Table 3 showed that spacing of 40 x 20 cm with mulching gave the gross return (Tk. 216.80 thousand per hectare) followed by mulching in 40 x 30 spacing (Tk. 210.16 thousand). But the
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highest benefit cost ratio (8.84) was obtained in 40 x 30 cm with mulching followed by 40 x 40 cm with mulching (6.22). The benefit cost ratio (4.22) from 40 x 20 cm with mulching was less due to the involvement of high seedling cost. The results indicate that although the biological response of lettuce was observed due to mulching with 40 x 20 cm spacing but the economic response was observed due to mulching with 40 x 30 cm spacing. The results of the present study suggest that lettuce cv, Green Wave can be grown in tropical areas at a plant spacing of 40 x 30 cm with mulching done by dried rice straw for higher economic return.