Effect of Nitrogen Sources, Micronutrients and Humic acid on Growth and Yield of Rice in an Alfisol

Abstract:

A field experiment was conducted during the late pishanam (Jan-May) season of 2021 at Agricultural College and Research Institute, Killikulam to evaluate the effects of nitrogen sources, micronutrients, and humic acid on the growth and yield of paddy. The experiment was laid out in a randomized block design with 11 treatment combinations replicated thrice using rice variety ASD 16. The experimental results reveal that soil application of STCR-IPNS N as Urea along with a foliar spray of 1% Humic acid,  2% WSF (19:19:19), 2% liquid micronutrients recorded significantly higher growth parameters like plant height (37.5, 65.7, 108.1 cm), number of tillers m^-2 (243, 321, 378), SPAD value (40.1, 41.3, 45.0) at 15, 30, 50 DAT respectively. It was also observed that the number of productive tillers m^-2 (348), 1000 grain weight (24.65 g), grain (6118 kg ha^-1), and straw (7239 kg ha^-1) yield were significantly higher with the same treatment combination. The yield of rice was 11.3% higher than the STCR-IPNS N application of urea alone. The highest NPK uptake (69.4, 22.3, 104.3 kg ha^-1) respectively and highest agronomic efficiency (25.6) were recorded in treatment STCR-IPNS N as Urea along with foliar spray of 1% humic acid, 2% WSF (19:19:19), 2% liquid micronutrients. Higher net returns (Rs. 67457 ha^-1) and B:C ratio (2.77) were recorded with STCR-IPNS N as Urea along with foliar spray of 1% humic acid, 2% WSF (19:19:19), 2% liquid micronutrients. This was followed by STCR-IPNS N as Urea with soil application of humic acid @ 4kg ha^-1 (Rs. 66726 ha^-1) which could be adopted in rice cultivation for higher grain yield and economic returns.