Elucidating morphogenic and physiological traits of rice with nitrogen substitution through nano-nitrogen under salt stress conditions

Abstract

Abstract Background Sustainable crop production along with best nutrient use efficiency is the key indicator of smart agriculture. Under abiotic stress conditions, nutrient uptake and translocation are restricted affecting plant growth and yield. The combined effect of nano-nitrogen and salt stress are very limited. Recent developments in slow releasing, nano-fertilizers in agriculture, begins a new era for sustainable use and management of natural resources. The aim of the study was to explore whether substitution with nano-urea could mitigate the detrimental effects of salt stress on plant growth and development along with physiological traits. Results With the onset of nano-formulations, this study was designed to explore the potential of nano-nitrogen by replacing traditional urea applications in 33, 50 and 60% doses on rice plant growth and development. Further, the strategic substitutions were compared in saline and sodic soils along with normal soils to dissect the beneficial response of nano-N in two rice varieties under saline stress of ECe ~ 6.0 dSm− 1 and sodic stress of pH ~ 9.1. With saline and sodic stresses, plant RWC decreased by 10.33% and total chlorophyll content by 1.32–1.52%, gas exchange attributes by 10.42–38.8%, leaf area upto 29.9% and yield upto 3.92%, respectively. Leaf greenness (SPAD index) was significantly higher with Nano-N along with number of grains/panicle, crop growth rate and net assimilation rate. Results depicted superiority of nitrogen replacement through nano-N with 0.2–1.64% enhancement in growth traits, 0.93–1.85% in physiological traits, and 1.92% in yield over 100% recommended dose of urea on cumulative basis in rice. Between varieties, salt tolerant rice variety, CSR-10 performed better than Pusa 1121 in terms of morphological, physiological and yield traits under stress conditions and nitrogen substitutions. Conclusions Overall, our experimental findings depicted promising potential of nano-N for enhancing the physiological growth and yield under salt stress and also optimizing better yield in normal soils with 33% replacement of conventional urea.