Strategic Optimization of Irrigation and Nitrogen Levels to Maximize Growth and Yield of Radish (Raphanus sativus L.)

A field experiment was conducted at the research farm of Gazipur Agricultural University, Salna, Gazipur, Bangladesh during the 2019-2020 rabi season to study the effects of irrigation and nitrogen level on the growth and yield of radish (Raphanus sativus L.). A split-plot design under three irrigation levels including I₁: one irrigation at 15 days after germination (DAG); I₂: two irrigations at 15 and 35 DAG; I₃: three irrigations at 15, 35 and 55 DAG, and four nitrogen rates (0, 100, 150, and 200 kg N/ha) to the subplots with three replications were applied. The radish variety ‘Mino Early Long White’ was used as the test crop. Results showed that both irrigation and nitrogen inputs influenced the vegetative growth, root yield and quality attributes of radish. The tallest plants (29.8 cm), greatest leaf area (400 cm²), and highest gross plant weight (920.5 g/plant) were obtained from I₃N₃. The maximum root yield (67.2 t/ha) was recorded in I₃N₃ with moderate pithiness and the next one is 56.7 t/ha under I₂N₂. The total water use ranged from 71.3 mm (I₁N₀) to 137.4 mm (I₃N₃), with higher nitrogen levels associated with increased water consumption. However, the combination of two irrigations with 100 kg N/ha (I₂N₁) showed most efficient, providing high yield with low pithiness and superior resource-use efficiency. Thus, moderate irrigation and nitrogen inputs were found the most effective for achieving optimal growth, yield, and sustainability of radish cultivation.

Keywords: Irrigation frequency; Nitrogen levels; Root yield; Water-use efficiency; Nitrogen-use efficiency.