Effects of irrigation management and nitrogen fertilizer on yield and yield components of Hashemi rice cultivar

The recent water shortage caused a need to find the best way of water and nitrogen management. In this study, the effects of nitrogen (N) fertilizer and irrigation interval at different growth stages were investigated on the yield and yield components of rice (Hashemi variety). The experiment was conducted in factorial based on randomized complete block design with three replications in Rice Research Institute of Iran (RRII), Rasht, Iran, during two years, 2017 and 2018. The studied factors included irrigation (flood irrigation, irrigation intervals of one and two weeks), growth stage (vegetative and reproductive stages) and nitrogen fertilizer levels (40, 60, and 80 kg.ha−1). The studied traits were plant height, panicle length, number of panicles per plant, number of spikelets per panicle, number of filled grains per panicle, number of unfilled grains per panicle, panicle fertility percentage, 1000-grain weight and grain yield. The results of analysis of variance showed that the main and interaction effects of the studied factors on grain yield was significant. Also, the interaction effect of growth period, nitrogen fertilizer and irrigation interval on grain yield during two years was significant at the 1% probability level. The results showed that the grain yield and yield components (except for the number of unfilled grain) significantly increased with the application of nitrogen fertilizer under flood irrigation conditions. Among the studied treatments, the highest and lowest grain yield were belonged to flood irrigation in the vegetative stage with 80 kg.ha−1 nitrogen fertilizer in 2018, and irrigation interval of two weeks in the reproductive stage with 40 kg.ha−1 of nitrogen fertilizer in 2017, respectively. Based on the results of this experiment, flood irrigation during the vegetative growth stage and the application of 80 kg.ha-1 nitrogen fertilizer is recommended as the best irrigation and nitrogen fertilizer management.