Seasonal variation of stable isotopes in precipitation of Kathmandu Valley on the southem slope of Himalaya was carried out to understand the controlling mechanism of amount and temperature effect on the basis of one ...Seasonal variation of stable isotopes in precipitation of Kathmandu Valley on the southem slope of Himalaya was carried out to understand the controlling mechanism of amount and temperature effect on the basis of one year stable isotope data from 2010 to 2011. Highly depleted isotope values in major rainy period are obtained just after the onset of precipitation in summer, which ac- counts for ＂amount effect＂ due to saturation isotopic compositions in high moisture condition, whereas, the higher values in winter are indicative to regional vapors （temperature effect） recycling of various sources. An abrupt depletion of isotope values in mid- June, indicates the onset date of monsoon precipitation, by the replacement of winter air mass with southem monsoon. Thus, pre- cipitation isotopes are a tool revealing the onset date of summer monsoon and temporal features of variability, in local and regional monsoons precipitations. A comparison of long term monthly values of 5180, temperature, and precipitation with GNIP 6180 data shows the temporal variations of stable isotopes are mostly controlled by amount and temperature effects. During summer mon- soon, the amount effects are stronger for high values of precipitation （R=0.7） and altitude effect appears for low moisture in late rainy season, thus from December to June （winter to pre-monsoon） the controlling features of isotopes remains under the temper- ature effect. A temporal rate of temperature effect is derived as 0.04%0 per year which indicates a dry signal of atmospheric condition and a temperature relation 5180=（0.371±0.08）T＋（0.156±0.05） is obtained from this analysis. The meteoric water lines of Kathmandu before and after monsoon onset of 2011, are found as 5D=（4.36±0.3）5180＋（15.66±1.2） and 5D=（6.91±0.2）S180-（7.92±2.26） from lab samples result, and 5D=9.25180＋11.725 and 5D=8.535180＋16.65 from GNIP data, which lacks the consistency both for slopes and intercepts values for the study period. The mean lapse rate values of δ18O and δD from GNIP data are obtained as -0.002‰/m and -0.015 ‰/m, which indicate the altitudinal effects in regional precipitation of the southern slope of Himalayas. This study estimates new stable isotopes data in recent precipitation using simple methodology which can be important for regional precipitation monitoring systems, environmental change and paleo-climatic studies.展开更多
In order to provide a theoretical basis for apple cultivation techniques and to provide a reference for preparation of scientific management measures,the occurrence and damage status of apple little leaf in northern G...In order to provide a theoretical basis for apple cultivation techniques and to provide a reference for preparation of scientific management measures,the occurrence and damage status of apple little leaf in northern Guizhou was investigated,and fertilizer control test against the disease was also conducted.（1）Apple little leaf occurred from April to October in apple producing areas in northern Guizhou every year,with heavy incidence from April to May,light incidence from June to July,and the lightest incidence from August to October.（2） Effectiveness test showed that application of zinc sulfate fertilizer 135 g ＋ cow dung 10 kg received the best control effect,followed by zinc sulfate fertilizer 165 g ＋ cow dung 10 kg,then zinc sulfate fertilizer 105 g ＋ cow dung 10 kg and zinc sulfate fertilizer 150 g ＋ cow dung 10 kg.（3） Based on local environmental conditions,occurrence and damage situation,incidence conditions and fertilizer efficacy test,comprehensive prevention and control technology with rational supplement of zinc fertilizer could be used to control apple little leaf.展开更多
为了明确黄土旱塬区不同降雨年型下秸秆覆盖量对土壤水温效应和冬小麦产量影响的机理,本研究连续7年研究了秸秆覆盖量在不同降雨年型对土壤水分、温度及冬小麦耗水和产量的影响。结果表明,秸秆覆盖显著提升越冬期地温,覆盖量越大,增温...为了明确黄土旱塬区不同降雨年型下秸秆覆盖量对土壤水温效应和冬小麦产量影响的机理,本研究连续7年研究了秸秆覆盖量在不同降雨年型对土壤水分、温度及冬小麦耗水和产量的影响。结果表明,秸秆覆盖显著提升越冬期地温,覆盖量越大,增温效果逐渐减弱。在干旱年和平水年,返青期1500 kg hm^(-2)处理呈增温趋势,而丰水年则表现为降温;不同年型下,覆盖量越大降温效果越显著。秸秆覆盖在冬小麦生育期内均增加了0~2 m土层的土壤贮水量,且覆盖量越大贮水量越高;干旱年和平水年,耗水量随覆盖量增加而减少,而丰水年则相反。干旱年返青—灌浆期,1500 kg hm^(-2)处理较露地贮水量增加11.8 mm,且全生育期耗水量在各年型下均高于露地6.9~14.8 mm,其中返青—拔节期和灌浆—成熟期的耗水量增加尤为显著。在产量和水分利用效率方面,1500 kg hm^(-2)处理分别较露地增加17.6%和14.8%,增产主要源于穗数增加;3000 kg hm^(-2)处理的产量和水分利用效率与露地接近,而覆盖量进一步增加则导致产量和水分利用效率下降。当1500 kg hm^(-2)覆盖条件下,可有效提高干旱年和平水年返青期土壤温度,达到高产和高水分利用效率,3000 kg hm^(-2)为临界值,过高覆盖量虽显著增强保水效果,但因降温过度,产量和水分利用效率下降。展开更多
利用IAEA\WMO\GNIP的降水稳定同位素资料,分析了中国降水稳定同位素的时空分布特征及其影响因素。结果表明,整体来看我国降水稳定同位素有明显的大陆效应和高度效应。各地大气降水线存在地域差异,内陆地区同一站点冬、夏半年也有明显差...利用IAEA\WMO\GNIP的降水稳定同位素资料,分析了中国降水稳定同位素的时空分布特征及其影响因素。结果表明,整体来看我国降水稳定同位素有明显的大陆效应和高度效应。各地大气降水线存在地域差异,内陆地区同一站点冬、夏半年也有明显差异,显示出水汽团特性的不同。不同地区降水稳定同位素(δ和过量氘)的季节变化特征明显不同,表明主要水汽来源存在季节性差异。通过对比长序列降水稳定同位素的年际变化与季风和ENSO指数的关系,发现ENSO与降水稳定同位素有显著的正相关,但不一定通过影响降水量来引起降水稳定同位素(stable isotope in precipitation,SIP)的变化。重点分析了我国降水量效应、温度效应的特点,指出沿海和西南等季风区主要受降水量的影响,北方非季风区温度效应起主要作用,交叉地带则两种效应都有影响。展开更多
基金supported by the Ph.D.program of Institute of Tibetan Plateau Research,ITPCAS
文摘Seasonal variation of stable isotopes in precipitation of Kathmandu Valley on the southem slope of Himalaya was carried out to understand the controlling mechanism of amount and temperature effect on the basis of one year stable isotope data from 2010 to 2011. Highly depleted isotope values in major rainy period are obtained just after the onset of precipitation in summer, which ac- counts for ＂amount effect＂ due to saturation isotopic compositions in high moisture condition, whereas, the higher values in winter are indicative to regional vapors （temperature effect） recycling of various sources. An abrupt depletion of isotope values in mid- June, indicates the onset date of monsoon precipitation, by the replacement of winter air mass with southem monsoon. Thus, pre- cipitation isotopes are a tool revealing the onset date of summer monsoon and temporal features of variability, in local and regional monsoons precipitations. A comparison of long term monthly values of 5180, temperature, and precipitation with GNIP 6180 data shows the temporal variations of stable isotopes are mostly controlled by amount and temperature effects. During summer mon- soon, the amount effects are stronger for high values of precipitation （R=0.7） and altitude effect appears for low moisture in late rainy season, thus from December to June （winter to pre-monsoon） the controlling features of isotopes remains under the temper- ature effect. A temporal rate of temperature effect is derived as 0.04%0 per year which indicates a dry signal of atmospheric condition and a temperature relation 5180=（0.371±0.08）T＋（0.156±0.05） is obtained from this analysis. The meteoric water lines of Kathmandu before and after monsoon onset of 2011, are found as 5D=（4.36±0.3）5180＋（15.66±1.2） and 5D=（6.91±0.2）S180-（7.92±2.26） from lab samples result, and 5D=9.25180＋11.725 and 5D=8.535180＋16.65 from GNIP data, which lacks the consistency both for slopes and intercepts values for the study period. The mean lapse rate values of δ18O and δD from GNIP data are obtained as -0.002‰/m and -0.015 ‰/m, which indicate the altitudinal effects in regional precipitation of the southern slope of Himalayas. This study estimates new stable isotopes data in recent precipitation using simple methodology which can be important for regional precipitation monitoring systems, environmental change and paleo-climatic studies.
文摘In order to provide a theoretical basis for apple cultivation techniques and to provide a reference for preparation of scientific management measures,the occurrence and damage status of apple little leaf in northern Guizhou was investigated,and fertilizer control test against the disease was also conducted.（1）Apple little leaf occurred from April to October in apple producing areas in northern Guizhou every year,with heavy incidence from April to May,light incidence from June to July,and the lightest incidence from August to October.（2） Effectiveness test showed that application of zinc sulfate fertilizer 135 g ＋ cow dung 10 kg received the best control effect,followed by zinc sulfate fertilizer 165 g ＋ cow dung 10 kg,then zinc sulfate fertilizer 105 g ＋ cow dung 10 kg and zinc sulfate fertilizer 150 g ＋ cow dung 10 kg.（3） Based on local environmental conditions,occurrence and damage situation,incidence conditions and fertilizer efficacy test,comprehensive prevention and control technology with rational supplement of zinc fertilizer could be used to control apple little leaf.
文摘为了明确黄土旱塬区不同降雨年型下秸秆覆盖量对土壤水温效应和冬小麦产量影响的机理,本研究连续7年研究了秸秆覆盖量在不同降雨年型对土壤水分、温度及冬小麦耗水和产量的影响。结果表明,秸秆覆盖显著提升越冬期地温,覆盖量越大,增温效果逐渐减弱。在干旱年和平水年,返青期1500 kg hm^(-2)处理呈增温趋势,而丰水年则表现为降温;不同年型下,覆盖量越大降温效果越显著。秸秆覆盖在冬小麦生育期内均增加了0~2 m土层的土壤贮水量,且覆盖量越大贮水量越高;干旱年和平水年,耗水量随覆盖量增加而减少,而丰水年则相反。干旱年返青—灌浆期,1500 kg hm^(-2)处理较露地贮水量增加11.8 mm,且全生育期耗水量在各年型下均高于露地6.9~14.8 mm,其中返青—拔节期和灌浆—成熟期的耗水量增加尤为显著。在产量和水分利用效率方面,1500 kg hm^(-2)处理分别较露地增加17.6%和14.8%,增产主要源于穗数增加;3000 kg hm^(-2)处理的产量和水分利用效率与露地接近,而覆盖量进一步增加则导致产量和水分利用效率下降。当1500 kg hm^(-2)覆盖条件下,可有效提高干旱年和平水年返青期土壤温度,达到高产和高水分利用效率,3000 kg hm^(-2)为临界值,过高覆盖量虽显著增强保水效果,但因降温过度,产量和水分利用效率下降。
文摘利用IAEA\WMO\GNIP的降水稳定同位素资料,分析了中国降水稳定同位素的时空分布特征及其影响因素。结果表明,整体来看我国降水稳定同位素有明显的大陆效应和高度效应。各地大气降水线存在地域差异,内陆地区同一站点冬、夏半年也有明显差异,显示出水汽团特性的不同。不同地区降水稳定同位素(δ和过量氘)的季节变化特征明显不同,表明主要水汽来源存在季节性差异。通过对比长序列降水稳定同位素的年际变化与季风和ENSO指数的关系,发现ENSO与降水稳定同位素有显著的正相关,但不一定通过影响降水量来引起降水稳定同位素(stable isotope in precipitation,SIP)的变化。重点分析了我国降水量效应、温度效应的特点,指出沿海和西南等季风区主要受降水量的影响,北方非季风区温度效应起主要作用,交叉地带则两种效应都有影响。
