Spikelet Fertility

Based on the experiment of measuring panicles and leaves, air temperature, and humidity above the canopy of rice cultivars after heading in 2005 and 2006, we investigated the temperature difference （TD） between the air and organs of rice plant and its relationship with spikelet fertility. The results showed that TDs between the air and organs of rice varied with air temperature, air humidity, and plant type. For similar air humidity, TDs were lower at the air temperature of 28.5℃ than at higher temperature of 35.5℃, whereas for the same air temperature, the TDs decreased as the air humidity increased. TDs were also affected by plant type of the cultivars. Erect panicle cultivars showed higher TDs than those with droopy panicles under similar climatic conditions, and cultivars with panicles above flag leaf （PAFL） had higher TDs than those with panicles below the flag leaf （PBFL）. Cultivars grown in a location with lower air humidity and higher temperature, such as Taoyuan, China, had higher spikelet fertility than those in higher humidity under the similar air temperature during the grain filling stage. This is partially attributed to the larger TDs under the lower humidity. Rowspacing and the ratio of basal-tillering to panicle-spikelet fertilizer showed a significant influence on TD and subsequently on spikelet fertility, suggesting the possibility of increasing spikelet fertility by agronomic management.     

Response of CO2 Emissions to the Change of Major EnvironmentalFactors in a Temperate Grassland Ecosystem

Using dark enclosed chamber technique, CO2 fluxes from meadow, Leymus chinensis grasslandand Stipa grandis grassland and major environmental factors were measured in Xilin RiverBasin of Inner Mongolia under abnormally dry circumstances during June to September2001, when rainfall was less than 1/6 of that in normal years. Results showed the diurnalvariation of CO2 flux was significantly positively correlated with the earth‘s surfacetemperature and air temperature. As to the response of the fluxes of CO2 to annualprecipitation, the average CO2 emission decreased from 268.7, 211.6 to 181.4 mg m^-2 h^-1 inmeadow, Leymus chinensis grassland and Stipa grandis grassland, respectively, with adecrease in annual precipitation. Therefore precipitation was an important environmentalfactor influencing CO2 flux from grassland. We also found close positively correlationbetween CO2 emissions and soil water content, organic content and total nitrogen contentin different soil layers. However, there was little correlation between the monthlyfluctuation of CO2 emissions with air temperature, topsoil temperature and soil temperaturesat 5 and i0 cm soil depth.     

Seasonal Variation of Moisture Availability at Water-wind Erosion Crisscross Region in Northern Loess Plateau China

The objectives of the current study were to estimate evapotranspiration（ET） over the grassland and assess seasonal variation of moisture availability at the wind-water erosion crisscross region in the northern Loess Plateau of China. The Liudaogou Catchment which has the representative climatic and hydrological characteristics of the wind-water erosion crisscross region was chosen as the study location. The reference crop evapotranspiration（ET 0） was estimated by Penmen method, which was recommended by FAO56 and the evapotranspiration over the grassland（ET） was estimated by Penmen-Monteith equation using the observed meteorological data with time unit of 1 h. The soil moisture availability factor was defined by m a =ET/ET 0. The calculated results for 2006 indicated that the total ET 0 was slightly more than the total yearly precipitation and ET accounted for 37 % of that, ET increased distinctly after the intensive rainfall event in the rainy season. Most of the m a was less than 0.4 and its annual mean was 0.34. It was expected that the results provided a basis for studies on dynamic functional analysis of soil moisture, relationship between soil water and crop growth at the wind-water erosion crisscross region in the northern Loess Plateau.     

Geographic Variation of Rice Yield Response to Past Climate Change in China

Previous studies demonstrated climate change had reduced rice yield in China, but the magnitude of the reduction and the spatial variations of the impact have remained in controversy to date. Based on a gridded daily weather dataset, we found there were obvious changes in temperatures, diurnal temperature range, and radiation during the rice-growing season from 1961 to 2010 in China. These changes resulted in a signiifcant decline of simulated national rice yield （simulated with CERES-Rice）, with a magnitude of 11.5%. However, changes in growing-season radiation and diurnal temperature range, not growing-season temperatures, contributed most to the simulated yield reduction, which conifrmed previous estimates by empirical studies. Yield responses to changes of the climatic variables varied across different rice production areas. In rice production areas with the mean growing-season temperature at 12-14＆#176;C and above 20＆#176;C, a 1＆#176;C growing-season warming decreased rice yield by roughly 4%. This decrease was partly attributed to increased heat stresses and shorter growth period under the warmer climate. In some rice areas of the southern China and the Yangtze River Basin where the rice growing-season temperature was greater than 20＆#176;C, decrease in the growing-season radiation partly interpreted the widespread yield decline of the simulation, suggesting the signiifcant negative contribution of recent global dimming on rice production in China＇s main rice areas. Whereas in the northern rice production areas with relatively low growing-season temperature, decrease of the diurnal temperature range was identiifed as the main climatic contributor for the decline of simulated rice yield, with larger decreasing magnitude under cooler areas.     

A Computer Program for Automatic Watering Based on Potential Evapotranspiration by Penman Method and Predicted Leaf Area in Miniature Pot Rose Production

In this study, we developed a computer program for automatic prediction of watering time point by considering the environmental factors such as solar radiation, air temperature and relative humidity based on the multiple linear regression equation of leaf area and Penman Method. The experiments were carried out for a year in two watering experimental plots, one of which was controlled by pF value, and the other by the computer program. After comparing the results of the two plots, the following findings were obtained. In the computer program plot, the observed and predicted values of both leaf area and evapotranspiration indicated significant correlation at the 1% level, which suggested that the computer program had high prediction accuracy. In addition, no significant difference was observed between the two experimental plots with respects to the plant height, plant diameter, leaf area, leaf number, fresh weight, and dry weight, which demonstrated that the plants in the computer program plot had normal growth. On the other hand, although the number of flower buds and flowering shoots showed higher values at the end of certain cultivations in the computer program plot than those in pF value plot, we proposed that it was due to the effect of cumulative daily solar radiation in the greenhouse, rather than the watering. Thus, we have reached the conclusion that the computer program for automatic prediction of watering time point developed by this study has high applicability in miniature pot rose production.     

三江源区人工草地蒸散量与气候因子的相关分析

该研究以小型自动气象站观测资料为基础,采用FAO Penman-Monteith方法估算三江源区人工草地参考作物蒸散量,并结合FAO-56推荐的综合作物系数值进行草地实际蒸散量的计算,分析了三江源区人工草地实际蒸散量的变化及其与气象因子的关系。结果表明,草地实际蒸散量的季节变化为单峰曲线,夏季日蒸散量明显大于冬季,在8月中旬达到年度最高值。蒸散与空气温度、太阳辐射和相对湿度均显著相关,但与风速的相关性不显著。各气象因子对人工草地蒸散量影响的大小顺序为:空气温度(T)>太阳辐射(Ra)>空气相对湿度(RH)>风速(u2)。     

不同灌溉水平下气象因子对草地早熟禾蒸散量的影响

[目的]研究不同灌溉水平下气象因子对草地早熟禾蒸散量的影响。[方法]以田间持水量为标准,用称重法控制土壤含水量并测量草地早熟禾蒸散量,利用Watchdog气象仪记录实时气象数据,研究在不同灌溉水平下草地早熟禾蒸散量及其动态,并研究草地早熟禾蒸散量与气象因子的关系。[结果]充分灌溉条件下草地早熟禾的蒸散量明显大于限制灌溉;除了8月限制灌溉草地早熟禾日蒸散量呈双峰型外,其他草地早熟禾日蒸散量均呈单峰型,且峰值均出现在当天气温最高值之前;月蒸散量随太阳辐射和气温的减小而逐月减少。草地早熟禾蒸散量受太阳辐射和气温的影响最显著,与相对湿度呈负相关关系,与风速的正相关性较不显著。[结论]该研究为草地早熟禾的栽培提供科学依据。     

黄土丘陵区山杏人工林蒸腾速率与环境因子的关系

为探究山杏蒸腾耗水规律与环境因子的关系，以内蒙古自治区呼和浩特市清水河县山杏造林树种作为研究对象，测定了山杏蒸腾速率，并结合太阳辐射、空气温度、空气相对湿度、水汽压亏缺、风速等因子，研究了山杏蒸腾速率与环境因子的连日动态变化。结果表明：①山杏蒸腾速率表现出明显的昼夜变化规律，变化趋势呈现双峰曲线，第一个峰值为148.82 g·h^-1，第二个峰值为144.75 g·h^-1，并存在“午休现象”，白天蒸腾速率较高，夜晚蒸腾速率较低且变化幅度相对平缓。②山杏蒸腾速率与太阳辐射、空气温度、水汽压亏缺、风速成极显著正相关，与空气相对湿度成极显著负相关，并且与环境因子的响应存在时滞性。③各环境因子对蒸腾速率的影响程度顺序为太阳辐射＞空气温度＞水汽压亏缺＞空气相对湿度＞风速。     

喀什噶尔河流域参考作物蒸散量变化趋势及其主要影响因素分析

根据喀什噶尔河流域2个气象台站的历史气候资料以及P-M公式,计算流域各地逐年参考作物蒸散量,采用线性回归方法,分析了近50年各站气候要素、年参考作物蒸散量的变化特征及参考作物蒸散量变化的气候成因。结果表明,全流域平均气温、日照时数、空气相对湿度呈升高趋势,年平均风速呈减小的趋势,降水量变化不明显;年参考作物蒸散量与平均气温、日照时数、风速呈正相关关系,与平均相对湿度呈负相关关系,与降水量没有直接的相关性;受各气候要素变化的综合影响,近50年喀什噶尔河流域的参考作物蒸散量总体呈减小趋势,这与全球和我国大部分地区的变化基本一致。     

黄土丘陵区山杏人工林蒸腾速率与环境因子的关系

为探究山杏蒸腾耗水规律与环境因子的关系,以内蒙古自治区呼和浩特市清水河县山杏造林树种作为研究对象,测定了山杏蒸腾速率,并结合太阳辐射、空气温度、空气相对湿度、水汽压亏缺、风速等因子,研究了山杏蒸腾速率与环境因子的连日动态变化。结果表明：①山杏蒸腾速率表现出明显的昼夜变化规律,变化趋势呈现双峰曲线,第一个峰值为148.82 g·h^-1,第二个峰值为144.75 g·h^-1,并存在“午休现象”,白天蒸腾速率较高,夜晚蒸腾速率较低且变化幅度相对平缓。②山杏蒸腾速率与太阳辐射、空气温度、水汽压亏缺、风速成极显著正相关,与空气相对湿度成极显著负相关,并且与环境因子的响应存在时滞性。③各环境因子对蒸腾速率的影响程度顺序为太阳辐射＞空气温度＞水汽压亏缺＞空气相对湿度＞风速。     

乌兰布和沙漠人工梭梭夏季茎干液流变化特征及其与气象因子的关系

为了揭示乌兰布和沙漠人工梭梭水分利用规律，探究人工梭梭的生态适应能力，利用PS TDP8树木茎流监测系统和自动气象站对乌兰布和沙漠1979年人工种植梭梭的液流变化及其周围的环境因子进行观测，采用逐步回归及相关分析法对茎干液流变化规律及其与太阳总辐射、空气温度、相对湿度、风速、土壤温度、土壤含水量的相关关系进行研究。结果表明：梭梭晴天茎干液流日变化呈“单峰型”，雨天茎干液流日变化呈“双峰型”；夏季晴天梭梭茎干液流在7:00左右启动，9:30左右出现峰值，液流在10:20以后开始迅速下降，至21:30基本下降到极低值，夜间仍有液流。直径125和895 cm的梭梭液流日累积量分别为1423 和260 L。晴天，茎干液流速率变化幅度较大，白天的液流速率高于夜间。雨天的液流峰值显著低于晴天，且夜间液流小于晴天。相关性分析表明，晴天，影响梭梭液流速率的环境因子依次为太阳总辐射、土壤含水量、空气温度、空气相对湿度、土壤温度、风速；雨天，影响梭梭液流速率的主要环境因子依次为太阳总辐射、空气温度、空气相对湿度、土壤温度、风速、土壤含水量。研究结果可为人工梭梭林的经营管理提供理论支撑，对沙漠地区人工梭梭的管理和保护有重要的理论和实际意义。     

长沙丘陵区油茶林地土壤蒸发的时空变化

2019年4—9月,采用微型蒸渗仪测定长沙丘陵区油茶林地土壤蒸发量;利用ETgage模拟蒸散仪监测林地局部蒸散量,对比分析长沙丘陵地区土壤蒸发量的时空变化,探讨土壤蒸发随气象因素和土壤含水量的变化关系。结果表明：长沙丘陵区油茶林土壤蒸发总量约为192.15 mm,日均为1.05 mm;不同空间位置上,阳面、绝对阴面、相对阴面的土壤蒸发量依次减少,平均值分别为1.14、0.98和0.94 mm/d;空气温度、地温、风速、太阳辐射强度、空气相对湿度对前期(4—5月)土壤蒸发量的影响依次减小,空气温度、空气相对湿度、太阳辐射强度、地温、风速对中期(6—7月)土壤蒸发量的影响依次减小,地温、太阳辐射强度、空气温度、风速、空气相对湿度对后期(8—9月)土壤蒸发量的影响依次减小;前期土壤蒸发量与土壤含水量的相关性较小,中期、后期土壤蒸发量与5 cm土层土壤含水量呈显著正相关,土壤蒸发前缘主要发生于0~5 cm土层;长沙丘陵区油茶林地局部蒸散量约为2.12 mm/d,局部油茶树蒸腾量约为1.11 mm/d,ETgage所测局部蒸散量与微型蒸渗仪测得的蒸发量变化趋势大体相同,且两者呈显著正相关。     

气象要素(气温、太阳辐射、风速和相对湿度) 日变化进程的数理模拟

在建立植物生态生理模型（如光合作用、蒸腾作用数理模型）的过程中，气温、太阳辐射、风速、相对湿度等气象要素的日变化及瞬时资料是必不可少的。本文根据常规台站的日常观测资料，建立了气温、太阳辐射、风速、相对湿度等气象要素日变化的数理模型。并应用实测资料对所建模型进行了验证。实验表明：（1）描述气温日变化的正弦－指数模型通常其模拟结果不甚理想，但通过引用最高温度的时间延迟参数及惯性系数，可增加模拟结果的准确性。（2）根据日平均风速资料，应用两条正弦曲线模型可模拟的日变化及瞬时值，并可根据具体地点，确定日最小风速及两条正弦曲线的起至时间。（3）根据测量的太阳辐射日总量值以及太阳高度的日变化值等，可准确地模拟太阳辐射的日变化;(2)根据日平均风速资料，应用两条正弦曲线模型可模拟的日变化及瞬时值，并可根据具体地点，确定日最小风速及两条正弦曲线的起至时间.(3)根据测量的太阳辐射日总量值以及太阳高度的日变化值等，可准确地模拟太阳辐射的日变化；（4）根据露点温度和气温常规资料可准确模拟相对湿度的日变化。如果区域参数已知或被正常估计，上述方法可得到较为理想的气象要素日变化的模拟结果。     

1961-2008年塔城地区气候变化特征

根据新疆塔城地区7个气象台站1961-2008年的气候资料,采用气候倾向率、累积距平、t检验和Mor-let小波等方法,对塔城地区1961-2008年年平均气温、日照时数、降水量、平均风速、年潜在蒸散量以及湿润指数的变化特征进行了分析。结果表明,1961-2008年塔城地区年平均气温、降水量呈升高(增多)趋势,日照时数、年平均风速和潜在蒸散量呈减少(减小)趋势,湿润指数呈增大趋势;突变检测表明,塔城地区1961-2008年年平均气温在1988年开始发生了突变性升高;降水量在1986年开始发生了突变性增多;日照时数、平均风速也分别在1981年、1985年发生了突变性减小,受气温、降水、日照和风速的综合影响,潜在蒸散量也于1985年发生了极显著的突变性减小,湿润指数在1986年发生了突变性增大。综合气温、降水和湿润指数的变化可以认定,塔城地区的气候在1986-1988年出现了"暖湿化"趋势;自然正交分解表明,塔城地区年平均气温、日照时数、降水量、平均风速、潜在蒸散量以及湿润指数的空间分布特征均是同向性,其中年平均气温、平均风速、湿润指数的空间分布特征的同向性强于日照时数、降水量和潜在蒸散量。各气候要素分别存在3～23a的不同时间尺度的周期性变化。     

1961—2008年新疆克拉玛依市气候变化分析

根据新疆克拉玛依市气象站1961—2008年的历史气候资料，采用气候倾向率、累积距平、t检验和Morlet小波等方法，对1961—2008年的年平均气温、降水量、日照时数和年平均风速以及年潜在蒸散量和地表干燥度等要素的变化趋势和变化特征进行了研究，结果表明：①1961—2008年克拉玛依市年平均气温和降水量呈上升趋势，日照时数和年平均风速呈减小的趋势，气候总体呈“暖湿化”趋势；②潜在蒸散量与日照时数和平均风速呈极显著的正相关关系，与年降水量呈极显著的负相关关系，但与气温的相关性不显著。受各气候要素变化的综合影响，1961—2008年，克拉玛依市潜在蒸散量和地表干燥度呈显著的减小趋势；③突变检测表明，克拉玛依市年平均气温、降水量分别在1988年发生了突变性的升高，而风速、潜在蒸散量和地表干燥度分别于1988年、1983年和1986年发生了显著的突变性减小，日照时数未发生突变。综合各要素的突变特征，可以确认，克拉玛依市的气候于1986—1988年发生了“暖湿化”的突变；④各要素分别存在4～22a的不同时间尺度的周期性变化。