Abstract
Shortage and increased cost of labor are forcing farmers to look for alternatives to
traditional puddling of soil and manual transplanting of rice. Development of riding type
rice transplanter for unpuddled transplanting by incorporating strip tillage mechanism
could decrease costs and use of labor as well as improve the transplanting performance.
A study was conducted to evaluate the rice transplanter under different tillage and soil
conditions at research farm and on farmers' field during Boro and Aman seasons.
Unpuddled tillage treatments were: shallow beds (BT), strip tillage (ST), zero tillage (ZT)
which was compared with puddled conventional tillage (CT). Another study was also
conducted to evaluate the rice transplanter at research farm and on farmers' field under
different tillage options and varied inundation period during Boro seasons. Tillage
treatments in a strip plot design were ST, ZT and CT and the treatment of inundation
period as sub-plots before transplanting were 12, 18 and 24 hrs. Unpuddled ST saved 50-
70% time and 46 to 60% fuel consumption for tillage relative to the puddled СТ.
However, unpuddled ST and ZT also reduced 10-18% fuel consumption for mechanical
transplanting. Contrary to, unpuddled ST and ZT reduced the irrigation water required
for transplanting by 14-22% and 22-28%, respectively. In ST and ZT, the transplanter had
significantly higher rate of area coverage (0.131 to 0.139 ha hr-1) than puddled CT and BT
(0.115 to 0.121 ha hr-1). Highest percentages of missing hills were observed for BT (13.3%)
and ZT (11.5 to 13.0%) because of more floating hills followed by CT (9.9 to 10.7%). ST
reduced the missing hills (7.5 to 9.7%) due to less buried, floating and damage plants.
Percentage of missing hills reduced (13.7 to 9.2%) with the increase of inundation period.
Transplanter slippage significantly reduced the plant to plant spacing in puddled soils (5
to 6%). Collectively, ST (5.3 to 5.85 t ha-¹) gave significantly higher yield followed by ZT
(5.1 to 5.58 t ha-1) and CT (5.1 to 5.67 t ha-1). Highest benefit-cost ratio (BCR) was attained
in ST (1.44 to 1.60) followed by ZT (1.36 to 1.56) then BT (1.50) and CT (1.36 to 1.52).
Riding type rice transplanter was developed by incorporating the strip tillage mechanism
suitable for unpuddled transplanting. A strip tillage mechanism was attached before and
in same line of the rotary picker. Engine power available at 3600 rpm and conveyed to the
strip tillage rotary shaft with the arrangement of a belt-pulley, worm gearing, shaftuniversal joint, involute spline shaft and bevel gear resulting in a 450 rpm rotary blade
speed. A lever-operated tension pulley was included into the belt drive to engagedisengage the power to the strip tillage shaft. During test, strip depth and width and
transplanting depth of seedling was found satisfactory. Floating hills was the main
concern of unpuddled transplanting which was reduced due to attaching strip tillage
before the picker. Fuel consumption of the transplanter was found 10.27 1 ha-1 for making
strip and transplanting simultaneously, whereas it was 22.5 1 ha-1 for strip formation and
transplanting by separate machines. Higher rice yield was observed in the unpuddled
field (6.97 t ha-¹) transplanted by the developed transplanter compared to the puddled
fields transplanted by the transplanter without strip (6.80 t ha-1) and manually (5.71 t ha-1)
because of more filled grains panicle-1 and 1000 grains weight. A supplementary study
was conducted to identify the effective growing media for mat type seedling raising. It
was observed that rolling quality of the seedling mat decreased and seedling height
increased with the increase of organic fertilizer except rice bran and mustard cake
whereas stem thickness decreased with the increase of organic fertilizer. In another study,
140, 130 and 120 g of seeds tray-1 for bold, medium slender and extra-long slender paddy
was found suitable for less missing hills and optimum number of seedlings per hill under
the 5-7, 5-7 and 4-7 seedling adjustment options of the transplanter, respectively. Finally,
it can be stated that farmers can establish rice in unpuddled conditions using the
developed rice transplanter to save fuel and labor costs while reducing missing hill and
achieving increased yield over mechanical and manual transplanting.