Foliar spray of glycine-chelated zinc (Zn) and iron (Fe) lowered the effect of macronutrient deficiencies and enhanced rice yield components, yield, and grain biofortification

Abstract

The current investigation amid the alleviating of the macronutrient [Nitrogen (N), Phosphorus (P), and Potassium (K)] deficiency effects on rice yield, yield components, and grain biofortification by foliar spraying of Zn and Fe chelated by glycine amino acid (ZFCG) on the flooded rice conditions. Three-factor factorial experiment was conducted based on a randomized complete block design with three replications. The experimental factors were: macronutrients [Nitrogen (N), Phosphorous (P), and Potassium (K)] soil application at two levels (100 and 50% of the recommended dose) and foliar application of ZFCG during the booting and ripening stages at three levels (0, 1, and 1.5 kg ha−1). The results clearly showed that the foliar spraying of 1.5 kg ha−1 ZFCG significantly increased the growth characters, yield attributes, yields, and white rice nutritional quality of Hashemi cultivar both at the application of 100% (normal condition) and 50% (nutrient stresses condition) of the recommended rate of NPK. The foliar application of 1.5 kg ha−1 ZFCG increased the rice grain, straw, biological yield, head rice yield, and harvest index of the plots that received 50% of the recommended rate by about 14.6, 10.12, 50, 7.5, and 6.7% compared to the values of the control plots (no adding the NPK), respectively and 49.25, 31.21, 31.60, and 16.67% at the plots that received 100% of recommended NPK, respectively. Moreover, the foliar application of glycine amino acid-Fe and Zn chelate at two vital rice growth stages increased the value of the Zn, Fe and protein content of white rice at the plots that received 1/2 of the recommended dose of NPK by about 52.37%, 2 times, and 8.64% compared to control plots, respectively, and also 20.77%, 2 times, and 12% at the plots that received 100% of recommended NPK, respectively. The observed values are close to their values in those plots that have received 100% of recommended rate of NPK without foliar application. Therefore, it can be concluded that the foliar co-application of 1.5 kg ha−1 ZFCG during the two important rice growth stages (booting and ripening) might both alleviate the improper and imbalanced macronutrient deficiency stresses and enhance the rice grain yield and biofortification at flooded rice cultivation.