Objectives Based on the critical role of micronutrients in rice nutrition and metabolism, the accurate determination of the best period of foliar application as a practical plant nutritional pathway is very important in the novel agricultural production. we assess the influence of micronutrients liquid fertilizer (Fe-EDTA 0.1%, Zn-EDTA 0.05%, B 0.02%, Cu-EDTA 0.05%, and Mn-EDTA 0.05%) on Shiroodi cultivar yield, to understand the optimum times and periods of foliar application of trace elements.

Methods This investigation was implemented in the Iran Rice Research Institution (Amol, Mazandaran) during two consecutive years (2017−2018). This extensive research was conducted with eight treatments and three replications. The treatments were T0(control), T1 (one foliar application) to T7 (seven foliar applications). The interval of foliar applications was seven days and the first foliar application was finished nine days after transplanting.

Results The results revealed that the effect of micronutrient application was significant in plant dry weight, grain yield, 1000-grain weight, and harvest index. Also, the interaction of the year and the foliar application was significant in seed Zn content, chlorophyll b, and 1000-grain weight. T4 had a grain yield of 4257 kg/hm² whereas T0 had a yield of 3499 kg/hm², indicating approximately 20% of yield enhancement from four times of leaf spraying. The treatment affects grain yield and yield components of rice (Oryza sativa L. cv. Shiroodi) through increasing the number of tillers/plant, improving panicle length, and increasing the number of grains/panicle.

Conclusions The supply of micronutrients through leaves is an effective procedure in the field of rice due to the higher absorption rate, and spraying 4 times is appropriate.