This study is exploratory research on a relationship between changes in cultivated area of major crops and farm income by regions. We investigated level of income, volatility of income, and migration of suitable region by climate changes as factors influencing changes in cultivated area. Research processes are as follows. First, we classify the regions where cultivated areas are expanded or reduced through the trends of cultivated area by region and crop during recent 10 years. Second, we compare the changes in income related factors between groups during the same periods. Finally, the results from portfolio analysis show changes in stable income-based optimal crops. From these procedures, we found that the changes in cultivated area are not simply explained by income-related factors. In cases of vegetables, however, we also found that high volatility of income could contribute to reduce cultivated area of the crops. The results from portfolio analysis are not always consistent in all of cases. This means that crop selection can be decided by other factors than stable income.

Due to changes in the agricultural market environment and both overseas and domestic farming conditions, uncertainties in agricultural production and management are becoming greater. Hence, there is a stronger need for farmers to choose crops in the optimal condition. This research aims to introduce the result and process of developing a decision support system for selecting crops, aimed to assist farmers in selecting the optimal crops most suitable in the given situation. There are basically three main factors to consider in the decision-making process for farmers when selecting a crop to introduce to their lands. First of all, one must consider how much profit crop A will produce when it is cultivated. Secondly, one must consider which crop to cultivate in order to earn a certain amount of profit. Thirdly, one must consider what is the best way to maximize Farm A’s business profit. For instance, a farm may have land as its resource, and one must research which location, type of crop, level of technology, and so forth, to maximize profit.This research creates a database of the profitability of a total of 180 crop types by analyzing Rural Development Administration’s survey of agricultural products income of 115 crop types, small land profitability index survey of 53 crop types, and Statistics Korea’s survey of production costs of 12 crop types. Furthermore, this research presents the result and developmental process of a web-based crop introduction decision support system that provides overseas cases of new crop introduction support programs, as well as databases of outstanding business success cases of each crop type researched by agricultural institutions.

In recent 10 years, mushroom cultivation area and number of cultivators have decreased, but mushroom production tends to increase. This shows that mushroom cultivation is being transformed from log and bed cultivation to bottle cultivation using automated facilities with high productivity per unit area. The bottle cultivation is possible to mechanized and automated, which can save manpower, less damage to pests, can be cultivated throughout the year, and is uniform in quality and advantageous for mass production. However, the investment in production facilities and farm materials is very large compared to the production of logs and bed cultivars, which can lead to large losses in the case of failure to grow. Therefore, it is necessary for the farmers who want to start the bottle cultivation to make careful management decisions by carefully examining the investment cost, the operating cost, and the expected income that are put into the bottle cultivation system. This study was conducted to analyze the management performance of bottle cultivation in mushroom farm and use it as farming decision making data. As a result of analysis of the management performance through farmers' survey, it was found that such as cost of spawn, substrate materials, other material, employment effort, and fuels & electricity power cost accounted for a large proportion of the cost of bottle cultivation.