Effect of Sowing Method and Seed Rate on Growth and Yield of Carrot (Daucus carota L.) in the River Nile State, Sudan

Abstract

Aims: Carrot (Daucus carota L.) is a nutritionally and economically important crop in Sudan, yet its productivity remains low due to suboptimal agronomic practices. Limited research has addressed the combined effects of sowing methods and seed rates under Sudanese conditions. This study evaluated traditional sowing methods, Sarsaba (SM₁) and Madrab (SM₂), across four seed rates (3.5–18.0 kg ha⁻¹) in River Nile State. The lack of locally validated planting protocols hinders yield optimization, particularly for smallholder farmers. By assessing growth and yield responses, this work identifies optimal practices for sustainable intensification. Study Design: A factorial experiment arranged in a completely randomized block design (CRBD) with four replications. Place and Duration of Study: The experiment was conducted at Hudaiba Research Station, River Nile State, Sudan (17°34′N, 33°56′E; 350 m above sea level), over two winter cropping seasons (2019–2020 and 2020–2021). Methodology: The carrot variety Royal Chantenay 2 was cultivated under ridge-based conditions with uniform irrigation and urea fertilization at 120 kg N ha⁻¹. Treatments included two sowing methods—SM₁ (continuous line sowing on ridge crests) and SM₂ (precision hill sowing at 10 cm spacing)—and four seed rates. Growth and yield parameters assessed were plant density (plants m⁻²), root length (cm), root diameter (cm), marketable yield (kg m⁻²), and total yield (kg m⁻²). Data were analyzed using ANOVA and LSD tests (P= 0.05) via the GRAPES statistical platform. Results: The results showed that the highest seed rate of 18.0 kg ha⁻¹ produced the greatest total yield (5.36 kg m⁻²) and marketable yield (3.49 kg m⁻²), although this rate negatively affected root dimensions, reducing both length and diameter. Conversely, the moderate seed rate of 12.0 kg ha⁻¹ offered a better balance between yield and root quality. Among the sowing methods, Madrab (SM₂) significantly improved marketable yield (3.52 kg m⁻²), while Sarsaba (SM₁) resulted in larger root dimensions, with a mean length of 14.82 cm and diameter of 2.28 cm. The interaction between sowing method and seed rate was generally non-significant (P > 0.05), except for root length, which was notably enhanced under SM₁ at the lowest seed rate of 3.5 kg ha⁻¹. Additionally, seasonal variation was evident, with higher yields obtained in the second season, likely due to more favorable agroclimatic conditions during that period. Conclusion: The combination of Madrab sowing (SM₂) and a moderate seed rate (12.0 kg ha⁻¹) optimizes both yield and root quality, supporting sustainable carrot production under semi-arid conditions similar to those in Sudan’s River Nile State.