The rolling resistance of narrow steel wheels in Italian paddy fields

Abstract

Research was carried out on very narrow, large diameter, lugged or smooth steel wheels fitted on Italian tractors and trailed implements to improve their mobility in wet paddy fields. These wheels differ considerably from those used in South East Asia. Measurements of soil texture and cone penetrometer resistance were carried out in 16 Italian paddy fields to compare their conditions with those found in Thailand during a previous survey. Two fields were located in Italy, representing the softest and hardest conditions. In these two fields, rolling resistance tests were carried out on two narrow lugged steel wheels of different diameter. The wheels were tested both singly and paired as dual wheels; the travelling speed and the vertical load were varied. The results show that the coefficient of rolling resistance is slightly affected by the travelling speed and increases with the vertical load only with the smaller diameter wheel. The values seem to be relatively low, ranging between 0·12 and 0·35 depending on the combination tested. These wheels permit locomotion on almost all flooded fields, forming very small ruts and allowing operation in the fields even during the mid-growing season with no apparent yield reduction.