Effect of irrigation management and humic acid rate on water use efficiency and some qualitative traits of peanuts (Arachis hypogaea L.)

Abstract

The effects of irrigation management and humic acid (HA) were explored on yield, grain qualitative traits, and water use efficiency (WUE) of peanuts (Arachis hypogaea L.) in an experiment in a peanut farm in Astaneh-ye Ashrafiyeh at Guilan province, Iran as a split-plot experiment based on a randomized complete block design with three replications in 2018–2019 and 2019–2020. The experimental treatments included irrigation management (rainfed and irrigation to meet 60%, 80%, and 100% of water requirement) as the main plot and HA rate (0, 3, 6, and 9 L ha-1) as the sub-plot. The results showed that grain yield reached 1,863 and 1,823 kg ha-1 in the plants irrigated to meet 80% and 100% of water requirement and 2,067 kg ha-1 in the plants treated with 9 L ha-1 HA. The oil, protein, phosphorus, and nitrogen contents of the grains were the highest at the irrigation level of 100% of water requirement. Regarding the interaction of irrigation and HA, the highest grain oil percentage (48%) was significantly the highest in the plants irrigated by 100% of water requirement and treated with 3 L ha-1 HA. The highest WUE based on grain, pod, and biological yields were 1.26, 1.62, and 4.12 kg m-3 obtained from the interaction of no irrigation and 9 L ha-1 HA, respectively. Based on the results, the application of 9 L ha-1 HA and the supply of 100% water requirement is recommended as the appropriate conditions in the study site.