Evaluation and optimization of border irrigation in different irrigation seasons based on temporal variation of infiltration and roughness

Abstract

Soil infiltration and Manning’s roughness values are key parameters to determine the performance of surface irrigation. However, temporal variability in these parameters due to tillage practices, irrigation, and crop growth greatly hinders efforts to improve irrigation quality. The objective of this experiment was to evaluate effects of infiltration and surface roughness variation on irrigation water movement and irrigation performance indicators for border irrigation with three border lengths. Field experiments were conducted from 2013 to 2015 in a wheat (Triticum aestivum)-maize (Zea mays L.) rotation planting system at the Jinghui Canal Irrigation Area in Guanzhong Plain of northwest China. In this work, Manning’s equation and a surface irrigation simulation model (WinSRFR) were used to estimate Manning’s roughness values and Kostiakov soil infiltration parameters. We determined that both parameters reached moderate levels of variation for both deep and shallow tillage treatments. The impacts of temporal variation in soil infiltration and surface roughness on irrigation water movement and irrigation quality were then evaluated. Results showed that water advance times varied significantly while recession times varied much more, affecting irrigation water amounts at various distances along the length of the border. Irrigation performance indicators were significantly different over various irrigation seasons, especially for borders that were 235 m in length. Finally, considering these temporal variations during the two rotation cycles, combinations of inflow rate and cut-off ratio during different irrigation seasons were optimized, and high irrigation quality could be achieved for 80 m and 120 m borders, but not for 235 m borders. Water percolation amounts during the 2013–2014 and 2014–2015 growing periods were reduced by 55 mm and 107 mm for 235 m borders, 26 mm and 23 mm for 120 m borders, and 36 mm and 39 mm for 80 m borders, respectively. Therefore, utilizing optimal combinations of inflow rate and cut-off ratio and considering temporal variation in soil infiltration and Manning’s roughness could maintain high water application efficiency and sustainable utilization of limited water resources.