Integrating Irrigation and Drainage Management to Sustain Agriculture in Northern Iran

Abstract

In Iran, as in the rest of the world, land and water for agricultural production is under pressure. Integrating irrigation and drainage management may help sustain intensified agriculture in irrigated paddy fields. This study was aimed to investigate the long-term effects of such management strategies in a newly subsurface drained paddy field in a pilot area in Mazandaran Province, northern Iran. Three strategies for managing subsurface drainage systems were tested, i.e., free drainage (FD), midseason drainage (MSD), and alternate wetting and drying (AWD). The pilot area consisted of subsurface drainage systems, with different combinations of drain depth (0.65 and 0.90 m) and spacing (15 and 30 m). The traditional surface drainage of the region’s consolidated paddy fields was the control. From 2011 to 2017, water table depth, subsurface drainage system outflow and nitrate, total phosphorous, and salinity levels of the drainage effluent were monitored during four rice- and five canola-growing seasons. Yield data was also collected. MSD and AWD resulted in significantly lower drainage rates, salt loads, and N losses compared to FD, with MSD having the lowest rates. Phosphorus losses were low for all three practices. However, AWD resulted in 36% higher rice yields than MSD. Subsurface drainage resulted in a steady increase in canola yield, from 0.89 ton ha−1 in 2011–2012 to 2.94 ton ha−1 in 2016–2017. Overall, it can be concluded that managed subsurface drainage can increase both water productivity and crop yield in poorly drained paddy fields, and at the same time reduce or minimize negative environmental effects, especially the reduction of salt and nutrient loads in the drainage effluent. Based on the results, shallow subsurface drainage combined with appropriate irrigation and drainage management can enable sustained agricultural production in northern Iran’s paddy fields.

Assessing water and nitrate‐N losses from subsurface‐drained paddy lands by DRAINMOD‐N II

“…DRAINMOD slightly underestimated daily drain flows in D0.65L15. In heavy‐textured soils, installation of shallow drains at narrow spacing provides suitable conditions for formation of cracks and preferential flow occurs due to wetting and drying of the soil (Darzi‐Naftchali and Ritzema, 2018) which could not be simulated by the model.…”

A Study on the Development of Reduction Facilities’ Management Standards for Agricultural Drainage for Disaster Reduction

“…Agricultural drainage facilities are installed to manage the production of crops through water supply and drainage. Flow-rate control, cultivation methods and drainage systems were studied in various ways to improve crop production [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. In spite of these efforts, if crops are flooded because of overflow damage due to the accumulation of debris in agricultural drainage, a huge amount of production is damaged.…”

“…To provide continuous water supply in agricultural areas, it set up agricultural drainage for groundwater flow rate and suggested a plan for control and management [8][9][10][11][12][13][14][15]. It was explained that the efficiency of water use through the installation of agricultural drainage has an effect on harvesting by diversifying crops and reducing costs [16,17]. In addition, historical reviews of drainage channels in agriculture as well as methods of utilization based on ancient hydraulic technology were proposed [18].…”

Effects of drainage intensity on water and nitrogen use efficiency and rice grain yield in a semi-arid marshland in Rwanda

“…A previous study on paddy fields in China found that reducing drainage depth resulted in a drainage flow reduction of 50-60%, but no clear trend was observed in N concentration changes in drainage water (Luo et al 2008). In a field study in Iran, Darzi-Naftchali and Ritzema (2018) concluded that managed drainage can reduce N losses in drainage water and improve paddy rice yields compared with conventional drainage.…”