Studies were undertaken in silty clay loam soil to identify optimum puddled soil condition for self-propelled rice transplanter. The experiment was conducted with three types of puddler, namely; rotary puddler (R), peg type puddler (P) and cultivator (C) with two levels of puddling viz. twice and thrice. Transplanting was done using a Chinese-made self-propelled rice transplanter (Model: 2ZT-238-8) at sedimentation periods of 24, 48 and 72 hours. The results indicate that the depth of puddling andhardpan was in the range of 10-15 cm and 19-22 cm, respectively. The sinkage of the traction wheel was well into the hardpan thereby providing sufficient traction to propel the transplanter and hence no mobility problem was observed. Buried and floatinghill percentage was considerably high after 24 hours of sedimentation period leading to high mortality. Buried hill, floating hill and hill mortality decreased with an increase in sedimentation time. At 48 hours of sedimentation period, the buried and floating hill percentage was within 2-3 percent and the hill mortality was within 4 percent in the case of P_2, C_2 and C_3. This indicates an ideal condition for transplanting. For other treatments (R_2, R_3 and P_3) ideal condition was obtained after 72hours of puddling. The cone index values increased at a faster rate between 24 to 48 hours of sedimentation period for P_2, C_2 and C_3. But the same phenomenon was observed between 48 to 72 hours in the case of R_3. For treatments R_2 and P_3, the coneindex increased at a uniform rate in all sedimentation periods. Hill-to-hill spacing, a function of traction wheel slip, was greater than the preset value due to less wheel slip at low sedimentation period. Hill-to-hill spacing decreased as sedimentationperiod and wheel slip increased. Actual field capacity and field efficiency were 0.149 ha/hr and 58.32 percent, respectively. Mat feeding time consumed 25.35 percent of total time of operation.
展开▼
