The objective of this paper was to evaluate the prediction ability of visible and near-infrared reflectance spectroscopy(VNIRP) to estimate soil total nitrogen concentration (TN) in the Sanjiang Yuan regions, Qinghai province, China by using partial least squares regression (PLSR) method. A total of 149 soil samples (0-30cm) were collected respectively from Yushu county and Maduo county in August 2012. The soil total nitrogen concentrations were measured using Vario EL Ⅲ elemental analyzer (Germany Elementar Inc), and the soil spectral reflectance of with spectral range 350-2500nm was measured using ASD FieldSpec 4 in the laboratory. PLSR model was used to relate the reflectance spectra and its five different pre-processing transformations including the first order derivative reflectance (FDR), the second order derivative reflectance(SDR), the logarithm of the inverse of the reflectance (Log (1/R)), the depth of the band (Band depth) and the first order derivative of the logarithm of reflectance (( Log R)′) to the soil total nitrogen contents measured. The results showed that the combination of visible-near infrared reflectance spectroscopy and PLSR to estimate TN produced a good prediction ability with R2 < 0.76 and RPD < 2.01 in the Sanjiang Yuan regions. The best prediction ability was obtained by (Log R) ' with R2CV = 0.87, R2V =0.88 and RPD <2.67, followed by Log (1/R), Band Depth, SDR, FDR and Reflectance. Visible and near infrared spectroscopy provided a rapid and effective method for estimating soil TN from five different soil types in the Sanjiang Yuan Regions, Qinghai province.
Huangyuan county is located in the eastern part of Qinghai province and is the transition zone of Loess
Plateau and Qinghai-Tibet Plateau. While the ecological environment in Huangyuan county is fragile
and is mainly characterized as serous soil erosion, frequent natural disasters. It is very important to
study the soil erosion. Hudan river basin was selected to study the soil erosion in Huangyuan county.
The soil erosion information was extracted from Landsat 5 TM data in 1987, 2000 and 2010. To
classify and grade soil erosion was according to the classification standard, Classification Standard for
Soil Erosion, issued by the Ministry of Water Resources of the People’s Republic of China.
The types of soil erosion in the basin were classified as water erosion, freeze-thaw erosion and
engineering erosion based on TM imagery, field survey and historical data. Water erosion was the most
important part and accounted for more than 90% of the whole area. Weak water erosion increased
significantly during the period, mainly distributing in the north of the basin. Slight-degree water
erosion increased from 1987 to 2000, while there was a steep reduce during the period from 2000 to
2010. Freeze-thaw erosion distributed mainly in northern areas with high altitude. What Engineering
erosion affected were narrow valley areas suitable for human settlements and agricultural production.
The Huangshui River basin is located in a transitional zone between the Loess Plateau and Qinghai-Tibetan Plateau in
northwest China. Rapid urbanization has resulted in loss of a large amount of cultivated land in valley region; at the
same time, a lot of steep slope cultivated land which located in hilly-gully region and mountain region was returned back
into forest land and grassland for ecological land use conservation. The objective of this study is to monitor and analyze
the spatial and temporal patterns change of cultivated land in the Huangshui river watershed by the combination method
of Landsat TM image and Geographical information System technologies. Our study results indicated that in 2007, the
total cultivated land was 540792.1ha whereas in 2007 it dropped to 484159.15 ha, with a net loss of 56633.01ha.
Specially, during 1996-2007, the irrigated land in valley region decreased from 110446.25 ha to 104141.07 ha with a net
loss of 6305.18ha, mainly being converted to built-up land. In hilly and gully region and mountain region, dry farmland
rapidly decreased from 430345.88ha in 1996 to 380018.08ha in 2007, with a net decease of 50327.8ha, respectively. The
decrease in cultivated land in hilly-gully region and mountain region was mainly converted to forest land and grassland.
The objective of the study was to quantify and analyze characteristics of LUCC in the spatial-temporal. Taking Manasi
oasis in the north slope of Tianshan Mountains as the study area, we obtained the two date Landsat TM,ETM images of
the late 1980s and the early 2000s. Radiometric correction was conducted using not less than 30 ground control points
based on 1:500,000 topographical maps. A land use field investigation was carried out in order to have a general
understanding to the area. Secondly, Land use maps were acquired by visual interpretation using EDRAS IMAGINE 8.7
and Arcinfo GIS 9.0. The conversion matrix of land use change was calculated to acquire the transition rates of land use
change from the late 1980s to the early 2000s.The characteristics of LUCC in the spatial-temporal were studied and
analyzed by adopting the land use dynamic degree model, conversion matrix model. Thirdly, landscape indices including
landscape percentage (%land), mean patch size (MPS), patch density (PD), area-weighted mean patch fractal dimension
(AWMPFD) were selected to quantify landscape pattern change of land use. The results indicated that during the 11
years, the areas of cultivated land, urban-built up, water land and marsh land increased, while those of grassland and
forestland, saline and alkaline land and sand land decreased. The grassland was converted to cultivated land and urbanbuilt
up. The landscape of the Manasi oasis has become more regularity, continuous and homogeneous. Favorable disturbance of human activity to landscape has made the oasis expansion process larger than the oasis desertification process.
The eastern Qinghai province is located in the transitional belt between the Loess Plateau and the Qinghai-Tibetan Plateau. In this paper, the spatial and temporal change patterns of land use were quantified by visually interpreting remote sensing (RS) data and use geographical information system (GIS). The objectives of this paper were to investigate the land use situation and the change trend of land use during 14 years from 1986-2000 and to understand causes of land use change. Firstly, land use maps were derived from visually interpreting the Landsat TM images with the help of MGE and ARC/INFO 7.11. In the analyzing process, digital maps were overlaid in order to generate land use dynamic map, transition matrix and to calculate rates of conversion. Secondly, the relative change rate model was introduced and calculated. The results showed that there has been a net decrease of 3736.84ha in grassland which was mainly converted to cultivated land. Urban and /or built up land increased by 4.39%, originated from the conversion of cultivated land. At the same time Relative change rates revealed that there were significant differences in quantitative change of land use in every county/city. The trend of land use change was that urban and built-up was expanded, farmland encroached and grassland continuously reclaimed as farmland. In the end, the driving factors of land use change were analyzed. The increasing population pressure and urban expansion and the development of industry were the major driving factors for land use change in the northeastern Qinghai province.
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