Effects of inundation period and tillage option on field performance of self-propelled rice transplanter

Mechanized transplanting of rice could decrease costs and use of labor in the peak of transplanting periods. Self-propelled rice transplanter requires an ideal field condition as well as optimal inundation of non-puddled soil before transplanting. Hence, self-propelled rice transplanters (four rows walking type, model DP480 except clay loam soil during the Boro season in 2013-2014 where six rows riding type rice transplanter, model S3-680) was evaluated in clay loam, loam and sandy loam soil during the irrigated dry season (Boro) in 2012-2013 and 2013-2014. Tillage treatments in a strip plot design were stripped, zero and conventional tillage and irrigation treatments as inundation periods before transplanting as sub-plots were 12, 18 and 24 hours (hrs). Soil penetration resistance decreased with the increased of inundation period in both the seasons and three soil types. Field capacity of both the walking (0.11 to 0.14 ha hr-1) and the riding type rice transplanter (0.21 to 0.22 ha hr-1) had not varied significantly with the tillage options. Averaged of two seasons, strip tillage gave higher field capacity for 12 hrs inundation period in clay loam soil and 18 hrs inundation period in loam and sandy loam soil whereas zero and conventional tillage gave higher for 24, 18 and 24 hrs inundation period and 18, 12 and 18 hrs inundation period in clay loam, loam and sandy loam soil, respectively. The non-puddled strip and zero tillage reduced fuel consumption by 22% to 13% and 8% to 13% for transplanting in clay loam and sandy loam soil compared to conventional tillage, respectively. However, strip tillage reduced the percentage of missing hills (9.7%) compared to zero (13.0%) and conventional tillage (10.7%) while percentage of missing hills, averaged of two seasons and three soil types, decreased 13.7% to 9.2% with the increased of inundation periods 12 to 24 hrs. The highest percentage of picker missing hills was observed in zero tillage irrespective of seasons and soil types. However, zero tillage also gave higher percentage of damage hills compared to conventional and strip tillage. Floating hills decreased with the increased of inundation periods in non-puddled strip and zero tillage. Conventional tillage increased the buried hills significantly in both the seasons. Strip tillage gave higher grain yield compared to zero and conventional tillage in both the seasons except clay loam soil during the Boro season in 2012-13 where zero tillage gave a higher grain yield. However, 18 hrs inundation periods for strip (6.1 t ha-1), 24 hrs for zero (6.0 t ha-1) and conventional (5.9 t ha-1) tillage gave the highest grain yields. Finally, it can be stated that non-puddled minimum tillage (strip and zero) is a resource saving technique while 18 hrs inundation prior to transplant for strip and 24 hrs inundation for zero tillage showed more benefited for rice production.