Water flow characteritics in the presence of mulch in furrow irrigation

Document Type : Research Paper

Authors

• Ali Pahlevani ¹
• Hamed Ebrahimian ²
• Teymour Sohrabi ³
• Fariborz Abbasi ⁴

¹ Corresponding Author, Department of Irrigation and Reclamation Engineering, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran. E-mail: ali.pahlevani@ut.ac.ir

² Department of Irrigation and Reclamation Engineering, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran. E-mail: ebrahimian@ut.ac.ir

³ Department of Irrigation and Reclamation Engineering, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran. E-mail: myousef@ut.ac.ir

⁴ Agricultural Engineering Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran. E-mail: fariborzabbasi@ymail.com

Abstract

Keywords

• Keywords: Advance time
• Organic mulch
• Plastic mulch
• Runoff
• Surface irrigation

Main Subjects

• آبیاری و زهکشی

EXTENDED ABSTRACT

Introduction:

Water is considered to be the most important factor limiting crop production in aid and semi-arid regions of the world, including Iran. According to records, approximately 70% of the water resources in the country is consumed in agricultural sector. The surface irrigation method is the most commonly used irrigation method in Iran, known for its high water losses and low efficiency attributed to inadequate management and design issues. Given the expansion of irrigated agriculture, one of the key programs for the country's water resources focuses on altering, modifying, and enhancing existing irrigation methods. According to the research, the use of mulch is a method that has led to reducing water losses, increasing water use efficiency, and water productivity. This method has been widely adopted by farmers worldwide. The mulches commonly used in agriculture are typically categorized as organic (plant residues such as straw, stems, and compost) and inorganic (plastic mulches including black or transparent mulch). Various research studies have examined the effect of mulches on crop germination date, Crop yield, water productivity, water use efficiency, water and nutrient distribution in different soil layers, and soil temperature changes throughout the season. However, very few studies have explored the potential effects of different mulch placements on furrow surfaces and their influence on the hydraulic characteristics of irrigation, including advance, recession, runoff, and infiltrated volume. This research aims to identify the optimum irrigation management for each treatment to reduce the water losses when utilizing mulch.

Purpose:

It is necessary to evaluate the effect of various mulch placements on the furrow surface on the infiltrated volume and water losses during different stages of an irrigation event (advance, recession, runoff) to determine the optimum irrigation method.

Method:

The irrigation system used in this study was the conventional furrow irrigation method with trapezoidal cross-section. The furrows were 100 m long with a spacing of 0.75 m in the direction of the general slope of the field. The treatments used in this experiment include one treatment without any mulch as a control treatment, one treatment with organic mulch consisting of wheat residues (OM), and three plastic mulch placements on the furrow. These plastic mulch types include LDPE transparent plastic layers with a thickness of 25 microns and a width of 0.75 m placed on the ridge (R), on the furrow bottom (F), and on both the ridge and the furrow bottom (FR). Four consecutive irrigation events with a 10-day interval were considered to allow the soil to dry between each irrigation event. The measured parameters included inflow, advance time, regression, runoff, and infiltration volume for each treatment.

Results and Discussion:

The results showed that by utilizing mulches (either plastic or organic) and maintaining the same irrigation management and inflow rate, the shorter advance time compared to the control treatment would result in higher water losses through runoff. On the other hand, the results showed that mulch, both organic and plastic, helps maintain soil moisture compared to soil without mulch. By covering a part of the soil surface and reducing the wetted perimeter in the irrigation process, mulch reduces the volume of infiltrated water. The larger volume of infiltration in the control treatment does not necessarily indicate its superiority. The extended advance time leads to decreased infiltration uniformity across the field, resulting in deep percolation losses at the beginning of the furrow. In general, it can be concluded that if mulch is used, irrigation management should also be adjusted to minimize losses. This is possible by changing the irrigation management parameters, such as the inflow rate, cut-off time, or a combination of the two, or by changing the length of the furrows.

Author Contributions

All authors contributed equally to the conceptualization of the article and writing of the original and subsequent drafts.

Data Availability Statement

 “Not applicable”

Acknowledgements

The authors would like to thank all participants of the present study.

Ethical considerations

The authors avoided data fabrication, falsification, plagiarism, and misconduct.

Conflict of interest

The author declares no conflict of interest.