Effect of irrigation and nitrogen on growth yield, oil content, nitrogen uptake and water-use of summer sesame (Sesamum indicum)

In a 2-year study at Pusa, maximum average yield (2.81 q/ha) of summer sesame (Sesamum indicum L.) was recorded with 3 irrigations each of 6 cm at IW : CPE of 0.7. Further reduction in frequency of irrigation to 1 or 2 based on IW : CPE or days after sowing resulted in a significant reduction in seed yield. The yield was minimum (1.78 q/ha) under the rainfed control. Among levels of nitrogen, significant increase in yield was recorded up to 90 kg N/ha (2.61 q/ha). A significant increase in leaf-area index (LAI), number of capsules/plant and 1,000-grain weight was recorded up to 2 irrigation. For LAI response to nitrogen was noticed up to 90 kg N/ha, whereas for number of capsules/ plant and 1,000-seed weight increased only up to 30 kg N/ha. Maximum oil (%) was recorded with 2 irrigations and at 30 kg N/ha. Higher N levels depressed oil (%) in sesame. Nitrogen uptake by plants increased significantly up to 3 irrigations and 90 kg N/ha. A major part of soil-moisture depletion was recorded from 0-60 cm profile layer. In deeper layer (60-90 cm) depletion was more in drier regimes than in wet ones.