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.

Abstract
1. Introduction
2. Precedent Study
    2.1 Factors influencing crop selection
    2.2 Methodological study for optimal crop selection
    2.3. Study on the changes in crop cultivation land inKorea
3. Research Method
    3.1 Data collection and Analysis Object
    3.2 Analysis procedure
    3.3 Optimal portfolio analysis method
4. Research Results
5. Conclusion
References

• Ikhoon Jang(Department of Agricultural Economics and Rural Development, Seoul National University)
• Yeonjin Kim(Department of Agricultural Economics and Rural Development, Seoul National University)
• Dohyeong Choi(Department of Agricultural Economics and Rural Development, Seoul National University)
• Young Chan Choe(Department of Agricultural Economics and Rural Development, Seoul National University) Corresponding author
• Guhyun Jung(Institute in Geonggi-do Agricultural Research, Korea)