답전윤환에서 유기농 찰옥수수 생육 및 수량과 토양특성의 연차간 변화
We used the upland field rotated from matured rice paddy field, which have been used as a rice paddy field long time, for three years from 2015 to 2017. Therefore, this study was conducted for three main purposes. The first was to investigate yearly changes of growth and yield for waxy maize in the organic farming waxy maize at rice paddy-upland rotation system, the second was to investigate yearly changes of soil physical and chemical characteristics of rice paddy field soil in organic farming waxy maize at rice paddy-upland rotation system and the third was to select the suitable varieties for organic farming waxy maize at rice paddy-upland rotation. The test varieties were that 8 varieties of waxy maize of Mibaek 2, Ilmichal, Daehakchal, Chalok 4, Miheukchal, Eolrukchal 1, Heukjinjuchal, Heugjeom 2. For yearly yield, the highest yield was obtained in the first year of 949.6 kg, the second highest was in the third year of 680.6 kg 10a-1, while the second year was the lowest yield (675.4 kg 10a-1). Both varieties of Chalok 4 and Ilmichal showed the highest yield with about 900 kg 10a-1 in the threeyear average of 8 varieties. Solid phase of deep soil was 10% higher than that of top soil. Porosity rate of the top soil (54.7%) was higher than that of deep soil (49.4%), and the porosity in the third year was 2.7% higher than that of the first year. Soil organic matter content was significant different between soil depths and between three years. Soil solid and liquid phase decreased by 1.6% and 4.3%, respectively, compared to the first year, and the gas phase increased by 4.3%. The porosity of the third year was 2.7% higher than that of the first year. The soil organic matter content was 9.5 g kg-1 in the third year compared with 12 g kg-1 in the first year. It has also trend to decrease as the number of years rotated from rice paddy field increased. In the three-year average yields of Ilmichal and Chalok 4 were 898.1 kg 10a-1 and 891.6 kg 10a-1 respectively and the yield of Chalok 4 was greater than the other 7 varieties. We compared and selected the two best waxy maize varieties of Chalok 4 and Ilmichal for rice paddy-upland rotation. When we look at the yearly variation for waxy maize, Waxy maize yield was the highest in the first year and decreased year by year. Therefore, it would be better to restore upland field to rice paddy fields after the first year.