Effects of Foliar Application of Liquid Fertilizer on Agronomical and Physiological Traits of Rice (Oryza sativa L.)

Providing rice (Oryza sativa L.) plants with the required nutrients is essential in order to avoid yield reduction. As such, an experiment was performed at the Rice Research Institute of Iran in Amol Township to evaluate the effects of foliar application of nutrients on rice plants. The experiment consisted of a randomized complete block design, with four replications during 2 crop years (2016 and 2017). Experimental treatments included foliar application of nutrients [the chemical composition of liquid fertilizer was as follows: nitrogen (N): 7%, phosphorus (P): 7%, potassium (K): 7%, iron (Fe): 0.05%, boron (B): 0.05%, zinc (Zn): 0.01%, manganese (Mn): 0.01%, and copper (Cu): 0.01%] in the following growth phases: (A) midtillering stage, (B) maximum tillering, (C) panicle initiation, (D) maximum tillering + panicle initiation, (E) all stages, and (F) control treatment (no liquid fertilizer applied). Our results indicate that foliar application of nutrients in different vegetative and generative stages significantly affected plant height, number of tillers per plant, chlorophyll concentration, number of filled grains per panicle, and grain yield. However, our treatments did not significantly affect the 1,000-grain weight. Furthermore, foliar application of nutrients significantly affected physiological traits including leaf area index, growth rate, and total dry weight of plants. Our results indicate that the mean values of the investigated traits were highest in the “maximum tillering + panicle initiation” and “all stages” treatments. In contrast, the lowest mean values of the investigated traits were found in the control treatment. Foliar application of nutrients at the “maximum tillering + panicle initiation” stage resulted in the highest chlorophyll concentrations, leaf area index, and crop growth rate in the flowering stage. Our results indicate that foliar application of nutrients was most effective when applied to Sahel variety rice during two vegetative and reproductive stages.