Analysis Method for Crop Rotations Based on Area Data II. The identification results of crop rotations and the verifications of the results

Major cropping sequences with three crops (MCS3) were classified in the previous report. In this report, crop rotations were identified by means of linking with MCS3, and the observed area ratios of the identified crop rotations were determined. Three crop rotations for light-colored andosols were identified : 1) sugar beet→potato→wheat (the observed area ratio was 11.4%), 2) sugar beet→potato→sweet corn→wheat (24.0%), 3) sugar beet→potato→wheat→wheat (11.6%). Two crop rotations for andosols were identified, and they were 4) sugar beet→potato→wheat→wheat (23.6%), 5) sugar beet→potato→sweet corn→wheat→wheat (7.5%). The identified crop rotations coincided with the cropping intervals of the major crops observed in these crop rotations, and the identification method in these reports was effective for numerical analysis to crop rotations. The identified crop rotations were regulated by the cultivated area ratio of each crop and cropping season of winter wheat.