Yield, Economics and Moisture Use by Ethiopian Mustard (Brassica carinata) as Influenced by Irrigation, Nitrogen and Sulphur Levels

A field experiment was carried out during winter season of 2004–05 and 2005–06 at the Water Technology Centre, IARI, New Delhi to study the effects of three levels of irrigation based on phytophases, three levels of nitrogen (30, 60 and 90 kg N ha⁻¹) and three levels of sulphur (0, 20 and 40 kg S ha⁻¹) on yield, economics and moisture use by Ethiopian mustard. Irrigation and nitrogen levels were allocated in main plots and sulphur levels in sub-plots of split plot design replicated thrice. Three irrigations applied at seedling, 50% flowering and pod development stages significantly increased the yield attributes (number of primary branches/plant, number of siliquae/plant and siliqua length), seed and stalk yields of Ethiopian mustard over one irrigation. Three irrigations also recorded the maximum gross return (Rs. 37449 ha⁻¹), net return (Rs. 27459 ha⁻¹) and B:C ratio (1.68) of mustard. Application of 90 kg N ha⁻¹ significantly increased the yield attributes, seed yield, stalk yield and gross return (Rs ha⁻¹), net return (Rs ha⁻¹) and B:C ratio as compared to 60 and 30 kg N ha⁻¹. Application of 20 and 40 kg S ha⁻¹ significantly increased the yield attributes, seed yield, stalk yield, gross return (Rs ha⁻¹) and net return (Rs ha⁻¹) over control. The maximum WUE was recorded with two irrigations (I_SP) i.e. 0.72 and 0.68 (kg seed/m⁻³ water used) in first and second year, respectively. Water use efficiency was increased progressively with each successive dose of N and S fertilizer. About 59–60% of moisture used was extracted from the top 0–30 cm soil layer when the crop was irrigated with three irrigations (I_SFP), 54–55% moisture extracted with two irrigations and 49.2–50.2% with one irrigation, respectively. Per cent soil moisture extracted irrespective of the treatments from 0–30 cm soil depth was maximum (49.2–59.7%) which decreased as the profile depth increased.