Loess deposits with varying thickness are widely distributed on the intermontane valleys and piedmont zones on the northern side of the central Shandong mountainous regions. However, the basal ages and material resour...Loess deposits with varying thickness are widely distributed on the intermontane valleys and piedmont zones on the northern side of the central Shandong mountainous regions. However, the basal ages and material resources of the loess deposits are not clear. The paper studied the Qingzhou loess profile in Shandong with magnetostratigraphic and optical stimulated luminescence （OSL） methods and further investigated its main provenances with the mineralogical methods. The magnetostratigraphic results showed that the Brunhes/Matuyama （B/M） reversal boundary was not recognized, suggesting a basal age younger than 0.78 Ma. Extrapolations by sedimentation rates, based on the upper part depositional rate from the OSL age, the basal age of the Qingzhou loess is about 0.5 Ma. Until now, older loess deposits have not been reported on the northern side of the central Shandong mountainous regions. The results of the paper indicate that the loess deposits in this area might have strated from the Middle Pleistocene. The basal age of Qingzhou loess is approximately synchronous with the Xiashu loess in the middle-lower reaches of Yangtze River. Major components of clay minerals in the Qingzhou profile are dominated by illite. Other clay mineral compositions are mainly smectite, chlorite and kaolinite, which are similar with the Xifeng loess in the Loess Plateau. However, the contents of smectite and the ratios of illite and kaolinte in the Qingzhou loess samples are higher than those in the Xifeng loess samples of the Loess Plateau, indicating that the loess in the northern side of the central Shandong mountainous regions has different sources from that of the loess deposits in the Loess Plateau. The clay mineral analysis further reinforces the earlier conclu- sion that the marine strata exposed in the Laizhou Bay and the fluvial plain of the lower reaches of Yellow River during the glacier periods are the main material sources for the Qingzhou loess deposits, which is an indicator to the local aridification of the lower reaches of the Yellow River. Loess deposition in the central Shandong mountainous regions started at around 0.5 Ma. The age of Qingzhou loess is approximately synchronous with the ongoing high-latitude cold since the Middle Pleistocene, which indicates that strengthened East Asian winter monsoon was sufficiently energetic to bring substantial quantities of material from the marine strata exposed in the Laizhou Bay and the fluvial plain of the lower reaches of the Yellow River to the central Shandong mountainous regions. The results therefore suggest that both regional geological process and global changes were responsible for the formation of Qingzhou loess since Middle Pleistocene.展开更多
To build a rapid and accurate method for greenhouse vegetable land information extraction using an index model derived from TM digital data of Qingzhou City, Shandong Province, based on a systematic analysis of the sp...To build a rapid and accurate method for greenhouse vegetable land information extraction using an index model derived from TM digital data of Qingzhou City, Shandong Province, based on a systematic analysis of the spectral characteristics of different land use types in the study area, a subset of the image was first made to eliminate the mountainous region not associated with vegetable distribution, and then water body pixels were masked. With this the V1 index model for greenhouse vegetable land extraction was developed. The index model indicated greenhouse vegetable land for Qingzhou in April 2002 was concentrated in the southeast and around rural residential areas. Field data used for an accuracy evaluation showed that greenhouse hectares determined with remote sensing were 95.9% accurate, and accuracy for the spatial distribution of greenhouse vegetable land cross checked with a random sample was 96.3%. Therefore, this approach provided an effective method for greenhouse vegetable land information extraction and has potential significance for management of greenhouse vegetable production in the study area, as well as North China.展开更多
On the basis of the data obtained from a field survey, the relationship between land use and soil nutrients was evaluated in Qingzhou County, Shandong Province, China, through a statistical analysis of differences in ...On the basis of the data obtained from a field survey, the relationship between land use and soil nutrients was evaluated in Qingzhou County, Shandong Province, China, through a statistical analysis of differences in 17 nutrients in five types of cultivated land. The results showed significant effects (P < 0.05 or P < 0.01) of land-use type on soil organic matter and concentration of macronutrients, secondary nutrients, and micronutrients, as well as total salt and soil pH. In vegetable land, because of the large amounts of fertilizer applied to vegetable crops, the concentrations of most soil nutrients, with exception of available Si and micronutrients, were higher than those in grain cropland. Grain cropland had a significantly lower total salt content (P < 0.01) and tended to have a higher soil pH than vegetable land. Within subtypes of land use, dry land, irrigable land, and open-air vegetable land had the highest coefficient of variation (CV) for available P, whereas protected vegetable land had the highest CV for total N and available S. In general, land-use types had greater impact on macronutrients than on secondary nutrients and micronutrients.展开更多
基金funded by the National Natural Science Foundation of China (41072260 and 40402026)
文摘Loess deposits with varying thickness are widely distributed on the intermontane valleys and piedmont zones on the northern side of the central Shandong mountainous regions. However, the basal ages and material resources of the loess deposits are not clear. The paper studied the Qingzhou loess profile in Shandong with magnetostratigraphic and optical stimulated luminescence （OSL） methods and further investigated its main provenances with the mineralogical methods. The magnetostratigraphic results showed that the Brunhes/Matuyama （B/M） reversal boundary was not recognized, suggesting a basal age younger than 0.78 Ma. Extrapolations by sedimentation rates, based on the upper part depositional rate from the OSL age, the basal age of the Qingzhou loess is about 0.5 Ma. Until now, older loess deposits have not been reported on the northern side of the central Shandong mountainous regions. The results of the paper indicate that the loess deposits in this area might have strated from the Middle Pleistocene. The basal age of Qingzhou loess is approximately synchronous with the Xiashu loess in the middle-lower reaches of Yangtze River. Major components of clay minerals in the Qingzhou profile are dominated by illite. Other clay mineral compositions are mainly smectite, chlorite and kaolinite, which are similar with the Xifeng loess in the Loess Plateau. However, the contents of smectite and the ratios of illite and kaolinte in the Qingzhou loess samples are higher than those in the Xifeng loess samples of the Loess Plateau, indicating that the loess in the northern side of the central Shandong mountainous regions has different sources from that of the loess deposits in the Loess Plateau. The clay mineral analysis further reinforces the earlier conclu- sion that the marine strata exposed in the Laizhou Bay and the fluvial plain of the lower reaches of Yellow River during the glacier periods are the main material sources for the Qingzhou loess deposits, which is an indicator to the local aridification of the lower reaches of the Yellow River. Loess deposition in the central Shandong mountainous regions started at around 0.5 Ma. The age of Qingzhou loess is approximately synchronous with the ongoing high-latitude cold since the Middle Pleistocene, which indicates that strengthened East Asian winter monsoon was sufficiently energetic to bring substantial quantities of material from the marine strata exposed in the Laizhou Bay and the fluvial plain of the lower reaches of the Yellow River to the central Shandong mountainous regions. The results therefore suggest that both regional geological process and global changes were responsible for the formation of Qingzhou loess since Middle Pleistocene.
基金Project supported by the Chinese Ministry of Education (No. [2002] 247).
文摘To build a rapid and accurate method for greenhouse vegetable land information extraction using an index model derived from TM digital data of Qingzhou City, Shandong Province, based on a systematic analysis of the spectral characteristics of different land use types in the study area, a subset of the image was first made to eliminate the mountainous region not associated with vegetable distribution, and then water body pixels were masked. With this the V1 index model for greenhouse vegetable land extraction was developed. The index model indicated greenhouse vegetable land for Qingzhou in April 2002 was concentrated in the southeast and around rural residential areas. Field data used for an accuracy evaluation showed that greenhouse hectares determined with remote sensing were 95.9% accurate, and accuracy for the spatial distribution of greenhouse vegetable land cross checked with a random sample was 96.3%. Therefore, this approach provided an effective method for greenhouse vegetable land information extraction and has potential significance for management of greenhouse vegetable production in the study area, as well as North China.
基金Project supported by the National Natural Science Foundation of China (No. 40571160)the Experimental Program of Cultivated Land Fertility Investigation and Quality Evaluation of the Agricultural Department of China (No. 2002-23).
文摘On the basis of the data obtained from a field survey, the relationship between land use and soil nutrients was evaluated in Qingzhou County, Shandong Province, China, through a statistical analysis of differences in 17 nutrients in five types of cultivated land. The results showed significant effects (P < 0.05 or P < 0.01) of land-use type on soil organic matter and concentration of macronutrients, secondary nutrients, and micronutrients, as well as total salt and soil pH. In vegetable land, because of the large amounts of fertilizer applied to vegetable crops, the concentrations of most soil nutrients, with exception of available Si and micronutrients, were higher than those in grain cropland. Grain cropland had a significantly lower total salt content (P < 0.01) and tended to have a higher soil pH than vegetable land. Within subtypes of land use, dry land, irrigable land, and open-air vegetable land had the highest coefficient of variation (CV) for available P, whereas protected vegetable land had the highest CV for total N and available S. In general, land-use types had greater impact on macronutrients than on secondary nutrients and micronutrients.
