نوع مقاله : مقاله پژوهشی
نویسندگان
1 نویسنده مسئول، گروه مهندسی آبیاری و آبادانی، دانشکدگان کشاورزی و منابع طبیعی دانشگاه تهران، کرج، ایران. رایانامه: ali.pahlevani@ut.ac.ir
2 گروه مهندسی آبیاری و آبادانی، دانشکدگان کشاورزی و منابع طبیعی دانشگاه تهران، کرج، ایران. رایانامه: ebrahimian@ut.ac.ir
3 گروه مهندسی آبیاری و آبادانی، دانشکدگان کشاورزی و منابع طبیعی دانشگاه تهران، کرج، ایران. رایانامه: myousef@ut.ac.ir
4 مؤسسه تحقیقات فنی و مهندسی کشاورزی، سازمان تحقیقات، آموزش و ترویج کشاورزی، کرج، ایران. رایانامه: fariborzabbasi@ymail.com
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Surface irrigation systems have been widely used in different regions worldwide, particularly in arid and semi-arid areas. However, inadequate management has resulted in significant water losses in the agricultural sector. Utilizing plastic and organic mulches in furrow irrigation systems reduces water loss and increases irrigation efficiency. The main purpose of this study is to investigate the effect of the type of mulch and the location of the plastic mulch in furrow irrigation on the hydraulic parameters of the surface flow, such as advance time, recession, runoff, and infiltrated water volume. Field experiments were conducted in 2021 in Karaj, Iran. In general, five treatments were considered: three treatments with plastic mulch, including mulch on the ridge (R), mulch on the bottom of the furrow (F), and mulch on the ridge and bottom of the furrow (FR), and one treatment with organic mulch of wheat straw (OM) and a treatment without mulch or control (C). Considering the same irrigation management and inflow rate, it was observed that using mulch would increase water losses due to maintaining the soil moisture and reducing the wet perimeter. The highest amounts of runoff and the fastest advance time were produced for the FR, F, OM, R, and C treatments, respectively. Conversely, the order was reversed for the volume of infiltrated water. When mulch is used, it is essential to make fundamental changes in irrigation management. This may involve adjusting the inflow rate, cut-off time, field length, or a combination of these methods. It is also suggested that deficit irrigation could be utilized in future experiments.
کلیدواژه‌ها [English]
EXTENDED ABSTRACT
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.
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.
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.
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.
All authors contributed equally to the conceptualization of the article and writing of the original and subsequent drafts.
“Not applicable”
The authors would like to thank all participants of the present study.
The authors avoided data fabrication, falsification, plagiarism, and misconduct.
The author declares no conflict of interest.
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