Effect of Spacing on Grain Yield and Yield Attributes of Three Rice (Oryza sativa L.) Varieties Grown in Rain-fed Lowland Ecosystem in Ghana

Row transplanting is one of the good agronomic practices being promoted for lowland rice production in Ghana. The recently introduced ‘Sawah’ system promotes effective land preparation, good water management and row transplanting as well as the use of hand tools for weed control in lowland rice production. To determine the appropriate crop density, a trial was conducted to evaluate the effect of different spacing on three rice varieties (Sikamo, Jasmine 85, Marshall). The experimental design was a split plot with four replications. Spacing which served as main treatments included: S1 (20 cm x 20 cm); S2 (20 cm x 25 cm); S3 (25 cm x 15 cm); S4 (15 cm x 15 cm) and S5 (30 cm x 10 cm). Rice was transplanted at 2 seedlings per stand. Results showed that spacing significantly affected tiller production, number of panicles per m2, total biomass and paddy yield. Both the number of tillers per stand and number of panicles per m2 were significantly reduced under closer spacing than wider spacing in the order: S1 = S2 > S3 > S4 = S5. Highest grain yield was obtained at 20 cm x 25 cm (11.4 t ha-1) and 20 cm x 20 cm (10.9 t ha-1) for all the three varieties while lowest grains yield (3.0” t ha-1) was recorded at 30 cm x 10 cm spacing. For increased yields and easy adoption of simple hand tools for weed control, wider spacing of 25 cm x 20 cm and 20 cm x 20 cm is recommended for rain-fed lowland rice production in Ghana.