Abstract:
Optimum plant spacing is among key agronomic parameters that influence growth and
yield of rice (Oryza sativa L.). A field experiment was conducted to evaluate the growth
and yield response of mechanical transplanted rice at the Rice Research Station,
Paranthan during Maha season, 2016/17. The machine transplanting method is
considered as a practical option to minimize the labour usage with the timeliness
cultivation of rice. Recent past, rice transplanter was introduced to paddy farmers of
Kilinochchi district by the government of Sri Lanka. However, adaptation of this method
is still low due to socio-economic background and lack of technical information. Four
rows of man-propelled paddy KUBOTA (SPW 48c) transplanter was used in this study
with 30 cm row spacing (non-adjustable) and 5 within row spacing levels (12, 14, 16, 18
and 21 cm), replicated four times in each. The rice variety Co-10 was used with the plot
size of 4 m x 6 m. The plant height, number of tillers at different stages, percentage of
canopy coverage and yield components such as panicle per hill, panicle length, grain
yield and 1000 grains weight were recorded. Results revealed that the spacing of 30 cm
X 16 cm produced significantly highest number of tillers and panicles than others. The
spacing of 30 cm X 16 cm recorded the highest (p<0.05) percentage of canopy coverage
(75%), 1000 grain weight (24.9 g) and grain yield (7921.9 kg/ha). This study concluded
that plant spacing of 30 cm X 16 cm can be considered as optimum plant density for
machanical transplanted rice crop for the variety Co-10 compared to other tested
spacing in this region.
