Abstract
As a policy corresponding to the instability of the long-term food supply and demand of our country, we considered that a development of the economical method of maintaining abandoned paddy field in the state which can be used at any time. Then, paying attention to restoration cost of abandoned paddy field, the maintenance methods were evaluated based on economical efficiency, and the aggregate total costs were compared under various vegetation conditions. Moreover, it compared also about the following conditions, i. e., the correspondence in an emergency, reservation of labor force, continuation of farmhouse volition, soil conservation, preservation of surrounding production condition, and scene preservation as a regulation factor of the maintenance methods other than economical efficiency. As a result, the preservation strategy of the abandoned paddy field which makes the following two items a standard was proposed.(1) To carry out a extensive management principle.(2) To continue a light level of management by annual fallow cultivation, in order to maintain abandoned paddy fields.(3) To maintain abandoned paddy fields in wet conditions as possible. Moreover, it is necessary to cut or exclude invaded trees at an early stage in order to prevent their enlargement.
