Substitution of molecular urea with nano particle along with nano zinc on performance of rabi maize (Zea mays L.)

Abstract

Efficient nutrient management is critical for sustainable maize (Zea mays L.) production, particularly under resource constrained and ecologically sensitive agricultural systems. This study aimed to evaluate the effects of substituting molecular urea with foliar-supplied nano nitrogen (FSNU) and different levels of nano zinc (FSNZ) on the growth, yield and nutrient uptake of rabi maize. The experiment was conducted at Uttar Banga Krishi Viswavidyalaya during the rabi seasons of 2023-24 and 2024-25 using a factorial randomized block design with two factors, zinc (four levels) and nitrogen (eight levels). Among the level of nitrogen, N4 (75% RDN through urea + nano urea @ 4 ml/l at knee height and tasseling stage) recorded tallest plant (109.32, 190.82 & 227.84 cm at 60 DAS, 901 DAS & at harvest respectively), maximum number of leaves plant-1 (11.07, 13.73 & 11.45 at 60 DAS, 901 DAS & at harvest respectively), higher cob diameter (16.67 cm), maximum number of kernels cob-1 (549.10), kernel yield cob-1 (176.25 g), higher uptake of nitrogen (254.30 & 287.35 kg ha-1 respectively during 2023-24 and 2024-25) and zinc (898.29 & 883.51 g ha-1 respectively during 2023-24 and 2024-25) which ultimately gave 3.97 and 86.31% yield advantage over 100% RDN through urea (N1) and control (without nitrogen, N0). Among the level of zinc, soil application of ZnSo4 @ 25 kg ha-1 (Z1) significantly improved plant height, chlorophyll content, cob diameter, kernel number cob-1 & kernel yield cob-1 which helped in producing highest grain yield 8.85 t ha-1 followed by application of nano zinc @150 ppm at150 ppm at V8 and GF stage (Z3) and nano zinc @100 ppm at V8 and GF stage (Z2). So, integration of 25 kg ZnSo4 ha-1 and 25% substitution of nitrogen through nano urea @ 4 ml/l at knee height and tasseling stage can enhance maize productivity and support sustainable intensification of rabi cropping systems. Further multi location and long-term trials are recommended to validate these results across varying soil and climatic conditions.