Impact of nano urea on growth, yield attributes, yield, quality and economics of Bt. cotton (Gossypium hirsutum L.) under irrigated condition

Abstract

A two-year field experiment was conducted during kharif 2023–24 and 2024–25 at the Cotton Research Station, Junagadh Agricultural University, Junagadh, to evaluate the effect of foliar-applied nano urea with different levels of the recommended dose of nitrogen (RDN) on the growth, yield and economics of irrigated Bt. cotton hybrid G. Cot. Hy. 24 BG II. The experiment was laid out in a Randomized Block Design with 14 treatments and three replications. Treatments included different combinations of 100, 75 and 50% RDN with foliar sprays of urea (1 or 2%) or nano urea (2 or 4 ml/lit) applied at 40, 70 and 90 DAS. Pooled analysis revealed non-significant year and year × treatment interaction effects for most parameters. Application of 100% RDN + nano urea 4 ml/lit (T ) produced significantly higher plant growth, dry matter, SPAD value, sympodial branches, 10 bolls per plant, seed cotton yield (2433 kg/ha), lint yield (861 kg/ha) and stalk yield (5458 kg/ha) which is representing increases of 90.8% over the absolute control. Treatments T (100 % RDN with foliar spray of nano urea 2 ml/ lit water at 40, 70 and 90 9 DAS), T (100 % RDN + foliar spray of 2 % urea at 40, 70 and 90 DAS), T (100 % RDN + foliar spray of 1 % urea at 40, 70 and 4 3 90 DAS), T (75 % RDN with foliar spray of nano urea 4 ml/ lit water at 40, 70 and 90 DAS) and T (75 % RDN with foliar 12 11 spray of nano urea 2 ml/ lit water at 40, 70 and 90 DAS) were statistically at par with T . Treatment T (75% RDN + nano urea 2 10 11 ml/lit) achieved comparable yield and benefit ratio of 1.80 despite 25% lower soil nitrogen. Fibre quality and oil content remained unaffected, indicating that nano urea can partially replace soil-applied nitrogen while sustaining productivity and improving profitability.