Optimizing Emitter Discharge and Plant-emitter Ratio for Improving Yield, Water Productivity, and Economic Returns of Lettuce under Drip Irrigation

Abstract

Efficient irrigation management is essential for improving crop productivity while conserving water resources. This study evaluated the effects of emitter discharge rate and plant–emitter ratio on the growth, yield, water productivity, and economic performance of lettuce (Lactuca sativa L.) under drip irrigation during the Rabi season of 2016–17 at the Research Farm of Jawaharlal Nehru Krishi Vishwa Vidyalaya (JNKVV), Jabalpur, India. The experiment was conducted in a split-plot design comprising two emitter discharge rates (1.27 and 1.54 L h⁻¹) as main treatments and three plant–emitter ratios (1.0, 1.66, and 2.0) as sub-treatments. Growth attributes, soil moisture distribution, crop yield, water productivity, and economic returns were assessed. The plant–emitter ratio significantly affected vegetative growth, leaf area index, yield, and water productivity, whereas the effect of emitter discharge rate was generally non-significant. The treatment combination T₂E₃, comprising a 1.54 L h⁻¹ emitter discharge and a plant–emitter ratio of 2.0, recorded the highest yield (8285.16 kg ha⁻¹), water productivity (1.30 kg m⁻³), and benefit–cost ratio (13.23). The drip irrigation system exhibited high emission uniformity (92%), indicating effective water distribution throughout the crop growth period. Overall, the combination of a 1.54 L h⁻¹ emitter discharge and a plant–emitter ratio of 2.0 was found to be the most suitable treatment for improving lettuce productivity, water productivity, and economic returns under the agro-climatic conditions of central India.