Abstract
Idle croplands were searched throughout the Tokachi region in Hokkaido to analyze their geographical distribution and soil chemical properties. More than 90% of the 313 idle croplands observed were located in hill and mountain areas surrounding the Tokachi plain. In >80% of the croplands, forage grasses were cropped before idling, thereby dominating the current vegetations together with perennial weeds and bamboo grasses. The soil analysis of 23 idle croplands showed that mean values for soil chemical properties were not less than local standards. However, values differed greatly between the croplands, >40% of which had smaller available phosphorus and manganese contents than the standards, as well as excess available potassium and nitrogen contents. The current results demonstrated that forage grasslands in hill and mountain areas tend to be idling for Hokkaido, and suggested that much attention to soil phosphorus content is required for the reuse of idle croplands.
