The average rainfall in whole growth period of winter wheat to plus or minus several times of sample variance was used to define different grades of drought.The reduction rate of production in meteorological which was...The average rainfall in whole growth period of winter wheat to plus or minus several times of sample variance was used to define different grades of drought.The reduction rate of production in meteorological which was equal to or greater than the rate of 3% was taken as standards to define wheat drought disaster years.The average reduction ratio of production in the wheat drought years in Hebei-Shandong-Henan was calculated.The frequency distribution rule of wheat in different drought disaster strength of winter wheat in Hebei-Shandong-Henan was analyzed.According to the conception and calculation method of drought disaster risk index of winter wheat,the regional distribution law of drought disaster risk index of winter wheat was analyzed.The division technical methods of winter wheat drought disaster risk zones in Hebei-Shandong-Henan under the irrigated conditions were put forward.Taking the average reduction rate of production in drought years,drought disaster risk index and precipitation of winter wheat in growth periods as indices,using the statistical analysis and overlay function of GIS,the production reduction risk of winter wheat caused by drought disaster in winter wheat zones of Hebei-Shandong-Henan was divided and evaluated.The risk evaluation of production reduction of winter wheat in different risk zones under different climate conditions was realized.The disaster prevention and mitigation measures of winter wheat drought were given.展开更多
[Objective] The aim was to study the reasons for consecutive severe droughts in autumn and winter. [Method] By dint of precipitation in the observatory station and NCEP/NCAR reanalysis data in observatory station, the...[Objective] The aim was to study the reasons for consecutive severe droughts in autumn and winter. [Method] By dint of precipitation in the observatory station and NCEP/NCAR reanalysis data in observatory station, the circulation background, vertical movement, abnormal temperature and changes of water vapor conditions in Xuzhou from October 2008 to January 2009 were expounded to reveal the causes for consecutive drought in autumn and winter. [Result] Xuzhou was under stable situation for a long time in autumn and winter in 2008, being behind east coastal trough, the downward airstream prevailing; the south trough intensity was weak, and in addition to the east subtropical high and weak intensity, the water vapor transportation condition in Indian Ocean and South Sea was unfavorable. The autumn was warm and the cold air was weak; ever since winter, there were several cold air activities. But the influencing body was in the east, and the south warm and wet airstream was insufficient. Thus, they couldn’t met, which resulted into gale and lower temperature and less precipitation when under the influence of cold air. [Conclusion] The study provided theoretical basis for the prevention of drought in the area.展开更多
[Objective]The study aimed to assess and zone the drought risk of winter wheat in Anhui Province. [Method] The zoning factors were chosen from three aspects of disaster-causing factors,disaster-bearing bodies and envi...[Objective]The study aimed to assess and zone the drought risk of winter wheat in Anhui Province. [Method] The zoning factors were chosen from three aspects of disaster-causing factors,disaster-bearing bodies and environment conducive to drought,and then their data were standardized,rasterized and graded. Using analytic hierarchy process（ AHP）,we determined the weight of each index at various levels and then established the assessment models of drought intensity,sensitivity,vulnerability and resistance of winter wheat in the whole growth period and at heading and filling stage. Finally,the zoning map of drought risk for winter wheat in Anhui Province was obtained using the farmland data mask of Anhui Province. [Result]The drought risk of winter wheat in Anhui Province in the whole growth period and at heading and filling stage was divided into six grades,which reflected the distribution characteristics and regional difference of drought risk for winter wheat in Anhui Province. Drought risk was the maximum in the main producing areas of winter wheat in the north of Huaihe River,followed by the area along Huaihe River and the area between Yangtze River and Huaihe River,while the drought risk of winter wheat was very low in the south of Anhui Province. The drought risk of winter wheat was markedly affected by the sensitivity to drought,vulnerability and the drought resistance of winter wheat. [Conclusion] The research could provide scientific references for rational distribution of winter wheat and establishment of strategies for disaster prevention and mitigation.展开更多
In recent years, the socio-economic impacts of winter extreme climate events have underscored the importance of winter climate anomalies in Southwest China （SWC）. The spatio-temporal variability of surface air tempe...In recent years, the socio-economic impacts of winter extreme climate events have underscored the importance of winter climate anomalies in Southwest China （SWC）. The spatio-temporal variability of surface air temperature （SAT） and precipitation in SWC and their possible causes have been investigated in this paper based on observational data from 1961 to 2010. The results indicate that SAT anomalies in SWC have two dominate modes, one is homogenous, and the other a zonal dipole. The former is caused by the anomalies of East Asian winter monsoon; the latter arises from the anomalies of both subtropical west Pacific high and regional cold air in lower troposphere. The most dominant mode of precipitation anomalies in SWC is homogenous and it has a high correlation with northern hemisphere annular mode （NAM, AO）. Neither NAM nor ENSO has significant impacts on SAT in SWC. The anomalies of NAM are associated with the anomalies of tropical circulations, and therefore precipitation over the SWC. When NAM is in positive （negative） phase, the winter precipitation is more （less） than normal in SWC. Winter precipitation increase over the whole SWC is associated with the El Nino. However, during La Nina winter, the pattern is not uniform. There is an increase in precipitation over the central parts and a decrease in western and eastern parts of SWC. The severe drought in SWC in winter 2010 is more likely caused by anomalies of NAM, not El Nino.展开更多
Based on the daily data of temperature and precipitation of 108 meteorological stations in Southwest China from 1960 to 2009, we calculate the monthly and yearly surface humid indexes, as well as the extreme drought f...Based on the daily data of temperature and precipitation of 108 meteorological stations in Southwest China from 1960 to 2009, we calculate the monthly and yearly surface humid indexes, as well as the extreme drought frequency. According to the data, the temporal and spatial characteristics of the extreme drought frequency in inter-annual, inter-decadal, summer monsoon period and winter monsoon period are analyzed. The results are indicated as follows. （1） In general, the southwestern Sichuan Basin, southern Hengduan Mountains, southern coast of Guangxi and northern Guizhou are the areas where the extreme drought frequency has significantly increased in the past 50 years. As for the decadal change, from the 1960s to the 1980s the extreme drought frequency has presented a decreasing trend, while the 1990s is the wettest decade and the whole area is turning wet. In the 2000s, the extreme drought frequency rises quickly, but the regional differences reduce. （2） During summer monsoon period, the extreme drought frequency is growing, which generally occurs in the high mountains around the Sichuan Basin, most parts of Guangxi and ＂the broom-shaped mountains＂ in Yunnan. It is distinct that the altitude has impacts on the ex- treme drought frequency; during winter monsoon period, the area is relatively wet and the extreme drought frequency is decreasing. （3） During summer monsoon period, the abrupt change is observed in 2003, whereas the abrupt change during winter monsoon period is in 1989. The annual extreme drought frequency variation is a superposition of abrupt changes during summer monsoon and winter monsoon periods. The departure sequence vibration of annual extreme drought frequency is quasi-5 years and quasi-12 years.展开更多
Field studies were conducted at Bushland, Texas, USA, in 2004 to examine usefulness of canopy temperature depression （CTD）, the difference of air-canopy temperature, in screening wheat （Triticum aestivum L.） genot...Field studies were conducted at Bushland, Texas, USA, in 2004 to examine usefulness of canopy temperature depression （CTD）, the difference of air-canopy temperature, in screening wheat （Triticum aestivum L.） genotypes for yield under dryland and irrigated. Forty winter wheat genotypes were grown under irrigation and dryland. CTDs were recorded after heading between 1 330 and 1 530 h on 6 clear days for dryland and 9 days for irrigation. Drought susceptible index （DSI） for each genotype was calculated using mean yield under dryland and irrigated conditions. Genotypes exhibited great differences in CTD under each environment. The dryland CTDs averaged 1.33℃ ranging from -0.67 to 2.57℃, and the average irrigation CTD were 4.59℃ ranging from 3.21 to 5.62℃. A low yield reduction was observed under dryland conditions relative to irrigated conditions for high-CTD genotypes. CTD values were highly negatively correlated with DSI under dryland, and genotypes of CTDs = 1.3℃ in dryland condition were identified as drought resistant. For 21 genotypes classified as drought resistant by DSI, their CTDs were 1.68℃ for dryland and 4.35℃ for irrigation on average; for 19 genotypes classified as drought susceptible by DSI, average CTD was 0.94℃ in dryland and 4.85℃ in irrigation. The high-yield genotypes consistently had high CTD values, and the low-yield ones had low CTD values for all measurements in dryland. After heading, genotypes maintained consistent ranking for CTD. Regression results for CTD and yield suggested that the best time for taking CTD measurement was 3-4 weeks after heading in irrigation but any time before senescence in dryland. Crop water stress index （CWSI） calculated from CTD data was highly correlated with CWSI calculated from yield, which suggesting traditional costly CWSI measurement may be improved by using portable infrared thermometers. Most importantly, grain yield was highly correlated with CTD under dryland （R^2 = 0.79-0.86） and irrigation （R^2 = 0.46-0.58） conditions. These results clearly indicated grain yield and water stress can be predicted by taking CTD values in field, which can be used by breeding programs as a potential selection criterion for grain yield and drought resistance in wheat, but a second study year is needed to confirm further.展开更多
The development of near isogenic lines(NILs) is an important tool for physiological dissection of drought resistance in wheat. To better understand the potential for improving grain yield, a split-plot experiment was ...The development of near isogenic lines(NILs) is an important tool for physiological dissection of drought resistance in wheat. To better understand the potential for improving grain yield, a split-plot experiment was conducted under a mobile rain shelter using NILs of winter wheat with significant differences in the photosynthetic rate: the 908120 line with a high photosynthetic rate and the 908206 line with a low photosynthetic rate. The results indicated that the net photosynthesis rate(Pn), stomatal conductance, and transpiration rate in flag leaves in line 908120 were significantly higher than that in line 908206 under uniform water treatments during the reproductive phase in replicated pooled-culture trials. The maximum quantum yield Fv/Fm value and ribulose-1,5-bisphosphate carboxylase/oxygenase(RuBPCase) activity value were higher in line 908120 than that in line 908206, whereas the intercellular CO_2 and cell membrane permeability in line 908120 were lower than that in line 908206. Higher leaf Pn, transpiration rate, and RuBPCase activity and lower membrane ion leakage rate ensured the robustness of line 908120 during times of irrigation and drought, which contributed to the maintenance of its high grain yield. Drought had a negative effect on these factors, resulting in decreased yield, and the photosynthesis rate of flag leaves markedly affected the yield in NILs of winter wheat. NILs are an important strategy for wheat adaptation to drought stress, but might not be the only mechanism causing the significant grain yield increase. Collectively, the characteristics of line 908120 resulted in a higher grain yield compared with that of line 908206. Further dissection of the drought avoidance mechanisms in wheat, as well as analysis and identification of the genes involved may be necessary.展开更多
The physiological effect of new FA antitranspirant on winter wheat was studied by field trial. The new FA antitranspirant was sprayed at ear filling stage, using the following concentrations： 0.5, 1.0, 1.5 and 2.0 mL...The physiological effect of new FA antitranspirant on winter wheat was studied by field trial. The new FA antitranspirant was sprayed at ear filling stage, using the following concentrations： 0.5, 1.0, 1.5 and 2.0 mL L^-1. The results indicated that new FA antitranspirant increased nitrate reductase activity （NRA）, free proline content, chlorophyll content and water content of leaf, thus drought stress can be mitigated. The new FA antitranspirant increased photosynthesis, enlarged stomatal conductance and reduced transpiration rate, thus led to growth stimulation and water loss reduction. New FA antitranspirant caused an increase of grain yield by 7.2%, under the optimal concentration 1.5 mL L^-1.展开更多
A field experiment was conducted in a manural loesial soil in middle of Shaanxi Province ofChina, a sub-humid area prone to drought, to study the effects of rainwater-harvestingcultivation on water use efficiency (WUE...A field experiment was conducted in a manural loesial soil in middle of Shaanxi Province ofChina, a sub-humid area prone to drought, to study the effects of rainwater-harvestingcultivation on water use efficiency (WUE) and yield of winter wheat. Ridge-furrow tillage wasused, the ridge being mulched by plastic sheets for rainwater harvesting while seeding in thefurrows. Results showed that from sowing to reviving stage of winter wheat, water stored in 0-100 cm layer was significantly decreased whereas that in 100-200 cm layer did not change.Compared to the non-mulching, plastic mulch retained 6.5 mm more water as an average of the twoN rate treatments, having a certain effect on conservation of soil moisture. In contrast, atharvest, water was remarkably reduced in both the 0-100 cm and the 100-200 cm layers, andmulched plots consumed 34.8 mm more water as an average of the two treatments: low N rate (75kg N ha-1) with low plant density (2 300 000 plants ha-1) and high N rate (225 kg N ha-1)with highplant density (2 800 000 plants ha-1), in 0-200 cm layer than those without mulching, the formerbeing beneficial to plants in utilization of deep layer water. Mulching was significant inharvesting water and in increase of yield. Mulched with plastic sheets, biological and grainyields were 22.5 and 22.6% higher for the average of the high N rate than for the low N rate,and the high N rate with low plant density was 29.8 and 29.1% higher in both biological andgrain yields than that of the low N rate with low plant density. With high N rate and high plantdensity, the mulched biological and grain yields were 39.5 and 28.9% higher than the correspondingtreatments without mulching. Of the treatments, that with high N rate and low plant density wasthe highest in both biological and grain yields, and the water use efficiency reached 43.7 kgmm-1 ha-1 for biological yield and 22 kg mm-1 ha-1 for grain yield, being the highest WUE reportedin the world up to now.展开更多
根据温度植被干旱指数(Temperature vegetation drought index,TVDI)的区域土壤含水率反演对于流域旱情监测、水资源规划等具有极大潜力,但TVDI特征空间干湿边量化的经验性和不确定性易导致反演精度受限。提出了TVDI干湿边多目标优化求...根据温度植被干旱指数(Temperature vegetation drought index,TVDI)的区域土壤含水率反演对于流域旱情监测、水资源规划等具有极大潜力,但TVDI特征空间干湿边量化的经验性和不确定性易导致反演精度受限。提出了TVDI干湿边多目标优化求解方法,通过最大化TVDI与地表反照率(Albedo,A)、土壤部分红波反射率(Soil red band reflectance,Rs,red)和土壤部分近红外波反射率(Soil near-infrared band reflectance,Rs,nir)的相关性实现特征空间干湿边定量求解,并对淮河流域麦田墒情进行了反演分析。结果表明:TVDI干湿边优化求解时,地表反照率对墒情反演精度的提升占主导作用,权重为0.5~0.8,其次是土壤红波和土壤近红外波反射率,分别为0.1~0.2和0.1~0.3;优化后TVDI对生育期内气象干旱变化具有更好的响应,特征空间涵盖范围增加了24.05%~54.02%,干边截距增加了1.72%~5.69%,干边斜率减小了8.04%~66.51%;优化后TVDI与实测土壤含水率的决定系数(Coefficient of determination,R^(2))增加了33.12%~82.61%,反演土壤含水率时的平均绝对误差(Mean absolute error,MAE)、均方根误差(Root mean square error,RMSE)、归一化均方根误差(Normalized root mean square error,NRMSE)降低了5.09%~20.52%、7.73%~21.16%、7.69%~21.27%,在不同生育期和土层深度均能保持较高精度;2023年淮河流域冬小麦拔节期、孕穗期、开花期和灌浆期0~40 cm平均土壤含水率分别为0.242、0.255、0.259、0.237 cm^(3)/cm^(3),流域内河南省和山东省麦地墒情较低,适宜在拔节期、开花期和灌浆期进行补充灌溉。综上,干湿边多目标优化求解方法提升了TVDI在区域尺度麦田墒情反演的适应性和准确性,可为旱情监测及防控研究提供理论依据和可靠工具。展开更多
基金Supported by The Ministry of Finance,Meteorological Industry Spe-cific(GYHY200706030)China Meteorological Administration 2009 Budget Item(CMATG2009M32)~~
文摘The average rainfall in whole growth period of winter wheat to plus or minus several times of sample variance was used to define different grades of drought.The reduction rate of production in meteorological which was equal to or greater than the rate of 3% was taken as standards to define wheat drought disaster years.The average reduction ratio of production in the wheat drought years in Hebei-Shandong-Henan was calculated.The frequency distribution rule of wheat in different drought disaster strength of winter wheat in Hebei-Shandong-Henan was analyzed.According to the conception and calculation method of drought disaster risk index of winter wheat,the regional distribution law of drought disaster risk index of winter wheat was analyzed.The division technical methods of winter wheat drought disaster risk zones in Hebei-Shandong-Henan under the irrigated conditions were put forward.Taking the average reduction rate of production in drought years,drought disaster risk index and precipitation of winter wheat in growth periods as indices,using the statistical analysis and overlay function of GIS,the production reduction risk of winter wheat caused by drought disaster in winter wheat zones of Hebei-Shandong-Henan was divided and evaluated.The risk evaluation of production reduction of winter wheat in different risk zones under different climate conditions was realized.The disaster prevention and mitigation measures of winter wheat drought were given.
基金Supported by Xuzhou Scientific Program (XM09B023)
文摘[Objective] The aim was to study the reasons for consecutive severe droughts in autumn and winter. [Method] By dint of precipitation in the observatory station and NCEP/NCAR reanalysis data in observatory station, the circulation background, vertical movement, abnormal temperature and changes of water vapor conditions in Xuzhou from October 2008 to January 2009 were expounded to reveal the causes for consecutive drought in autumn and winter. [Result] Xuzhou was under stable situation for a long time in autumn and winter in 2008, being behind east coastal trough, the downward airstream prevailing; the south trough intensity was weak, and in addition to the east subtropical high and weak intensity, the water vapor transportation condition in Indian Ocean and South Sea was unfavorable. The autumn was warm and the cold air was weak; ever since winter, there were several cold air activities. But the influencing body was in the east, and the south warm and wet airstream was insufficient. Thus, they couldn’t met, which resulted into gale and lower temperature and less precipitation when under the influence of cold air. [Conclusion] The study provided theoretical basis for the prevention of drought in the area.
基金Supported by the Special Project for Meteorological Industry of Ministry of Science and Technology in 2010(GYHY201006027)Yearly Project of Anhui Science and Technology Agency in 2011(10021303032)Major Business Project of Anhui Meteorological Bureau in 2009"Zoning of Agricultural Climate in Anhui Province"
文摘[Objective]The study aimed to assess and zone the drought risk of winter wheat in Anhui Province. [Method] The zoning factors were chosen from three aspects of disaster-causing factors,disaster-bearing bodies and environment conducive to drought,and then their data were standardized,rasterized and graded. Using analytic hierarchy process（ AHP）,we determined the weight of each index at various levels and then established the assessment models of drought intensity,sensitivity,vulnerability and resistance of winter wheat in the whole growth period and at heading and filling stage. Finally,the zoning map of drought risk for winter wheat in Anhui Province was obtained using the farmland data mask of Anhui Province. [Result]The drought risk of winter wheat in Anhui Province in the whole growth period and at heading and filling stage was divided into six grades,which reflected the distribution characteristics and regional difference of drought risk for winter wheat in Anhui Province. Drought risk was the maximum in the main producing areas of winter wheat in the north of Huaihe River,followed by the area along Huaihe River and the area between Yangtze River and Huaihe River,while the drought risk of winter wheat was very low in the south of Anhui Province. The drought risk of winter wheat was markedly affected by the sensitivity to drought,vulnerability and the drought resistance of winter wheat. [Conclusion] The research could provide scientific references for rational distribution of winter wheat and establishment of strategies for disaster prevention and mitigation.
基金National Natural Science Foundation of China, No.40875060 No.60832012 Basic Research and Operation Program of institute of Plateau Meteorology, China Meteorological Administration, No.BROP201017 Acknowledgements We thank Hyacinth Cyprain Nnamchi for his kind help in improving our English writing.
文摘In recent years, the socio-economic impacts of winter extreme climate events have underscored the importance of winter climate anomalies in Southwest China （SWC）. The spatio-temporal variability of surface air temperature （SAT） and precipitation in SWC and their possible causes have been investigated in this paper based on observational data from 1961 to 2010. The results indicate that SAT anomalies in SWC have two dominate modes, one is homogenous, and the other a zonal dipole. The former is caused by the anomalies of East Asian winter monsoon; the latter arises from the anomalies of both subtropical west Pacific high and regional cold air in lower troposphere. The most dominant mode of precipitation anomalies in SWC is homogenous and it has a high correlation with northern hemisphere annular mode （NAM, AO）. Neither NAM nor ENSO has significant impacts on SAT in SWC. The anomalies of NAM are associated with the anomalies of tropical circulations, and therefore precipitation over the SWC. When NAM is in positive （negative） phase, the winter precipitation is more （less） than normal in SWC. Winter precipitation increase over the whole SWC is associated with the El Nino. However, during La Nina winter, the pattern is not uniform. There is an increase in precipitation over the central parts and a decrease in western and eastern parts of SWC. The severe drought in SWC in winter 2010 is more likely caused by anomalies of NAM, not El Nino.
基金National Natural Science Foundation of China,No.41161012，Program for New Century Excellent Talents in University from the Ministry of Education of China,No.NCET-10-0019，Basic Scientific Research Foundation in University of Gansu Province
文摘Based on the daily data of temperature and precipitation of 108 meteorological stations in Southwest China from 1960 to 2009, we calculate the monthly and yearly surface humid indexes, as well as the extreme drought frequency. According to the data, the temporal and spatial characteristics of the extreme drought frequency in inter-annual, inter-decadal, summer monsoon period and winter monsoon period are analyzed. The results are indicated as follows. （1） In general, the southwestern Sichuan Basin, southern Hengduan Mountains, southern coast of Guangxi and northern Guizhou are the areas where the extreme drought frequency has significantly increased in the past 50 years. As for the decadal change, from the 1960s to the 1980s the extreme drought frequency has presented a decreasing trend, while the 1990s is the wettest decade and the whole area is turning wet. In the 2000s, the extreme drought frequency rises quickly, but the regional differences reduce. （2） During summer monsoon period, the extreme drought frequency is growing, which generally occurs in the high mountains around the Sichuan Basin, most parts of Guangxi and ＂the broom-shaped mountains＂ in Yunnan. It is distinct that the altitude has impacts on the ex- treme drought frequency; during winter monsoon period, the area is relatively wet and the extreme drought frequency is decreasing. （3） During summer monsoon period, the abrupt change is observed in 2003, whereas the abrupt change during winter monsoon period is in 1989. The annual extreme drought frequency variation is a superposition of abrupt changes during summer monsoon and winter monsoon periods. The departure sequence vibration of annual extreme drought frequency is quasi-5 years and quasi-12 years.
基金This study was financially supported by the China National 863 Program(2002AA2Z4011)the China National R&D Program(2004BA508B09)Texas wheat breed and physiology program.These assistances are gratefully acknowledged.We also thank Gail Petersion and Melanie Allred for their assistance when the study was going on.
文摘Field studies were conducted at Bushland, Texas, USA, in 2004 to examine usefulness of canopy temperature depression （CTD）, the difference of air-canopy temperature, in screening wheat （Triticum aestivum L.） genotypes for yield under dryland and irrigated. Forty winter wheat genotypes were grown under irrigation and dryland. CTDs were recorded after heading between 1 330 and 1 530 h on 6 clear days for dryland and 9 days for irrigation. Drought susceptible index （DSI） for each genotype was calculated using mean yield under dryland and irrigated conditions. Genotypes exhibited great differences in CTD under each environment. The dryland CTDs averaged 1.33℃ ranging from -0.67 to 2.57℃, and the average irrigation CTD were 4.59℃ ranging from 3.21 to 5.62℃. A low yield reduction was observed under dryland conditions relative to irrigated conditions for high-CTD genotypes. CTD values were highly negatively correlated with DSI under dryland, and genotypes of CTDs = 1.3℃ in dryland condition were identified as drought resistant. For 21 genotypes classified as drought resistant by DSI, their CTDs were 1.68℃ for dryland and 4.35℃ for irrigation on average; for 19 genotypes classified as drought susceptible by DSI, average CTD was 0.94℃ in dryland and 4.85℃ in irrigation. The high-yield genotypes consistently had high CTD values, and the low-yield ones had low CTD values for all measurements in dryland. After heading, genotypes maintained consistent ranking for CTD. Regression results for CTD and yield suggested that the best time for taking CTD measurement was 3-4 weeks after heading in irrigation but any time before senescence in dryland. Crop water stress index （CWSI） calculated from CTD data was highly correlated with CWSI calculated from yield, which suggesting traditional costly CWSI measurement may be improved by using portable infrared thermometers. Most importantly, grain yield was highly correlated with CTD under dryland （R^2 = 0.79-0.86） and irrigation （R^2 = 0.46-0.58） conditions. These results clearly indicated grain yield and water stress can be predicted by taking CTD values in field, which can be used by breeding programs as a potential selection criterion for grain yield and drought resistance in wheat, but a second study year is needed to confirm further.
基金Supported by National Key Research and Development Program(2017YFD0201702)the Innovation Program of Chinese Academy of Agricultural Sciences(CAAS-XTCX2016019)
文摘The development of near isogenic lines(NILs) is an important tool for physiological dissection of drought resistance in wheat. To better understand the potential for improving grain yield, a split-plot experiment was conducted under a mobile rain shelter using NILs of winter wheat with significant differences in the photosynthetic rate: the 908120 line with a high photosynthetic rate and the 908206 line with a low photosynthetic rate. The results indicated that the net photosynthesis rate(Pn), stomatal conductance, and transpiration rate in flag leaves in line 908120 were significantly higher than that in line 908206 under uniform water treatments during the reproductive phase in replicated pooled-culture trials. The maximum quantum yield Fv/Fm value and ribulose-1,5-bisphosphate carboxylase/oxygenase(RuBPCase) activity value were higher in line 908120 than that in line 908206, whereas the intercellular CO_2 and cell membrane permeability in line 908120 were lower than that in line 908206. Higher leaf Pn, transpiration rate, and RuBPCase activity and lower membrane ion leakage rate ensured the robustness of line 908120 during times of irrigation and drought, which contributed to the maintenance of its high grain yield. Drought had a negative effect on these factors, resulting in decreased yield, and the photosynthesis rate of flag leaves markedly affected the yield in NILs of winter wheat. NILs are an important strategy for wheat adaptation to drought stress, but might not be the only mechanism causing the significant grain yield increase. Collectively, the characteristics of line 908120 resulted in a higher grain yield compared with that of line 908206. Further dissection of the drought avoidance mechanisms in wheat, as well as analysis and identification of the genes involved may be necessary.
文摘The physiological effect of new FA antitranspirant on winter wheat was studied by field trial. The new FA antitranspirant was sprayed at ear filling stage, using the following concentrations： 0.5, 1.0, 1.5 and 2.0 mL L^-1. The results indicated that new FA antitranspirant increased nitrate reductase activity （NRA）, free proline content, chlorophyll content and water content of leaf, thus drought stress can be mitigated. The new FA antitranspirant increased photosynthesis, enlarged stomatal conductance and reduced transpiration rate, thus led to growth stimulation and water loss reduction. New FA antitranspirant caused an increase of grain yield by 7.2%, under the optimal concentration 1.5 mL L^-1.
基金part of the projects(49890330,30230230 and 30070429)supported by the National Natural Science Foundation of China(NSFC)project(G1999011707)supported by the National Key Basic Research Support Funds,China(NKBRSF).
文摘A field experiment was conducted in a manural loesial soil in middle of Shaanxi Province ofChina, a sub-humid area prone to drought, to study the effects of rainwater-harvestingcultivation on water use efficiency (WUE) and yield of winter wheat. Ridge-furrow tillage wasused, the ridge being mulched by plastic sheets for rainwater harvesting while seeding in thefurrows. Results showed that from sowing to reviving stage of winter wheat, water stored in 0-100 cm layer was significantly decreased whereas that in 100-200 cm layer did not change.Compared to the non-mulching, plastic mulch retained 6.5 mm more water as an average of the twoN rate treatments, having a certain effect on conservation of soil moisture. In contrast, atharvest, water was remarkably reduced in both the 0-100 cm and the 100-200 cm layers, andmulched plots consumed 34.8 mm more water as an average of the two treatments: low N rate (75kg N ha-1) with low plant density (2 300 000 plants ha-1) and high N rate (225 kg N ha-1)with highplant density (2 800 000 plants ha-1), in 0-200 cm layer than those without mulching, the formerbeing beneficial to plants in utilization of deep layer water. Mulching was significant inharvesting water and in increase of yield. Mulched with plastic sheets, biological and grainyields were 22.5 and 22.6% higher for the average of the high N rate than for the low N rate,and the high N rate with low plant density was 29.8 and 29.1% higher in both biological andgrain yields than that of the low N rate with low plant density. With high N rate and high plantdensity, the mulched biological and grain yields were 39.5 and 28.9% higher than the correspondingtreatments without mulching. Of the treatments, that with high N rate and low plant density wasthe highest in both biological and grain yields, and the water use efficiency reached 43.7 kgmm-1 ha-1 for biological yield and 22 kg mm-1 ha-1 for grain yield, being the highest WUE reportedin the world up to now.
文摘根据温度植被干旱指数(Temperature vegetation drought index,TVDI)的区域土壤含水率反演对于流域旱情监测、水资源规划等具有极大潜力,但TVDI特征空间干湿边量化的经验性和不确定性易导致反演精度受限。提出了TVDI干湿边多目标优化求解方法,通过最大化TVDI与地表反照率(Albedo,A)、土壤部分红波反射率(Soil red band reflectance,Rs,red)和土壤部分近红外波反射率(Soil near-infrared band reflectance,Rs,nir)的相关性实现特征空间干湿边定量求解,并对淮河流域麦田墒情进行了反演分析。结果表明:TVDI干湿边优化求解时,地表反照率对墒情反演精度的提升占主导作用,权重为0.5~0.8,其次是土壤红波和土壤近红外波反射率,分别为0.1~0.2和0.1~0.3;优化后TVDI对生育期内气象干旱变化具有更好的响应,特征空间涵盖范围增加了24.05%~54.02%,干边截距增加了1.72%~5.69%,干边斜率减小了8.04%~66.51%;优化后TVDI与实测土壤含水率的决定系数(Coefficient of determination,R^(2))增加了33.12%~82.61%,反演土壤含水率时的平均绝对误差(Mean absolute error,MAE)、均方根误差(Root mean square error,RMSE)、归一化均方根误差(Normalized root mean square error,NRMSE)降低了5.09%~20.52%、7.73%~21.16%、7.69%~21.27%,在不同生育期和土层深度均能保持较高精度;2023年淮河流域冬小麦拔节期、孕穗期、开花期和灌浆期0~40 cm平均土壤含水率分别为0.242、0.255、0.259、0.237 cm^(3)/cm^(3),流域内河南省和山东省麦地墒情较低,适宜在拔节期、开花期和灌浆期进行补充灌溉。综上,干湿边多目标优化求解方法提升了TVDI在区域尺度麦田墒情反演的适应性和准确性,可为旱情监测及防控研究提供理论依据和可靠工具。
