Abstract
The aim of this paper is to present a making method and some applications of the soil organic matter content (hereinafter referred to as O.M.) map of Obihiro Area, Hokkaido, made by using Landsat TM data. The O.M. of each site is derived from the correlation between measured O.M. in the field and CCT value of TM band 3. The O.M. of vegetationcovered cropland is estimated from CCT value of band 3 on the soil line transformed by the soil index method (Fukuhara et al., 1979). The map consists of eighteen sheets and covers whole cropland of Obihiro Area (1, 083, 000 ha). The map is characterized by four points as follows; (i) grid cell size is 25 m×25 m, (ii) the O.M. is devided into seven classes (0-2%, 2-5%, 5-8%, 8-10%, 10-12%, 12-15% and 15-20%) and shown on 1 : 50, 000 to pographical maps in seven colors (red, brown, yellow, light green, cyan and violet), (iii) users can make a desired scaled map since this map is also provided in floppy disks, and (iv) users can see laying it on top of our map since the soil map is appended as the overlay sheet. Users can know the O.M. of the desired point from this large-scaled map in detail. When our map is used together with the soil map, it is of great use for some purposes such as scheduling irrigation, improving draining, improving soil and managing crop.
