Effect of Alternating Irrigation Using Freshwater and Drainage Water on Quinoa Yield and Soil Quality

Abstract

Agricultural drainage water production in southwestern Iran is a serious problem, but this low-quality water can be considered a potential alternative source of freshwater. In this regard, the cultivation of salinity-resistant plants using drainage water can be considered a suitable measure. Quinoa (Chenopodium quinoa Willd.) is a valuable halophyte, and the World Health Organization has recognized it as a plant that can guarantee the world’s future food security. For this purpose, this study was conducted to investigate the sustainable use of drainage water for quinoa cultivation (2019–2020). First, quinoa seed germination experiments were conducted in the laboratory using four different salinity solutions [0 (control), 9, 18, and 27 dS/m]. Then, field research was conducted in the form of a split-plot factorial design so that irrigation management and planting date were implemented as the main treatments and genotype factor as subtreatment in small plots. Four genotypes of quinoa were planted on the research farm on three dates, January 20 (D1), February 5 (D2), and February 20 (D3). Irrigation managements include irrigation with water from the Karun River (as freshwater, I1), drainage water from sugarcane fields (I2), and alternating irrigation with freshwater and drainage water (I3). An average reduction of 4% in the total germination at 27 dS/m salinity compared to the control treatment indicated that quinoa was well adapted to salinity during germination. The highest biomass was produced by the Rosada genotype cultivated on the D3 under I1 management at a rate of 540 g/m2, followed by the Q26 genotype cultivated on the D1 under I3 management (499 g/m2). Finally, it can be concluded that, to maintain the salt balance in the soil, leaching at the end of the growing season is necessary to remove salts and maintain sustainable haloculture.