Relationships between Land Use and River Nutrient in the River Basins of Kitakami River and Ishikari River Using Remote Sensing and GIS

Original Pape

Relationship between watershed environments and growth of coastal diatoms

Effect of watershed environments on river water quality and the subsequent influence of water quality on the growth of diatoms in coastal seawater were studied. Land use in the upper and lower site of the Ohkawa River (O-up and O-low) and the upper site of the Nanakita River (N-up) were dominated by forestry, whereas the lower site of the Nanakita River (N-low) was characterized by urbanization. Seasonal changes in nutrients in the Ohkawa and Nanakita Rivers suggested that the concentrations of NH_4-N, NO_3-N, PO_4-P and acid extractable-Fe were influenced by human activities, while Si concentration reflected geological conditions. The average concentrations of fulvic acid-like Fe (FA-Fe), closely associated with the growth of coastal diatoms, were 1 and 16μgL^ at the O-up and O-low sites, respectively, while those of the Nanakita River were 5μgL^ (N-up) and 53μgL^ (N-low). For each river, FA-Fe concentrations of the lower sites were much higher than the upper sites. Moreover, the concentration of FA-Fe at N-low was much higher than at O-low. Therefore, it was concluded that FA-Fe originates not only from forest vegetation but also from urban activity. The growth of the Skeletonema, a typical diatom of coastal waters, was stimulated by the addition of O-low river water compared to addition of O-up, reflecting the FA-Fe content. Diatom growth stimulation with the addition of lower river water was much more prominent in the Nanakita River, whose watershed is characterized by runoff from Sendai city.Original Pape

Development of a Hyperspectral Sensor on UAV for Biomass estimation at Costal Zone

Poster Sessio

A System Development for Remote Sensing, and Interpretation for Rice Fields in the World Using Satellite Data

Remote Sensing Laboratory, Field Science Center, Graduate School of Agriculture Science, Tohoku University started at April 2004. For the studies and education at the laboratory we are now developing the system of remote sensing and GIS. Our system consists of ordinary PCs, one digitizer and one color laser printer. The PCs are assembled by us for the optimal performance and the low cost. Gigabit LAN connects each PC, and one PC is used as file server to store remote sensing images and GIS data such as digital maps, geocoded satellite images and digital elevation models (DEM). The file server has RAID system for safety storage from HD trouble. We use ARC/GIS as GIS software and many kinds of Remote Sensing software such as, ERDAS/Imagine, ENVI, eCognition, PG-Steamer and SILCAST. Using the developing system, we understand and teach for regional differences of agriculture especially with the interpretation of ASTER data analysis. A kind of project "Determination of Local Characteristics at Global Agriculture Using archive ASTER Data" was started at the middle of November 2005. We establish data processing system and get some results. Paddy rice fields analysis was started at first, we analyze 1) the Shonai Plains in Japan, 2) the Yangtze River delta in Middle-East China, 3) Mekong Delta in South Vietnam, 4) North-east Thai Plaines, Thailand, 5) Sacrament Valley, California, USA. The results of this studies are as follows, 1) Using ASTER images, we can easily understand agricultural characteristics of each local area. 2) ASTER data have high accuracy for location, and the accuracy is suitable for global study without the fine topographical maps, 3) By five years observation of ASTER, there are huge numbers of ASTER scenes, but not enough volumes for cloud free data for seasonal analysis. It means that follow-on program of ASTER is necessary, 4) We need not only paddy field, but also all crop fields and all area, 5) The studies are necessary to international corroboration.Original Pape

Spectral detection of grazing degradation in the Xilingol Steppe, Inner Mongolia

In order to detect the grazing degradation of steppe vegetation, spectral reflectance was measured using a portable spectral radiometer in the Xilingol steppe, Inner Mongolia. There is only one main drinking place for animals, which is supplied by a water tank at the center of Branch No.4 site-00. In addition to the measurement of surface reflectance, vegetation surveys were carried out involving floristic composition and plant growth parameters as a function of the distance from site-00 at every 1-km interval until the 5-km point. It becomes clear that the effects of grazing on vegetation and soil mitigated according to the distance from site-00. Negative plant indicators of grazing intensity such as Stipa grandis and Filifolium sibiricum increased in dominance with distance from site-00, whereas positive indicators of grazing intensity, such as Cleistogenens squarrosa and Agropyron cristatum, decreased in dominance. Changes in growth parameters along the environmental gradients were reflected on NDVI (Normalized Difference Vegetation Index), in which NDVI was positively correlated with the aboveground biomass (r=0.77, P<0.001), plant height (r=0.69, P<0.001) and coverage (r=0.89, P<0.001), respectively. These results suggested that a spectral vegetation index is effective in the detection of the degradation of grazing grassland in a non-destruction way.Original Pape