Evaluation of energy and cumulative exergy demand indicators of different lettuce production methods in Alborz province

Articles in Press

Document Type : Research Paper

Authors

1 Department of Agricultural Machinery Engineering, Faculty of Agricultural Engineering and Technology, University of Tehran, Karaj, Iran

2 Department of Agricultural Machinery Engineering, Faculty of Agriculture, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran

Abstract

Due to population growth and heightened awareness of healthy nutrition, the consumption of vegetables, particularly lettuce, has significantly increased in recent years. This study evaluated the energy use and cumulative exergy demand (CExD) of different lettuce production systems in Alborz province and proposed strategies to reduce energy consumption. Data were collected through face-to-face interviews and completion of 60 questionnaires. The results indicated a considerable variation in total energy inputs across the methods, with the highest consumption observed in the seed-flood irrigation at 107,409.79 MJ ha⁻¹, and the lowest in the seed-drip irrigation at 54,734.04 MJ ha⁻¹. Diesel fuel was the predominant energy input in flood irrigation systems, whereas diesel fuel and nylon were the primary inputs in drip irrigation systems. The energy ratio was less than one in all systems and the highest energy ratio (0.68) occurred in seed–drip irrigation. The highest water productivity was recorded in the seedling-drip irrigation (18.75 kg m⁻³). Moreover, the CExD analysis revealed that fossil non-renewable resources in the flood irrigation systems for seeds and seedlings accounted for the highest burdens, with 3,438.51 and 2,188.70 MJ, respectively. Inputs such as diesel fuel and nylon were identified as the main contributors to this dependency, underscoring the decisive role of energy-intensive inputs in increasing exergy burden and reducing the sustainability of lettuce production systems. Ultimately, it is recommended that farm management practices optimize the use of energy-intensive inputs like diesel fuel and chemical fertilizers, substitute chemical fertilizers with organic alternatives, and replace nylon with biodegradable material.

Keywords

Main Subjects

Iranian Journal of Biosystem Engineering

Articles in Press, Accepted Manuscript
Available Online from 28 October 2025

Files

History

  • Receive Date: 26 September 2025
  • Revise Date: 21 October 2025
  • Accept Date: 28 October 2025

Share

How to cite

Statistics