Rice husk derived nanosilica for boosting morpho-physiological properties and micronutrient nutrition of hybrid maize (Zea mays L.)

Climate change induced drought stress and agricultural waste management are significant challenges in the 21 st century. Hence, the present study aimed to address the recycling of agricultural wastes for synthesising newer products for mitigating the stress. The nanosilica synthesized from rice husk via the modified sol-gel method has a spherical morphology, an amorphous structure, siloxane bonding and high purity. A pot culture experiment was conducted to evaluate the effects of synthesized nanosilica on hybrid maize under irrigated and drought situations. The results revealed that, soil application of nanosilica has significantly increased the growth attributes, gas exchange parameters, silicon and micronutrient contents in hybrid maize plants and the optimal response was observed with the addition of 20 mg kg −1 nanosilica for irrigated plants and 30 mg kg −1 for drought stressed plants. It was observed that, a linear increase in the silicon content and uptake in root and shoot was noted with increasing nanosilica levels whereas differential response was noted with the micronutrient contents. Except manganese, other micronutrients were higher in roots than in shoots. Higher Zn and Cu content in root and shoot was increased with increasing levels of nanosilica whereas higher Mn content was recorded with the addition of 20 mg kg −1 in irrigated and 30 mg kg −1 in drought stressed plants. Higher Fe, content was recorded with lesser doses of nanosilica viz., 10 and 20 mg kg −1 respectively in irrigated and drought stressed plants. Furthermore, higher levels of nanosilica has significantly reduced the growth attributes, indicating its slight toxicity on hybrid maize. Hence, we conclude that, rice husk derived silica nanoparticles applied at 20 mg kg −1 to irrigated plants and 30 mg kg −1 to drought stressed hybrid maize plants is optimum for boosting the plant growth and micronutrients content. • Rice husk derived nanosilica showed spherical morphology with higher purity, siloxane bonding and amorphous structure. • Drought stress has adverse impacts on hybrid maize growth attributes, root traits and micronutrient uptake. • Soil application of rice husk derived nanosilica has improved biomass and micronutrient content of hybrid maize.