Drought stress can affect the growth and development of crops, which can bring huge disaster to crop planting. With the aim to master plant drought condition accurately, an easy and efficient drought monitoring method...Drought stress can affect the growth and development of crops, which can bring huge disaster to crop planting. With the aim to master plant drought condition accurately, an easy and efficient drought monitoring method using remote sensing was constructed through the establishment of the normalized difference vegetation index （NDVI）, which was a kind of universality index, based on the high temporal resolution MODIS data with the summer crops in Shandong Province as the study object, as well as the growing state and drought conditions of the crops judged by observing and analyzing the changes in time and space. The method was fit for the crops during vegetative growth stage, and with simple principle and easy operation, the method was easy for technology promotion.展开更多
The water budget of the examined wetland was extremely variable in the past six years. Principally, it was affected by the water regime of the River Danube and the climatic factors. In order to investigate the changes...The water budget of the examined wetland was extremely variable in the past six years. Principally, it was affected by the water regime of the River Danube and the climatic factors. In order to investigate the changes of these elements, and to succeed to forecast, statistical methods by using SPSS program were performed. The time series of the evaporation, of the precipitation and of the river＇s water-level were analysed by linear regression, by exponential smoothing, by deterministic models. In consequence of the river regulation, the low-water and the mean stage of Danube were decreasing during the last hundred years, because the riverbed was permanently deepening. Since the river has overflowed its bed and has inundated to the wide floodplain, the decrease of high-water did not appear. The decline of the flooded days signed the quicker passage of flood. These processes have prevented that the examined wetland is going to fill up from the floods. The difference in summer semester between the evaporation and the precipitation was increasing during the last fifty years. Therefore, the drying out of the wetland is going to be more frequent in the future. In the interests of the survival of this wetland, it is necessary to construct the restoring-system in the floodplain.展开更多
文摘Drought stress can affect the growth and development of crops, which can bring huge disaster to crop planting. With the aim to master plant drought condition accurately, an easy and efficient drought monitoring method using remote sensing was constructed through the establishment of the normalized difference vegetation index （NDVI）, which was a kind of universality index, based on the high temporal resolution MODIS data with the summer crops in Shandong Province as the study object, as well as the growing state and drought conditions of the crops judged by observing and analyzing the changes in time and space. The method was fit for the crops during vegetative growth stage, and with simple principle and easy operation, the method was easy for technology promotion.
文摘The water budget of the examined wetland was extremely variable in the past six years. Principally, it was affected by the water regime of the River Danube and the climatic factors. In order to investigate the changes of these elements, and to succeed to forecast, statistical methods by using SPSS program were performed. The time series of the evaporation, of the precipitation and of the river＇s water-level were analysed by linear regression, by exponential smoothing, by deterministic models. In consequence of the river regulation, the low-water and the mean stage of Danube were decreasing during the last hundred years, because the riverbed was permanently deepening. Since the river has overflowed its bed and has inundated to the wide floodplain, the decrease of high-water did not appear. The decline of the flooded days signed the quicker passage of flood. These processes have prevented that the examined wetland is going to fill up from the floods. The difference in summer semester between the evaporation and the precipitation was increasing during the last fifty years. Therefore, the drying out of the wetland is going to be more frequent in the future. In the interests of the survival of this wetland, it is necessary to construct the restoring-system in the floodplain.
